新增积雪深度客观预报技术研究及其应用  

Fresh Snowfall Depth Forecast Technology and Its Application

作　　者：符娇兰 陈博宇 陈双 董全 曹勇 杨舒楠 FU Jiaolan;CHEN Boyu;CHEN Shuang;DONG Quan;CAO Yong;YANG Shunan(National Meteorological Centre,Beijing 100081)

机构地区：[1]国家气象中心,北京100081

出　　处：《气象》2022年第10期1230-1241,共12页Meteorological Monthly

基　　金：国家自然科学基金青年科学基金项目(41105030);国家重点研发计划(2018YFF0300104)共同资助。

摘　　要：利用地面历史观测数据对我国冬季典型降雪过程的雪水比进行了统计分析,在此基础上,利用改进后的Cobb算法、ECMWF IFS模式预报及中央气象台降水和相态网格预报构建了雪水比和新增积雪深度物理预报模型。结果表明:我国降雪过程的雪水比分布较广,最小为0.3∶1,最大为100∶1,仅有4%左右的雪水比为10∶1;雪水比具有明显的区域和季节特征,新疆、西北地区东部、华北以及东北地区雪水比大于其他区域,冬季较春、秋季雪水比大;改进后的Cobb算法建立了随地形高度变化的云识别方案,利用云内温度与雪水比统计关系及垂直速度构建了雪水比和新增积雪深度预报模型,其预报的雪水比和新增积雪深度空间分布特征较原Cobb算法的预报更接近实况;结合雪水比预报模型和中央气象台降雪网格技术的新增积雪深度预报较ECMWF IFS模式预报有明显的改进,相对模式新增积雪深度预报TS评分提高率基本在10%以上,尤其对20 cm以上新增积雪深度预报能力提升明显。Based on the surface historical observation data,the statistical analysis of the snow to liquid ratio of the typical winter snowfall events in China is conducted.Then the snow to liquid ratio and fresh snowfall depth forecast models are built using the Cobb method,ECMWF IFS model forecast and the gridded precipitation and its type grid forecast from the National Meteorological Centre.The statistical analysis shows that the snow to liquid ratio in the snowfall events in China is widely distributed,with a minimum of 0.3∶1 and a maximum of 100∶1.Only about 4%of the snow to liquid ratio records are 10∶1.The snow to liquid ratio has obvious regional and seasonal characteristics.The snow to liquid ratios in Xinjiang,eastern Northwest China,North China and Northeast China are larger than those in other regions.The snow to liquid ratio in winter is larger than that in spring and autumn.Based on the modified Cobb method,which can identify the cloud according to topography,the snow to liquid ratio is firstly constructed based on the statistical relationship between the temperature in the cloud and the snow to liquid ratio and the related vertical velocity.The snow to liquid ratio and fresh snowfall depth forecasted by modified Cobb method can reflect the spatial characteristics of the actual snow to liquid ratio in the precipitation process,compared with the original Cobb method.The fresh snowfall depth forecast performance is obtained by combining the snow to liquid ratio forecast model and the National Meteorological Centre’s gridded snowfall forecast and it significantly improves the fresh snowfall depth forecast compared with that by the ECMWF IFS model.In particular,the ability to predict fresh snowfall depth over 20 cm has been significantly improved,and the TS score increase rate of the fresh snowfall depth forecast built in this paper relative to that by the ECMWF IFS model is basically over 10%.At present,this technology has been applied in the National Meteorological Center,providing strong support for wi

关 键 词：新增积雪 雪水比 云内温度 物理预报模型 

分 类 号：P456[天文地球—大气科学及气象学]