本文首先基于地面自动站、探空、雷达和卫星资料,开展局地分析预报系统(Local Analysis and Prediction System,LAPS)上海本地化研究,并结合2010—2014年夏季6个局地对流天气个例对其性能进行检验评估。结果表明:雷达径向风资料对LAPS...本文首先基于地面自动站、探空、雷达和卫星资料,开展局地分析预报系统(Local Analysis and Prediction System,LAPS)上海本地化研究,并结合2010—2014年夏季6个局地对流天气个例对其性能进行检验评估。结果表明:雷达径向风资料对LAPS风速分析影响较大,使分析场风速廓线与探空廓线的均方根误差缩小约7.66%;风云卫星资料能够改善LAPS温度和相对湿度,使分析场温度、相对湿度廓线与探空廓线的均方根误差分别缩小约9.09%和14.01%;探空气球飘移对本文LAPS分析场检验影响不明显。进一步将LAPS分析场用于2011年8月13日、2014年8月4日两次局地对流个例分析表明:LAPS高时空分辨率的分析场能够反映中小尺度天气系统的时空变化,在天气尺度背景并不十分有利于对流生成的情况下,热岛、海陆风环流的形成和持续对上海夏季局地对流天气的发生和发展起到关键作用。展开更多
Constructing βmesoscale weather systems in initial fields remains a challenging problem in a mesoscale numerical weather prediction （NWP） model. Without vertical velocity matching the βmesoscale weather system, co...Constructing βmesoscale weather systems in initial fields remains a challenging problem in a mesoscale numerical weather prediction （NWP） model. Without vertical velocity matching the βmesoscale weather system, convection activities would be suppressed by downdraft and cooling caused by precipitating hydrom eteors. In this study, a method, basing on the threedimensional variational （3DVAR） assimilation technique, was developed to obtain reasonable structures of βmesoscale weather systems by assimilating radar data in a nextgeneration NWP system named GRAPES （the Global and Regional Assimilation and Prediction System） of China. Singlepoint testing indicated that assimilating radial wind significantly improved the horizontal wind but had little effect on the vertical velocity, while assimilating the retrieved vertical velocity （taking Richardson’s equation as the observational operator） can greatly improve the vertical motion. Ex periments on a typhoon show that assimilation of the radial wind data can greatly improve the prediction of the typhoon track, and can ameliorate precipitation to some extent. Assimilating the retrieved vertical velocity and rainwater mixing ratio, and adjusting water vapor and cloud water mixing ratio in the initial fields simultaneously, can significantly improve the tropical cyclone rainfall forecast but has little effect on typhoon path. Joint assimilating these three kinds of radar data gets the best results. Taking into account the scale of different weather systems and representation of observational data, data quality control, error setting of background field and observation data are still requiring further indepth study.展开更多
文摘本文首先基于地面自动站、探空、雷达和卫星资料,开展局地分析预报系统(Local Analysis and Prediction System,LAPS)上海本地化研究,并结合2010—2014年夏季6个局地对流天气个例对其性能进行检验评估。结果表明:雷达径向风资料对LAPS风速分析影响较大,使分析场风速廓线与探空廓线的均方根误差缩小约7.66%;风云卫星资料能够改善LAPS温度和相对湿度,使分析场温度、相对湿度廓线与探空廓线的均方根误差分别缩小约9.09%和14.01%;探空气球飘移对本文LAPS分析场检验影响不明显。进一步将LAPS分析场用于2011年8月13日、2014年8月4日两次局地对流个例分析表明:LAPS高时空分辨率的分析场能够反映中小尺度天气系统的时空变化,在天气尺度背景并不十分有利于对流生成的情况下,热岛、海陆风环流的形成和持续对上海夏季局地对流天气的发生和发展起到关键作用。
基金supported by the National Key Scientific and Technological Project (Grant No 2006BAC02B00)National Natural Science Foundation of China (Grant No40518001)
文摘Constructing βmesoscale weather systems in initial fields remains a challenging problem in a mesoscale numerical weather prediction （NWP） model. Without vertical velocity matching the βmesoscale weather system, convection activities would be suppressed by downdraft and cooling caused by precipitating hydrom eteors. In this study, a method, basing on the threedimensional variational （3DVAR） assimilation technique, was developed to obtain reasonable structures of βmesoscale weather systems by assimilating radar data in a nextgeneration NWP system named GRAPES （the Global and Regional Assimilation and Prediction System） of China. Singlepoint testing indicated that assimilating radial wind significantly improved the horizontal wind but had little effect on the vertical velocity, while assimilating the retrieved vertical velocity （taking Richardson’s equation as the observational operator） can greatly improve the vertical motion. Ex periments on a typhoon show that assimilation of the radial wind data can greatly improve the prediction of the typhoon track, and can ameliorate precipitation to some extent. Assimilating the retrieved vertical velocity and rainwater mixing ratio, and adjusting water vapor and cloud water mixing ratio in the initial fields simultaneously, can significantly improve the tropical cyclone rainfall forecast but has little effect on typhoon path. Joint assimilating these three kinds of radar data gets the best results. Taking into account the scale of different weather systems and representation of observational data, data quality control, error setting of background field and observation data are still requiring further indepth study.
