Volume 32,Issue 6,2004 Table of Contents
2004, 32(6):385-392.
Abstract:
Since the 1980s, theoretical and applied artificial neural network researches have developed rapidly and gained great achievements in many fields. The main developmental courses of theoretical and applied researches in artificial neural network both at home and abroad in China are described. Emphases are put on the application of artificial neural network in many fields, such as mid-term and short-term weather forecasting, short-term climate prediction, agrometeorology, air pollution forecasting, recognition of satellite cloud images, meteorological observation data processing, and so on. Descriptions are further made on the recent researches on the key technology of modeling researches in weather forecasting using artificial neural network: over-fitting, network structure, fuzzy neural network (the combination of fuzzy system with neural network), and the weather forecast modeling of combining Genetic Algorithms with neural network.
Since the 1980s, theoretical and applied artificial neural network researches have developed rapidly and gained great achievements in many fields. The main developmental courses of theoretical and applied researches in artificial neural network both at home and abroad in China are described. Emphases are put on the application of artificial neural network in many fields, such as mid-term and short-term weather forecasting, short-term climate prediction, agrometeorology, air pollution forecasting, recognition of satellite cloud images, meteorological observation data processing, and so on. Descriptions are further made on the recent researches on the key technology of modeling researches in weather forecasting using artificial neural network: over-fitting, network structure, fuzzy neural network (the combination of fuzzy system with neural network), and the weather forecast modeling of combining Genetic Algorithms with neural network.
2004, 32(6):393-398.
Abstract:
A simple cost-loss ratio decision model is used to illustrate the relationship between the skill of a weather forecasting system and its economic value. Using the ECMWF ensemble forecasting system as an example, a deterministic forecast case and a probability forecast case are discussed, respectively. The comparative analysis of the relative economic value curve of EPS probability and deterministic forecasts of the ensemble forecasting system shows that the probability forecasting system is obviously superior to a deterministic forecast system with the same quality in value. The results indicate that for a forecacting syctem,it is useful for users only in the case of the cost-loss ratio C/L being in a certain range. It is very important for realizing the maximum forecast value to choose the optimal probability threshold value based on C/L.
A simple cost-loss ratio decision model is used to illustrate the relationship between the skill of a weather forecasting system and its economic value. Using the ECMWF ensemble forecasting system as an example, a deterministic forecast case and a probability forecast case are discussed, respectively. The comparative analysis of the relative economic value curve of EPS probability and deterministic forecasts of the ensemble forecasting system shows that the probability forecasting system is obviously superior to a deterministic forecast system with the same quality in value. The results indicate that for a forecacting syctem,it is useful for users only in the case of the cost-loss ratio C/L being in a certain range. It is very important for realizing the maximum forecast value to choose the optimal probability threshold value based on C/L.
2004, 32(6):399-403.
Abstract:
The opportunity and challenges induced by the development of bridge building facing the special meteorological researches and service are probed. The necessity and the main content of the special meteorological research and service are discussed based on our researches and practice in the aspects of climate background and meteorological parameter researches around bridge construction sites, methods of bridge meteorological researches, and meteorological service and support during construction and operation. A meteorological environmental monitoring and warning system, which has been applied during the construction period of some bridges, was described.
The opportunity and challenges induced by the development of bridge building facing the special meteorological researches and service are probed. The necessity and the main content of the special meteorological research and service are discussed based on our researches and practice in the aspects of climate background and meteorological parameter researches around bridge construction sites, methods of bridge meteorological researches, and meteorological service and support during construction and operation. A meteorological environmental monitoring and warning system, which has been applied during the construction period of some bridges, was described.
2004, 32(6):404-409.
Abstract:
Urban heavy smog is a serious environmental problem. Based on the field observation in Beijing from November 1 to December 20 of 1999, differences between heavy smog and fog are analyzed, and the structures of the atmospheric boundary layer for heavy smog and fog are discussed. Some results are founded. For example, heavy smog and fog can be distinguished from visibility, relative humidity and long-wave radiation equilibrium. The differences of heavy smog and fog in physical and chemic natures induce the boundary layer profile differences in relative moisture, inversion layer, wind speed, vapor, etc.
Urban heavy smog is a serious environmental problem. Based on the field observation in Beijing from November 1 to December 20 of 1999, differences between heavy smog and fog are analyzed, and the structures of the atmospheric boundary layer for heavy smog and fog are discussed. Some results are founded. For example, heavy smog and fog can be distinguished from visibility, relative humidity and long-wave radiation equilibrium. The differences of heavy smog and fog in physical and chemic natures induce the boundary layer profile differences in relative moisture, inversion layer, wind speed, vapor, etc.
2004, 32(6):410-413.
Abstract:
The classified statistic model of urban ambient air quality forecasting was established by means of pollutant concentration data from June 2000 to December 2002 in Shanghai, and its forecast capability was tested by 1-year (2003) data. Variance analysis was selected to classify the samples, empirically taking season, surface wind direction and precipitation as 3 indicators: winter-half-year and summer-half-year sub-samples (season), west wind and non-west wind sub-samples (wind direction), and rainfall and non-rainfall sub-samples (precipitation). After the 3-layer classification, the whole sample was divided into 18 sub-samples. The high and low concentration sections of the sample classification are practically in accordance with the season, surface wind direction and precipitation distributions of pollutant concentrations. Finally the classified sub-samples were processed to establish a set of forecasting models by the linear successive regression technique. In the capability testing, the classified statistic model has proved feasible in the urban ambient air quality forecasting with higher prediction accuracy compared to the total sample statistic model.
The classified statistic model of urban ambient air quality forecasting was established by means of pollutant concentration data from June 2000 to December 2002 in Shanghai, and its forecast capability was tested by 1-year (2003) data. Variance analysis was selected to classify the samples, empirically taking season, surface wind direction and precipitation as 3 indicators: winter-half-year and summer-half-year sub-samples (season), west wind and non-west wind sub-samples (wind direction), and rainfall and non-rainfall sub-samples (precipitation). After the 3-layer classification, the whole sample was divided into 18 sub-samples. The high and low concentration sections of the sample classification are practically in accordance with the season, surface wind direction and precipitation distributions of pollutant concentrations. Finally the classified sub-samples were processed to establish a set of forecasting models by the linear successive regression technique. In the capability testing, the classified statistic model has proved feasible in the urban ambient air quality forecasting with higher prediction accuracy compared to the total sample statistic model.
2004, 32(6):414-416424.
Abstract:
A contrast analysis of CAPPS1 and CAPPS2 prediction models for Guang Xi air quality was conducted, including their pollutant diffusion theories, weather forecasting models, operating systems, run time, and valid time. It is concluded that both CAPPS1 and CAPPS2 models have a correlation coefficient of over 0 44 for all kinds of pollutants, and both models are applicable to air quality forecasts in Guang Xi and have the best prediction precision on SO 2, the second on NO 2 , while PM10 prediction is relatively worse. CAPPS2 has higher correlation coefficients for all pollutants than CAPPS1 with the highest on NO 2. In contrast to CAPPS1, CAPPS2 has higher prediction precision on NO 2 and PM10 and lower prediction precision on SO 2. The prediction precision of CAPPS2 on chief pollutant is 11 percent higher than those of CAPPS1, and 9 percent higher for grade prediction.
A contrast analysis of CAPPS1 and CAPPS2 prediction models for Guang Xi air quality was conducted, including their pollutant diffusion theories, weather forecasting models, operating systems, run time, and valid time. It is concluded that both CAPPS1 and CAPPS2 models have a correlation coefficient of over 0 44 for all kinds of pollutants, and both models are applicable to air quality forecasts in Guang Xi and have the best prediction precision on SO 2, the second on NO 2 , while PM10 prediction is relatively worse. CAPPS2 has higher correlation coefficients for all pollutants than CAPPS1 with the highest on NO 2. In contrast to CAPPS1, CAPPS2 has higher prediction precision on NO 2 and PM10 and lower prediction precision on SO 2. The prediction precision of CAPPS2 on chief pollutant is 11 percent higher than those of CAPPS1, and 9 percent higher for grade prediction.
2004, 32(6):417-419.
Abstract:
Based on the air pollution data provided by the Wuhan Environment Monitoring Station and the conventional meteorological data in recent two years, the characteristics of air quality and the causes of air pollution in Wuhan were analyzed by means of dynamic statistical and synoptic analyses. The results show that air quality in Wuhan is good in summer and relatively bad in autumn and winter, and air quality is closely related with the distribution characteristics of meteorological factors in different seasons in Wuhan.
Based on the air pollution data provided by the Wuhan Environment Monitoring Station and the conventional meteorological data in recent two years, the characteristics of air quality and the causes of air pollution in Wuhan were analyzed by means of dynamic statistical and synoptic analyses. The results show that air quality in Wuhan is good in summer and relatively bad in autumn and winter, and air quality is closely related with the distribution characteristics of meteorological factors in different seasons in Wuhan.
2004, 32(6):420-424.
Abstract:
From April 30 to May 5, 2001, Beijing experienced a continuous floating dust and heavy air pollution event. The main causes and the weather situation of the event are analyzed. The results show that a cold vortex at the upper level developed while moving eastward and a cold front on the surface moved across the dry and loose areas in the southern Mongolia and North China, thus resulted in the blowing dust or sand-dust storm. A large amount of fine dust particles moved to Beijing with the upper-level westerly flow and then floating dusts formed over Beijing. At the same time, Beijing was located at the convergence zone and had a stable stratification, small wind speed and frequent inversions in the weather charts. These were unfavorable to the local dust particle and pollutant diffusion; therefore, dust particles were gradually cumulated and heavy air pollution occurred.
From April 30 to May 5, 2001, Beijing experienced a continuous floating dust and heavy air pollution event. The main causes and the weather situation of the event are analyzed. The results show that a cold vortex at the upper level developed while moving eastward and a cold front on the surface moved across the dry and loose areas in the southern Mongolia and North China, thus resulted in the blowing dust or sand-dust storm. A large amount of fine dust particles moved to Beijing with the upper-level westerly flow and then floating dusts formed over Beijing. At the same time, Beijing was located at the convergence zone and had a stable stratification, small wind speed and frequent inversions in the weather charts. These were unfavorable to the local dust particle and pollutant diffusion; therefore, dust particles were gradually cumulated and heavy air pollution occurred.
9 Review of Researches on Relationship of Meteorological Factors and Cardiovascular Diseases in China
2004, 32(6):425-428437.
Abstract:
To provide the information for further researches, a review is given on researches on the relationship between meteorological factors and cardiovascular and cerebrovascular diseases in China since 1998. These studies show that meteorological factors, such as temperature, relative humidity, air pressure, wind speed, etc., affect, more or less, the mortality and morbidity of cardiovascular and cerebrovascular diseases. Limitations and problems existed in the past researches and developmental trends are discussed. It is pointed out that new research and prediction methods for the mortality and morbidity of cardiovascular and cerebrovascular diseases are needed in the further studies.
To provide the information for further researches, a review is given on researches on the relationship between meteorological factors and cardiovascular and cerebrovascular diseases in China since 1998. These studies show that meteorological factors, such as temperature, relative humidity, air pressure, wind speed, etc., affect, more or less, the mortality and morbidity of cardiovascular and cerebrovascular diseases. Limitations and problems existed in the past researches and developmental trends are discussed. It is pointed out that new research and prediction methods for the mortality and morbidity of cardiovascular and cerebrovascular diseases are needed in the further studies.
2004, 32(6):429-432.
Abstract:
To study the impacts of weather processes on various diseases, a diseases investigation in two community hospitals were conducted in combination with eight different weather processes in 2002 and 2003. Results indicate that cold and fogy weather events have the greatest influence on human health;for the human group of sixty or over, the influence of weather, such as cold, severe convective, muggy and heavy snowing weather, is greater on men than on women;the elderly people of sixty or over is the most sensitive group to special weather. It is concluded that cardiovascular patients should be very careful in heavy fogy, muggy and cold weather, and hypertension patients should pay attention to low-pressure weather, especially in snowy days in winter.
To study the impacts of weather processes on various diseases, a diseases investigation in two community hospitals were conducted in combination with eight different weather processes in 2002 and 2003. Results indicate that cold and fogy weather events have the greatest influence on human health;for the human group of sixty or over, the influence of weather, such as cold, severe convective, muggy and heavy snowing weather, is greater on men than on women;the elderly people of sixty or over is the most sensitive group to special weather. It is concluded that cardiovascular patients should be very careful in heavy fogy, muggy and cold weather, and hypertension patients should pay attention to low-pressure weather, especially in snowy days in winter.
2004, 32(6):433-437.
Abstract:
After carefully analyzing of high temperature in July from 11 stations in Shanghai in the past 10 years, it is founded: (1) July 2003 is the hottest in recent 30 years with the maximum temperatures breaking the 30-years record both in urban and rural areas but the Intensity of Heat Island Effect (IHIE) was not the highest compared with the records of the past 30 years. (2) The suburban average maximum temperature changed slightly in the past 10 years while the average maximum temperature in the urban area went up distinctly. It indicates that the heat island effect resulted from environment exchanges is the main cause of the recent urban temperature increase. (3) The inter-annual variation of IHIE has a rapid period and a smooth period, which was caused by various human activities. The change of IHIE has a positive correlation with the regional temperature fluctuation. (4) IHIE in Shanghai will still increase slowly in the coming years, but if the Shanghai Municipal Government has a reasonable city development plan, the temperature increase will be slow down gradually, and IHIE in Shanghai will become stable finally.
After carefully analyzing of high temperature in July from 11 stations in Shanghai in the past 10 years, it is founded: (1) July 2003 is the hottest in recent 30 years with the maximum temperatures breaking the 30-years record both in urban and rural areas but the Intensity of Heat Island Effect (IHIE) was not the highest compared with the records of the past 30 years. (2) The suburban average maximum temperature changed slightly in the past 10 years while the average maximum temperature in the urban area went up distinctly. It indicates that the heat island effect resulted from environment exchanges is the main cause of the recent urban temperature increase. (3) The inter-annual variation of IHIE has a rapid period and a smooth period, which was caused by various human activities. The change of IHIE has a positive correlation with the regional temperature fluctuation. (4) IHIE in Shanghai will still increase slowly in the coming years, but if the Shanghai Municipal Government has a reasonable city development plan, the temperature increase will be slow down gradually, and IHIE in Shanghai will become stable finally.
2004, 32(6):438-443.
Abstract:
用哈尔滨市1951～2003年日平均气温资料，从气候角度阐述了哈尔滨市冬季采暖开、闭炉日期的意义，分析了日平均气温稳定通过5℃初、终日和采暖期平均气温的变化特征，结果表明：日平均气温稳定大于等于5℃终、初日分别与采暖期平均气温有显著的正、负相关关系；随着采暖期平均气温逐渐升高，日平均气温稳定大于等于5℃终日逐渐拖后，初日逐渐提前；采暖期平均气温和日平均气温稳定大于等于5℃终、初日均存在突变现象。有必要改变以往的采暖模式，根据采暖期气温进行采暖能源调控。利用均生函数模型对2004～2006年日平均气温稳定大于等于5℃终、初日和采暖开、闭炉日期进行了预测试验。
用哈尔滨市1951～2003年日平均气温资料，从气候角度阐述了哈尔滨市冬季采暖开、闭炉日期的意义，分析了日平均气温稳定通过5℃初、终日和采暖期平均气温的变化特征，结果表明：日平均气温稳定大于等于5℃终、初日分别与采暖期平均气温有显著的正、负相关关系；随着采暖期平均气温逐渐升高，日平均气温稳定大于等于5℃终日逐渐拖后，初日逐渐提前；采暖期平均气温和日平均气温稳定大于等于5℃终、初日均存在突变现象。有必要改变以往的采暖模式，根据采暖期气温进行采暖能源调控。利用均生函数模型对2004～2006年日平均气温稳定大于等于5℃终、初日和采暖开、闭炉日期进行了预测试验。
2004, 32(6):444-449.
Abstract:
分析了兰州1932～2002年年平均气温、年平均最高和最低气温及年平均气温日较差的气候变化特征。分析表明：1932年以来，4个气温要素的线性增温率依次为每10年0．14℃、0．06℃、0．38℃、-0．32℃。兰州20世纪40年代最高气温对增暖的贡献大，80年代最低气温对增暖的贡献大，而90年代的异常偏暖表现为最高和最低气温的同时上升。另外，在40年代各季平均最高和最低气温均呈相反的趋势，表现为最高气温的上升和最低气温的下降；在1950～1970年间最高和最低气温的变化趋势和幅度非常接近，但维持时间各季略有不同；80年代以来，最低和最高气温均在上升，但最低气温的增温率明显高于最高气温的增温率。
分析了兰州1932～2002年年平均气温、年平均最高和最低气温及年平均气温日较差的气候变化特征。分析表明：1932年以来，4个气温要素的线性增温率依次为每10年0．14℃、0．06℃、0．38℃、-0．32℃。兰州20世纪40年代最高气温对增暖的贡献大，80年代最低气温对增暖的贡献大，而90年代的异常偏暖表现为最高和最低气温的同时上升。另外，在40年代各季平均最高和最低气温均呈相反的趋势，表现为最高气温的上升和最低气温的下降；在1950～1970年间最高和最低气温的变化趋势和幅度非常接近，但维持时间各季略有不同；80年代以来，最低和最高气温均在上升，但最低气温的增温率明显高于最高气温的增温率。
2004, 32(6):450-455.
Abstract:
Fog field observation data during December 2002 and historic data from 1951 to 2002 in the Shapingba district of Chongqing were analyzed, and major characteristics of fog were described. The occurrence frequency of heavy fogs has a decreasing trend. Heavy fogs in the downtown area are the mixture of natural fog, smoke and dust, and the river valley and urban effects densify fogs. The PBL characteristics associated with heavy fogs are the temperature inversion, humidity increase and temperature decrease in the near-surface layer. The net radiation effect of high-concentration aerosol prevents the daytime mixing layer from developing, leading to the stabilization of PBL. It is the main reason for heavy fogs to last several days in the Chongqing downtown area. Heavy fogs play a role of wet deposition, cleaning the air to a certain degree. It is suggested that the total emission of pollutants should be controlled during heavy fog days to avoid the occurrence of heavy pollution events.
Fog field observation data during December 2002 and historic data from 1951 to 2002 in the Shapingba district of Chongqing were analyzed, and major characteristics of fog were described. The occurrence frequency of heavy fogs has a decreasing trend. Heavy fogs in the downtown area are the mixture of natural fog, smoke and dust, and the river valley and urban effects densify fogs. The PBL characteristics associated with heavy fogs are the temperature inversion, humidity increase and temperature decrease in the near-surface layer. The net radiation effect of high-concentration aerosol prevents the daytime mixing layer from developing, leading to the stabilization of PBL. It is the main reason for heavy fogs to last several days in the Chongqing downtown area. Heavy fogs play a role of wet deposition, cleaning the air to a certain degree. It is suggested that the total emission of pollutants should be controlled during heavy fog days to avoid the occurrence of heavy pollution events.
2004, 32(6):456-460.
Abstract:
利用气象常规资料，对天津机场地区1979～2002年出现的3次冻雨天气进行对比分析，找出了冻雨发生的天气形势特点和大气垂直结构特征：地面受低压控制，高空处在槽前，有明显的增温现象，槽前西南暖湿气流强盛，存在低空急流；850hPa到地面存在逆温层；700～500hPa之间有冰晶层，冰晶层内的温度为-10～-14℃：850hPa附近为暖层，暖层底部的高度在1．0～2．0km左右，暖层的厚度大约为1．0～2．0km，暖层内的温度大约为0～2℃；从地面到1．0～2．0km的高度存在冷层，冷层内温度大约为0～-2℃。以2002年12月13～14日的冻雨天气为代表个例，利用客观分析产品进行诊断分析，总结出冻雨天气预报的着眼点，为冻雨天气预报提供参考。
利用气象常规资料，对天津机场地区1979～2002年出现的3次冻雨天气进行对比分析，找出了冻雨发生的天气形势特点和大气垂直结构特征：地面受低压控制，高空处在槽前，有明显的增温现象，槽前西南暖湿气流强盛，存在低空急流；850hPa到地面存在逆温层；700～500hPa之间有冰晶层，冰晶层内的温度为-10～-14℃：850hPa附近为暖层，暖层底部的高度在1．0～2．0km左右，暖层的厚度大约为1．0～2．0km，暖层内的温度大约为0～2℃；从地面到1．0～2．0km的高度存在冷层，冷层内温度大约为0～-2℃。以2002年12月13～14日的冻雨天气为代表个例，利用客观分析产品进行诊断分析，总结出冻雨天气预报的着眼点，为冻雨天气预报提供参考。
2004, 32(6):461-466.
Abstract:
Based the classification of fogs in Chongqing, the circulation patterns, streamline field features and the vertical circulation structures during several typical radiation and water fog events were analyzed by using of a composite method. The formation causes of the two types of fogs were studied. Radiation fogs may form under the background of longitudinal circulation with the main influencing system being the high-pressure ridge over Middle Asia. In the longitudinal vertical circulation cross-section, there existed a well-developed and deasil vertical longitudinal circulation in the middle troposphere on the east side of the Tibet Plateau. The descending currents in the front forced an anticlockwises vertical circulation over the Sichuan basin along the topographical sloping fields, which strengthened the low-level downdraft around Chongqing. The nighttime radiation cooling was obvious and there occurred temperature inversion around the ground with the air stratification being stable. Water fogs may form under the condition of relatively weak longitudinal circulation over the Asia region. The Tibetan Plateau low-pressure trough and the surface cold front were the main influencing systems. The vertical circulation cross-section shows that the eastward moving upper low-pressure trough led to an anticlockwises vertical circulation. The updraft on the east side of the circulation was coupled with the updraft of the deasil longitudinal vertical circulation, which was produced by the weak surface cold air over the Sichuan basin. Thus the updraft around Chongqing was strengthened; surface warm and moist air was relatively active; and the obvious humidity increasing process played an important role in water fog forming.
Based the classification of fogs in Chongqing, the circulation patterns, streamline field features and the vertical circulation structures during several typical radiation and water fog events were analyzed by using of a composite method. The formation causes of the two types of fogs were studied. Radiation fogs may form under the background of longitudinal circulation with the main influencing system being the high-pressure ridge over Middle Asia. In the longitudinal vertical circulation cross-section, there existed a well-developed and deasil vertical longitudinal circulation in the middle troposphere on the east side of the Tibet Plateau. The descending currents in the front forced an anticlockwises vertical circulation over the Sichuan basin along the topographical sloping fields, which strengthened the low-level downdraft around Chongqing. The nighttime radiation cooling was obvious and there occurred temperature inversion around the ground with the air stratification being stable. Water fogs may form under the condition of relatively weak longitudinal circulation over the Asia region. The Tibetan Plateau low-pressure trough and the surface cold front were the main influencing systems. The vertical circulation cross-section shows that the eastward moving upper low-pressure trough led to an anticlockwises vertical circulation. The updraft on the east side of the circulation was coupled with the updraft of the deasil longitudinal vertical circulation, which was produced by the weak surface cold air over the Sichuan basin. Thus the updraft around Chongqing was strengthened; surface warm and moist air was relatively active; and the obvious humidity increasing process played an important role in water fog forming.
2004, 32(6):467-470.
Abstract:
A 24-hour high wind objective forecast method over the Yellow and Bohai Seas was devised through calculating analogous coefficients to identify similar weather patterns, using surface air-pressure as the index, based on the data from MICAPS. A database containing 109 historical high wind events was established. The results of the experiment indicate that the forecasting error is below 20%, which meets the criteria for operational forecasts. The analogous method has the advantagement of being independent of data from foreign countries and being simple and quick in calculation. Therefore, the method can not only complement the daily operational service, but also, more importantly, be used as a weather forecasting method in the case of war and other emergency situations.
A 24-hour high wind objective forecast method over the Yellow and Bohai Seas was devised through calculating analogous coefficients to identify similar weather patterns, using surface air-pressure as the index, based on the data from MICAPS. A database containing 109 historical high wind events was established. The results of the experiment indicate that the forecasting error is below 20%, which meets the criteria for operational forecasts. The analogous method has the advantagement of being independent of data from foreign countries and being simple and quick in calculation. Therefore, the method can not only complement the daily operational service, but also, more importantly, be used as a weather forecasting method in the case of war and other emergency situations.
2004, 32(6):471-474.
Abstract:
The temporal and spatial variations of daily range of temperature were analyzed by using conventional data. The results show that there was a tendency of year-to-year decrease in daily range of temperature; daily ranges of temperature in summer and autumn were greater than those in winter and spring; the type of the underlying surface has great impact on daily range of temperature. Several case studies of obvious daily range of temperature were conducted, and the main influencing synoptic systems were the cold high, cold front, warm depress and subtropic high.
The temporal and spatial variations of daily range of temperature were analyzed by using conventional data. The results show that there was a tendency of year-to-year decrease in daily range of temperature; daily ranges of temperature in summer and autumn were greater than those in winter and spring; the type of the underlying surface has great impact on daily range of temperature. Several case studies of obvious daily range of temperature were conducted, and the main influencing synoptic systems were the cold high, cold front, warm depress and subtropic high.
2004, 32(6):475-478.
Abstract:
The inter-annual and inter-decadal periodic change and abrupt change characteristics of Qiqihar's temperature variation were analyzed by means of the Morlet wavelet transforming method and the month-to-month mean temperature anomaly data from 1991 to 2002, and the main regularities of temperature variation were discussed. It is found that there were inter-annual periodic variations of quasi-biennial, 4 to 6 years, and 8 years, and inter-decadal periodic variations of 40 to 60 years, as well as abrupt changes, in Qiqihar in recent 100 years; the temperature variation in Qiqihar was the composite result of multi-scale periodic fluctuations. The conclusions can be used as references in short-term climate forecasting in Qiqihar.
The inter-annual and inter-decadal periodic change and abrupt change characteristics of Qiqihar's temperature variation were analyzed by means of the Morlet wavelet transforming method and the month-to-month mean temperature anomaly data from 1991 to 2002, and the main regularities of temperature variation were discussed. It is found that there were inter-annual periodic variations of quasi-biennial, 4 to 6 years, and 8 years, and inter-decadal periodic variations of 40 to 60 years, as well as abrupt changes, in Qiqihar in recent 100 years; the temperature variation in Qiqihar was the composite result of multi-scale periodic fluctuations. The conclusions can be used as references in short-term climate forecasting in Qiqihar.
2004, 32(6):479-481.
Abstract:
用营口市所管辖3个站1981～2000年的日最高气温资料，查找大于等于33℃高温个例，统计分析了高温当日的气象要素特征；根据近20年历史天气图等资料，系统总结了营口市高温的天气气候特征和高温出现的高空、低空及地面形势场特征。运用经验性预报方法，提取预报指标；结合各种数值预报产品，进行逐条检验是否符合条件，最后建立经验性预报模式。建立的大于等于33℃高温的预报方法，经近几年的检验，能够比较好地预测夏季高温天气。
用营口市所管辖3个站1981～2000年的日最高气温资料，查找大于等于33℃高温个例，统计分析了高温当日的气象要素特征；根据近20年历史天气图等资料，系统总结了营口市高温的天气气候特征和高温出现的高空、低空及地面形势场特征。运用经验性预报方法，提取预报指标；结合各种数值预报产品，进行逐条检验是否符合条件，最后建立经验性预报模式。建立的大于等于33℃高温的预报方法，经近几年的检验，能够比较好地预测夏季高温天气。
2004, 32(6):482-484.
Abstract:
The statistical relation between precipitation in mid-summer in Tianjin and circulation features over North China in early summer was analyzed. It is shown that when the North China High was stronger in early summer, the precipitation over Tianjin was less than normal in mid-summer, and vice versa. Furthermore, the causes for more-than-normal precipitation in mid-summer in Tianjin before 1980 and less-than-normal precipitation after 1980 were studied preliminarily. Hereby, a short-range climatic prediction method of precipitation in Tianjin by atmospheric circulation in early summer was developed, which performed well in the trial operation from 1998 to 2003.
The statistical relation between precipitation in mid-summer in Tianjin and circulation features over North China in early summer was analyzed. It is shown that when the North China High was stronger in early summer, the precipitation over Tianjin was less than normal in mid-summer, and vice versa. Furthermore, the causes for more-than-normal precipitation in mid-summer in Tianjin before 1980 and less-than-normal precipitation after 1980 were studied preliminarily. Hereby, a short-range climatic prediction method of precipitation in Tianjin by atmospheric circulation in early summer was developed, which performed well in the trial operation from 1998 to 2003.
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Supported by:Beijing E-Tiller Technology Development Co., Ltd.
Supported by:Beijing E-Tiller Technology Development Co., Ltd.