河南省夏玉米生长季洪涝灾害的环流背景及水汽输送特征

Circulation Background and Water Vapor Characteristics on Flood Disaster During Growth Season of Summer Maize in Henan Province

采用1°×1°NCEP再分析资料及地面、高空实况观测资料,分析了2000年以来发生在淮河上游河南境内的4次持续性暴雨过程的大尺度环流背景和水汽输送特征.结果表明:淮河上游持续性暴雨有纬向型和经向型两类,以纬向型居多.两类暴雨的持续与副热带高压及长波槽脊的稳定维持密切相关,两类暴雨均发生在亚欧环流为两槽两脊的大尺度环流背景下(槽、脊位置不同),北方南下的冷空气与副热带高压外围的暖湿气流长时间交汇于淮河上游上空,致使该地区暴雨持续;4次持续暴雨过程的水汽来自于南海、孟加拉湾或东部海面,东边界和南边界是水汽的主要流入边界.

Based on the NCEP 1°×1°reanalysis data,surface and high observation data,we analyzed the large scale circulation background and water vapor transport of four persistent heavy rainfall processes occurred since 2000 in the upper reaches of Huai River in Henan province. The results show that the persistent storm rainfall over the Huai River upstream are zonal type and meridional type,meanwhile the zonal are majority. Persistence of two storm rainfall types are closely related with stable maintenance of subtropical high,long-wave ridge and trough.Both of two types happen under the macroscale circulation with two ridge and two trough over the Eurasian continent which the position of ridge and trough are different. We find the north cold air southward and converge with the warm air which is around the subtropical high in a long time over the Huai River upstream of causing the storm rainfall continuous in this area. The vapor source of four persistent storm rainfall process is the South China Sea,the bay of Bengal and the eastern sea. The eastern and southern boundaries are the main inflow boundary of water vapor.