Volume 43,Issue 5,2015 Table of Contents
2015, 43(5):775-782.
Abstract:
In contrast to conventional weather radar, the dual polarity weather radar transmits and receives both horizontal and vertical polarized signals, which significantly improves the accuracy of radarbased rainfall measurements and enhances the ability to classify precipitation. However, the measuring results can be affected by the radar system itself. The differential reflectivity ZDR can be estimated imprecisely, resulting in a decreased reliability of generated meteorological products. The National Weather Service made a large number of experiments on upgraded WSR88D radar and found that it is necessary to straighten the deviation made by signal differences in both transmit and receive paths. After a plenty of experiments on the Cband dual polarity vehicle Doppler radar and comparing the results with United States WSR88D test reports, it is concluded that that bias of the ZDR calibration consists mostly of 3 components which are transmit bias, receive bias, and sun measurement bias. The biases can be adjusted by using cross and parallel methods to eliminate effects of test signals, cables, and other equipment differences. Furthermore, dry aggregated snow is considered as an optimal weather target for the calibration of ZDR. The results show that the calibration method is an effective and practical way to reduce the system bias of ZDR so to ensure the precision of dual polarization radar system.
In contrast to conventional weather radar, the dual polarity weather radar transmits and receives both horizontal and vertical polarized signals, which significantly improves the accuracy of radarbased rainfall measurements and enhances the ability to classify precipitation. However, the measuring results can be affected by the radar system itself. The differential reflectivity ZDR can be estimated imprecisely, resulting in a decreased reliability of generated meteorological products. The National Weather Service made a large number of experiments on upgraded WSR88D radar and found that it is necessary to straighten the deviation made by signal differences in both transmit and receive paths. After a plenty of experiments on the Cband dual polarity vehicle Doppler radar and comparing the results with United States WSR88D test reports, it is concluded that that bias of the ZDR calibration consists mostly of 3 components which are transmit bias, receive bias, and sun measurement bias. The biases can be adjusted by using cross and parallel methods to eliminate effects of test signals, cables, and other equipment differences. Furthermore, dry aggregated snow is considered as an optimal weather target for the calibration of ZDR. The results show that the calibration method is an effective and practical way to reduce the system bias of ZDR so to ensure the precision of dual polarization radar system.
2015, 43(5):783-787.
Abstract:
With a wide range distribution of CINRAD, the work of repair and maintenance became increasingly important. The virtual instrument system used in radar parameter index test is a convenient and effective tool. Starting from the transmit RF pulse envelope and the measurement, a PXIbased virtual instrument system is described. The system achieves the test and measurement functions through LabVIEW software programming. The virtual instrument test system hardware and software systems are introduced, and the pulse envelope testing tasks are conducted through experiments. Compared with traditional instruments, the results of virtual instrument test system proved reliable.
With a wide range distribution of CINRAD, the work of repair and maintenance became increasingly important. The virtual instrument system used in radar parameter index test is a convenient and effective tool. Starting from the transmit RF pulse envelope and the measurement, a PXIbased virtual instrument system is described. The system achieves the test and measurement functions through LabVIEW software programming. The virtual instrument test system hardware and software systems are introduced, and the pulse envelope testing tasks are conducted through experiments. Compared with traditional instruments, the results of virtual instrument test system proved reliable.
2015, 43(5):788-793.
Abstract:
Many newgeneration weather radar sets are located in mountainous areas with complex terrain in China, and the terrain occultation results in blind zones of detection, which influences the application of radar echo data seriously. A method of using the vertical profile of reflectivity factor to fill up occultation regions of lower elevation, applicable to stratiform precipitation, is introduced, which uses the beam blockage based on DEM data to confirm the rate of echo occultation and uses the data of highelevation zero occultation regions to obtain that of the lowelevation complete occultation regions according to the changes of reflectivity with height in the vertical profile of reflectivity. Taking Hangzhou radar as an example, the results are verified through comparing the revised reflectivity and original reflectivity and comparing radar precipitation estimations before and after revision. The results show that the revised and original radar echoes have good consistency, and the revised reflectivity is better than the original in quantitative precipitation estimation.
Many newgeneration weather radar sets are located in mountainous areas with complex terrain in China, and the terrain occultation results in blind zones of detection, which influences the application of radar echo data seriously. A method of using the vertical profile of reflectivity factor to fill up occultation regions of lower elevation, applicable to stratiform precipitation, is introduced, which uses the beam blockage based on DEM data to confirm the rate of echo occultation and uses the data of highelevation zero occultation regions to obtain that of the lowelevation complete occultation regions according to the changes of reflectivity with height in the vertical profile of reflectivity. Taking Hangzhou radar as an example, the results are verified through comparing the revised reflectivity and original reflectivity and comparing radar precipitation estimations before and after revision. The results show that the revised and original radar echoes have good consistency, and the revised reflectivity is better than the original in quantitative precipitation estimation.
2015, 43(5):794-798.
Abstract:
In order to analyze whether the HighFrequency SurfaceWave Radar (HFSWR) can be applied to detect winds from sea surface, taking the wind direction and speed from Nanpeng Island automatic weather stations (AWS) within the Yangjiang HFSWR detection range as a reference, the wind field data from HFSWR are compared with the wind data from AWS’s, and the acquisition rates of radar wind data, standard deviations, and availability are analyzed for different seasons and in such situations as wind speed between 6 to 10 m/s and less than 6 m/s. The results show that, relatively speaking, the wind direction acquisition rates and availability are high, and the standard deviation is small; wind speed acquisition rates and availability are high when the wind speed is between 6 to 10 m/s, but the availability is low at the lowspeed sea state (less than 6 m/s).
In order to analyze whether the HighFrequency SurfaceWave Radar (HFSWR) can be applied to detect winds from sea surface, taking the wind direction and speed from Nanpeng Island automatic weather stations (AWS) within the Yangjiang HFSWR detection range as a reference, the wind field data from HFSWR are compared with the wind data from AWS’s, and the acquisition rates of radar wind data, standard deviations, and availability are analyzed for different seasons and in such situations as wind speed between 6 to 10 m/s and less than 6 m/s. The results show that, relatively speaking, the wind direction acquisition rates and availability are high, and the standard deviation is small; wind speed acquisition rates and availability are high when the wind speed is between 6 to 10 m/s, but the availability is low at the lowspeed sea state (less than 6 m/s).
2015, 43(5):799-804.
Abstract:
Remote sensing of water vapor amount along the slant path (SWV: Slantpath Water Vapor) using the groundbased GPS is the basis of getting the threedimensional distribution (water vapor tomography) of water vapor on the immediate vicinity of the site. Many estimation methods have been developed in recent year, but more or less there are problems that hindered these method from putting into operational use, such as nonrealtime resolving, low accuracy resolving result, or complex convert formula. By running the Bernese (version 5.0) doubledifference processing script and the zerodifference processing script respectively, the key elements of noisotropic component of water vapor in different azimuths above the GPS receiver, the wet gradient, and zerodifferenced residuals are calculated. Then slant path water vapor amount can be accurately retrieved. In order to prove the accuracy of this new method, the observation data of a comparative observation experiment of slantpath water vapor between groundbased GPS and microwave radiometer conducted in summer 2007 are recalculated. Comparison between GPS and MR shows that RMS is less than 4 mm, which means that the estimates of SWV can be used to retrieve the three dimensional information of water vapor.
Remote sensing of water vapor amount along the slant path (SWV: Slantpath Water Vapor) using the groundbased GPS is the basis of getting the threedimensional distribution (water vapor tomography) of water vapor on the immediate vicinity of the site. Many estimation methods have been developed in recent year, but more or less there are problems that hindered these method from putting into operational use, such as nonrealtime resolving, low accuracy resolving result, or complex convert formula. By running the Bernese (version 5.0) doubledifference processing script and the zerodifference processing script respectively, the key elements of noisotropic component of water vapor in different azimuths above the GPS receiver, the wet gradient, and zerodifferenced residuals are calculated. Then slant path water vapor amount can be accurately retrieved. In order to prove the accuracy of this new method, the observation data of a comparative observation experiment of slantpath water vapor between groundbased GPS and microwave radiometer conducted in summer 2007 are recalculated. Comparison between GPS and MR shows that RMS is less than 4 mm, which means that the estimates of SWV can be used to retrieve the three dimensional information of water vapor.
2015, 43(5):805-813.
Abstract:
The lightning detection from a geostationary platform plays a significant role in monitoring strong convection in real time and providing early warning. However, the false signals have an negatively impact on lighting detection. The false signal filtering algorithms in lightning detection by geostationary satellite are explored, which can greatly improve the accuracy of lightning data analysis. Based on the origins and characteristics of these false events, the existing filtering algorithms are systematically analyzed and summarized. The investigation shows that the existing filtering algorithms usually have distinctive characteristics with regards to noise sources, and the false events that can be identified today can be restrained to a certain extent. The future work include: (1) designing the false signal filtering algorithm based on the characteristics of FY4 GLI, (2) designing more universal and efficient algorithm to ensure the capability for observing lightning in real time and continuously, and (3) considering the accuracy evaluation of the algorithm in order to improve it continuously.
The lightning detection from a geostationary platform plays a significant role in monitoring strong convection in real time and providing early warning. However, the false signals have an negatively impact on lighting detection. The false signal filtering algorithms in lightning detection by geostationary satellite are explored, which can greatly improve the accuracy of lightning data analysis. Based on the origins and characteristics of these false events, the existing filtering algorithms are systematically analyzed and summarized. The investigation shows that the existing filtering algorithms usually have distinctive characteristics with regards to noise sources, and the false events that can be identified today can be restrained to a certain extent. The future work include: (1) designing the false signal filtering algorithm based on the characteristics of FY4 GLI, (2) designing more universal and efficient algorithm to ensure the capability for observing lightning in real time and continuously, and (3) considering the accuracy evaluation of the algorithm in order to improve it continuously.
2015, 43(5):814-822.
Abstract:
The realtime data of Automatic Meteorological Station (AWS) is of great significance to meteorological warning, decisionmaking service, and forecast verification. Developing the quality control of realtime data is necessary to ensure the rationality and accuracy of realtime data of AWS’s. The data quality of national AWS’s from the Atmospheric observing System Operation and Monitoring platform (ASOM) in 2013 is statistically analyzed,〖JP2〗 and the variation regularities and internal consistency of meteorological elements when special weather happens are studied on the basis of historical data of AWS’s, 〖JP〗and then criterions for judging highhumidity and sudden weather change events are proposed to improve the data quality control algorithm of AWS’s. The application results of the new algorithms indicate that the improved data quality control algorithms can reduce the misjudgment rate effectively and achieve good control effect.
The realtime data of Automatic Meteorological Station (AWS) is of great significance to meteorological warning, decisionmaking service, and forecast verification. Developing the quality control of realtime data is necessary to ensure the rationality and accuracy of realtime data of AWS’s. The data quality of national AWS’s from the Atmospheric observing System Operation and Monitoring platform (ASOM) in 2013 is statistically analyzed,〖JP2〗 and the variation regularities and internal consistency of meteorological elements when special weather happens are studied on the basis of historical data of AWS’s, 〖JP〗and then criterions for judging highhumidity and sudden weather change events are proposed to improve the data quality control algorithm of AWS’s. The application results of the new algorithms indicate that the improved data quality control algorithms can reduce the misjudgment rate effectively and achieve good control effect.
2015, 43(5):823-828.
Abstract:
The statistical analysis of meteorological data processing is dataintensive and always conducts on a single machine. The speed is too slow when the data set is large, which restrains researches of meteorological data. Hadoop and MapReduce are used to speed up the dataintensive processing of meteorological data. In allusion to the low efficiency of processing enormous and small files by using Hadoop, a preprocess is conducted to integrate the enormous and small files to a large one. The experiment proved that this method can solve the low efficiency problem when using Hadoop to process enormous and small files. Comparing with Oracle, it is more useful to use Hadoop to process dataintensive Meteorological computing.
The statistical analysis of meteorological data processing is dataintensive and always conducts on a single machine. The speed is too slow when the data set is large, which restrains researches of meteorological data. Hadoop and MapReduce are used to speed up the dataintensive processing of meteorological data. In allusion to the low efficiency of processing enormous and small files by using Hadoop, a preprocess is conducted to integrate the enormous and small files to a large one. The experiment proved that this method can solve the low efficiency problem when using Hadoop to process enormous and small files. Comparing with Oracle, it is more useful to use Hadoop to process dataintensive Meteorological computing.
2015, 43(5):829-832.
Abstract:
For the needs of shortrange wireless automatic meteorological station detection data transmission, a wireless meteorological data transmission system is designed. The system consists of transmitter and receiver, based on the 51SCM and NRF905 radio frequency control chip, and it has good adaptability to different types of automated meteorological stations. The system makes it possible to transmit wirelessly, display, and storage meteorological data. As being tested, the system has reached the requirements of the design both in terms of environmental compatibility and transmission capacity. It runs stably and reliably. The development methods of the transmitter, mainly from aspects of working principle and composition of the system, the design of the hardware, the programming of SCM, and the testing of the system are introduced.
For the needs of shortrange wireless automatic meteorological station detection data transmission, a wireless meteorological data transmission system is designed. The system consists of transmitter and receiver, based on the 51SCM and NRF905 radio frequency control chip, and it has good adaptability to different types of automated meteorological stations. The system makes it possible to transmit wirelessly, display, and storage meteorological data. As being tested, the system has reached the requirements of the design both in terms of environmental compatibility and transmission capacity. It runs stably and reliably. The development methods of the transmitter, mainly from aspects of working principle and composition of the system, the design of the hardware, the programming of SCM, and the testing of the system are introduced.
2015, 43(5):833-838.
Abstract:
Based on OPENGL and the related 3D computer imaging algorithms, a 3D visualization platform system of radar networking data is developed. As examples, the radar data from typhoons Ramasun and Kalmaegi and Wind Profiler radar data are introduced into this 3D visualization platform display system. The results show that the platform system can not only display fully intuitive construction of 3D structure of the typhoon, but also show the internal structure according to the demand. The combination of Doppler weather radar and wind Profiler radar improve the monitoring capability of atmospheric winds. It is a good complementation of SWAN and also an advance in operational applications of 3D radar networking products.
Based on OPENGL and the related 3D computer imaging algorithms, a 3D visualization platform system of radar networking data is developed. As examples, the radar data from typhoons Ramasun and Kalmaegi and Wind Profiler radar data are introduced into this 3D visualization platform display system. The results show that the platform system can not only display fully intuitive construction of 3D structure of the typhoon, but also show the internal structure according to the demand. The combination of Doppler weather radar and wind Profiler radar improve the monitoring capability of atmospheric winds. It is a good complementation of SWAN and also an advance in operational applications of 3D radar networking products.
2015, 43(5):839-843.
Abstract:
The Atmospheric Observing System Operations and Monitoring (ASOM) is an operational application system for meteorological technology and equipment maintenance. This system realizes operational status monitoring, data quality monitoring, maintenance information management, and instrument logistics support management, assessment for operations and monitoring, monitoring information distribution and metadata management, etc. More than 4000 reported breakdowns between July 2008 and June 2014 are analyzed based the onsite maintenance reports from ASOM, and some recommendations to standardize the breakdown reports of newgeneration weather radar in China are given, aiming at the restoration of maintenance processes, the improvement of debug technology, and the enhancement of site maintenance techniques afterwards.
The Atmospheric Observing System Operations and Monitoring (ASOM) is an operational application system for meteorological technology and equipment maintenance. This system realizes operational status monitoring, data quality monitoring, maintenance information management, and instrument logistics support management, assessment for operations and monitoring, monitoring information distribution and metadata management, etc. More than 4000 reported breakdowns between July 2008 and June 2014 are analyzed based the onsite maintenance reports from ASOM, and some recommendations to standardize the breakdown reports of newgeneration weather radar in China are given, aiming at the restoration of maintenance processes, the improvement of debug technology, and the enhancement of site maintenance techniques afterwards.
2015, 43(5):844-848.
Abstract:
Quality monitoring, controlling, and evaluating of radisonde data have important influence on the study of upperair observations, which is an important problem need to be solved urgently for meteorological researchers. The method to study the data quality is introduced, and assessment is conducted on the monitoring and controlling of the original data from the aspects of integrity, timeliness, and accuracy. According to the preliminary estimated data of the National Meteorological Center, the monthly average deviation and standard deviation of all radisonde stations are calculated, and the left and right ultrapoor boundaries are obtained by combining with the average standard deviation of each station. The errors of nonmeteorological significance are calculated and analyzed to form the external and quantitative quality information and scientific report. The method was implemented and applied in practice, and achieved good results, which could effectively, comprehensively evaluate the quality of radiosonde data. Problems in the data processing method and equipment could be indirectly found by analyzing and studying the radiosonde data, which was advantageous to improve the equipment and algorithm.
Quality monitoring, controlling, and evaluating of radisonde data have important influence on the study of upperair observations, which is an important problem need to be solved urgently for meteorological researchers. The method to study the data quality is introduced, and assessment is conducted on the monitoring and controlling of the original data from the aspects of integrity, timeliness, and accuracy. According to the preliminary estimated data of the National Meteorological Center, the monthly average deviation and standard deviation of all radisonde stations are calculated, and the left and right ultrapoor boundaries are obtained by combining with the average standard deviation of each station. The errors of nonmeteorological significance are calculated and analyzed to form the external and quantitative quality information and scientific report. The method was implemented and applied in practice, and achieved good results, which could effectively, comprehensively evaluate the quality of radiosonde data. Problems in the data processing method and equipment could be indirectly found by analyzing and studying the radiosonde data, which was advantageous to improve the equipment and algorithm.
2015, 43(5):849-857.
Abstract:
By using the NS equation and a basic hypothesis, the stellar atmospheric mean zonal wind and mean pressure formulas are derived. Based on these equations, the causes of earth atmospheric zonal wind system, mean pressure and subtropical high are discussed and numerically simulated. The results show that earth atmospheric zonal wind is formed by the density difference between atmospheric microcells and benchmark atmosphere. When the density of atmospheric microcells is greater (less) than benchmark atmospheric density, the direction of wind is westerly (easterly); the greater the density difference is, the stronger the wind will be. In middle and high latitude regions, the solar radiation absorbed by atmospheric microcell is less than their radiation into the space, which makes the density increase, so the west wind prevails in middle and high latitude regions; in the low latitude region, east wind prevails because the solar radiation absorbed by atmospheric microcell is more than their radiation. In summer (winter), the solar radiation strengthens (weakens), which makes the density of atmospheric microcells increase (decrease) and leads to the west wind in middle and high latitude areas weakening (strengthening) and east wind in the low latitude areas strengthening (weakening). The wind speed is proportional to cosine of latitude, which makes the strongest westerly belt located in the middle latitude region but not polar region where the density of atmospheric microcells is the biggest, and it also makes the strongest east wind appears not around the direct sunlight point but near the equator side. According to the pressure formula and the meridional difference of atmospheric density, the distribution feature that the pressure decreases as latitude increases in the middle and high latitude regions can be gained. The decreasing of density caused by solar radiation in the low latitude region is the main reason to make the pressure higher in this region than in middle and high latitude areas. The sine of latitude on equator is zero, so there exists a minimum of pressure on the equator, which leads to the formation of the equatorial trough and subtropical high, and the stronger the solar radiation is, the stronger the subtropical high will be. Because of the existence of latitude sine factor, the axis of ridge is always on the polar side of the direct sunlight point. Based on assumption that the solar atmosphere is ideal gas, the formula of the solar atmospheric rotation angular velocity with latitude is derived by using the NS equation, which explains the cause of the solar differential rotation; that is, the micelle density at low latitudes is larger than that at high latitudes and it is largest at the equator. The formula is fully consistent with the empirical formula by observation in omitted higher order small items. These results indicate that the movement of the solar atmosphere has no difference with the earth atmosphere in formation mechanisms; the difference is that there is no solar radiation on the surface of the sun as the earth surface; the NS equation is suitable for all stars.
By using the NS equation and a basic hypothesis, the stellar atmospheric mean zonal wind and mean pressure formulas are derived. Based on these equations, the causes of earth atmospheric zonal wind system, mean pressure and subtropical high are discussed and numerically simulated. The results show that earth atmospheric zonal wind is formed by the density difference between atmospheric microcells and benchmark atmosphere. When the density of atmospheric microcells is greater (less) than benchmark atmospheric density, the direction of wind is westerly (easterly); the greater the density difference is, the stronger the wind will be. In middle and high latitude regions, the solar radiation absorbed by atmospheric microcell is less than their radiation into the space, which makes the density increase, so the west wind prevails in middle and high latitude regions; in the low latitude region, east wind prevails because the solar radiation absorbed by atmospheric microcell is more than their radiation. In summer (winter), the solar radiation strengthens (weakens), which makes the density of atmospheric microcells increase (decrease) and leads to the west wind in middle and high latitude areas weakening (strengthening) and east wind in the low latitude areas strengthening (weakening). The wind speed is proportional to cosine of latitude, which makes the strongest westerly belt located in the middle latitude region but not polar region where the density of atmospheric microcells is the biggest, and it also makes the strongest east wind appears not around the direct sunlight point but near the equator side. According to the pressure formula and the meridional difference of atmospheric density, the distribution feature that the pressure decreases as latitude increases in the middle and high latitude regions can be gained. The decreasing of density caused by solar radiation in the low latitude region is the main reason to make the pressure higher in this region than in middle and high latitude areas. The sine of latitude on equator is zero, so there exists a minimum of pressure on the equator, which leads to the formation of the equatorial trough and subtropical high, and the stronger the solar radiation is, the stronger the subtropical high will be. Because of the existence of latitude sine factor, the axis of ridge is always on the polar side of the direct sunlight point. Based on assumption that the solar atmosphere is ideal gas, the formula of the solar atmospheric rotation angular velocity with latitude is derived by using the NS equation, which explains the cause of the solar differential rotation; that is, the micelle density at low latitudes is larger than that at high latitudes and it is largest at the equator. The formula is fully consistent with the empirical formula by observation in omitted higher order small items. These results indicate that the movement of the solar atmosphere has no difference with the earth atmosphere in formation mechanisms; the difference is that there is no solar radiation on the surface of the sun as the earth surface; the NS equation is suitable for all stars.
2015, 43(5):858-865.
Abstract:
The recent progresses in understanding the multiscale interactions between ENSO and Indian Ocean Basin (IOB) Sea Surface Temperature (SST)are reviewed, including the existing facts and mechanisms of interannual and interdecadal correlation between ENSO and IOB SST variations, as well as their associated climate effects, and the anomalies of Asian Monsoon System and global climate particularly. Specifically, on interannual timescale, ENSO dominates the Indian Ocean SST changes through the “Atmospheric Bridge” process, while the latter might in turn influence ENSO events through the “Gear Coupling” of zonal circulation. On interdecadal timescale, on the one hand, the summer warming of Indian Ocean Basin SST can be attributed to a significant delay in seasonal timing of El Nio decay phase since 1970s, and the variations of SST patterns in the Indian Ocean during boreal fall can modulate the ongoing El Nio on the other hand. Based on the review of the progresses above, the prospects and significance of further research on the global climate change influenced by ENSO and IOB SST multiscale variations are also discussed.
The recent progresses in understanding the multiscale interactions between ENSO and Indian Ocean Basin (IOB) Sea Surface Temperature (SST)are reviewed, including the existing facts and mechanisms of interannual and interdecadal correlation between ENSO and IOB SST variations, as well as their associated climate effects, and the anomalies of Asian Monsoon System and global climate particularly. Specifically, on interannual timescale, ENSO dominates the Indian Ocean SST changes through the “Atmospheric Bridge” process, while the latter might in turn influence ENSO events through the “Gear Coupling” of zonal circulation. On interdecadal timescale, on the one hand, the summer warming of Indian Ocean Basin SST can be attributed to a significant delay in seasonal timing of El Nio decay phase since 1970s, and the variations of SST patterns in the Indian Ocean during boreal fall can modulate the ongoing El Nio on the other hand. Based on the review of the progresses above, the prospects and significance of further research on the global climate change influenced by ENSO and IOB SST multiscale variations are also discussed.
2015, 43(5):866-873.
Abstract:
In order to meet the requirements of refinement rainfall prediction in the urban rainstorm waterlogging model. Based on the urban rainstorm waterlogging model of Tianjin, the products of quantitative estimation using jointly radar and rain gauges are used in area rainfall calculation of the urban torrential rain waterlogging model. Based on four products of quantitative estimation using radar and two interpolation methods, a test of rainfall calculation in the urban torrential rain waterlogging model based on the torrential rain process in Tianjin on 25 and 26 July 2012 is performed. The comparison indicates that the variational method is the best in the quantitative estimation of precipitation using jointly radar and rain gauges in combination with a curved surface interpolation method to calculate the area rainfall.
In order to meet the requirements of refinement rainfall prediction in the urban rainstorm waterlogging model. Based on the urban rainstorm waterlogging model of Tianjin, the products of quantitative estimation using jointly radar and rain gauges are used in area rainfall calculation of the urban torrential rain waterlogging model. Based on four products of quantitative estimation using radar and two interpolation methods, a test of rainfall calculation in the urban torrential rain waterlogging model based on the torrential rain process in Tianjin on 25 and 26 July 2012 is performed. The comparison indicates that the variational method is the best in the quantitative estimation of precipitation using jointly radar and rain gauges in combination with a curved surface interpolation method to calculate the area rainfall.
2015, 43(5):874-879.
Abstract:
Based on the data of CINRAD in Hubei Province, the lightning location system and atmospheric electric field instrument in Wuhan area, and the statistical analysis of 1067 lightning strikes during 184 thunderstorm processes from January 2012 to July 2014, an analysis is made of the correlation between warning indexes and lightning occurrence, and the thresholds in Wuhan are determined. It is shown that the occurrence of lightning is closely related to the intensity of atmospheric electric field, radar reflectivity, height of echo top, and vertically integrated liquid: the threshold of atmospheric electric field intensity is about 2 kV/m; at -10 ℃ height, the intensity 〖WTBX〗I〖WTBZ〗≥40 dBz; the height of echo top is about 6 km; and VIL≥10 kg/m2 in Wuhan area, which are different in different months.
Based on the data of CINRAD in Hubei Province, the lightning location system and atmospheric electric field instrument in Wuhan area, and the statistical analysis of 1067 lightning strikes during 184 thunderstorm processes from January 2012 to July 2014, an analysis is made of the correlation between warning indexes and lightning occurrence, and the thresholds in Wuhan are determined. It is shown that the occurrence of lightning is closely related to the intensity of atmospheric electric field, radar reflectivity, height of echo top, and vertically integrated liquid: the threshold of atmospheric electric field intensity is about 2 kV/m; at -10 ℃ height, the intensity 〖WTBX〗I〖WTBZ〗≥40 dBz; the height of echo top is about 6 km; and VIL≥10 kg/m2 in Wuhan area, which are different in different months.
2015, 43(5):880-887.
Abstract:
Based on the lightning detection and radar echo data, the CG (CloudtoGround) lightning characteristics of three kinds of enhanced thunderstorms (namely downtown, hilly and coastal areas) on the three different underlying surfaces are investigated. Result shows that there exists relationship between the CG lightning frequency at 6 min intervals and the coverage of composite reflectivity and echo top for the three kinds of intensified thunderstorms. In the downtown areas, the CG lightning frequency at 6 min intervals is closely related to the coverage of the composite reflectivity above 50 dBz, and the coverage of echo top exceeding 9 km and 10 km respectively. In the hilly areas, the frequency is correlated with the coverage of the composite reflectivity above 45 dBz and the coverage of echo top exceeding 12 km, while in the hilly areas, there is obvious linear relation between the CG lightning frequency and the coverage of echo top exceeding 10 km, with correlation coefficient up to 0.916. The CG lightning characteristics in three kinds of the intensified thunderstorm are different, and more CG lightning happens in urban thunderstorms.
Based on the lightning detection and radar echo data, the CG (CloudtoGround) lightning characteristics of three kinds of enhanced thunderstorms (namely downtown, hilly and coastal areas) on the three different underlying surfaces are investigated. Result shows that there exists relationship between the CG lightning frequency at 6 min intervals and the coverage of composite reflectivity and echo top for the three kinds of intensified thunderstorms. In the downtown areas, the CG lightning frequency at 6 min intervals is closely related to the coverage of the composite reflectivity above 50 dBz, and the coverage of echo top exceeding 9 km and 10 km respectively. In the hilly areas, the frequency is correlated with the coverage of the composite reflectivity above 45 dBz and the coverage of echo top exceeding 12 km, while in the hilly areas, there is obvious linear relation between the CG lightning frequency and the coverage of echo top exceeding 10 km, with correlation coefficient up to 0.916. The CG lightning characteristics in three kinds of the intensified thunderstorm are different, and more CG lightning happens in urban thunderstorms.
18 Comparisive Research on Characteristics of Urban Heat Island Effects between Chengdu and Chongqing
2015, 43(5):888-897.
Abstract:
The scale and pace of urbanization in China continue to increase at an unprecedented rate, and as a result, the intensity and extent of urban heat island effect increase. Based on MODIS and GIS data, the spatial and temporal characteristics of urban heat island effect in Chengdu and Chongqing are analyzed. The results show:(1) The urban heat island effect both in Chengdu and Chongqing were marked. The heat island intensity in Chengdu was 4.32 ℃, while that in Chongqing was 3.11 ℃. The land surface temperature (LST) of Chengdu increased from rural areas to center of the city, and that in Chongqing increased from southeast to northwest. (2) The heat island intensity in Chengdu and Chongqing was 4.32 ℃ and 3.11 ℃ in spring, respectively, which are much higher than those in other seasons. Additionally, the heat island intensity in Chengdu was stronger than that in Chongqing in most seasons. (3) During the last ten years, the scale of urban heat island effect increased both in Chengdu and Chongqing. The areas of strong and extremely strong heat island expanded, while the areas of weak and medium heat island reduced in Chengdu. On the contrary, the areas of strong and extremely strong heat island reduced, while the areas of weak and medium heat island expanded in Chongqing.
The scale and pace of urbanization in China continue to increase at an unprecedented rate, and as a result, the intensity and extent of urban heat island effect increase. Based on MODIS and GIS data, the spatial and temporal characteristics of urban heat island effect in Chengdu and Chongqing are analyzed. The results show:(1) The urban heat island effect both in Chengdu and Chongqing were marked. The heat island intensity in Chengdu was 4.32 ℃, while that in Chongqing was 3.11 ℃. The land surface temperature (LST) of Chengdu increased from rural areas to center of the city, and that in Chongqing increased from southeast to northwest. (2) The heat island intensity in Chengdu and Chongqing was 4.32 ℃ and 3.11 ℃ in spring, respectively, which are much higher than those in other seasons. Additionally, the heat island intensity in Chengdu was stronger than that in Chongqing in most seasons. (3) During the last ten years, the scale of urban heat island effect increased both in Chengdu and Chongqing. The areas of strong and extremely strong heat island expanded, while the areas of weak and medium heat island reduced in Chengdu. On the contrary, the areas of strong and extremely strong heat island reduced, while the areas of weak and medium heat island expanded in Chongqing.
2015, 43(5):898-904.
Abstract:
Atmospheric visibility trends in Xiqing and Tanggu meteorological stations in Tianjin from 2000 to 2010 are analyzed by using three different statistical methods (gradational analysis, Ridit analysis, and the frequency of “very good” visibility and “bad” visibility). The characteristics of lowvisibility weather and visibility effect factors are also analyzed. The results show that the atmospheric visibility exceeding 40 km did not appear in two meteorological stations during 11 years. The frequency of 2 to 9 km visibility increased at Xiqing Station year by year, while the frequency of 20 to 39 km visibility decreased from 2006 at Tanggu Station. The Ridit value decreased below 0.5 from 2006 at Xiqing Station. For Tanggu station, the Ridit value has a fluctuant and decreasing trend, and the least Ridit value appeared in 2006 (0.43). The frequency of “very good” visibility appears to have a decline trend at both stations, while the frequency of “bad” visibility appears to have an increase trend. Autumn and winter are highoccurrence seasons of lowvisibility weather, which is often accompanied by high relative humidity and low wind speed. The direction of the prevailing winds had differences at Xiqing and Tanggu stations. A negative correlation is found between relative humidity and atmospheric visibility, and wind speed and visibility has positive correlation. Visibility decreased in fluctuations, and on the contrary, total energy consumption increased year by year.
Atmospheric visibility trends in Xiqing and Tanggu meteorological stations in Tianjin from 2000 to 2010 are analyzed by using three different statistical methods (gradational analysis, Ridit analysis, and the frequency of “very good” visibility and “bad” visibility). The characteristics of lowvisibility weather and visibility effect factors are also analyzed. The results show that the atmospheric visibility exceeding 40 km did not appear in two meteorological stations during 11 years. The frequency of 2 to 9 km visibility increased at Xiqing Station year by year, while the frequency of 20 to 39 km visibility decreased from 2006 at Tanggu Station. The Ridit value decreased below 0.5 from 2006 at Xiqing Station. For Tanggu station, the Ridit value has a fluctuant and decreasing trend, and the least Ridit value appeared in 2006 (0.43). The frequency of “very good” visibility appears to have a decline trend at both stations, while the frequency of “bad” visibility appears to have an increase trend. Autumn and winter are highoccurrence seasons of lowvisibility weather, which is often accompanied by high relative humidity and low wind speed. The direction of the prevailing winds had differences at Xiqing and Tanggu stations. A negative correlation is found between relative humidity and atmospheric visibility, and wind speed and visibility has positive correlation. Visibility decreased in fluctuations, and on the contrary, total energy consumption increased year by year.
2015, 43(5):905-910.
Abstract:
The evolution of haze and its synoptic characteristics in Guilin are stuied by means of the 50year observation data from the urban station and four the surrounding stations, with relative humidity and visibility to proofread the haze days in records, so to determine haze days objectively. Through analyzing the basic weather situation leading to haze formation, maintenance, and dissipation respectively, the haze weather characteristics are studied to provide a basis for haze weather forecast. The results indicate that haze in Guilin presents an obvious increasing trend from the beginning of the 21st century, and haze happens more frequently in winter than in summer. The basic synoptic features of haze in Guilin are: there is no wind or weak wind (≤3.0 m/s) on the ground; the atmospheric is dry (relative humidity ≤70%); there is a temperature inversion near the surface; ground temperature changes are positive and the humidity changes are negative. The corresponding weather situations are: straight flow or weak ridge at high altitudes, weak high pressure or strain field on the ground, subtropical high pressure belt, warm sector before front, near surface layer inversion, stable upper atmosphere. According to the weather situation analysis, the forecast platform of Guilin haze weather was build, which received good results in haze forecasting.
The evolution of haze and its synoptic characteristics in Guilin are stuied by means of the 50year observation data from the urban station and four the surrounding stations, with relative humidity and visibility to proofread the haze days in records, so to determine haze days objectively. Through analyzing the basic weather situation leading to haze formation, maintenance, and dissipation respectively, the haze weather characteristics are studied to provide a basis for haze weather forecast. The results indicate that haze in Guilin presents an obvious increasing trend from the beginning of the 21st century, and haze happens more frequently in winter than in summer. The basic synoptic features of haze in Guilin are: there is no wind or weak wind (≤3.0 m/s) on the ground; the atmospheric is dry (relative humidity ≤70%); there is a temperature inversion near the surface; ground temperature changes are positive and the humidity changes are negative. The corresponding weather situations are: straight flow or weak ridge at high altitudes, weak high pressure or strain field on the ground, subtropical high pressure belt, warm sector before front, near surface layer inversion, stable upper atmosphere. According to the weather situation analysis, the forecast platform of Guilin haze weather was build, which received good results in haze forecasting.
2015, 43(5):911-917.
Abstract:
With the realtime data measured minutely by the lightning monitoring and warning network, the precipitation data measured minutely from automated precipitation stations, as well as satellite cloud pictures, the cloudtoground lightning (CG) characteristics of a local rainstorm in Hubei on 29 April 2013 are analyzed. The results show that CGs appeared at 500 hPa between the shear line of 700 hPa and 850 hPa, with TBB≤220 K, and negative CGs were dominant during the rainstorm; the strong precipitation occurred in rhe negative CG concentrated area. CGs had different phase with MCS. There is a good temporal and spatial relationship between CG, TBB and strong precipitation. Further analysis shows that when TBB decreased to the lowest value, CG flashes rate reaches the peak, and the trend of negative lightning frequency and strong precipitation are consistent. Precipitation appeared 1 to 18 minutes after the first negative CG, and the sudden increase of negative CG is 18 to 24 minutes in advance of heavy precipitation. This case shows that the MCS would move toward the front of the negative lightning path.
With the realtime data measured minutely by the lightning monitoring and warning network, the precipitation data measured minutely from automated precipitation stations, as well as satellite cloud pictures, the cloudtoground lightning (CG) characteristics of a local rainstorm in Hubei on 29 April 2013 are analyzed. The results show that CGs appeared at 500 hPa between the shear line of 700 hPa and 850 hPa, with TBB≤220 K, and negative CGs were dominant during the rainstorm; the strong precipitation occurred in rhe negative CG concentrated area. CGs had different phase with MCS. There is a good temporal and spatial relationship between CG, TBB and strong precipitation. Further analysis shows that when TBB decreased to the lowest value, CG flashes rate reaches the peak, and the trend of negative lightning frequency and strong precipitation are consistent. Precipitation appeared 1 to 18 minutes after the first negative CG, and the sudden increase of negative CG is 18 to 24 minutes in advance of heavy precipitation. This case shows that the MCS would move toward the front of the negative lightning path.
2015, 43(5):918-924.
Abstract:
Based on the meteorological data of 20 stations in Beijing form 1981 to 2010, the daily comfort indexes in 20 stations and the annual averages of warmest and coldest comfort indexes in urban and rural areas are calculated, as well as hot days, extreme hot days, cold days and severe cold days. The time and spatial variation characteristics of comfort indexes in urban and rural sites are analyzed, and the differences between urban and rural comfort indexes are compared. The results show that in the 1980s, there was no obvious difference between urban and rural sites in the warmest comfort index under the hot standard; however, since the 1990s, the summer comfort was warming obviously, and hot days and extreme hot days increased significantly, especially in the plain area. The spatial distribution of hot days and extreme hot days constantly extended, which extended to the most part of the urban area except for the eastern Chaoyang district after 2000. 〖JP2〗The warming magnitude was larger in urban areas than in rural areas, and it was warmer in plain areas than in mountain areas. The winters were warmer in Urban areas than in rural areas, and cold days and severe cold days were also less in the urban areas than in rural areas. The gap became obvious gradually from the mid and late 1980s, and the biggest gap can be up to 10 to 20 days in a year. The severe cold area reduced since the 1990s, and the cold days reduced 10 days compared with the 1980s.〖JP〗
Based on the meteorological data of 20 stations in Beijing form 1981 to 2010, the daily comfort indexes in 20 stations and the annual averages of warmest and coldest comfort indexes in urban and rural areas are calculated, as well as hot days, extreme hot days, cold days and severe cold days. The time and spatial variation characteristics of comfort indexes in urban and rural sites are analyzed, and the differences between urban and rural comfort indexes are compared. The results show that in the 1980s, there was no obvious difference between urban and rural sites in the warmest comfort index under the hot standard; however, since the 1990s, the summer comfort was warming obviously, and hot days and extreme hot days increased significantly, especially in the plain area. The spatial distribution of hot days and extreme hot days constantly extended, which extended to the most part of the urban area except for the eastern Chaoyang district after 2000. 〖JP2〗The warming magnitude was larger in urban areas than in rural areas, and it was warmer in plain areas than in mountain areas. The winters were warmer in Urban areas than in rural areas, and cold days and severe cold days were also less in the urban areas than in rural areas. The gap became obvious gradually from the mid and late 1980s, and the biggest gap can be up to 10 to 20 days in a year. The severe cold area reduced since the 1990s, and the cold days reduced 10 days compared with the 1980s.〖JP〗
2015, 43(5):925-931.
Abstract:
Based on the data of fog days and the concentrations of SO2, NO2 and PM10 from 2006 to 2012, the characteristics of fogs and air quality and the difference of the influence of sea fog in summer and radiation fog in winter on the air quality in Qingdao are statistically analyzed. The results show that the annual mean number of fog days is 55 days and sea fog days account for 58% of the fog days throughout the year. The highincidence periods of sea fogs are June and July. The annual mean number of pollution days is 30 days and air pollution occurred mostly in winter and spring, and PM10 is the main pollutant in Qingdao. With the process of urbanization, the annual concentration of NO2 tends to increase and SO2 tends to decline. The heavy fogs accompany pollutant days of different levels. The air quality worsens during winter fog days, and the concentrations of SO2, NO2 and PM10 are higher than those in summer.
Based on the data of fog days and the concentrations of SO2, NO2 and PM10 from 2006 to 2012, the characteristics of fogs and air quality and the difference of the influence of sea fog in summer and radiation fog in winter on the air quality in Qingdao are statistically analyzed. The results show that the annual mean number of fog days is 55 days and sea fog days account for 58% of the fog days throughout the year. The highincidence periods of sea fogs are June and July. The annual mean number of pollution days is 30 days and air pollution occurred mostly in winter and spring, and PM10 is the main pollutant in Qingdao. With the process of urbanization, the annual concentration of NO2 tends to increase and SO2 tends to decline. The heavy fogs accompany pollutant days of different levels. The air quality worsens during winter fog days, and the concentrations of SO2, NO2 and PM10 are higher than those in summer.
24 Variation Characteristics and Meteorological Influencing Factors of Air Pollution Index in Yueyang
2015, 43(5):932-938.
Abstract:
Based on the air pollution index data from December 2003 to December 2013, the variation characteristics of air pollution in Yueyang, and the actual weather, largescale circulation backgrounds, and causes of typical air pollution processes in 2013 in Yueyang are analyzed. The results show that API index reduced significantly in Yueyang in recent 10 years. The air pollution in winter was the most serious with big annual change, and relatively light and small in summer with small annual change. API index showed a Vshaped change from January to December, and monthly average API was higher in winter (from October to next March) and lower in summer (April to September). The time and space distribution of air quality in Yueyang was influenced significantly by the industrial layout, dominant wind direction, and geographical conditions. The atmosphere in a stable condition, such as great diurnal range and temperature inversion, aggravated air pollution. Local meteorological and nonlocal input factors resulted in the typical air pollution process over Yueyang in 2013. Using the multiple regression method to establish the API index forecast equation, the results show that meteorological elements and weather phenomenon in Yueyang had a significant influence on API index.
Based on the air pollution index data from December 2003 to December 2013, the variation characteristics of air pollution in Yueyang, and the actual weather, largescale circulation backgrounds, and causes of typical air pollution processes in 2013 in Yueyang are analyzed. The results show that API index reduced significantly in Yueyang in recent 10 years. The air pollution in winter was the most serious with big annual change, and relatively light and small in summer with small annual change. API index showed a Vshaped change from January to December, and monthly average API was higher in winter (from October to next March) and lower in summer (April to September). The time and space distribution of air quality in Yueyang was influenced significantly by the industrial layout, dominant wind direction, and geographical conditions. The atmosphere in a stable condition, such as great diurnal range and temperature inversion, aggravated air pollution. Local meteorological and nonlocal input factors resulted in the typical air pollution process over Yueyang in 2013. Using the multiple regression method to establish the API index forecast equation, the results show that meteorological elements and weather phenomenon in Yueyang had a significant influence on API index.
2015, 43(5):939-944.
Abstract:
The characteristics of atmospheric particles in a lowvisibility event in Hefei is analyzed using high time resolution observations from 13 to 15 January 2013. Based on the data of visibility, relative humidity, and PM2.5 concentration, the process is divided into three stages:fog, mist, and haze, and thus the microphysical characteristics of atmospheric particles in different stage are studied. The results show that: The low visibility event experienced a conversion process of mist-haze-mist-fog-mist-fog-mist. PM2.5/PM10 and PM1/PM2.5 were negatively correlated with the visibility in whole process; PM2.5/PM10 was large in the fog stage, with fine particles accumulated faster; while PM2.5/PM10 was small at the mist and haze stages, with coarse particles generated faster. There was large difference in the spectral distribution of particles between different stages, and the number concentration, surface concentration, and volume concentration of fine particles had a similar spectral shape at mist and haze stages; the sedimentation effects were found from the number concentration, surface concentration, and volume concentration of particles with different size scales at the fog stage. The longer the fog stage lasted, the stronger the sedimentation effect of atmospheric particles.
The characteristics of atmospheric particles in a lowvisibility event in Hefei is analyzed using high time resolution observations from 13 to 15 January 2013. Based on the data of visibility, relative humidity, and PM2.5 concentration, the process is divided into three stages:fog, mist, and haze, and thus the microphysical characteristics of atmospheric particles in different stage are studied. The results show that: The low visibility event experienced a conversion process of mist-haze-mist-fog-mist-fog-mist. PM2.5/PM10 and PM1/PM2.5 were negatively correlated with the visibility in whole process; PM2.5/PM10 was large in the fog stage, with fine particles accumulated faster; while PM2.5/PM10 was small at the mist and haze stages, with coarse particles generated faster. There was large difference in the spectral distribution of particles between different stages, and the number concentration, surface concentration, and volume concentration of fine particles had a similar spectral shape at mist and haze stages; the sedimentation effects were found from the number concentration, surface concentration, and volume concentration of particles with different size scales at the fog stage. The longer the fog stage lasted, the stronger the sedimentation effect of atmospheric particles.
2015, 43(5):945-952.
Abstract:
Based on the meteorological data from 17 stations of Shijiazhuang from 1960 to 2012,〓by using methods of the trend analysis, MannKendall test, and Morlet wavelet analysis, the variation characteristics of agricultural climate resources of temperature being ≥10 ℃ are analyzed. The results show that in recent 53 years, the beginning date with the temperature being ≥10 ℃ stably advanced at a trend rate of 1.4 days per 10 years; the ending date lagged at a trend rate of 1.1 days per 10 years; the durations were extended at a trend rate of 2.5 days per 10 years; the increased trend rate of accumulated temperature was 64.5 ℃·d per 10 years; precipitation change was not obvious, and the sunshine durations decreased obviously at a trend rate of 53.4 hours per 10 years. All the meteorological elements had sudden changes but precipitation. The changes of ending date, durations, accumulated temperature. and sunshine durations are relatively obvious. The ending date lagged obviously in 2007; the durations increased obviously after 1998; the accumulated temperature increased obviously after 2000; sunshine durations decreased obviously after 1993. The Morlet wavelet analysis of the meteorological elements indicates that there existed periodic changes in the recent 53 years. The beginning date and accumulated temperature had 2 to 4year quasiperiodic oscillation; the ending date had 2 to 3year periodic oscillation; the durations had 2year quasiperiodic oscillation; the precipitation had 3year quasiperiodic and 3 to 7year quasiperiodic oscillations; sunshine durations had 2 to 3year quasiperiodic oscillation. The changes of agricultural climate resources of temperature being ≥10 ℃ in Shijiazhuang made the crop growth earlier and the growth cycle shorter. The reduced sunshine duration had negative impacts on crops.
Based on the meteorological data from 17 stations of Shijiazhuang from 1960 to 2012,〓by using methods of the trend analysis, MannKendall test, and Morlet wavelet analysis, the variation characteristics of agricultural climate resources of temperature being ≥10 ℃ are analyzed. The results show that in recent 53 years, the beginning date with the temperature being ≥10 ℃ stably advanced at a trend rate of 1.4 days per 10 years; the ending date lagged at a trend rate of 1.1 days per 10 years; the durations were extended at a trend rate of 2.5 days per 10 years; the increased trend rate of accumulated temperature was 64.5 ℃·d per 10 years; precipitation change was not obvious, and the sunshine durations decreased obviously at a trend rate of 53.4 hours per 10 years. All the meteorological elements had sudden changes but precipitation. The changes of ending date, durations, accumulated temperature. and sunshine durations are relatively obvious. The ending date lagged obviously in 2007; the durations increased obviously after 1998; the accumulated temperature increased obviously after 2000; sunshine durations decreased obviously after 1993. The Morlet wavelet analysis of the meteorological elements indicates that there existed periodic changes in the recent 53 years. The beginning date and accumulated temperature had 2 to 4year quasiperiodic oscillation; the ending date had 2 to 3year periodic oscillation; the durations had 2year quasiperiodic oscillation; the precipitation had 3year quasiperiodic and 3 to 7year quasiperiodic oscillations; sunshine durations had 2 to 3year quasiperiodic oscillation. The changes of agricultural climate resources of temperature being ≥10 ℃ in Shijiazhuang made the crop growth earlier and the growth cycle shorter. The reduced sunshine duration had negative impacts on crops.
2015, 43(5):953-957.
Abstract:
Through the comparative analysis of Red Fuji apple surface cracks and weather conditions at the same time from 1991 to 2013 in Wanrong County, the correlation between fruit surface crack grades and such meteorological factors as temperature, precipitation, sunshine, humidity, and precipitation days is studied to search for the key factors influencing Red Fuji apple surface cracks, by using Excel and SPSS software. The results show that sunshine duration in early August, rainfall in September, relative humidity in September, and rainfall in June affect surface cracks. Fruit surface crack grades are negatively correlated with precipitation and relative humidity in September and precipitation in June, but positively with sunshine duration in early August.
Through the comparative analysis of Red Fuji apple surface cracks and weather conditions at the same time from 1991 to 2013 in Wanrong County, the correlation between fruit surface crack grades and such meteorological factors as temperature, precipitation, sunshine, humidity, and precipitation days is studied to search for the key factors influencing Red Fuji apple surface cracks, by using Excel and SPSS software. The results show that sunshine duration in early August, rainfall in September, relative humidity in September, and rainfall in June affect surface cracks. Fruit surface crack grades are negatively correlated with precipitation and relative humidity in September and precipitation in June, but positively with sunshine duration in early August.
Ma Xincheng
,
Han Guang
,
Jiao Shengyuan
,
Wang Yuankun
,
Guo Linlang
,
He Hui
,
Jin Yongli
,
Ji Lei
2015, 43(5):958-963.
Abstract:
The field experiments were conducted during a heavy fog event occurred in Tianjing on 30 November and 1 December 2009. The corresponding boundary layer and microphysical structure for the fog event are analyzed. Liquid Nitrogen (LN) was seeded into the heavy fog, and significant response was found after seeding. The results show that: cooling near the ground, warm advection of water vapor transmission, and deep inversion are the main causes of the strong fog. The broadening of droplet spectral is of explosive development characteristic. Average spectrum peaked at 6, 14, and 22 μm in diameter, respectively. Liquid nitrogen was seeded into the heavy fog, and the fog droplet spectral peak appeared near 11 μm. The number concentration increased significantly in the diameter range of 8 to 21 μm, with the order of magnitude of about 10 times higher, which is related to the ice crystal effect of liquid nitrogen.
The field experiments were conducted during a heavy fog event occurred in Tianjing on 30 November and 1 December 2009. The corresponding boundary layer and microphysical structure for the fog event are analyzed. Liquid Nitrogen (LN) was seeded into the heavy fog, and significant response was found after seeding. The results show that: cooling near the ground, warm advection of water vapor transmission, and deep inversion are the main causes of the strong fog. The broadening of droplet spectral is of explosive development characteristic. Average spectrum peaked at 6, 14, and 22 μm in diameter, respectively. Liquid nitrogen was seeded into the heavy fog, and the fog droplet spectral peak appeared near 11 μm. The number concentration increased significantly in the diameter range of 8 to 21 μm, with the order of magnitude of about 10 times higher, which is related to the ice crystal effect of liquid nitrogen.
2015, 43(5):964-968.
Abstract:
According to the causal analysis of building and internal system damage induced by lightning, in combination with the standard GB/T21714 Lightning Protection, it is found that that the damage probability (〖WTBX〗P〖WTBZ〗B and 〖WTBX〗P〖WTBZ〗SPDof GB/T21714.2) is related to the probability distribution of lightning current and the extreme value of lightning current, which corresponds to Lightning Protection Level (LPL). The value of 〖WTBX〗P〖WTBZ〗Bequals to the sum of the probability of the lightning current greater than the maximal lightning current and the probability of the lightning current less than minimum corresponding to LPL; the value of 〖WTBX〗P〖WTBZ〗SPD equals to the probability of lightning current greater than maximal lightning current corresponding to LPL. It is pointed out that for the damage probability (〖WTBX〗P〖WTBZ〗B and 〖WTBX〗P〖WTBZ〗SPD in GB500572010) at various lightning protection levels, the values stipulated in GB/T21714.2 should not adopted directly, rather computing according to the lightning current parameters given in GB50057, or using the information sources on the lightning detection network to obtain the data of cloudtoground lightning within a certain scope nearby the building, so to calculate the probability distribution function of lightning current and further the value of 〖WTBX〗P〖WTBZ〗B and 〖WTBX〗P〖WTBZ〗SPD by the abovementioned probability distribution function of lightning current.
According to the causal analysis of building and internal system damage induced by lightning, in combination with the standard GB/T21714 Lightning Protection, it is found that that the damage probability (〖WTBX〗P〖WTBZ〗B and 〖WTBX〗P〖WTBZ〗SPDof GB/T21714.2) is related to the probability distribution of lightning current and the extreme value of lightning current, which corresponds to Lightning Protection Level (LPL). The value of 〖WTBX〗P〖WTBZ〗Bequals to the sum of the probability of the lightning current greater than the maximal lightning current and the probability of the lightning current less than minimum corresponding to LPL; the value of 〖WTBX〗P〖WTBZ〗SPD equals to the probability of lightning current greater than maximal lightning current corresponding to LPL. It is pointed out that for the damage probability (〖WTBX〗P〖WTBZ〗B and 〖WTBX〗P〖WTBZ〗SPD in GB500572010) at various lightning protection levels, the values stipulated in GB/T21714.2 should not adopted directly, rather computing according to the lightning current parameters given in GB50057, or using the information sources on the lightning detection network to obtain the data of cloudtoground lightning within a certain scope nearby the building, so to calculate the probability distribution function of lightning current and further the value of 〖WTBX〗P〖WTBZ〗B and 〖WTBX〗P〖WTBZ〗SPD by the abovementioned probability distribution function of lightning current.
2015, 43(5):969-972.
Abstract:
An analysis is made of the types of electric surges that invade weak current equipment, and the problem that the threshold voltage and residual voltage of Zn0 surge protection devices, which are commonly used in lightning protection engineering, tend to be high and cannot protect weak current equipment well. It is proposed that the commonmode and differentialmode components of the lightninginduced overvoltage should be treated separately while protecting. Isolating transformers are introduced as antisurge devices into the lightning protection engineering of weak current equipment, considering the characteristic that there is only electromagnetic coupling and no direct electrical channel between primary winding and secondary winding to isolate the commonmode voltage. The magnetic saturation and magnetic creeping phenomena of iron cores are used to restrain and reduce the differentialmode components of the lightninginduced overvoltage. Using the isolating transformer as essential protection unit in the Zn0 surge protection device to cover the disadvantage of Zn0 surge protection device, the weak current equipment can be protected. The effect of lightning protection is proved through practical application.
An analysis is made of the types of electric surges that invade weak current equipment, and the problem that the threshold voltage and residual voltage of Zn0 surge protection devices, which are commonly used in lightning protection engineering, tend to be high and cannot protect weak current equipment well. It is proposed that the commonmode and differentialmode components of the lightninginduced overvoltage should be treated separately while protecting. Isolating transformers are introduced as antisurge devices into the lightning protection engineering of weak current equipment, considering the characteristic that there is only electromagnetic coupling and no direct electrical channel between primary winding and secondary winding to isolate the commonmode voltage. The magnetic saturation and magnetic creeping phenomena of iron cores are used to restrain and reduce the differentialmode components of the lightninginduced overvoltage. Using the isolating transformer as essential protection unit in the Zn0 surge protection device to cover the disadvantage of Zn0 surge protection device, the weak current equipment can be protected. The effect of lightning protection is proved through practical application.
2015, 43(5):973-977.
Abstract:
The recommended method for calculating the number of lightning strikes to overhead lines in the technical specification is studied, and it is pointed out that in the method, there is mismatch between the collection area and the amplitude of lightning current corresponding to the lightning ground flash density. To solve the problem, the method for calculating the number of lightning strikes using integration is introduced through a example. Comparison of calculated results between the recommendation and integration methods illustrates the elaboration of the integration method and the rationality of the results. The integration method is based on the electrical geometric model to deduce the computational formula of overheadline collection width related to the amplitude of lightning current, and to determine the ground flash density corresponding to any lightning current amplitude by means of the polynomial fitting of frequency distribution regularities of lightning current amplitude. The product of collection area and lightning ground flash density corresponding to any lightning current amplitude is the annual mean number of lightning strikes corresponding to the lightning current amplitude. Integrating the computed number of lightning strikes within the distribution range of lightning current amplitude for this region, the annual mean number of lightning strikes considering the distribution characteristics of lightning current amplitude can be obtained.
The recommended method for calculating the number of lightning strikes to overhead lines in the technical specification is studied, and it is pointed out that in the method, there is mismatch between the collection area and the amplitude of lightning current corresponding to the lightning ground flash density. To solve the problem, the method for calculating the number of lightning strikes using integration is introduced through a example. Comparison of calculated results between the recommendation and integration methods illustrates the elaboration of the integration method and the rationality of the results. The integration method is based on the electrical geometric model to deduce the computational formula of overheadline collection width related to the amplitude of lightning current, and to determine the ground flash density corresponding to any lightning current amplitude by means of the polynomial fitting of frequency distribution regularities of lightning current amplitude. The product of collection area and lightning ground flash density corresponding to any lightning current amplitude is the annual mean number of lightning strikes corresponding to the lightning current amplitude. Integrating the computed number of lightning strikes within the distribution range of lightning current amplitude for this region, the annual mean number of lightning strikes considering the distribution characteristics of lightning current amplitude can be obtained.
2015, 43(5):978-985.
Abstract:
By means of precipitation, air temperature, snow cover, wind speed, and relative humidity influencing the construction, the Construction Workability Weather Index (CWI) is defined comprehensively. The construction weather conditions are classified in 5 levels according to CWI and their influences. With the data from 38 meteorological stations in Tibet from 1980 to 2013, the climatic conditions for construction workability in Tibet and its changes under the background of global climate change are analyzed. The results show that temperature and precipitation are the main factors that influence the meteorological grades for construction workability in Tibet; June, July, August and September are suitable periods for constructions; the number of suitable days for constructions appears to reduce from southeast to northwest; the start time of suitable periods delays from the southeast to the northwest; and the end time of suitable periods delays form the northwest to the southeast. At lower altitudes, there are more suitable days for construction, the sooner the construction period starts, and later the suitable construction period ends. With global climate warming, the number of suitable days for construction in Tibet increases, and the start time of suitable periods for constructions advances and the end time delays.
By means of precipitation, air temperature, snow cover, wind speed, and relative humidity influencing the construction, the Construction Workability Weather Index (CWI) is defined comprehensively. The construction weather conditions are classified in 5 levels according to CWI and their influences. With the data from 38 meteorological stations in Tibet from 1980 to 2013, the climatic conditions for construction workability in Tibet and its changes under the background of global climate change are analyzed. The results show that temperature and precipitation are the main factors that influence the meteorological grades for construction workability in Tibet; June, July, August and September are suitable periods for constructions; the number of suitable days for constructions appears to reduce from southeast to northwest; the start time of suitable periods delays from the southeast to the northwest; and the end time of suitable periods delays form the northwest to the southeast. At lower altitudes, there are more suitable days for construction, the sooner the construction period starts, and later the suitable construction period ends. With global climate warming, the number of suitable days for construction in Tibet increases, and the start time of suitable periods for constructions advances and the end time delays.
2015, 43(5):986-991.
Abstract:
In order to provide a basis for the deployment and countermeasures of disaster prevention and mitigation work in Qinghai Province, through analyzing the variation regularity and spatial distribution patterns of frost disasters from 1961 to 2010, based on the historical data of daily minimum temperature, total crop planting area, the yield of crops, etc., in Qinghai Province, the risk regionalization of frost disasters is carried out and the variation characteristics of frost disasters are analyzed by means of the graphics, exponential product method. The statistic method is used to build the hazard, exposure and sensitivity indexes of disasterinducing factors. The results show that all the crop planting areas in Qinghai Province are attacked by frost disasters, which are concentrated in Delingha, Dulan and Wulan counties in the eastern Qaidam basin, Menyuan, Datong, Huzhu and Huangzhong counties in the eastern agricultural area, and Guinan and Gonghe. Frost disasters happen mainly from April to September, and the frequency of occurrence reaches the highest in May. The interannual variation of frost disasters exhibits an increasing trend, but not significant, while the interdecadal variation of frost disasters shows a significantly increasing trend. The high risk areas of frost disasters include Menyuan, Huzhu, Datong, the eastern Qilian in the northeast of Qinghai.
In order to provide a basis for the deployment and countermeasures of disaster prevention and mitigation work in Qinghai Province, through analyzing the variation regularity and spatial distribution patterns of frost disasters from 1961 to 2010, based on the historical data of daily minimum temperature, total crop planting area, the yield of crops, etc., in Qinghai Province, the risk regionalization of frost disasters is carried out and the variation characteristics of frost disasters are analyzed by means of the graphics, exponential product method. The statistic method is used to build the hazard, exposure and sensitivity indexes of disasterinducing factors. The results show that all the crop planting areas in Qinghai Province are attacked by frost disasters, which are concentrated in Delingha, Dulan and Wulan counties in the eastern Qaidam basin, Menyuan, Datong, Huzhu and Huangzhong counties in the eastern agricultural area, and Guinan and Gonghe. Frost disasters happen mainly from April to September, and the frequency of occurrence reaches the highest in May. The interannual variation of frost disasters exhibits an increasing trend, but not significant, while the interdecadal variation of frost disasters shows a significantly increasing trend. The high risk areas of frost disasters include Menyuan, Huzhu, Datong, the eastern Qilian in the northeast of Qinghai.
2015, 43(5):992-997.
Abstract:
Starting with the weather service needs of public transportation before departure, it is to study the ideas and techniques of highway traffic weather service to conduct monitoring, forecasting, and early warning. First, the highway traffic meteorological observation network principles and site selection rules for highway traffic are determined. Second, some key techniques, including the road inversion based on hybrid spatial analysis technology and route analysis, are studied. Third, integrating such high impact meteorological elements as weather, visibility, and wind, a model of highway meteorological conditions is established. The weather products of monitoring, forecasting and early warning gave the public an intuitive and effective service. The Highway Traffic Weather Service System (HTWS) began to provide service through the traffic channel of Weather China during Spring Festival of 2014， effectively promoting public's convenience and travel safety.
Starting with the weather service needs of public transportation before departure, it is to study the ideas and techniques of highway traffic weather service to conduct monitoring, forecasting, and early warning. First, the highway traffic meteorological observation network principles and site selection rules for highway traffic are determined. Second, some key techniques, including the road inversion based on hybrid spatial analysis technology and route analysis, are studied. Third, integrating such high impact meteorological elements as weather, visibility, and wind, a model of highway meteorological conditions is established. The weather products of monitoring, forecasting and early warning gave the public an intuitive and effective service. The Highway Traffic Weather Service System (HTWS) began to provide service through the traffic channel of Weather China during Spring Festival of 2014， effectively promoting public's convenience and travel safety.
2015, 43(5):998-1002.
Abstract:
Details of a selfdesigned small DC uninterruptible power charger for automatic weather stations are described. It is based on the UC3906 chip design, in conjunction with LM2576 chip to constitute an integrated buck switching regulator circuit, triggered by high and low levels to control the charging process of the different states. It has functions of not only high efficiency precision charging, but also accessing and cutting off standby power, so to enable the power supply management of small automatic weather stations. In addition, the charger is also designed to measure sunshine duration, which is calculated based on the change rate of level outputs of the solar panel. Compared with conventional singlechip chargers, the charger improves the charging efficiency and lifetime of the system, so to make full use of solar energy. The practical application indicates that it performs well and has certain potential of promotion.
Details of a selfdesigned small DC uninterruptible power charger for automatic weather stations are described. It is based on the UC3906 chip design, in conjunction with LM2576 chip to constitute an integrated buck switching regulator circuit, triggered by high and low levels to control the charging process of the different states. It has functions of not only high efficiency precision charging, but also accessing and cutting off standby power, so to enable the power supply management of small automatic weather stations. In addition, the charger is also designed to measure sunshine duration, which is calculated based on the change rate of level outputs of the solar panel. Compared with conventional singlechip chargers, the charger improves the charging efficiency and lifetime of the system, so to make full use of solar energy. The practical application indicates that it performs well and has certain potential of promotion.
2015, 43(5):1003-1006.
Abstract:
Research is conducted on the components and working principles of CTL713C Doppler weather radar servo system and various issues encountered in actual operation of CTL713C Doppler weather radar servo system. Through examples and practical experience summary, two quickrepairing methods for CTL713C Doppler weather radar servo system are put forward: fast fault location method and difficultoriented method, which provide some references for technology protection of CTL713C Doppler weather radar, and effectively improve the efficiency of weather radar protection.
Research is conducted on the components and working principles of CTL713C Doppler weather radar servo system and various issues encountered in actual operation of CTL713C Doppler weather radar servo system. Through examples and practical experience summary, two quickrepairing methods for CTL713C Doppler weather radar servo system are put forward: fast fault location method and difficultoriented method, which provide some references for technology protection of CTL713C Doppler weather radar, and effectively improve the efficiency of weather radar protection.
External LinksChina Meteorological AdministrationCMA Meteorological Observation CentreChinese Academy of Meteorological SciencesBeijing Meteorological ServiceNational Satellite Meteorological Center
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Supported by:Beijing E-Tiller Technology Development Co., Ltd.
Supported by:Beijing E-Tiller Technology Development Co., Ltd.