Volume 34,Issue 3,2006 Table of Contents
2006, 34(3).
Abstract:
高山雷达站天线高度对雷达的垂直探测范围影响较大，加之中小尺度灾害性天气演生、发展的关键区域在高度1500～4500m左右，所以高山雷达站在选址时应考虑当地零度层平均高度和雷达的垂直探测范围。通过定量估测层状云降水的个例实践，发现探测高度会限制定量估测降水，探测高度对近距离降水估测影响较小，但对远距离降水估测影响较大，原因主要是雷达的垂直探测范围及当地零度层亮带高度的影响。故在高山雷达站选址中应考虑雷达的垂直探测范围及当地零度层亮带高度的影响，同时对已建设完成的高山天气雷达应考虑对高山雷达做0。仰角的观测可行性研究。
高山雷达站天线高度对雷达的垂直探测范围影响较大，加之中小尺度灾害性天气演生、发展的关键区域在高度1500～4500m左右，所以高山雷达站在选址时应考虑当地零度层平均高度和雷达的垂直探测范围。通过定量估测层状云降水的个例实践，发现探测高度会限制定量估测降水，探测高度对近距离降水估测影响较小，但对远距离降水估测影响较大，原因主要是雷达的垂直探测范围及当地零度层亮带高度的影响。故在高山雷达站选址中应考虑雷达的垂直探测范围及当地零度层亮带高度的影响，同时对已建设完成的高山天气雷达应考虑对高山雷达做0。仰角的观测可行性研究。
2006, 34(3):241-245.
Abstract:
The slant wet delay of GPS signals is subjected to the non-uniform distribution of the water vapor in the atmosphere.The three dimensional field of water vapor can be recovered by the computerized tomography(CT) method through accurately determining the slant wet delays from satellites to antennas on the ground.Two sorts of methods for determining the slant wet delays,the point precise positioning(PPP) and the double-difference method,are introduced.Two CT approaches for obtaining the water vapor profiles((Gaussian) constraint and the Kalman filtering) are discussed.
The slant wet delay of GPS signals is subjected to the non-uniform distribution of the water vapor in the atmosphere.The three dimensional field of water vapor can be recovered by the computerized tomography(CT) method through accurately determining the slant wet delays from satellites to antennas on the ground.Two sorts of methods for determining the slant wet delays,the point precise positioning(PPP) and the double-difference method,are introduced.Two CT approaches for obtaining the water vapor profiles((Gaussian) constraint and the Kalman filtering) are discussed.
2006, 34(3):246-249.
Abstract:
Meteorological Lidar is one of main means of atmospheric sounding, being applicable for probing clouds, fog, visibility, temperature, density, and atmospheric wind fields and for tracing atmosphere gases. The development of a series of Lidar used in meteorological research and service is introduced, including semiconductor Lidar, micro-pulse Lidar, Mie Lidar, Doppler Lidar, differential absorption Lidar, and Raman Lidar. The meteorological Lidar with high repetition rate and wide detecting range and without causing damage to human eyes is considered the trend of meteorological Lidar development. Solid Lidar has bright application prospects in atmospheric probing and semiconductor Lidar is an ideal tool to measure the height of cloud bases.
Meteorological Lidar is one of main means of atmospheric sounding, being applicable for probing clouds, fog, visibility, temperature, density, and atmospheric wind fields and for tracing atmosphere gases. The development of a series of Lidar used in meteorological research and service is introduced, including semiconductor Lidar, micro-pulse Lidar, Mie Lidar, Doppler Lidar, differential absorption Lidar, and Raman Lidar. The meteorological Lidar with high repetition rate and wide detecting range and without causing damage to human eyes is considered the trend of meteorological Lidar development. Solid Lidar has bright application prospects in atmospheric probing and semiconductor Lidar is an ideal tool to measure the height of cloud bases.
2006, 34(3):250-253.
Abstract:
A forecast model for long-term weather forecast is established in terms of a BP neural network using solar-lunar positions as input factors. The results of the operational experiments show that the model is superior compared to the model using solar-lunar position probability directly. The forecasting capability of the model based on the BP neural network technology is good for relatively large rainfall and temperature-increasing/decreasing weather processes. It is an important and useful model for operational forecasting practice at present.
A forecast model for long-term weather forecast is established in terms of a BP neural network using solar-lunar positions as input factors. The results of the operational experiments show that the model is superior compared to the model using solar-lunar position probability directly. The forecasting capability of the model based on the BP neural network technology is good for relatively large rainfall and temperature-increasing/decreasing weather processes. It is an important and useful model for operational forecasting practice at present.
5 Dynamic and Moisture Characteristics of Frontal Heavy Rains under Summer Monsoon System over Guangxi
2006, 34(3):254-259.
Abstract:
By means of high-resolution MRI TBB data and NCEP reanalyzed data,an analysis is made of 13 frontal large-scale rainstorm processes influenced by the summer monsoon system in flood season(May to July) from 1980 to 2002 in Guangxi Autonomous Region.Through composite analysis combining with case studies,the evolutionary characteristics of the influencing systems(upper-level jet, low-level jet,South Asia High,etc.) and the dynamical and vapor characteristics of rainstorms are analyzed by using the high-resolution TBB data.The results indicate that Guangxi locates,during rainstorms,in the positive divergent area within the right exit region of the high-level jet,the intensive updraft region at 500 hPa,to the left side of the low-level jet;the coupling between highlevel and low-level jets is the trigger mechanism of rainstorms;further more,the analysis of wet potential vorticity indicates that heavy rainstorms are more likely to occur while the vertical component of moist potential vorticity being less than 0 and the vertical component of moist potential vorticity at the isobaric surface being greater than 0 near 700 hPa.
By means of high-resolution MRI TBB data and NCEP reanalyzed data,an analysis is made of 13 frontal large-scale rainstorm processes influenced by the summer monsoon system in flood season(May to July) from 1980 to 2002 in Guangxi Autonomous Region.Through composite analysis combining with case studies,the evolutionary characteristics of the influencing systems(upper-level jet, low-level jet,South Asia High,etc.) and the dynamical and vapor characteristics of rainstorms are analyzed by using the high-resolution TBB data.The results indicate that Guangxi locates,during rainstorms,in the positive divergent area within the right exit region of the high-level jet,the intensive updraft region at 500 hPa,to the left side of the low-level jet;the coupling between highlevel and low-level jets is the trigger mechanism of rainstorms;further more,the analysis of wet potential vorticity indicates that heavy rainstorms are more likely to occur while the vertical component of moist potential vorticity being less than 0 and the vertical component of moist potential vorticity at the isobaric surface being greater than 0 near 700 hPa.
2006, 34(3):260-265.
Abstract:
Using the data of North Pacific SST,subtropical high characteristic indices and deluges in Hubei Province from 1951 to 1994,a detailed investigation is made on the relationship between deluges in Hubei Province and North Pacific SST,and subtropical high characteristic indices.The results show that there is close relationship between the abnormality of SST in several key regions and deluges.Especially the abnormal distribution of subtropical high in spring and early summer is the main factor influencing deluges in Hubei Province.Besides,the abnormal changes of SST and subtropical high are closely connected: the former is about 1 to 3 months earlier than the latter.Using the statistic analysis method,the models are established by using sea temperature and subtropical high characteristic factors respectively to predict heavy waterlogging over Hubei.The models were put to trial use in Hubei flood season.The result indicates that the heavy waterlogging in Hubei has close relation with air-sea interaction.The abnormality of the sea temperature over the North Pacific Ocean resulted in the abnormality of subtropical high,which caused heavy waterlogging over Hubei.
Using the data of North Pacific SST,subtropical high characteristic indices and deluges in Hubei Province from 1951 to 1994,a detailed investigation is made on the relationship between deluges in Hubei Province and North Pacific SST,and subtropical high characteristic indices.The results show that there is close relationship between the abnormality of SST in several key regions and deluges.Especially the abnormal distribution of subtropical high in spring and early summer is the main factor influencing deluges in Hubei Province.Besides,the abnormal changes of SST and subtropical high are closely connected: the former is about 1 to 3 months earlier than the latter.Using the statistic analysis method,the models are established by using sea temperature and subtropical high characteristic factors respectively to predict heavy waterlogging over Hubei.The models were put to trial use in Hubei flood season.The result indicates that the heavy waterlogging in Hubei has close relation with air-sea interaction.The abnormality of the sea temperature over the North Pacific Ocean resulted in the abnormality of subtropical high,which caused heavy waterlogging over Hubei.
2006, 34(3):266-270.
Abstract:
Using the drought/flood data from representative stations over the eastern Northwest China from 1470 to 2003 collected by the Chinese Academy of Meteorological Sciences, according to different features of terrain, physiognomy and climate, the eastern Northwest China is divided into three climatic regions. By means of statistic methods such as periodic analysis and coil3 wavelet transform, an analysis is made of the decadal variation of drought/flood index in three climatic regions and the difference among them. Results indicate that the spatial and temporal distribution features of drought/flood in three regions are different, and the variation trend and periods not only show consistency, but also exist obvious difference. The drought climate tended gradually to be normal or became wet in the north and the central parts of the area in past 534 years. From 1470 to 1724, the drought climate in the south part tended to be wet. However, after 1724, the wet climate became dry again. There are notable periods of 25 and 10 years in drought/flood in the three regions, respectively. In addition, there are obvious periods of 14 to 15 years in the central part. It is illustrated that the alternation of droughts and floodd is more distinct in the central part than those in the north and south parts.
Using the drought/flood data from representative stations over the eastern Northwest China from 1470 to 2003 collected by the Chinese Academy of Meteorological Sciences, according to different features of terrain, physiognomy and climate, the eastern Northwest China is divided into three climatic regions. By means of statistic methods such as periodic analysis and coil3 wavelet transform, an analysis is made of the decadal variation of drought/flood index in three climatic regions and the difference among them. Results indicate that the spatial and temporal distribution features of drought/flood in three regions are different, and the variation trend and periods not only show consistency, but also exist obvious difference. The drought climate tended gradually to be normal or became wet in the north and the central parts of the area in past 534 years. From 1470 to 1724, the drought climate in the south part tended to be wet. However, after 1724, the wet climate became dry again. There are notable periods of 25 and 10 years in drought/flood in the three regions, respectively. In addition, there are obvious periods of 14 to 15 years in the central part. It is illustrated that the alternation of droughts and floodd is more distinct in the central part than those in the north and south parts.
2006, 34(3):271-274.
Abstract:
Based on the 51-year annual precipitation data of Ningbo from 1953 to 2003,a detailed analysis is performed by means of several diagnosis methods,including EOF,climatic abrupt change testing,Mexico hat wavelet and spectrum analysis.The results show that annual rainfall amount across the city tends to descend from the southwest to north-northeast,which accords with the topographic features of the city;the difference between maximum and minimum precipitation is about 400 mm.EOF1 of spatial characteristic vectors indicates that the annual precipitation of all the seven weather stations has a coincident tendency.Ningbo experienced an abrupt climate change in annual precipitation during the late 1960's and the early 1970's,and another significant change took place in recent years.The annual precipitation has been less than normal since the beginning of the 21st century with the minimum in 2003.There is a quasi-four year periodicity in annual precipitation.
Based on the 51-year annual precipitation data of Ningbo from 1953 to 2003,a detailed analysis is performed by means of several diagnosis methods,including EOF,climatic abrupt change testing,Mexico hat wavelet and spectrum analysis.The results show that annual rainfall amount across the city tends to descend from the southwest to north-northeast,which accords with the topographic features of the city;the difference between maximum and minimum precipitation is about 400 mm.EOF1 of spatial characteristic vectors indicates that the annual precipitation of all the seven weather stations has a coincident tendency.Ningbo experienced an abrupt climate change in annual precipitation during the late 1960's and the early 1970's,and another significant change took place in recent years.The annual precipitation has been less than normal since the beginning of the 21st century with the minimum in 2003.There is a quasi-four year periodicity in annual precipitation.
2006, 34(3):275-279.
Abstract:
利用NCEP 1°×1°再分析资料对2001年8月3~4日浙南闽北的东风波暴雨过程,根据螺旋度(Helicity)分析了过程中的暴雨演变以及雁荡山脉诱生中尺度低涡发生发展的原因。同时,利用中尺度有限区域模式MM5V2对该东风波诱生中尺度低涡进行模拟。结果表明:螺旋度大值中心强度和位置的演变较好地反映了暴雨落区和中尺度低涡的诱生、移动,螺旋度的时空演变对暴雨发生有一定的预示意义,螺旋度计算较中尺度模式得出诱生低涡初生位置、路径预报准确率高,二者集成可以提高诱生低涡的预报准确率。
利用NCEP 1°×1°再分析资料对2001年8月3~4日浙南闽北的东风波暴雨过程,根据螺旋度(Helicity)分析了过程中的暴雨演变以及雁荡山脉诱生中尺度低涡发生发展的原因。同时,利用中尺度有限区域模式MM5V2对该东风波诱生中尺度低涡进行模拟。结果表明:螺旋度大值中心强度和位置的演变较好地反映了暴雨落区和中尺度低涡的诱生、移动,螺旋度的时空演变对暴雨发生有一定的预示意义,螺旋度计算较中尺度模式得出诱生低涡初生位置、路径预报准确率高,二者集成可以提高诱生低涡的预报准确率。
2006, 34(3):280-285.
Abstract:
An analysis is made of a persistent heavy rainfall process in Yunnan occurred from 18 to 20 in May 2004 by means of MICAPS data and FY-2 satellite cloud pictures. It is found out that main influencing weather systems include the Bay of Bengal Tropical Cyclone, shear line on 700 hPa, and cold front on the ground. The incursion of clod air into the periphery circumfluence of the Bay of Bengal Tropical Cyclone resulted in the strong development of the precipitation system. The plentiful vapor and strong ascending motion brought by the Bay of Bengal Tropical Cyclone, as well as the unstable atmosphere of high temperature and high humidity, provided favorable conditions for the development of the heavy rainfall. The maintaining mechanisms of the heavy rainfall also include the establishment and maintenance of the upper- and lower-level jets, and the continual triggering of strong frontogenesis.
An analysis is made of a persistent heavy rainfall process in Yunnan occurred from 18 to 20 in May 2004 by means of MICAPS data and FY-2 satellite cloud pictures. It is found out that main influencing weather systems include the Bay of Bengal Tropical Cyclone, shear line on 700 hPa, and cold front on the ground. The incursion of clod air into the periphery circumfluence of the Bay of Bengal Tropical Cyclone resulted in the strong development of the precipitation system. The plentiful vapor and strong ascending motion brought by the Bay of Bengal Tropical Cyclone, as well as the unstable atmosphere of high temperature and high humidity, provided favorable conditions for the development of the heavy rainfall. The maintaining mechanisms of the heavy rainfall also include the establishment and maintenance of the upper- and lower-level jets, and the continual triggering of strong frontogenesis.
2006, 34(3):286.
Abstract:
Through analyzing the weather situation, a local torrential rain event is analyzed in detail based on the intensity and velocity data from Doppler weather radar as well as vertical wind profilers and two dimensional wind fields derived from velocity data. It is found out that this highly convective local torrential rainfall was caused by both large-scale and mesoscale weather systems. The large-scale circulation provided abundant vapors for the torrential rain; the stratification in Bejing was very unstable, which is a necessary condition for the severe storms; and the low-level mesoscale convergence line triggered and intensified the convection.
Through analyzing the weather situation, a local torrential rain event is analyzed in detail based on the intensity and velocity data from Doppler weather radar as well as vertical wind profilers and two dimensional wind fields derived from velocity data. It is found out that this highly convective local torrential rainfall was caused by both large-scale and mesoscale weather systems. The large-scale circulation provided abundant vapors for the torrential rain; the stratification in Bejing was very unstable, which is a necessary condition for the severe storms; and the low-level mesoscale convergence line triggered and intensified the convection.
2006, 34(3):291-295.
Abstract:
An analysis is made of the process of a hail-storm event occurred in Shandong Province on 27 September 2002. The primary results indicate that the main influencing systems include the southward movement of an upper-level cold trough in cooperation with the low-level shear line and the frontal zone on the ground. The cold advection in the upper air and the warm advection in the lower level resulted in the large-scale unstable zone of potential energy from the middle-level to the low-level of the troposphere. The coupling of a meso-scale low pressure and the divergence zone of an upper-level jet caused strong upward motion. This is a typical small super-cell storm. The mesocyclone is found in the storm by analyzing the radar echo.
An analysis is made of the process of a hail-storm event occurred in Shandong Province on 27 September 2002. The primary results indicate that the main influencing systems include the southward movement of an upper-level cold trough in cooperation with the low-level shear line and the frontal zone on the ground. The cold advection in the upper air and the warm advection in the lower level resulted in the large-scale unstable zone of potential energy from the middle-level to the low-level of the troposphere. The coupling of a meso-scale low pressure and the divergence zone of an upper-level jet caused strong upward motion. This is a typical small super-cell storm. The mesocyclone is found in the storm by analyzing the radar echo.
2006, 34(3):296-300.
Abstract:
用序列试验法、回归分析法、双比分析法和区域回归数值模拟试验方案4种效果评估方法对北京地区2001～2004年6～9月的37次火箭、高炮催化作业进行效果评估,并比较各种方法的优缺点.结果表明：①这4种方案统计结果均得到显著的增雨效果,平均增雨分别为：用序列试验的方法6.99%,用回归分析法30.68%,双比分析法20.11%,区域回归数值模拟试验方案13.37%.②误差分析表明,区域回归数值模拟试验方案产生的绝对误差仅为2.1%～2.2%,是一种较科学的评价方法.
用序列试验法、回归分析法、双比分析法和区域回归数值模拟试验方案4种效果评估方法对北京地区2001～2004年6～9月的37次火箭、高炮催化作业进行效果评估,并比较各种方法的优缺点.结果表明：①这4种方案统计结果均得到显著的增雨效果,平均增雨分别为：用序列试验的方法6.99%,用回归分析法30.68%,双比分析法20.11%,区域回归数值模拟试验方案13.37%.②误差分析表明,区域回归数值模拟试验方案产生的绝对误差仅为2.1%～2.2%,是一种较科学的评价方法.
2006, 34(3):301-305.
Abstract:
The system of airspace application for weather modification by cannons and rockets in Henan Province was developed in order to solve the problems encountered in the process of airspace request by telephone, such as slow transmitting, consuming too much manpower and frequent failures. The system makes full use of the advanced meteorological operation network, adopts the Client/Sever mode, and can deal with the real time information about the airspace requests and answers by computers. It can also save automatically the information of the airspace requests and answers in the database, the seeding information, and the information about seeding effectiveness and operating positions. The system can give alarms and make prior airspace requests while the weather situations being favorable to weather modification. The design method and a new model of the technology system of precipitation enhancement by cannons and rockets are presented.
The system of airspace application for weather modification by cannons and rockets in Henan Province was developed in order to solve the problems encountered in the process of airspace request by telephone, such as slow transmitting, consuming too much manpower and frequent failures. The system makes full use of the advanced meteorological operation network, adopts the Client/Sever mode, and can deal with the real time information about the airspace requests and answers by computers. It can also save automatically the information of the airspace requests and answers in the database, the seeding information, and the information about seeding effectiveness and operating positions. The system can give alarms and make prior airspace requests while the weather situations being favorable to weather modification. The design method and a new model of the technology system of precipitation enhancement by cannons and rockets are presented.
2006, 34(3):306-310.
Abstract:
利用青海省8个农气观测站草本植物物候期观测资料,分析了草本植物物候期变化及其对气温、降水、日照变化的响应.结果表明：①草本植物物候期有明显的地域性.②青海草本植物物候现象生长期除河南、互助等地呈现出缩短趋势外,其余大部地区呈现出作物生长季延长的趋势.③草本植物物候对气温、降水、日照的响应：气温,对上年黄枯期月至当年各物候出现期上月平均气温升高1 ℃,草本植物物候期除个别地、个别物候期推迟（1～11 d） ,生长期缩短（5～9 d）,绝大部分地区草本植物物候期提早（2～12 d）, 生长期延长（3～13 d）; 降水,对上年黄枯期月至当年各物候出现期上月降水量增多10 mm,曲麻莱、互助萌动期提早2 d,湟源萌动期推迟1 d,甘德展叶期推迟3 d, 其余响应微弱;日照, 对上年黄枯期月至当年各物候出现期上月的日照时数增多10 h,各地个别物候期提早1 d, 其余响应微弱.
利用青海省8个农气观测站草本植物物候期观测资料,分析了草本植物物候期变化及其对气温、降水、日照变化的响应.结果表明：①草本植物物候期有明显的地域性.②青海草本植物物候现象生长期除河南、互助等地呈现出缩短趋势外,其余大部地区呈现出作物生长季延长的趋势.③草本植物物候对气温、降水、日照的响应：气温,对上年黄枯期月至当年各物候出现期上月平均气温升高1 ℃,草本植物物候期除个别地、个别物候期推迟（1～11 d） ,生长期缩短（5～9 d）,绝大部分地区草本植物物候期提早（2～12 d）, 生长期延长（3～13 d）; 降水,对上年黄枯期月至当年各物候出现期上月降水量增多10 mm,曲麻莱、互助萌动期提早2 d,湟源萌动期推迟1 d,甘德展叶期推迟3 d, 其余响应微弱;日照, 对上年黄枯期月至当年各物候出现期上月的日照时数增多10 h,各地个别物候期提早1 d, 其余响应微弱.
2006, 34(3):311-314.
Abstract:
Owing to the improvement of farmland irrigation in the recent 30 years,the present soil moisture data cannot reflect the variation regularity of natural soil moisture.The variation(gain and loss) of soil moisture is calculated on a ten-day base by using the soil moisture balance equation and the Penman formula.Compared to the soil moisture data without irrigation from 2001 to 2003,the fitting equation and drought index are established and the drought series from 1970 to 2001 on a ten-day base is reconstructed.The results show that the effect of irrigation is well filtrated out in the calculated drought series,which is very close to the natural soil moisture.
Owing to the improvement of farmland irrigation in the recent 30 years,the present soil moisture data cannot reflect the variation regularity of natural soil moisture.The variation(gain and loss) of soil moisture is calculated on a ten-day base by using the soil moisture balance equation and the Penman formula.Compared to the soil moisture data without irrigation from 2001 to 2003,the fitting equation and drought index are established and the drought series from 1970 to 2001 on a ten-day base is reconstructed.The results show that the effect of irrigation is well filtrated out in the calculated drought series,which is very close to the natural soil moisture.
2006, 34(3):315-318.
Abstract:
根据0414号台风“云娜”灾情调查,使用模糊聚类方法对1949～2004年影响浙江省的重大台风灾害进行分析比较,认为台风“云娜”是浙江省1956年以来所遭遇的最严重台风灾害.综合评估结论：①建国以来台风灾害损失与工农业总产值的比值呈上升趋势,台风“云娜”造成的经济损失与当年生产总值之比为3.54：100;②风暴潮为沿海台风灾害的主要因子,建成标准海塘后,大风上升为首要致灾因子;③沿海农村新建（构）筑物和城市广告牌在台风“云娜”中安全问题突出,民营企业抗灾能力也凸显薄弱环节.
根据0414号台风“云娜”灾情调查,使用模糊聚类方法对1949～2004年影响浙江省的重大台风灾害进行分析比较,认为台风“云娜”是浙江省1956年以来所遭遇的最严重台风灾害.综合评估结论：①建国以来台风灾害损失与工农业总产值的比值呈上升趋势,台风“云娜”造成的经济损失与当年生产总值之比为3.54：100;②风暴潮为沿海台风灾害的主要因子,建成标准海塘后,大风上升为首要致灾因子;③沿海农村新建（构）筑物和城市广告牌在台风“云娜”中安全问题突出,民营企业抗灾能力也凸显薄弱环节.
2006, 34(3):319-325.
Abstract:
针对AMSR-E的特点,采用物理统计方法,对洋面非降水云区水汽总量（V）的反演进行了模拟研究,并用实测亮温数据对反演算式进行了初步验证.主要结果有：①为了有效解决亮温随V值增加而趋于饱和的问题,采用多元线性回归方法,研究比较了算式中不同亮温函数形式的效果,结果表明,在反演算式中采用ln（T0-TB）形式有更好的回归和反演效果,但这种形式不太适合于V值偏大的情况;②采用逐步回归方法,对各通道不同亮温函数形式的回归因子进行了比较分析,引进了对因变量作用最显著的6个因子,生成了新的反演算式,并且对应于不同V值均有较好的回归和反演效果;③可以根据V值大小的变化分段采用以上两种方法生成的反演算式,实际反演的结果与业务产品基本符合.
针对AMSR-E的特点,采用物理统计方法,对洋面非降水云区水汽总量（V）的反演进行了模拟研究,并用实测亮温数据对反演算式进行了初步验证.主要结果有：①为了有效解决亮温随V值增加而趋于饱和的问题,采用多元线性回归方法,研究比较了算式中不同亮温函数形式的效果,结果表明,在反演算式中采用ln（T0-TB）形式有更好的回归和反演效果,但这种形式不太适合于V值偏大的情况;②采用逐步回归方法,对各通道不同亮温函数形式的回归因子进行了比较分析,引进了对因变量作用最显著的6个因子,生成了新的反演算式,并且对应于不同V值均有较好的回归和反演效果;③可以根据V值大小的变化分段采用以上两种方法生成的反演算式,实际反演的结果与业务产品基本符合.
19 Measurement and Analysis of Electromagnetic Environment of Meteorological Satellite Ground Station
2006, 34(3):326-331.
Abstract:
An analysis is made of the current actual influence of electromagnetic environment on data receiving at three national meteorological satellite ground stations.The data transmission frequency of China's next generation polar orbit meteorological satellite is given.The necessity of electromagnetic environment measurement and analysis before a ground station is built and while ground station is operating is discussed.Taking the measurement and analysis of the electromagnetic environment of the Beijing meteorological satellite ground station as an example,the measuring principles and the calculation and analysis method are described,including the classification of interference sources,the calculation of allowed maximum interference,measurement system parameters,measuring procedures,and measuring data;and the measuring data is analyzed.Based on the results of the analysis,the interference sources are determined and a solution is presented,including to identify the location of interference sources through radio environment measurement,then coordinating through the administrative agency and meanwhile adopting certain interference-preventing devices on the receiving facility.
An analysis is made of the current actual influence of electromagnetic environment on data receiving at three national meteorological satellite ground stations.The data transmission frequency of China's next generation polar orbit meteorological satellite is given.The necessity of electromagnetic environment measurement and analysis before a ground station is built and while ground station is operating is discussed.Taking the measurement and analysis of the electromagnetic environment of the Beijing meteorological satellite ground station as an example,the measuring principles and the calculation and analysis method are described,including the classification of interference sources,the calculation of allowed maximum interference,measurement system parameters,measuring procedures,and measuring data;and the measuring data is analyzed.Based on the results of the analysis,the interference sources are determined and a solution is presented,including to identify the location of interference sources through radio environment measurement,then coordinating through the administrative agency and meanwhile adopting certain interference-preventing devices on the receiving facility.
2006, 34(3):332-335.
Abstract:
A brief introduction is made to the characteristics, structure, and phase stability requirement of the low-phase noise Doppler weather radar transmitter, as well as the key technique problems in having transmitter meet the requirement of the pulse Doppler weather radar. To improve the phase noise, several technique used in the transmitter, including the full-solid modulator, flyback electrification, electrification verification, and synchronous AC square-wave steady-current power supply and so on. An analyzed are made of the main factors that influence the inspecting performance of the pulse Doppler weather radar and the side-band phase noise resulted from the effect of the autoeciousness modulator on the RF pulse signals. The analysis results indicate that the unneeded autoeciousness modulation and noise are produced by a series of sources, and the main factors influencing the phasic stability of the Doppler weather radar include RF-Driven sources, power-supply ripple waves, pulse time jitter, amplitude modulation, microphonic effect, electromagnet induction, electromagnetic interference radiation sources, etc. These unneeded side-band noises limit the sounding capability in clutter of theDopplerweather radar.
A brief introduction is made to the characteristics, structure, and phase stability requirement of the low-phase noise Doppler weather radar transmitter, as well as the key technique problems in having transmitter meet the requirement of the pulse Doppler weather radar. To improve the phase noise, several technique used in the transmitter, including the full-solid modulator, flyback electrification, electrification verification, and synchronous AC square-wave steady-current power supply and so on. An analyzed are made of the main factors that influence the inspecting performance of the pulse Doppler weather radar and the side-band phase noise resulted from the effect of the autoeciousness modulator on the RF pulse signals. The analysis results indicate that the unneeded autoeciousness modulation and noise are produced by a series of sources, and the main factors influencing the phasic stability of the Doppler weather radar include RF-Driven sources, power-supply ripple waves, pulse time jitter, amplitude modulation, microphonic effect, electromagnet induction, electromagnetic interference radiation sources, etc. These unneeded side-band noises limit the sounding capability in clutter of theDopplerweather radar.
2006, 34(3):336.
Abstract:
An automatic weather station can directly measure the rainfall of a single station or within a small range with higher precision,but it often omits severe rainfall centers or gusts because of its inadequate distribution density.Radars can probe the structure of clouds and precipitation,trace them from beginning to the end in real time,and provide the real-time precipitation of a specific region rapidly,but their measurement errors are relatively large and the precision of local rainfall measurements is not high.Combining automatic weather stations with radars,applying mathematical methods and GIS techniques,the areal rainfall that represents the mean rainfall of a specific region can be obtained.As an example of deducing the areal rainfall,the regression relationship between six-minute accumulative rain by automatic weather stations and radar echoes over Shenzhen is established by means of GIS techniques and the geographic modification of the three factors(longitude,latitude,and sea level elevation).The calculation model of the area rainfall of a specific area on radar map is developed;and then the high-precision high-resolution(spatial) grid fitting rainfall is gained;thus the areal rainfall distribution of a specific area from radar map is obtained.
An automatic weather station can directly measure the rainfall of a single station or within a small range with higher precision,but it often omits severe rainfall centers or gusts because of its inadequate distribution density.Radars can probe the structure of clouds and precipitation,trace them from beginning to the end in real time,and provide the real-time precipitation of a specific region rapidly,but their measurement errors are relatively large and the precision of local rainfall measurements is not high.Combining automatic weather stations with radars,applying mathematical methods and GIS techniques,the areal rainfall that represents the mean rainfall of a specific region can be obtained.As an example of deducing the areal rainfall,the regression relationship between six-minute accumulative rain by automatic weather stations and radar echoes over Shenzhen is established by means of GIS techniques and the geographic modification of the three factors(longitude,latitude,and sea level elevation).The calculation model of the area rainfall of a specific area on radar map is developed;and then the high-precision high-resolution(spatial) grid fitting rainfall is gained;thus the areal rainfall distribution of a specific area from radar map is obtained.
2006, 34(3):344-348.
Abstract:
The faults of CINRAD/SA radar occurred in one year of operation in Shijiazhuang are analyzed statisticaUy, and the common warning massages and faults, as well as the countermeasures, are introduced. It is pointed out that the running status of CINRAD/SA has close relation with the communication network, computers, and environment temperature of radar. The local environment has obvious influence on the working conditions of radar. Faults are found more frequently in the transmitter, antenna, and control system, which are key parts of routine maintenance. In order to ensure the normal running of radar, it is important to have a safe network management system, high-performance computers, good maintenance, and optimum environment.
The faults of CINRAD/SA radar occurred in one year of operation in Shijiazhuang are analyzed statisticaUy, and the common warning massages and faults, as well as the countermeasures, are introduced. It is pointed out that the running status of CINRAD/SA has close relation with the communication network, computers, and environment temperature of radar. The local environment has obvious influence on the working conditions of radar. Faults are found more frequently in the transmitter, antenna, and control system, which are key parts of routine maintenance. In order to ensure the normal running of radar, it is important to have a safe network management system, high-performance computers, good maintenance, and optimum environment.
2006, 34(3):349-352.
Abstract:
The CE318 sun photometers are installed at 20 weather stations, which constituted the dust storm network for monitoring aerosol by the China Meteorological Administration since 2002. These measurements have not been well utilized because users are unfamiliar with the principles, data format and retrieval methodology of CE318 sun photometers. The impact of aerosol on climate and the application of data observed by photometers are discussed. At the same time, the retrieval method of sun photometer data, including the calibration and retrieval of aerosol optical depth and the quality control of data, is introduced. Combing with data at Tazhong, the Langley method for calculating the aerosol optical depth and the related issues are described.
The CE318 sun photometers are installed at 20 weather stations, which constituted the dust storm network for monitoring aerosol by the China Meteorological Administration since 2002. These measurements have not been well utilized because users are unfamiliar with the principles, data format and retrieval methodology of CE318 sun photometers. The impact of aerosol on climate and the application of data observed by photometers are discussed. At the same time, the retrieval method of sun photometer data, including the calibration and retrieval of aerosol optical depth and the quality control of data, is introduced. Combing with data at Tazhong, the Langley method for calculating the aerosol optical depth and the related issues are described.
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.