Volume 34,Issue 4,2006 Table of Contents
2006, 34(4):353-357.
Abstract:
A conceivable BIcubic Numerical Model(BINM) is studied,which is used to fit the cubic curve function(spline) and the Coons Bicubic Surface.It is like fitting the three-dimension curved surface with a set of bicubic surface patches at the horizontal and vertical directions,on which many atmospheric physical quantity fields are all cubic continuous.So BINM is a new numerical model used to fit n bicubic surfaces in the mathematic R~n-space and the n squares of atmospheric quantity fields in the atmosphere,getting their all cubic continuous fields with their derivative,square derivative quotients.One of BINM's main mathematical characteristics is that the special differential quotients of the basic system of equations have their analytical solutions for the atmospheric kinematics,if the synoptic systems can be embodied by the "bicubic surface" of mathematics.Different from the finite-difference(linear) model and the truncated spectral model,which have their special and wave-number truncation error correspondingly,BINM has its special fitting error only. A computing case is given with a linear advection equation on the spherical coordinates,which is an air pressure field at sea level in a limited area,and got successfully its 6 hour forecast field with a time step of 12 seconds(1800 steps).So, it is concluded that BINM's mathematical truss can adapt to the physical packages of the atmosphere;BINM may be the third kind of meteorological numerical forecast model and may be superior to our linear model and spectral model.
A conceivable BIcubic Numerical Model(BINM) is studied,which is used to fit the cubic curve function(spline) and the Coons Bicubic Surface.It is like fitting the three-dimension curved surface with a set of bicubic surface patches at the horizontal and vertical directions,on which many atmospheric physical quantity fields are all cubic continuous.So BINM is a new numerical model used to fit n bicubic surfaces in the mathematic R~n-space and the n squares of atmospheric quantity fields in the atmosphere,getting their all cubic continuous fields with their derivative,square derivative quotients.One of BINM's main mathematical characteristics is that the special differential quotients of the basic system of equations have their analytical solutions for the atmospheric kinematics,if the synoptic systems can be embodied by the "bicubic surface" of mathematics.Different from the finite-difference(linear) model and the truncated spectral model,which have their special and wave-number truncation error correspondingly,BINM has its special fitting error only. A computing case is given with a linear advection equation on the spherical coordinates,which is an air pressure field at sea level in a limited area,and got successfully its 6 hour forecast field with a time step of 12 seconds(1800 steps).So, it is concluded that BINM's mathematical truss can adapt to the physical packages of the atmosphere;BINM may be the third kind of meteorological numerical forecast model and may be superior to our linear model and spectral model.
2006, 34(4):358-363.
Abstract:
Data assimilation experiments are conducted with the MM5 adjoint-model assimilation system made by adjoint codes.With a case of heavy rainfall occurred on 23 and 24 July 2002,several numerical simulation experiments with different schemes are performed.The results indicate: the MM5 Adjoint-model Assimilation System can not only improve the initial field effectively and promote the coordination with the model but also enhance precipitation and other elements' forecasts;the assimilation of cloud-derived wind(CDW) can improve the quality of upper-level winds;the effect of direct numerical simulation with CDW to improve the initial field is better than that without CDW;when using the adjoint-model assimilation system,the experiment adding CDW can directly improve the wind forecast,but comparing that without adding CDW,there is no obvious improvement over other elements' forecasts.
Data assimilation experiments are conducted with the MM5 adjoint-model assimilation system made by adjoint codes.With a case of heavy rainfall occurred on 23 and 24 July 2002,several numerical simulation experiments with different schemes are performed.The results indicate: the MM5 Adjoint-model Assimilation System can not only improve the initial field effectively and promote the coordination with the model but also enhance precipitation and other elements' forecasts;the assimilation of cloud-derived wind(CDW) can improve the quality of upper-level winds;the effect of direct numerical simulation with CDW to improve the initial field is better than that without CDW;when using the adjoint-model assimilation system,the experiment adding CDW can directly improve the wind forecast,but comparing that without adding CDW,there is no obvious improvement over other elements' forecasts.
2006, 34(4):364-369.
Abstract:
By means of the new generation numerical forecast model WRF(Weather Research Forecast) and MM5 used widely,a simulation study is conducted on a heavy rainfall process occurred on 3 to 4 August 2002 in Liaoning Province.The results indicate that WRF can rather successfully reflect the circumfluence background in the upper or lower level which induced the rainfall and the rainfall distribution.The comparative analysis of the simulation results made by means of WRF and MM5 shows that owing to the superiority of the WRF's dynamic framwork,WRF has better ability to simulate the mesoscale weather system in this heavy rainfall process than MM5 does under the condition of the same physical processes and same pre-processing;the area and intensity of the simulated precipitation by WRF is closer to the fact.
By means of the new generation numerical forecast model WRF(Weather Research Forecast) and MM5 used widely,a simulation study is conducted on a heavy rainfall process occurred on 3 to 4 August 2002 in Liaoning Province.The results indicate that WRF can rather successfully reflect the circumfluence background in the upper or lower level which induced the rainfall and the rainfall distribution.The comparative analysis of the simulation results made by means of WRF and MM5 shows that owing to the superiority of the WRF's dynamic framwork,WRF has better ability to simulate the mesoscale weather system in this heavy rainfall process than MM5 does under the condition of the same physical processes and same pre-processing;the area and intensity of the simulated precipitation by WRF is closer to the fact.
2006, 34(4):370-375.
Abstract:
A numerical experiment is conducted on typhoon Rananim(0414) by use of the PSU/NCAR non-hydrostatic mesoscale model(MM5) and verified against observations;the track,speed,and detailed mesoscale precipitation distributions are well reproduced.Based on the successful simulation of the typhoon process,the characteristics of the typhoon before and after the landfalling are analyzed in circulation patterns and dynamical and thermodynamic structures such as horizontal circulation,temperature/humidity structure,vorticity,divergence,etc.It is found that the distribution of rainfall is related to the asymmetric distribution of moisture transportation,which affects the thermodynamic structure of the typhoon to a great extent.In vertical direction,the extension of physical elements is not only low in height but also small in amount.
A numerical experiment is conducted on typhoon Rananim(0414) by use of the PSU/NCAR non-hydrostatic mesoscale model(MM5) and verified against observations;the track,speed,and detailed mesoscale precipitation distributions are well reproduced.Based on the successful simulation of the typhoon process,the characteristics of the typhoon before and after the landfalling are analyzed in circulation patterns and dynamical and thermodynamic structures such as horizontal circulation,temperature/humidity structure,vorticity,divergence,etc.It is found that the distribution of rainfall is related to the asymmetric distribution of moisture transportation,which affects the thermodynamic structure of the typhoon to a great extent.In vertical direction,the extension of physical elements is not only low in height but also small in amount.
2006, 34(4):376-380.
Abstract:
采用19年3～9月常规探空观测资料、对南昌△T（850-500）≥27℃这种强垂直温度梯度与江西强对流天气过程的关系进行了相关分析，并将区域强对流天气、局部强对流天气、无强对流天气的3类情况下的中低层气压、温度、湿度、风场及稳定度进行分类合成分析，结果表明：当南昌△T（850-500）≥27℃时，且有天气系统作为触发条件时，江西强对流天气发生的概率达85％；中低层低槽和切变等影响系统、江南华南暖湿气流、河套地区的冷空气都有利于江西强对流天气出现。对典型个例的探空曲线和对流有效位能分析表明：强垂直温度梯度结合中低层高湿度是强对流天气发生的重要条件。在强对流天气潜势预报中，强垂直温度梯度有时比对流有效位能更有指示性。根据上述分析结果，建立了相应的预报流程，并在业务试用中取得较好的效果。
采用19年3～9月常规探空观测资料、对南昌△T（850-500）≥27℃这种强垂直温度梯度与江西强对流天气过程的关系进行了相关分析，并将区域强对流天气、局部强对流天气、无强对流天气的3类情况下的中低层气压、温度、湿度、风场及稳定度进行分类合成分析，结果表明：当南昌△T（850-500）≥27℃时，且有天气系统作为触发条件时，江西强对流天气发生的概率达85％；中低层低槽和切变等影响系统、江南华南暖湿气流、河套地区的冷空气都有利于江西强对流天气出现。对典型个例的探空曲线和对流有效位能分析表明：强垂直温度梯度结合中低层高湿度是强对流天气发生的重要条件。在强对流天气潜势预报中，强垂直温度梯度有时比对流有效位能更有指示性。根据上述分析结果，建立了相应的预报流程，并在业务试用中取得较好的效果。
2006, 34(4):381-386.
Abstract:
The impacts of abnormal solar activities on precipitation and temperature in summer and winter in China are analyzed based on the 10.7 cm solar radio flux data and the precipitation and temperature data of 160 weather stations across China from 1951 to 2000.The results show:(1) In high solar activity years,there occurs more precipitation in summer in the upper and middle reaches of the Yellow River and the Changjiang River,as well as over the Huanghuai region,but there occurs less precipitation in summer in South China and Northeast China.At the same time,there is more precipitation in winter across China.There is higher temperature in winter in North China,especially in Northeast China and Xinjiang,and lower temperature in summer.(2) In low solar activity years,there is more precipitation in summer in South China and the regions north of the Yellow River,while there is less precipitation in summer over the Changjiang River basin and the upper and middle reaches of the Yellow River.In winter,there is less precipitation across China and lower temperature in North China.The close relation of summer precipitation in Northeast China and solar activities is further discussed.
The impacts of abnormal solar activities on precipitation and temperature in summer and winter in China are analyzed based on the 10.7 cm solar radio flux data and the precipitation and temperature data of 160 weather stations across China from 1951 to 2000.The results show:(1) In high solar activity years,there occurs more precipitation in summer in the upper and middle reaches of the Yellow River and the Changjiang River,as well as over the Huanghuai region,but there occurs less precipitation in summer in South China and Northeast China.At the same time,there is more precipitation in winter across China.There is higher temperature in winter in North China,especially in Northeast China and Xinjiang,and lower temperature in summer.(2) In low solar activity years,there is more precipitation in summer in South China and the regions north of the Yellow River,while there is less precipitation in summer over the Changjiang River basin and the upper and middle reaches of the Yellow River.In winter,there is less precipitation across China and lower temperature in North China.The close relation of summer precipitation in Northeast China and solar activities is further discussed.
2006, 34(4):387-393.
Abstract:
Statistic methods are used to analyze the climate and anomaly characteristics of summer precipitation in Northeast China in recent 50 years.Results indicate that precipitation is unevenly distributed.Rains occurs mostly in July over most parts of Northeast China except the Sanjiang Plain.The occurrence probability of severe droughts is greater than that of severe floods,which indicates that drought disasters are more frequent than floods.Floods/droughts occur more frequently in the west part of Liaoning Province than in the other regions of Northeast China.Generally speaking,the wet/dry trend isn't obvious in recent 50 years,but there exists the alternative flood/drought variation feature with the interdecadal periods being about 27 and 11 years and the interannual periods being 3 to 6 years.Droughts occur more frequently in June;there often occur persistent droughts from June to July,and the regional severe floods are usually reported in July.Th opposite phase is found in the interdecadal scale variation between June and August.
Statistic methods are used to analyze the climate and anomaly characteristics of summer precipitation in Northeast China in recent 50 years.Results indicate that precipitation is unevenly distributed.Rains occurs mostly in July over most parts of Northeast China except the Sanjiang Plain.The occurrence probability of severe droughts is greater than that of severe floods,which indicates that drought disasters are more frequent than floods.Floods/droughts occur more frequently in the west part of Liaoning Province than in the other regions of Northeast China.Generally speaking,the wet/dry trend isn't obvious in recent 50 years,but there exists the alternative flood/drought variation feature with the interdecadal periods being about 27 and 11 years and the interannual periods being 3 to 6 years.Droughts occur more frequently in June;there often occur persistent droughts from June to July,and the regional severe floods are usually reported in July.Th opposite phase is found in the interdecadal scale variation between June and August.
2006, 34(4):394-399.
Abstract:
The Eltahir calculation model is improved by considering the derivatives of water vapor to adapt to the under-monthly scale assessment of precipitation recycling ratio. By using the ten-day precipitation and evaporation data and NCEP/NCAR daily pressure level reanalysis data, the precipitation recycling ratio over the middlelower reaches of the Changjiang River during Meiyu season in 1998 is estimated. It is found out that about 30 % of precipitation in the research area is contributed by local evaporation during continual heavy rainfall summer in 1998. The greatest contribution is over the southern Anhui and eastern Hubei provinces. The ten-day precipitation recycling ratio varies frequently, The highest value is 67, 8%, while the lowest is just 0,8%. That indicates the high sensibility of land surface hydrology and the instability of land-atmosphere interaction.
The Eltahir calculation model is improved by considering the derivatives of water vapor to adapt to the under-monthly scale assessment of precipitation recycling ratio. By using the ten-day precipitation and evaporation data and NCEP/NCAR daily pressure level reanalysis data, the precipitation recycling ratio over the middlelower reaches of the Changjiang River during Meiyu season in 1998 is estimated. It is found out that about 30 % of precipitation in the research area is contributed by local evaporation during continual heavy rainfall summer in 1998. The greatest contribution is over the southern Anhui and eastern Hubei provinces. The ten-day precipitation recycling ratio varies frequently, The highest value is 67, 8%, while the lowest is just 0,8%. That indicates the high sensibility of land surface hydrology and the instability of land-atmosphere interaction.
2006, 34(4):400-404.
Abstract:
The temporal and spatial distributions of hails are studied based on the data of the number of monthly hail days in early summer(from 1961 to 2001) at 194 stations in Northwest China,and the climate characteristics of the circulation patterns in typical more/less-than-normal hail years are discussed.The results indicate that hail events occurs more frequently in such areas as the Pamirs Plateau in Xinjiang,the area along the Qilian Mountain and the most part of Qinghai Province south of the Qilian Mountain(except for the Chaidamu basin),and the high-elevation areas of the Southern Gansu plateau.There is more obvious interdecadal variation in hailing days over the area with the greater number of hailing days,and vice versa.The numbers of hailing days exhibited an increasing trend from the 1960s to the middle 1970s,with its peak in 1977 and the years of high-frequency hail events concentrated around the 1970s.From the 1980s,the numbers of hailing days exhibited a decreasing trend with the minimum in 2001.In addition,there are significant differences in the polar vortex,height fields over the Tibetan Plateau,trough over India and Burma,circulation patterns over Europe,and 500 hPa circulation patterns and OLR in the Northern Hemisphere in more/less-than-normal hail years.
The temporal and spatial distributions of hails are studied based on the data of the number of monthly hail days in early summer(from 1961 to 2001) at 194 stations in Northwest China,and the climate characteristics of the circulation patterns in typical more/less-than-normal hail years are discussed.The results indicate that hail events occurs more frequently in such areas as the Pamirs Plateau in Xinjiang,the area along the Qilian Mountain and the most part of Qinghai Province south of the Qilian Mountain(except for the Chaidamu basin),and the high-elevation areas of the Southern Gansu plateau.There is more obvious interdecadal variation in hailing days over the area with the greater number of hailing days,and vice versa.The numbers of hailing days exhibited an increasing trend from the 1960s to the middle 1970s,with its peak in 1977 and the years of high-frequency hail events concentrated around the 1970s.From the 1980s,the numbers of hailing days exhibited a decreasing trend with the minimum in 2001.In addition,there are significant differences in the polar vortex,height fields over the Tibetan Plateau,trough over India and Burma,circulation patterns over Europe,and 500 hPa circulation patterns and OLR in the Northern Hemisphere in more/less-than-normal hail years.
2006, 34(4):405-409.
Abstract:
The standards of concentrated heavy rainfall in Hubei Province are defined. There occurred 12 cases of concentrated heavy rainfall in the range of the standards in Hubei Province since 1954, of which the detailed analysis is made, It is showed that concentrated heavy rainfall usually consists of three or more heavy rain events. The first is cold-front heavy rain, which forms in the process of East-Asia trough building-up and weakening. The second occurs in the eastward-moving process of the Qinghai-Tibet Plateau vortex, which is superimposed above the dew-point front. It is usually severe heavy rainfall. The third is low-trough heavy rainfall, relatively weak. The environmental conditions and large- and meso-scale synoptic features for concentrated heavy rainfall are summed up. The results are useful for the short- and medium-range heavy rain forecasting,
The standards of concentrated heavy rainfall in Hubei Province are defined. There occurred 12 cases of concentrated heavy rainfall in the range of the standards in Hubei Province since 1954, of which the detailed analysis is made, It is showed that concentrated heavy rainfall usually consists of three or more heavy rain events. The first is cold-front heavy rain, which forms in the process of East-Asia trough building-up and weakening. The second occurs in the eastward-moving process of the Qinghai-Tibet Plateau vortex, which is superimposed above the dew-point front. It is usually severe heavy rainfall. The third is low-trough heavy rainfall, relatively weak. The environmental conditions and large- and meso-scale synoptic features for concentrated heavy rainfall are summed up. The results are useful for the short- and medium-range heavy rain forecasting,
2006, 34(4):410-414.
Abstract:
根据陕西省1959～2002年汛期（6～9月）降水资料，采用旋转经验正交（REOF）分解方法，将陕西省按汛期降水划分为4个自然气候区：Ⅰ区包括关中及渭北地区，Ⅱ区为陕北长城沿线地区，Ⅲ区、Ⅳ区分别为陕南东部和陕南西部地区。对各气候区的降水变化特征进行分析，结果表明：汛期降水除陕南东部呈线性增加趋势外，其余各区均呈线性减少趋势。分析陕西省典型旱（涝）年北半球500hPa环流形势距平场和环流特征量发现：典型旱（涝）年，Nino3区海温为明显的正（负）距平；西太平洋副热带高压强度偏强（弱），脊线位置偏南（北）、西伸脊点偏东（西），欧亚地区西风环流指数偏弱（强），以经（纬）向环流为主。
根据陕西省1959～2002年汛期（6～9月）降水资料，采用旋转经验正交（REOF）分解方法，将陕西省按汛期降水划分为4个自然气候区：Ⅰ区包括关中及渭北地区，Ⅱ区为陕北长城沿线地区，Ⅲ区、Ⅳ区分别为陕南东部和陕南西部地区。对各气候区的降水变化特征进行分析，结果表明：汛期降水除陕南东部呈线性增加趋势外，其余各区均呈线性减少趋势。分析陕西省典型旱（涝）年北半球500hPa环流形势距平场和环流特征量发现：典型旱（涝）年，Nino3区海温为明显的正（负）距平；西太平洋副热带高压强度偏强（弱），脊线位置偏南（北）、西伸脊点偏东（西），欧亚地区西风环流指数偏弱（强），以经（纬）向环流为主。
12 Variation Characteristics of Sunshine Duration in Tianjin in Recent 40 Years and Influential Factors
2006, 34(4):415-420.
Abstract:
The yearly averaged sunshine duration,cloud cover,surface vapor pressure and visibility from four meteorological stations(the urban area,Xiqing,Jixian and Tanggu) in Tianjin are analyzed.The results show that the sunshine duration decreased significantly for the past 40 years at the four stations;the variation rates of the annual sunshine duration are-177.3,-165.2,-174.1 and-145.6 hours per ten years,respectively;compared to the 1960s,the mean annual sunshine durations decreased by 425.1,403.4,486.0,and 377.5 hours in the 1990s,which is equivalent to a decrease of 1.2,1.1,1.3,and 1.0 hours in daily sunshine duration for the four stations;there is no long-term variation trend in cloud cover and surface vapor pressure for the four stations,but surface visibility witnessed a tremendous drop in the analyzed period.It indicates that the principal cause for the sunshine duration variation is the decrease of surface visibility resulted from the increase of atmospheric aerosol concentration due to the rapid development of the local industries and economy.
The yearly averaged sunshine duration,cloud cover,surface vapor pressure and visibility from four meteorological stations(the urban area,Xiqing,Jixian and Tanggu) in Tianjin are analyzed.The results show that the sunshine duration decreased significantly for the past 40 years at the four stations;the variation rates of the annual sunshine duration are-177.3,-165.2,-174.1 and-145.6 hours per ten years,respectively;compared to the 1960s,the mean annual sunshine durations decreased by 425.1,403.4,486.0,and 377.5 hours in the 1990s,which is equivalent to a decrease of 1.2,1.1,1.3,and 1.0 hours in daily sunshine duration for the four stations;there is no long-term variation trend in cloud cover and surface vapor pressure for the four stations,but surface visibility witnessed a tremendous drop in the analyzed period.It indicates that the principal cause for the sunshine duration variation is the decrease of surface visibility resulted from the increase of atmospheric aerosol concentration due to the rapid development of the local industries and economy.
2006, 34(4):421-425.
Abstract:
对银川市1961~2004年的实测太阳总辐射资料分析表明,银川市的太阳总辐射40年来呈逐渐减少的趋势。方差分析表明,银川市的太阳总辐射突变点出现在1980年,此前银川处于相对偏多的时段,此后虽然在20世纪80年代后期有一次明显波动,但总体上呈下降趋势,银川处于相对偏少的时段,突变后比突变前平均年总辐射量减少了295.41 MJ/(m2.a)。银川市各月总辐射减少幅度不同,9月减少幅度最大,4月减少幅度最小。日照时数的变化趋势与太阳总辐射的变化趋势一致。分析其对气候的影响可知,银川市总辐射和年平均气温、夏季降水量呈负相关,与年蒸发量呈正相关,呈线性趋势。若总辐射减少100 MJ/(m2.a),年平均气温将升高0.15℃,5~9月降水量将增加6 mm,蒸发量将减少18 mm。
对银川市1961~2004年的实测太阳总辐射资料分析表明,银川市的太阳总辐射40年来呈逐渐减少的趋势。方差分析表明,银川市的太阳总辐射突变点出现在1980年,此前银川处于相对偏多的时段,此后虽然在20世纪80年代后期有一次明显波动,但总体上呈下降趋势,银川处于相对偏少的时段,突变后比突变前平均年总辐射量减少了295.41 MJ/(m2.a)。银川市各月总辐射减少幅度不同,9月减少幅度最大,4月减少幅度最小。日照时数的变化趋势与太阳总辐射的变化趋势一致。分析其对气候的影响可知,银川市总辐射和年平均气温、夏季降水量呈负相关,与年蒸发量呈正相关,呈线性趋势。若总辐射减少100 MJ/(m2.a),年平均气温将升高0.15℃,5~9月降水量将增加6 mm,蒸发量将减少18 mm。
2006, 34(4):426-431.
Abstract:
The statistical analysis of monthly rainfall data from 11 observation stations in Southeastern Shanxi Province from March to August, 1960 to 2000 is made. The spring and summer droughts are divided into 5 grades according to the number of droughts, the months that the droughts occurred, drought extent, etc. , to study the occurrence regularities of droughts. It is found that the southeastern Shanxi Province is an area that droughts strikes frequently. The precipitation forecast equations are devised by means of the optimum subset regression method, and the forecasting results appear promising. Based on the equations, the key factor impacting rainfall in the Southeastern Shanxi Province are identified preliminarily.
The statistical analysis of monthly rainfall data from 11 observation stations in Southeastern Shanxi Province from March to August, 1960 to 2000 is made. The spring and summer droughts are divided into 5 grades according to the number of droughts, the months that the droughts occurred, drought extent, etc. , to study the occurrence regularities of droughts. It is found that the southeastern Shanxi Province is an area that droughts strikes frequently. The precipitation forecast equations are devised by means of the optimum subset regression method, and the forecasting results appear promising. Based on the equations, the key factor impacting rainfall in the Southeastern Shanxi Province are identified preliminarily.
15 Analysis of Circulation Characteristics of Spring-Summer Droughts over Northwestern Yunnan Province
2006, 34(4):432-435.
Abstract:
The correlation analysis is made between the May mean rainfall over Lijiang from 1971 to 2000 and the height fields of 100 hPa and 500 hPa during the same time.It is found out that the main influencing weather systems influencing rainfall in May in Lijiang include the 100 hPa South Asia high,500 hPa South Sea subtropical high,low system over the Bay of Bengal,and Xinjiang high(ridge) at mid-high latitudes.Through abalysing the observed and anomaly fields in May 2005 at 100 hPa and 500 hPa,it is shown that the circulationpattern causes of the drought persisting from spring to summer in May 2005 include the strong the subtropical high over the South Sea,the weak low over the Bay of Bengal,and the weak-than-normal South Asia high and Xinjiang high,which together obstructed the confluence of the Southwest Monsoon cloud cluster and the cold air from noth over Yunnan,so to result in the severe drought.
The correlation analysis is made between the May mean rainfall over Lijiang from 1971 to 2000 and the height fields of 100 hPa and 500 hPa during the same time.It is found out that the main influencing weather systems influencing rainfall in May in Lijiang include the 100 hPa South Asia high,500 hPa South Sea subtropical high,low system over the Bay of Bengal,and Xinjiang high(ridge) at mid-high latitudes.Through abalysing the observed and anomaly fields in May 2005 at 100 hPa and 500 hPa,it is shown that the circulationpattern causes of the drought persisting from spring to summer in May 2005 include the strong the subtropical high over the South Sea,the weak low over the Bay of Bengal,and the weak-than-normal South Asia high and Xinjiang high,which together obstructed the confluence of the Southwest Monsoon cloud cluster and the cold air from noth over Yunnan,so to result in the severe drought.
2006, 34(4):436-440.
Abstract:
The relationship among glaze in Nanyue Mountain, winter temperature, the subtropical high over the West Pacific Ocean is analyzed. The result shows that the number of glaze days in Nanyue Mountain is greater in cold winter and smaller in warm winters. The relationship between the subtropical high in the West Pacific Ocean and the winter temperature in Nanyue Mountain is quite evident. The winter in Nanyue is colder while the subtropical high is stronger, and vice versa. When the north boundary of the line 588 of the subtropical high deflects to the north, the winter in Nanyue becomes warmer, and vice versa. When the west crest point of the subtropical high deflects to the east, the number of glaze days in Nanyue is greater, and vice versa. The subtropical high varies ahead of cold and warm winters. The findings give evidences and references to glaze forecasting in Nanyue Mountain.
The relationship among glaze in Nanyue Mountain, winter temperature, the subtropical high over the West Pacific Ocean is analyzed. The result shows that the number of glaze days in Nanyue Mountain is greater in cold winter and smaller in warm winters. The relationship between the subtropical high in the West Pacific Ocean and the winter temperature in Nanyue Mountain is quite evident. The winter in Nanyue is colder while the subtropical high is stronger, and vice versa. When the north boundary of the line 588 of the subtropical high deflects to the north, the winter in Nanyue becomes warmer, and vice versa. When the west crest point of the subtropical high deflects to the east, the number of glaze days in Nanyue is greater, and vice versa. The subtropical high varies ahead of cold and warm winters. The findings give evidences and references to glaze forecasting in Nanyue Mountain.
2006, 34(4):441-445.
Abstract:
Using the precipitation data of 18 weather stations in the southeastern Guizhou Province from 1960 to 2000, the temporal and spatial distribution, variation regularities, and influencing factors of heavy rains are analyzed statistically. The results indicate that there is notable interdecadal variation in heavy rainfall over the southeastern Guizhou Province with a quasi-15 year period and the same phase with precipitation variation in the whole Guizhou Province and the middle and lower reaches of the Changjiang River; there are two high-occurrence centers; heavy rainfall occurs more frequently in the evenings; heavy rains are disturbed highly unevenly, mostly local rainfall, which are related to the special topography in the southeastern Guizhou Province. The climatic causes are also discussed.
Using the precipitation data of 18 weather stations in the southeastern Guizhou Province from 1960 to 2000, the temporal and spatial distribution, variation regularities, and influencing factors of heavy rains are analyzed statistically. The results indicate that there is notable interdecadal variation in heavy rainfall over the southeastern Guizhou Province with a quasi-15 year period and the same phase with precipitation variation in the whole Guizhou Province and the middle and lower reaches of the Changjiang River; there are two high-occurrence centers; heavy rainfall occurs more frequently in the evenings; heavy rains are disturbed highly unevenly, mostly local rainfall, which are related to the special topography in the southeastern Guizhou Province. The climatic causes are also discussed.
2006, 34(4):446-454.
Abstract:
采用常规观测、地面加密降水资料、逐时云顶亮温TBB资料以及高分辨率模式输出资料，对2003年7月4～5日南京特大暴雨过程中尺度对流系统的发生发展、结构特征及成因进行了综合分析。结果表明：①此次暴雨是由两个中0尺度云团合并而成的MαCS产生，期间有2个强降雨时段，每个时段持续5h左右；②MαCS发生在低层切变线南侧的中尺度辐合线（或辐合中心）上，并在减弱阶段演变为明显的低涡结构；③在其发展强盛期，MαCS垂直倾斜的上升气流显示出对流风暴云特点，并在对流层中高层具有一定的暖心结构；④低空急流脉动引起急流左侧出口区非地转风辐合的急剧增强以及凝结潜热释放和边界层干冷空气的侵入，导致了MαCS的发生发展。
采用常规观测、地面加密降水资料、逐时云顶亮温TBB资料以及高分辨率模式输出资料，对2003年7月4～5日南京特大暴雨过程中尺度对流系统的发生发展、结构特征及成因进行了综合分析。结果表明：①此次暴雨是由两个中0尺度云团合并而成的MαCS产生，期间有2个强降雨时段，每个时段持续5h左右；②MαCS发生在低层切变线南侧的中尺度辐合线（或辐合中心）上，并在减弱阶段演变为明显的低涡结构；③在其发展强盛期，MαCS垂直倾斜的上升气流显示出对流风暴云特点，并在对流层中高层具有一定的暖心结构；④低空急流脉动引起急流左侧出口区非地转风辐合的急剧增强以及凝结潜热释放和边界层干冷空气的侵入，导致了MαCS的发生发展。
2006, 34(4):455-459.
Abstract:
An overview of the weather conditions associated with the very-short-range torrential rains in Guangzhou is presented,with emphasis on the evolution of environmental and several storm-cell's Doppler characteristics relevant to the forecasting of heavy rains,using data from a new generation Doppler weather radar(CINRAD-SA) in Guangzhou and conventional weather observation networks.The formation mechanisms of the torrential rains are investigated.It is found that this severe rainstorm case occurred in the favorable synoptic conditions with the multi-cell echo band orientated from northeast to southwest,being consistent with its moving direction.The weak mesocyclone features are found in the strongest cell with the longest life time.The "inverse-wind region" played an important role in the development and maintenance of convection.
An overview of the weather conditions associated with the very-short-range torrential rains in Guangzhou is presented,with emphasis on the evolution of environmental and several storm-cell's Doppler characteristics relevant to the forecasting of heavy rains,using data from a new generation Doppler weather radar(CINRAD-SA) in Guangzhou and conventional weather observation networks.The formation mechanisms of the torrential rains are investigated.It is found that this severe rainstorm case occurred in the favorable synoptic conditions with the multi-cell echo band orientated from northeast to southwest,being consistent with its moving direction.The weak mesocyclone features are found in the strongest cell with the longest life time.The "inverse-wind region" played an important role in the development and maintenance of convection.
20 Decision Analysis of Grain Crop Rational Layout in Inner Mongolia Typical Farming-Pastoral Region
2006, 34(4):460-464.
Abstract:
The grain crop rational layout schemes in various drought conditions are analyzed by means of the linear programming method, taking Balinzuo Qi in Inner Mongolia as an example of the typical farming-pastoral region. In order to verify the yield-increasing effectiveness of the schemes and decrease the planting risk, the comparison analysis and assessment of the results between crop rational layout and reality are made. It is proved that the actual yields of various crops increased through using the optimal schemes, and the yield increase is more evident when drought types were defined compared with the case without defined drought types. However, the crop yield increment is steady with the risk index being lower through adopting the random scheme when the drought type cannot be determined accurately.
The grain crop rational layout schemes in various drought conditions are analyzed by means of the linear programming method, taking Balinzuo Qi in Inner Mongolia as an example of the typical farming-pastoral region. In order to verify the yield-increasing effectiveness of the schemes and decrease the planting risk, the comparison analysis and assessment of the results between crop rational layout and reality are made. It is proved that the actual yields of various crops increased through using the optimal schemes, and the yield increase is more evident when drought types were defined compared with the case without defined drought types. However, the crop yield increment is steady with the risk index being lower through adopting the random scheme when the drought type cannot be determined accurately.
21 Analysis of Weather Conditions for Lightning-Caused Forest Fire in Southwestern Zhejiang Province
2006, 34(4):465-469.
Abstract:
The southwestern Zhejiang Province has a forest coverage of over 79 %. Lightning strikes caused forest fires more frequently in the last two years. Based on four representative examples, an analysis is made of the surface and weather conditions for lightning-caused forest fires. Some valuable results arg obtained. It is found out that some of the surface and weather conditions for lightning-caused forest fires in the southwestern Zhejiang Province are different from those in North China. The findings may provide useful references for forest-fire fighting in South China.
The southwestern Zhejiang Province has a forest coverage of over 79 %. Lightning strikes caused forest fires more frequently in the last two years. Based on four representative examples, an analysis is made of the surface and weather conditions for lightning-caused forest fires. Some valuable results arg obtained. It is found out that some of the surface and weather conditions for lightning-caused forest fires in the southwestern Zhejiang Province are different from those in North China. The findings may provide useful references for forest-fire fighting in South China.
2006, 34(4):470-473.
Abstract:
The ground-based control system is essential to ensure the safety and effectiveness of airplane precipitation enhancement operations. The command system of precipitation enhancement operations for Heilongjiang Province is developed. The system uses the experiences of other provincial precipitation enhancement command systems for reference, emphasizing the application of automatic generation and output of operation plans, and satellite cloud picture data embedded in the GIS ing plan and flight route according to the changes of use, the system has proved practical and reliable. Doppler radar. The decision-making subsystem realized the and the communication subsystem uses the real-time radar system to track the seeding plane. It can adjust the operatthe target cloud systems. Through the two-year operational
The ground-based control system is essential to ensure the safety and effectiveness of airplane precipitation enhancement operations. The command system of precipitation enhancement operations for Heilongjiang Province is developed. The system uses the experiences of other provincial precipitation enhancement command systems for reference, emphasizing the application of automatic generation and output of operation plans, and satellite cloud picture data embedded in the GIS ing plan and flight route according to the changes of use, the system has proved practical and reliable. Doppler radar. The decision-making subsystem realized the and the communication subsystem uses the real-time radar system to track the seeding plane. It can adjust the operatthe target cloud systems. Through the two-year operational
2006, 34(4):474-477.
Abstract:
Considering the disadvantages of stitistical methods,the degree of grey incidence is adopted in the suitability analysis of tobacco planting.The basic data is collected from 125 meteorological observation stations from 1971 to 2000.The IDS(Inverse Distance Spuared) method is used to infer the climatic information at the county/town level.The areas that are suitable for planting tobacco at the county/town level are given.Mile County is considered as the optimum place for growing tobacco,and its ecological condition was used as the bases for suitability analysis.The application results show that using the degree of grey incidence in the suitability analysis of tobacco planting is simple,practical,and reliable.
Considering the disadvantages of stitistical methods,the degree of grey incidence is adopted in the suitability analysis of tobacco planting.The basic data is collected from 125 meteorological observation stations from 1971 to 2000.The IDS(Inverse Distance Spuared) method is used to infer the climatic information at the county/town level.The areas that are suitable for planting tobacco at the county/town level are given.Mile County is considered as the optimum place for growing tobacco,and its ecological condition was used as the bases for suitability analysis.The application results show that using the degree of grey incidence in the suitability analysis of tobacco planting is simple,practical,and reliable.
2006, 34(4):478-481.
Abstract:
The characteristics of the spatial and temporal distribution of red tides in China along the China coast are analyzed based on Oceanic Calamity Communique in China.The results show that red tides increase very fast in recent years,and they occurs almost at any time of a year in every coastal province and more frequently from May to September,most likely in Zhejiang Province around the estuary of the Yangtze River.The meteorological elements at the Zhoushan Station during the red tides are analyzed.The main characteristics include high humidity,low atmospheric pressure,long sunshine duration,and east winds.The weather patterns during red tides are summed up from the weather charts of the same time: there exists northwest wind at the upper level and low uniformed surface pressure;at the near surface layer,there are massive high temperature gradient areas along the east coastal area of China.The relation of red tides and weather patterns are discussed.
The characteristics of the spatial and temporal distribution of red tides in China along the China coast are analyzed based on Oceanic Calamity Communique in China.The results show that red tides increase very fast in recent years,and they occurs almost at any time of a year in every coastal province and more frequently from May to September,most likely in Zhejiang Province around the estuary of the Yangtze River.The meteorological elements at the Zhoushan Station during the red tides are analyzed.The main characteristics include high humidity,low atmospheric pressure,long sunshine duration,and east winds.The weather patterns during red tides are summed up from the weather charts of the same time: there exists northwest wind at the upper level and low uniformed surface pressure;at the near surface layer,there are massive high temperature gradient areas along the east coastal area of China.The relation of red tides and weather patterns are discussed.
2006, 34(4):482-484.
Abstract:
It is very important to send the warning message timely to decision makers when there occurs severe weather. The communication between PC and GSM module by utilizing VB 6.0 communication technology is introduced, and the short message compiling and sending, system management and some related critical techniques are described in detail. It can provide technical support for the development of the meteorological decisionmaking short message service platform. The system emphasizes the authoritativeness of information announcement; the issued messages must be examined strictly and signed and the authorization management is performed for user codes.
It is very important to send the warning message timely to decision makers when there occurs severe weather. The communication between PC and GSM module by utilizing VB 6.0 communication technology is introduced, and the short message compiling and sending, system management and some related critical techniques are described in detail. It can provide technical support for the development of the meteorological decisionmaking short message service platform. The system emphasizes the authoritativeness of information announcement; the issued messages must be examined strictly and signed and the authorization management is performed for user codes.
2006, 34(4):485-489.
Abstract:
The integrated operation and service system for drought monitoring and forecasting in Northwest China(V2.0) is optimized and upgraded based on the former version(V1.0)and the findings of the project"Formation Causes of Droughts in Northwest China and Their Application Study"sponsored by the Gansu Provincial Science & Technology Department in 2002.The system includes seven parts: database,monitoring and diagnosis,climate prediction,weather influence appraisal,weather prediction evaluation,product distribution,and auxiliary tools.It is an integrated and highly automatic system with own features,having a good physical base and good capability of monitoring and servicing.The system has a user-friendly interface,clear structure,strong independence,high extensibility,strong flexibility,and high running rate.
The integrated operation and service system for drought monitoring and forecasting in Northwest China(V2.0) is optimized and upgraded based on the former version(V1.0)and the findings of the project"Formation Causes of Droughts in Northwest China and Their Application Study"sponsored by the Gansu Provincial Science & Technology Department in 2002.The system includes seven parts: database,monitoring and diagnosis,climate prediction,weather influence appraisal,weather prediction evaluation,product distribution,and auxiliary tools.It is an integrated and highly automatic system with own features,having a good physical base and good capability of monitoring and servicing.The system has a user-friendly interface,clear structure,strong independence,high extensibility,strong flexibility,and high running rate.
2006, 34(4):490-493.
Abstract:
A program is developed to draw the isolines of meteorological element fields automatically by connecting discrete points into irregular triangle grids that conform to Delaunay features. The resulting isolines conform to the principles of isoline drawing by hand. The meteorological fields of Shandong Province and the sea surface temperature field of the North Pacific are drawn by the program, which include coastlines and color-filled areas. Through a user-defined coordinate system, it can switch between screen and actual coordinates and realize map projection, etc. The program has good drawing capability, can draw vector graphics, insert and revise the graphics, and set up the display order and Alpha mixing-transparence display. The graphics achieved the vector zoom without grades.
A program is developed to draw the isolines of meteorological element fields automatically by connecting discrete points into irregular triangle grids that conform to Delaunay features. The resulting isolines conform to the principles of isoline drawing by hand. The meteorological fields of Shandong Province and the sea surface temperature field of the North Pacific are drawn by the program, which include coastlines and color-filled areas. Through a user-defined coordinate system, it can switch between screen and actual coordinates and realize map projection, etc. The program has good drawing capability, can draw vector graphics, insert and revise the graphics, and set up the display order and Alpha mixing-transparence display. The graphics achieved the vector zoom without grades.
2006, 34(4):494-497.
Abstract:
It is very important to develop computerized surface meteorological data examination technology for improving data quality and data processing efficiency.The ordination analysis technique of cloud records is one of key difficulties in surface meteorological observation data examination.A classification analysis method is introduced,which divides the cloud records into several types according to various collocations of total cloudiness,low cloudiness,and clouds forms,and for each type,the analysis is made respectively according to various circumstances.In the analysis,the cloud symbols of 29 types are projected into the two-word(32 bits) variables,which makes the analyzing procedure simple and clear.As a test,the software has been applied in the artificial examination of surface meteorological observational data in Zhejiang Province.It has been proven that this method is very useful in improving the cloud observation data examination quality.
It is very important to develop computerized surface meteorological data examination technology for improving data quality and data processing efficiency.The ordination analysis technique of cloud records is one of key difficulties in surface meteorological observation data examination.A classification analysis method is introduced,which divides the cloud records into several types according to various collocations of total cloudiness,low cloudiness,and clouds forms,and for each type,the analysis is made respectively according to various circumstances.In the analysis,the cloud symbols of 29 types are projected into the two-word(32 bits) variables,which makes the analyzing procedure simple and clear.As a test,the software has been applied in the artificial examination of surface meteorological observational data in Zhejiang Province.It has been proven that this method is very useful in improving the cloud observation data examination quality.
2006, 34(4):498-500.
Abstract:
The LAN(Local Area Network) failures can be divided into common and rare faults.For common breakdowns,the detection procedures usually include such techniques as object check,sectionalized check,and one-by-one eliminating.The rare faults are usually complex and irregular.To deal with the rare faults,it is usually necesarry to combine various techniques together to identify fault sources,such as theoretical analysis,empirical judgement,screen suggestions,etc.
The LAN(Local Area Network) failures can be divided into common and rare faults.For common breakdowns,the detection procedures usually include such techniques as object check,sectionalized check,and one-by-one eliminating.The rare faults are usually complex and irregular.To deal with the rare faults,it is usually necesarry to combine various techniques together to identify fault sources,such as theoretical analysis,empirical judgement,screen suggestions,etc.
2006, 34(4):501-504.
Abstract:
In order to improve soil moisture and drought monitoring with remote sensing technology, on the basis of commonly used methods and soil thermodynamics, a new way of drought monitoring with EOS/MODIS data, the energy index method, is proposed. The outcome of application shows that the method performs well in soil moisture and drought monitoring, obviously superior to presently used methods. It is pointed out that drought prewarning should be base on soil moisture and remote-sensing drought monitoring measurements, as well as precipitation and temperature forecasts, which need to be converted into the corrected soil moisture and added into the resulting drought level according to the related standards.
In order to improve soil moisture and drought monitoring with remote sensing technology, on the basis of commonly used methods and soil thermodynamics, a new way of drought monitoring with EOS/MODIS data, the energy index method, is proposed. The outcome of application shows that the method performs well in soil moisture and drought monitoring, obviously superior to presently used methods. It is pointed out that drought prewarning should be base on soil moisture and remote-sensing drought monitoring measurements, as well as precipitation and temperature forecasts, which need to be converted into the corrected soil moisture and added into the resulting drought level according to the related standards.
2006, 34(4):505-508.
Abstract:
It is essential to understand the structure and content of HDF-EOS data,as well as the calculation method of physical quantities,for applications of MODIS.The HDF-EOS is developed by NASA to manage and distribute EOS data,being set up as the standards of EOS data and information systems.MODIS 1B products adopt the HDF-EOS format,including the calibrated data with the resolutions being 250 m,500 m and 1000 m,as well as the data from onboard calibrators and other data.There are 36 channels in daytime and 17 channels in nighttime.The detection signals are compressed to a scale into 16-bits integers,and the reflectance and radiance can be calculated by the scales and the offsets.
It is essential to understand the structure and content of HDF-EOS data,as well as the calculation method of physical quantities,for applications of MODIS.The HDF-EOS is developed by NASA to manage and distribute EOS data,being set up as the standards of EOS data and information systems.MODIS 1B products adopt the HDF-EOS format,including the calibrated data with the resolutions being 250 m,500 m and 1000 m,as well as the data from onboard calibrators and other data.There are 36 channels in daytime and 17 channels in nighttime.The detection signals are compressed to a scale into 16-bits integers,and the reflectance and radiance can be calculated by the scales and the offsets.
2006, 34(4):509-512.
Abstract:
To meet the needs of meteorological operation,especially for weather modification,a radar echo positioning system is developed,which can locate radar echoes by means of the radar images from the Internet,including the azimuth angle,height above sea level and distance relative to radar station,and locating elevation,azimuth angle and distance that the echo relative to operation station.The system can provide more exact information for weather modification operation to reduce blindness and increase efficiency in operation.The system adopts Visual C~(++) in programming and has a user-friendly,visualized and convenient interface and good practicability.
To meet the needs of meteorological operation,especially for weather modification,a radar echo positioning system is developed,which can locate radar echoes by means of the radar images from the Internet,including the azimuth angle,height above sea level and distance relative to radar station,and locating elevation,azimuth angle and distance that the echo relative to operation station.The system can provide more exact information for weather modification operation to reduce blindness and increase efficiency in operation.The system adopts Visual C~(++) in programming and has a user-friendly,visualized and convenient interface and good practicability.
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.