动态垂直变率降尺度方法在气温智能网格预报中的应用  

Application of a dynamic vertical change rate downscaling method in gridded temperature forecast

作　　者：赵瑞霞 代刊 王勇[2] 曹勇 朱跃建 王宝利 ZHAO Ruixia;DAI Kan;WANG Yong;CAO Yong;ZHU Yuejian;WANG Baoli(National Meteorological Centre,Beijing 100081,China;Nanjing University of Information Science and Technology,Nanjing 210044,China;NOAA/NWS/NCEP/Environmental Modeling Center,Maryland 20740,USA;Beijing Wenzezhiyuan Information Technology Co.,Ltd,Beijing 100081,China)

机构地区：[1]国家气象中心,北京100081 [2]南京信息工程大学,南京210044 [3]美国国家环境预报中心/环境模式中心,马里兰207404 [4]北京文泽智远信息技术有限公司,北京100081

出　　处：《气象学报》2023年第5期788-800,共13页Acta Meteorologica Sinica

基　　金：国家重点研发计划项目(2021YFC3000903);国家气象中心预报员专项(Y202132);中国气象局重点创新团队项目(CMA2022ZD04)。

摘　　要：为提高气温智能网格预报的空间精细特征刻画能力和准确率,设计了考虑高程的动态垂直变率降尺度方法(DRD),利用模式地面气温预报随高程的变化关系实时统计地面气温的垂直变率(VCE),应用于目标网格和站点的降尺度预报,生成更加精细和准确的初始背景预报场。基于ECMWF模式预报、5 km精细高程信息、中国10154个站观测资料及其地理信息数据,开展春、夏、秋、冬季预报试验,分析了VCE的时空分布特征、DRD气温预报的准确率及空间精细特征刻画能力。结果表明,受地表长波辐射的日、季节变化以及地面热力属性和地形动力作用等影响,中国区域地面气温的VCE存在明显的日、季节和空间变化。VCE通常在早晨最大、傍晚最小,即早晨地面气温随着高度上升表现为一天中递减最慢或递增最快,而至傍晚则变为递减最快或者递增最慢;VCE空间变幅冬季最大、夏季最小;VCE与地形、海陆和内陆湖水体分布密切相关,大地形边缘、白天的海陆边界、春季白天和夏季全天的内陆湖边缘通常为VCE大值区,且复杂地形区VCE变幅更大。DRD预报性能整体明显优于双线性插值气温预报(DMO),复杂地形区提升效果更显著,如青藏高原南部春季DRD预报的平均绝对误差比DMO减小约14.3%—52.5%;同时,DRD方法显著提高了对气温预报空间精细特征的刻画能力。可见DRD方法可以有效提升气温智能网格预报性能。To improve spatially fine characteristics and accuracy of objective gridded temperature forecast,a dynamic vertical change rate downscaling method(DRD)considering elevation is proposed.Real-time vertical changes of surface air temperature with elevation(VCE)are calculated using the relationship between surface air temperature forecast and elevation at different grid points in the numerical model,and the results are applied to downscaling forecasts at target grids and stations to generate a more accurate initial background forecast field.Based on ECMWF model forecasts,5 km resolution gridded elevation information,observations collected at 10154 stations and their geographic information in China,forecast experiments for spring,summer,autumn and winter are carried out.Spatial and temporal distribution characteristics of VCE,the accuracy of DRD temperature forecast and its ability to depict spatially fine characteristics are analyzed.The results show obvious diurnal,seasonal and spatial variations of VCE over China corresponding to diurnal and seasonal variations of surface long wave radiation,thermal properties and topographic dynamic effects.The value of VCE usually reaches the largest in the morning and the smallest in the evening.This means that surface air temperature decreases the slowest or increases the fastest with increasing height in the morning,and decreases the fastest or increases the slowest in the evening.Spatial variability of VCE is the largest in winter and the smallest in summer.The VCE value is closely related to the distributions of topography,land-sea,and inland lakes.Large VCE values usually appear over large topography edges,daytime landsea margins,and inland lake edges in the daytime in spring and the whole day in summer.VCE often varies more greatly in complex terrain areas.The DRD surface air temperature forecast is significantly better than the bilinear-interpolated value of model prediction(DMO),especially over complex terrain areas.For example,the mean absolute error(MAE)of DRD forecast

关 键 词：动态垂直变率 地面气温 网格预报 降尺度 中国区域 

分 类 号：P456.7[天文地球—大气科学及气象学]