Volume 33,Issue 1,2005 Table of Contents
2005, 33(1):1-6.
Abstract:
Recent progress in researches on tropical cyclone (TC) intensity and structure changes is reviewed. According to the maximum potential intensity (MPI) theory, at the given thermodynamic state of the atmosphere and ocean, there exists MPI. In fact, tropical cyclones' maximum intensity is generally less than that of MPI theory. There are many internal and external dynamic factors to prohibit TC intensification through structure changes. The changes of intensity and structure involve complex different-scale interactions. The recent researches show that the mesoscale processes resulting in TC asymmetry are crucial to the variation of both intensities and structures of TCs, including vortex Rossby waves, spiral rainbands, mesoscale vortices, environmental flow, and boundary layer processes. The external environment flow also influences the intensities and structures of TCs through these mesoscale processes over the eyewalls
Recent progress in researches on tropical cyclone (TC) intensity and structure changes is reviewed. According to the maximum potential intensity (MPI) theory, at the given thermodynamic state of the atmosphere and ocean, there exists MPI. In fact, tropical cyclones' maximum intensity is generally less than that of MPI theory. There are many internal and external dynamic factors to prohibit TC intensification through structure changes. The changes of intensity and structure involve complex different-scale interactions. The recent researches show that the mesoscale processes resulting in TC asymmetry are crucial to the variation of both intensities and structures of TCs, including vortex Rossby waves, spiral rainbands, mesoscale vortices, environmental flow, and boundary layer processes. The external environment flow also influences the intensities and structures of TCs through these mesoscale processes over the eyewalls
2005, 33(1):7.
Abstract:
Helicity denotes the conjunct intensity of rotation and the movement along the rotation, and it is conservative in isentropic fluid. Helicity is the basic physical pattern for the maintenance of atmospheric activities. Boundary layer fluids, turbulences, severe storms and tropical cyclones are highly helical in their structures. Severe storms often occur in highly helical environments. The stability of fluid is closely associated with helicity. High helicity prevents transient energy from leaping to other energy classes, thus has great importance for the maintenance of supercell. Z-helicity is a good indicator of heavy rainfall. The relative helicity of a storm has great importance in the evolution of the storm. The occurrence of a meso-cyclone is highly depended on the value of helicity. The relative helicity of a storm is also a good indicator of hail occurrence. It is difficult for the application of relative storm helicity in predicting storms for the uncertainty of storm velocity. There exists inherent relationship between atmospheric temperature and helicity, and the surface relative helicity can be used to measure the temperature advection caused by geostrophic flow.
Helicity denotes the conjunct intensity of rotation and the movement along the rotation, and it is conservative in isentropic fluid. Helicity is the basic physical pattern for the maintenance of atmospheric activities. Boundary layer fluids, turbulences, severe storms and tropical cyclones are highly helical in their structures. Severe storms often occur in highly helical environments. The stability of fluid is closely associated with helicity. High helicity prevents transient energy from leaping to other energy classes, thus has great importance for the maintenance of supercell. Z-helicity is a good indicator of heavy rainfall. The relative helicity of a storm has great importance in the evolution of the storm. The occurrence of a meso-cyclone is highly depended on the value of helicity. The relative helicity of a storm is also a good indicator of hail occurrence. It is difficult for the application of relative storm helicity in predicting storms for the uncertainty of storm velocity. There exists inherent relationship between atmospheric temperature and helicity, and the surface relative helicity can be used to measure the temperature advection caused by geostrophic flow.
3 Area Rainfall Forecast Method and Its Error Analysis Based on T213 Products and Water-Vapor Budget
2005, 33(1):12-16.
Abstract:
Based on T213 numerical prediction products and the equation of water-vapor budget, the method of predicting rainfall areas and their intensity is introduced. The area rainfall prediction in 6 hours was made. The method was applied in the flood season along the Huaihe River in 2003. The error analysis was made between prediction and observation. The results indicate that the method is useful and reliable.
Based on T213 numerical prediction products and the equation of water-vapor budget, the method of predicting rainfall areas and their intensity is introduced. The area rainfall prediction in 6 hours was made. The method was applied in the flood season along the Huaihe River in 2003. The error analysis was made between prediction and observation. The results indicate that the method is useful and reliable.
2005, 33(1):17-21.
Abstract:
In order to improve the single-station precipitation forecast accuracy, a case study was conducted on a strong precipitation event on 19 July 2003 in Hubei Province. Through diagnostic analysis, the causes of circulation formation were discussed. The results show that it was a typical large-scale heavy rain process resulted from a mid-latitude barocline system, and its formation mechanism can be explained by the quasi-geostrophic theory. For strong precipitation forecast, especially severe heavy rainfall forecasts within or at the edge of the raining area, secondary circulation must be diagnosed and analyzed. Only when the conditions of the secondary circulation are met, heavy rainfall will occur; or else there will be an absent forecast.
In order to improve the single-station precipitation forecast accuracy, a case study was conducted on a strong precipitation event on 19 July 2003 in Hubei Province. Through diagnostic analysis, the causes of circulation formation were discussed. The results show that it was a typical large-scale heavy rain process resulted from a mid-latitude barocline system, and its formation mechanism can be explained by the quasi-geostrophic theory. For strong precipitation forecast, especially severe heavy rainfall forecasts within or at the edge of the raining area, secondary circulation must be diagnosed and analyzed. Only when the conditions of the secondary circulation are met, heavy rainfall will occur; or else there will be an absent forecast.
2005, 33(1):22-24.
Abstract:
The commensurability indicates a certain order existing in natural phenomena. The commensurability (approximate periodicity) is the expansion of periodicity. In order to forecast the occurrence year of a landing typhoon in Zhejiang, a commensurable formula of three elements was used in arrangement and calculation. Thus the commensurable formula for several years in the future can be given, and the occurrence year of a landing typhoon can be judged according to the peak value of frequency of the commensurable formula. The long-term change process of a landing typhoon can be forecasted and analyzed by means of the principle and method of commensurability. The result is relatively good and is of practical significance for typhoon prevention and disaster reduction along the coast regions. Being able to reveal the interrelation of natural phenomena, the method has broad prospects in application.
The commensurability indicates a certain order existing in natural phenomena. The commensurability (approximate periodicity) is the expansion of periodicity. In order to forecast the occurrence year of a landing typhoon in Zhejiang, a commensurable formula of three elements was used in arrangement and calculation. Thus the commensurable formula for several years in the future can be given, and the occurrence year of a landing typhoon can be judged according to the peak value of frequency of the commensurable formula. The long-term change process of a landing typhoon can be forecasted and analyzed by means of the principle and method of commensurability. The result is relatively good and is of practical significance for typhoon prevention and disaster reduction along the coast regions. Being able to reveal the interrelation of natural phenomena, the method has broad prospects in application.
2005, 33(1):25-31.
Abstract:
A dust storm forecasting experiment was conducted with a dust storm integrated forecasting system in the spring of 2002. The system includes a regional atmospheric model, a land-surface model, a wind erosion model, and a dust transport and deposition model. Geographic information data, such as soil type, vegetation height, fractional vegetation cover and leaf-area index, were used in the integrated forecasting system. By means of the numerical products of the integrated forecasting system, two case studies were conducted through analyzing sand flux, dust flux, vertically integrated mass, and so on. The results were compared with surface observation data and satellite images. The test results show that the system is feasible as a dust storm operational model.
A dust storm forecasting experiment was conducted with a dust storm integrated forecasting system in the spring of 2002. The system includes a regional atmospheric model, a land-surface model, a wind erosion model, and a dust transport and deposition model. Geographic information data, such as soil type, vegetation height, fractional vegetation cover and leaf-area index, were used in the integrated forecasting system. By means of the numerical products of the integrated forecasting system, two case studies were conducted through analyzing sand flux, dust flux, vertically integrated mass, and so on. The results were compared with surface observation data and satellite images. The test results show that the system is feasible as a dust storm operational model.
2005, 33(1):32-36.
Abstract:
应用EOF—CCA方法对福建省前汛期(5～6月)降水量场进行试预测，预测因子选取关键区海温场及13项物理量场，降水量场为35个地面气象站降水资料。采用3种方案进行试预测，分别以关键区海温场为因子，13项物理量场为因子，或两者相结合。通过5年的独立样本预测检验表明，3种方案对福建省前汛期降水量场进行短期气候预测均有一定的预报技巧，预报时效最佳的时期是前一年的11、12月分，以关键区海温为因子的预测效果最好，12月份关键区海温结合13项物理量场为因子预测稳定性最好，可用于日常预测业务中。
应用EOF—CCA方法对福建省前汛期(5～6月)降水量场进行试预测，预测因子选取关键区海温场及13项物理量场，降水量场为35个地面气象站降水资料。采用3种方案进行试预测，分别以关键区海温场为因子，13项物理量场为因子，或两者相结合。通过5年的独立样本预测检验表明，3种方案对福建省前汛期降水量场进行短期气候预测均有一定的预报技巧，预报时效最佳的时期是前一年的11、12月分，以关键区海温为因子的预测效果最好，12月份关键区海温结合13项物理量场为因子预测稳定性最好，可用于日常预测业务中。
2005, 33(1):37.
Abstract:
Brief introduction of wavelet analysis and its application in atmospheric science is presented and the periodicity of 41 years (1960 to 2000) in the Chongqing precipitation time series (single station data) was diagnosed by the means of one-dimension Morlet wavelet transformation. The results show that there exists an obvious quasi 18-year period oscillation in Chongqing rainfall and less pronounced periods of 11, 3-5 and 8 years. It is found that the zero points of Morlet wavelet transformation coefficients correspond with the inflexions of the 40-year precipitation variation in Chongqing, and the zero-point positions of the of Morlet wavelet transformation coefficients correspond with the positions of the abrupt change points of the precipitation variation in Chongqing. Either over a large time scale or small scale, for summer and annual precipitation variations, Chongqing was in an obviously more-than-normal period, while for autumn precipitation, in an obviously less-than-normal period.
Brief introduction of wavelet analysis and its application in atmospheric science is presented and the periodicity of 41 years (1960 to 2000) in the Chongqing precipitation time series (single station data) was diagnosed by the means of one-dimension Morlet wavelet transformation. The results show that there exists an obvious quasi 18-year period oscillation in Chongqing rainfall and less pronounced periods of 11, 3-5 and 8 years. It is found that the zero points of Morlet wavelet transformation coefficients correspond with the inflexions of the 40-year precipitation variation in Chongqing, and the zero-point positions of the of Morlet wavelet transformation coefficients correspond with the positions of the abrupt change points of the precipitation variation in Chongqing. Either over a large time scale or small scale, for summer and annual precipitation variations, Chongqing was in an obviously more-than-normal period, while for autumn precipitation, in an obviously less-than-normal period.
2005, 33(1):41-44.
Abstract:
The characteristics of temporal and spatial distribution of hails over Yunnan Province were analyzed by using of the recent 40-year hail data, to reveal the variation regularities of hails and main influencing factors. The analysis shows that the seasonal distribution of hails was very complicated. The peak values usually occurred in spring and summer. The seasonal distribution of hails was related with elevation: generally in springtime hails happened more frequently at lower-elevation areas, and in summertime at high-elevation areas. The inter-annual change of the numbers of hailing days in the western Yunnan was more obvious than in the eastern Yunnan, while the inter-decadal change of hailing-day numbers was more obvious in the eastern Yunnan than in the western Yunnan. The numbers of hailing days in mountainous and high-elevation areas were greater than those in basin or plain areas and lower-elevation areas.
The characteristics of temporal and spatial distribution of hails over Yunnan Province were analyzed by using of the recent 40-year hail data, to reveal the variation regularities of hails and main influencing factors. The analysis shows that the seasonal distribution of hails was very complicated. The peak values usually occurred in spring and summer. The seasonal distribution of hails was related with elevation: generally in springtime hails happened more frequently at lower-elevation areas, and in summertime at high-elevation areas. The inter-annual change of the numbers of hailing days in the western Yunnan was more obvious than in the eastern Yunnan, while the inter-decadal change of hailing-day numbers was more obvious in the eastern Yunnan than in the western Yunnan. The numbers of hailing days in mountainous and high-elevation areas were greater than those in basin or plain areas and lower-elevation areas.
2005, 33(1):45.
Abstract:
By using the analyzed and 6-hour prediction data provided by the T213 model, the causes of a heavy rain and the energy and moisture conditions were analyzed. The dynamic trigger mechanism was studied through analyzing the features of helicity and Q* vectors. The result shows that the heavy rain was influenced mainly by the low vortex at 850 hPa and the surface cyclone; the convergence and ascending motion in the center of the vortex and north of the cyclone center triggered convective instability energy release, resulting in the heavy rain. The low-level Southwest Jet provided sufficient moisture and instability energy. The strong positive helicity and the intensive convergence of Q* vectors at the low level in the raining area indicate that there was superposition of mesoscale and synoptic-scale ascending motions. Differing from summer heavy rains, the systems in the westerly belt played a dominant role in spring heavy rain formation, but the subtropical systems are weaker and cool and warm air motions were very active before and after the heavy rain.
By using the analyzed and 6-hour prediction data provided by the T213 model, the causes of a heavy rain and the energy and moisture conditions were analyzed. The dynamic trigger mechanism was studied through analyzing the features of helicity and Q* vectors. The result shows that the heavy rain was influenced mainly by the low vortex at 850 hPa and the surface cyclone; the convergence and ascending motion in the center of the vortex and north of the cyclone center triggered convective instability energy release, resulting in the heavy rain. The low-level Southwest Jet provided sufficient moisture and instability energy. The strong positive helicity and the intensive convergence of Q* vectors at the low level in the raining area indicate that there was superposition of mesoscale and synoptic-scale ascending motions. Differing from summer heavy rains, the systems in the westerly belt played a dominant role in spring heavy rain formation, but the subtropical systems are weaker and cool and warm air motions were very active before and after the heavy rain.
2005, 33(1):50-52.
Abstract:
Through comparing forecast with observation, a forecasting failure is analyzed. On the basis of the analysis of the numerical forecasts and the meteorology elements, the predicting thoughts of the forecasters then are discussed. It is pointed out that the main physical mechanism inducing the sudden change of the weather system is the southward moving of the northwestly jet over the central Asia at 300 hPa. The changing high-level trough from backward to forward was unfavorable for the upward air motion. With the real time data, the reasons for forecasting failure are analyzed. The unexpected evolvement of the high level trough and the underestimated changing of the low-level path of the cold air as well as the amount of warm air are the main reasons for the forecast failure.
Through comparing forecast with observation, a forecasting failure is analyzed. On the basis of the analysis of the numerical forecasts and the meteorology elements, the predicting thoughts of the forecasters then are discussed. It is pointed out that the main physical mechanism inducing the sudden change of the weather system is the southward moving of the northwestly jet over the central Asia at 300 hPa. The changing high-level trough from backward to forward was unfavorable for the upward air motion. With the real time data, the reasons for forecasting failure are analyzed. The unexpected evolvement of the high level trough and the underestimated changing of the low-level path of the cold air as well as the amount of warm air are the main reasons for the forecast failure.
2005, 33(1):53-57.
Abstract:
通过对河西走廊1971～2000年3～5月大风和沙尘暴个例普查，运用相关法分析了河西走廊大风和沙尘暴天气在时间上的分布差异和沙尘暴与沙源地区前期降水的关系，同时对“起沙风”也作了初步探讨，结果表明：河西走廊地区在10min平均风速大于等于9m／s时，极易起沙；河西走廊的西部、中部、东部分别在南疆中东部、南疆东部内蒙西部河西西部、内蒙中西部出现5～8mm降水后5天才有可能出现沙尘暴。文中给出了河西走廊大风沙尘暴的几种典型环流形势及每一种环流形势可引发沙尘暴的预报着眼点。
通过对河西走廊1971～2000年3～5月大风和沙尘暴个例普查，运用相关法分析了河西走廊大风和沙尘暴天气在时间上的分布差异和沙尘暴与沙源地区前期降水的关系，同时对“起沙风”也作了初步探讨，结果表明：河西走廊地区在10min平均风速大于等于9m／s时，极易起沙；河西走廊的西部、中部、东部分别在南疆中东部、南疆东部内蒙西部河西西部、内蒙中西部出现5～8mm降水后5天才有可能出现沙尘暴。文中给出了河西走廊大风沙尘暴的几种典型环流形势及每一种环流形势可引发沙尘暴的预报着眼点。
2005, 33(1):58-62.
Abstract:
An analysis was made of observed data around the Qinghai Lake from 1961 to 2000, and the results show that the climatic tendencies of the annual and seasonal air temperature and surface evaporation and summer and winter precipitation change were all positive, while the climatic tendencies of spring and autumn precipitation change were negative. The tendencies of temperature rising and surface evaporation increasing were more significant, while the tendency of precipitation increasing was less obvious and its inter-annual change was slightly greater. The meteorological factors such as air temperature and surface evaporation shows the tendency of transiting toward warm and dry, which is the main cause of the falling water level of the Qinghai Lake.
An analysis was made of observed data around the Qinghai Lake from 1961 to 2000, and the results show that the climatic tendencies of the annual and seasonal air temperature and surface evaporation and summer and winter precipitation change were all positive, while the climatic tendencies of spring and autumn precipitation change were negative. The tendencies of temperature rising and surface evaporation increasing were more significant, while the tendency of precipitation increasing was less obvious and its inter-annual change was slightly greater. The meteorological factors such as air temperature and surface evaporation shows the tendency of transiting toward warm and dry, which is the main cause of the falling water level of the Qinghai Lake.
2005, 33(1):63-67.
Abstract:
On the basis of meteorological data from 1965 to 2001 around the Hunshandake sandy land, the characteristics of main climatic factors and their temporal and spatial variation regularities are analyzed. The research results indicate: there are obvious differences in main climatic factors along longitudes and less obvious along latitudes in the Hunshandake sandy land; from 1965 to 2001 in the most parts of the Hunshandake sandy land, the mean annual and seasonal temperatures had an evidently increasing tendency, and the mean annual wind velocity had an evidently decreasing tendency, especially in the spring; in the main part of the sandy land, the changing tendencies of annual and seasonal precipitation were not very clear, while there were slowly increasing tendencies in the annual dry/wet index, and not very clearly decreasing tendencies in annual evaporation.
On the basis of meteorological data from 1965 to 2001 around the Hunshandake sandy land, the characteristics of main climatic factors and their temporal and spatial variation regularities are analyzed. The research results indicate: there are obvious differences in main climatic factors along longitudes and less obvious along latitudes in the Hunshandake sandy land; from 1965 to 2001 in the most parts of the Hunshandake sandy land, the mean annual and seasonal temperatures had an evidently increasing tendency, and the mean annual wind velocity had an evidently decreasing tendency, especially in the spring; in the main part of the sandy land, the changing tendencies of annual and seasonal precipitation were not very clear, while there were slowly increasing tendencies in the annual dry/wet index, and not very clearly decreasing tendencies in annual evaporation.
2005, 33(1):68-72.
Abstract:
Based on winter wheat and summer corn growth regularities in Henan Province and application experiences in optimal irrigation techniques for winter wheat, as well as observed soil moisture data for winter wheat and summer corn from 1994 to 2000, a computer model of soil water prediction and optimal irrigation of winter wheat and summer corn was set up according to the soil water balance equation. The model results were verified by the observed data from wheat fields in Zhengzhou in 1998 and 1999. The relative errors of soil moisture for the next 10, 20, 30 days are -7.3% to 7.7%, -8.3% to 6.8%,-7.6% to 7.7%, respectively. It indicates that soil water can be predicted in one month ahead accurately with this model. Some irrigation suggestions with respect to different wheat and corn growth phases are given, aiming to obtain the maximum yield and the optimal economic benefits.
Based on winter wheat and summer corn growth regularities in Henan Province and application experiences in optimal irrigation techniques for winter wheat, as well as observed soil moisture data for winter wheat and summer corn from 1994 to 2000, a computer model of soil water prediction and optimal irrigation of winter wheat and summer corn was set up according to the soil water balance equation. The model results were verified by the observed data from wheat fields in Zhengzhou in 1998 and 1999. The relative errors of soil moisture for the next 10, 20, 30 days are -7.3% to 7.7%, -8.3% to 6.8%,-7.6% to 7.7%, respectively. It indicates that soil water can be predicted in one month ahead accurately with this model. Some irrigation suggestions with respect to different wheat and corn growth phases are given, aiming to obtain the maximum yield and the optimal economic benefits.
16 Impact of Climate Change and Natural Disasters on Grain Yields in Shandong Province in Past 40 Years
2005, 33(1):73.
Abstract:
根据山东省196l～2000年气象与粮食产量资料，利用统计分析方法，分析了气候变化、农业自然灾害对粮食产量的影响。研究表明：①20世纪60年代以来，山东省气候有变暖和变干的趋势，各季节中，变暖趋势最明显的是冬季，变干表现最突出的是夏季；②气温和降水是造成山东省粮食产量波动的主要原因，在“暖干”气候背景下，气温与气候产量为负相关，降水量与气候产量呈较显著的正相关；③农业自然灾害是造成粮食单产产生波动的主要原因之一。
根据山东省196l～2000年气象与粮食产量资料，利用统计分析方法，分析了气候变化、农业自然灾害对粮食产量的影响。研究表明：①20世纪60年代以来，山东省气候有变暖和变干的趋势，各季节中，变暖趋势最明显的是冬季，变干表现最突出的是夏季；②气温和降水是造成山东省粮食产量波动的主要原因，在“暖干”气候背景下，气温与气候产量为负相关，降水量与气候产量呈较显著的正相关；③农业自然灾害是造成粮食单产产生波动的主要原因之一。
2005, 33(1):77-80.
Abstract:
对2002年红肉脐橙各物候期、落花落果数等观测资料进行了分析，结果表明：红肉脐橙春梢的生长量随积温的增加而增加，生长曲线符合指数规律。生理落花落果时间在4月30日至6月10日之间，着果率1．59％。果实膨大停止并达到商品成熟期为12月中下旬，成熟时间比国内最优脐橙纽荷尔晚30余天，大于等于10℃的积温5685．5℃，降雨量1039．9mm，日照时数1416．9h，丰产性能好。生理落果期平均温度22．6℃，平均相对湿度73％．落果率86．9％；平均温度21．1℃，平均相对湿度82％，落果率96．9％。
对2002年红肉脐橙各物候期、落花落果数等观测资料进行了分析，结果表明：红肉脐橙春梢的生长量随积温的增加而增加，生长曲线符合指数规律。生理落花落果时间在4月30日至6月10日之间，着果率1．59％。果实膨大停止并达到商品成熟期为12月中下旬，成熟时间比国内最优脐橙纽荷尔晚30余天，大于等于10℃的积温5685．5℃，降雨量1039．9mm，日照时数1416．9h，丰产性能好。生理落果期平均温度22．6℃，平均相对湿度73％．落果率86．9％；平均温度21．1℃，平均相对湿度82％，落果率96．9％。
2005, 33(1):81-86.
Abstract:
综合应用NOAA卫星AVHRR／3和FY-1极轨气象卫星高分辨0．58～0．68μm可见光、1．58～1．64μm近红外和10．3～11．3μm红外多通道资料，充分考虑了云的厚度、云中粒子尺度和云顶亮温的信息，给出了适宜飞机增雨作业云层的卫星遥感判据，建立了云层作业条件分析模型。实际应用表明，卫星遥感分析图可以有效地监测、判识和分析云层的增雨作业条件，应用效果好，可作为飞机增雨航线设计、作业决策的重要依据。通过增雨个例的微波图像特征分析，初步分析了AMSU—B微波图像在人工增雨作业中的作用和应用前景。
综合应用NOAA卫星AVHRR／3和FY-1极轨气象卫星高分辨0．58～0．68μm可见光、1．58～1．64μm近红外和10．3～11．3μm红外多通道资料，充分考虑了云的厚度、云中粒子尺度和云顶亮温的信息，给出了适宜飞机增雨作业云层的卫星遥感判据，建立了云层作业条件分析模型。实际应用表明，卫星遥感分析图可以有效地监测、判识和分析云层的增雨作业条件，应用效果好，可作为飞机增雨航线设计、作业决策的重要依据。通过增雨个例的微波图像特征分析，初步分析了AMSU—B微波图像在人工增雨作业中的作用和应用前景。
2005, 33(1):87-90.
Abstract:
统计分析了陕西中北部1991～2001年4个711雷达站附近15个气候观测站日降雨量大于等于5mm降水过程的时空分布及雷达回波特征。陕西中部适宜人工增雨的时段为2月10日至11月15日，北部为2月25日至11月10日。陕西降雨性层状云0℃层高度变化范围为3．63～5．03km，平均高度为4．65km，融化层强回波区厚度为0．4～1．0km。冷云、暖云降雪(雨)量级较小，不适宜大范围开展人工增雪(雨)作业。适宜人工增雨的稳定性层状云雷达回波特征为：PPI回波结构密实，范围大于30km，雷达回波强度大于等于30dBz，RHI显示云顶高度大于等于5．8km或者融化层明显，强度达30dBz以上。适宜人工增雨的混合性层状云雷达回波特征为：PPI有明显强回波中心，强度大于等于30dBz，15dB回波宽度大于等于25km，回波最大高度大于等于5km；或者融化层明显，雷达观测融化层下挂回波明显倾斜或呈锯齿型排列。
统计分析了陕西中北部1991～2001年4个711雷达站附近15个气候观测站日降雨量大于等于5mm降水过程的时空分布及雷达回波特征。陕西中部适宜人工增雨的时段为2月10日至11月15日，北部为2月25日至11月10日。陕西降雨性层状云0℃层高度变化范围为3．63～5．03km，平均高度为4．65km，融化层强回波区厚度为0．4～1．0km。冷云、暖云降雪(雨)量级较小，不适宜大范围开展人工增雪(雨)作业。适宜人工增雨的稳定性层状云雷达回波特征为：PPI回波结构密实，范围大于30km，雷达回波强度大于等于30dBz，RHI显示云顶高度大于等于5．8km或者融化层明显，强度达30dBz以上。适宜人工增雨的混合性层状云雷达回波特征为：PPI有明显强回波中心，强度大于等于30dBz，15dB回波宽度大于等于25km，回波最大高度大于等于5km；或者融化层明显，雷达观测融化层下挂回波明显倾斜或呈锯齿型排列。
2005, 33(1):91-95.
Abstract:
After 15-year study, as the core program of the global change research, IGBP is evolving into the second phase. The advancement of IGBP is described, including the study of key processes in the earth system and the cross-program synthesis study. In future, the research directions of IGBP will change greatly: the synthesis study will be up to a higher level, adapt to the study of the global sustainable development,and realize the conversion from the academic study to practical application and the integration of global problems with the regional problems. Moreover, according to the structure of the earth system, the key issues of relative programs in future and the progress and prospects of IGBP researches in China are discussed.
After 15-year study, as the core program of the global change research, IGBP is evolving into the second phase. The advancement of IGBP is described, including the study of key processes in the earth system and the cross-program synthesis study. In future, the research directions of IGBP will change greatly: the synthesis study will be up to a higher level, adapt to the study of the global sustainable development,and realize the conversion from the academic study to practical application and the integration of global problems with the regional problems. Moreover, according to the structure of the earth system, the key issues of relative programs in future and the progress and prospects of IGBP researches in China are discussed.
2005, 33(1):96.
Abstract:
MTSAT卫星系列是日本运输省和日本气象厅合作投资的多功能(气象观测和飞行控制)卫星。第1颗卫星MTSAT-1在1999年11月发射，但由于火箭故障，星箭具毁，之后重新生产了MTSAT-1R，由于等待火箭的故障排除及改进，发射时间一再推延，直到2005年2月26日才发射，发射成功后约2～3个月播发图像。
MTSAT卫星系列是日本运输省和日本气象厅合作投资的多功能(气象观测和飞行控制)卫星。第1颗卫星MTSAT-1在1999年11月发射，但由于火箭故障，星箭具毁，之后重新生产了MTSAT-1R，由于等待火箭的故障排除及改进，发射时间一再推延，直到2005年2月26日才发射，发射成功后约2～3个月播发图像。
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Supported by:Beijing E-Tiller Technology Development Co., Ltd.