采用美国国家环境预报中心(NCEP)500 h Pa高度场逐日再分析资料,基于计算机客观识别方法,统计了1948~2012年5~8月东北冷涡活动过程。结果表明:共计发生东北冷涡过程956次,平均每年5~8月发生约14.7次;东北冷涡活动共4 129 d,5~8月平均分...采用美国国家环境预报中心(NCEP)500 h Pa高度场逐日再分析资料,基于计算机客观识别方法,统计了1948~2012年5~8月东北冷涡活动过程。结果表明:共计发生东北冷涡过程956次,平均每年5~8月发生约14.7次;东北冷涡活动共4 129 d,5~8月平均分别为14 d、18 d、18 d和14 d,共64 d,占5~8月总天数的52%;5~8月东北冷涡过程以持续3~6 d为主,冷涡活动主要位于121°E^131°E,48°N^53°N区间;5~8月东北冷涡发生频次和活动天数均存在显著增长趋势。7~8月东北冷涡活动异常多年份,贝湖至鄂海阻高与东北冷涡多同时发生,异常少年份,贝湖至鄂海阻高亦不盛行,且阻高先发生冷涡后发生年份占多数。5~6月和7~8月东北冷涡典型特多年高度距平合成场与特少年的主要异常区分布呈反位相,且这种反位相特征在对流层中、高层(200 h Pa、500 h Pa)均呈近半球尺度的波列分布;5~6月和7~8月东北冷涡活动特少年和特多年差值高度场合成分布相近,均呈现显著的南北向"+、-"波列分布(置信度水平≥99%),正负波列分别位于西北太平洋区域和鄂霍次克海至白令海区域,该波列对应高度层风场中的相对位置为气旋和反气旋式环流。展开更多
The cold vortex is a major high impact weather system in northeast China during the warm season, its frequent activities also affect the short-term climate throughout eastern China. How to objectively and quantitative...The cold vortex is a major high impact weather system in northeast China during the warm season, its frequent activities also affect the short-term climate throughout eastern China. How to objectively and quantitatively predict the intensity trend of the cold vortex is an urgent and difficult problem for current short-term climate prediction. Based on the dynamical-statistical combining principle, the predicted results of the Beijing Climate Center＇s global atmosphereocean coupled model and rich historical data are used for dynamic-statistical extra-seasonal prediction testing and actual prediction of the summer 500-hPa geopotential height over the cold vortex activity area. The results show that this method can significantly reduce the model＇s prediction error over the cold vortex activity area, and improve the prediction skills. Furthermore, the results of the sensitivity test reveal that the predicted results are highly dependent on the quantity of similar factors and the number of similar years.展开更多
In this paper we try to extract stable components in the extended-range forecast for the coming 10–30 days by using empirical orthogonal function （EOF） analysis, similarity coefficient, and some other methods based...In this paper we try to extract stable components in the extended-range forecast for the coming 10–30 days by using empirical orthogonal function （EOF） analysis, similarity coefficient, and some other methods based on the National Center for Environmental Prediction （NCEP）/National Center for Atmospheric Research （NCAR） reanalysis daily data. The comparisons of the coefficient of variance of climatological background field and truth data in winter between 2010 and 2011 are made. The method of extracting stable components and climatological background field can be helpful to increase forecasting skill. The forecasting skill improvement of air temperature is better than geopotential height at 500 hPa. Moreover, this method improves the predictability better in the Pacific Ocean. In China, the forecast in winter in Northeast China is more uncertain than in the other parts.展开更多
基于2013年8月中国中东部地区持续高温及其减弱过程,利用美国国家环境预报中心/美国国家大气研究中心逐日平均的500 h Pa高度场、风场再分析资料和美国国家海洋和大气管理局的海温重建扩展资料进行分析,通过前期海温强迫相似年的选取方...基于2013年8月中国中东部地区持续高温及其减弱过程,利用美国国家环境预报中心/美国国家大气研究中心逐日平均的500 h Pa高度场、风场再分析资料和美国国家海洋和大气管理局的海温重建扩展资料进行分析,通过前期海温强迫相似年的选取方法以及带通滤波和经验正交函数分解等方法提取出10—30 d的稳定分量,并通过对稳定分量的诊断分析探究了这次持续高温及其减弱过程的维持机制.研究发现:通过选取与个例前期海温强迫最相似的30年来代替常规的气候态30年(1981—2010年),所提取的气候态稳定分量所占的比重变化不大,稍有减弱,而异常型稳定分量占的比重显著性提高,且其所刻画的影响异常事件的天气系统强度及稳定性明显提高,能够更加清晰地显示延伸期天气过程的维持机制.这表明在提取稳定分量时考虑前期的海温强迫作用是非常有必要的.同时,通过对延伸期稳定分量的分析,表明此次持续高温及减退过程主要受到北极涛动、亚洲大陆中高纬纬向环流形势和西太平洋副热带高压(西太副高)强度、位置的共同影响.展开更多
文摘采用美国国家环境预报中心(NCEP)500 h Pa高度场逐日再分析资料,基于计算机客观识别方法,统计了1948~2012年5~8月东北冷涡活动过程。结果表明:共计发生东北冷涡过程956次,平均每年5~8月发生约14.7次;东北冷涡活动共4 129 d,5~8月平均分别为14 d、18 d、18 d和14 d,共64 d,占5~8月总天数的52%;5~8月东北冷涡过程以持续3~6 d为主,冷涡活动主要位于121°E^131°E,48°N^53°N区间;5~8月东北冷涡发生频次和活动天数均存在显著增长趋势。7~8月东北冷涡活动异常多年份,贝湖至鄂海阻高与东北冷涡多同时发生,异常少年份,贝湖至鄂海阻高亦不盛行,且阻高先发生冷涡后发生年份占多数。5~6月和7~8月东北冷涡典型特多年高度距平合成场与特少年的主要异常区分布呈反位相,且这种反位相特征在对流层中、高层(200 h Pa、500 h Pa)均呈近半球尺度的波列分布;5~6月和7~8月东北冷涡活动特少年和特多年差值高度场合成分布相近,均呈现显著的南北向"+、-"波列分布(置信度水平≥99%),正负波列分别位于西北太平洋区域和鄂霍次克海至白令海区域,该波列对应高度层风场中的相对位置为气旋和反气旋式环流。
基金supported by the National Natural Science Foundation of China(Grant No.41375078)the National Basic Research Program of China(Grant Nos.2012CB955902 and 2013CB430204)the Special Scientific Research Fund of Public Welfare Profession of China(Grant No.GYHY201306021)
文摘The cold vortex is a major high impact weather system in northeast China during the warm season, its frequent activities also affect the short-term climate throughout eastern China. How to objectively and quantitatively predict the intensity trend of the cold vortex is an urgent and difficult problem for current short-term climate prediction. Based on the dynamical-statistical combining principle, the predicted results of the Beijing Climate Center＇s global atmosphereocean coupled model and rich historical data are used for dynamic-statistical extra-seasonal prediction testing and actual prediction of the summer 500-hPa geopotential height over the cold vortex activity area. The results show that this method can significantly reduce the model＇s prediction error over the cold vortex activity area, and improve the prediction skills. Furthermore, the results of the sensitivity test reveal that the predicted results are highly dependent on the quantity of similar factors and the number of similar years.
基金Project supported by the National Basic Research Program of China(Grant No.2013CB430204)the National Natural Science Foundation of China(Grant Nos.40930952 and 41105070)the State Key Development Program for Basic Research of China(Grant No.2012CB955902)
文摘In this paper we try to extract stable components in the extended-range forecast for the coming 10–30 days by using empirical orthogonal function （EOF） analysis, similarity coefficient, and some other methods based on the National Center for Environmental Prediction （NCEP）/National Center for Atmospheric Research （NCAR） reanalysis daily data. The comparisons of the coefficient of variance of climatological background field and truth data in winter between 2010 and 2011 are made. The method of extracting stable components and climatological background field can be helpful to increase forecasting skill. The forecasting skill improvement of air temperature is better than geopotential height at 500 hPa. Moreover, this method improves the predictability better in the Pacific Ocean. In China, the forecast in winter in Northeast China is more uncertain than in the other parts.
文摘基于2013年8月中国中东部地区持续高温及其减弱过程,利用美国国家环境预报中心/美国国家大气研究中心逐日平均的500 h Pa高度场、风场再分析资料和美国国家海洋和大气管理局的海温重建扩展资料进行分析,通过前期海温强迫相似年的选取方法以及带通滤波和经验正交函数分解等方法提取出10—30 d的稳定分量,并通过对稳定分量的诊断分析探究了这次持续高温及其减弱过程的维持机制.研究发现:通过选取与个例前期海温强迫最相似的30年来代替常规的气候态30年(1981—2010年),所提取的气候态稳定分量所占的比重变化不大,稍有减弱,而异常型稳定分量占的比重显著性提高,且其所刻画的影响异常事件的天气系统强度及稳定性明显提高,能够更加清晰地显示延伸期天气过程的维持机制.这表明在提取稳定分量时考虑前期的海温强迫作用是非常有必要的.同时,通过对延伸期稳定分量的分析,表明此次持续高温及减退过程主要受到北极涛动、亚洲大陆中高纬纬向环流形势和西太平洋副热带高压(西太副高)强度、位置的共同影响.
