江淮流域大范围雨带降水的精细化特征研究  

Refined characteristics of precipitation and circulation in large-scale rainbelts derived from CMPAS and ERA5 over the Yangtze-Huaihe river valley

作　　者：卜文惠 陈昊明[1] 李普曦 BU Wenhui;CHEN Haoming;LI Puxi(State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081,China;Heilongjiang Provincial Meteorological Observatory,Harbin 150030,China)

机构地区：[1]中国气象科学研究院灾害天气国家重点实验室,北京100081 [2]黑龙江省气象台,哈尔滨150030

出　　处：《气象学报》2023年第3期361-374,共14页Acta Meteorologica Sinica

基　　金：国家自然科学基金项目(U2142214、42075154、42005039)。

摘　　要：利用中国地面与CMORPH融合逐小时降水产品(CMPAS)和欧洲中期天气预报中心的全球气候第5代大气再分析产品(ERA5),基于面向对象的诊断评估方法(MODE)量化雨带空间特征信息挑选大范围雨带,再根据雨带形态不同将其分为纬向型和经向型。基于江淮流域雨带不同空间型的分类合成,分析了江淮流域不同空间型雨带的降水和环流特征。对比不同空间型雨带的降水时、空特征发现,大范围雨带多呈西南—东北向,降水量、降水频率的日变化表现为夜间主峰值、午后次峰值的双峰特征,降水强度存在夜间至凌晨的单峰特征。纬向型雨带空间分布为西南—东北向,在暖季随时间自南向北推进,降水集中在6月中、下旬至7月上、中旬,对应江淮梅雨期降水,强降水的发生频率高、雨区面积大,雨带的降水量、降水频率及降水强度的日变化特征同大范围雨带基本一致。经向型雨带降水在8月季风间歇期发生的频次较高,降水影响范围相对较小,降水量、降水频率日变化为午后单峰特征,降水强度也是午后较夜间大。进一步对比两类不同空间型雨带对应的环流特征发现:两类雨带降水都对应中高层暖、低层冷的温度异常垂直结构,风场的异常环流在高层为反气旋,低层为气旋。纬向型正异常南北两侧温度梯度较大,经向型东西两侧温度梯度较大。纬向型位于高层反气旋的中心,高层辐散提供了上升需要的动力条件,低层西南风异常提供了丰沛的水汽,有利于形成大范围的降水。经向型位于高层反气旋的后部,低层风场主要为东南风或东北风异常,形成经向度较大降水空间分布,辐合上升的局地性较强,强降水中心较为分散。Using CMPAS precipitation product and ERA5 reanalysis dataset,spatial characteristics of rainbelts are quantified based on the method of object-based diagnostic evaluation(MODE).The widescale rainbelts are selected and further sorted into zonal and meridional types based on different orientations.The rainbelts in the Yangtze-Huaihe river valley have been classified according to their spatial distributions.Precipitation characteristics and associated atmospheric structure have been analyzed.Comparing spatiotemporal characteristics of different rainbelts,it is found that the widescale rainbelts tend to have a southwest-northeast orientation,and the diurnal variation of precipitation amount(frequency)shows two peaks,i.e.,one is in the early-morning(midnight),and the other is in the late afternoon.Precipitation intensity peaks from night to early morning.The zonal rainbelts are southwest-northeast oriented,advancing from south to north during the warm season.Precipitation is concentrated from mid-June to mid-July,corresponding to the Meiyu period.The zonal rainbelts are featured by high frequency of heavy precipitation and broad area.The diurnal variations of precipitation amount,frequency and intensity of the zonal rainbelts are basically the same as those of widescale rainbelts.The meridional rainbelts occur more frequently during the monsoon break period in August,featured by frequent precipitation over relatively small area.The diurnal variation of precipitation amount(frequency)in the meridional rainbelts peaks in the afternoon,and precipitation intensity in the late-afternoon is greater than that at night.Further comparison of the atmospheric structure associated with the two different types reveals that both rainbelts have notable baroclinic structures with warm anomalies in the mid-to-upper levels and cold anomalies in the lower levels.The anomalous circulation of wind field is characterized by an anticyclone in the upper layer and a cyclone in the lower layer.However,the zonal warm anomaly has a large temper

关 键 词：大范围雨带 小时尺度降水特征 降水时空特征 环流结构 

分 类 号：P426.61[天文地球—大气科学及气象学]