2013年7-8月浙江省异常高温特点及成因分析

Analysis on Characteristics and Cause of Abnormal High Temperature in the Summer of 2013 in Zhejiang Province

利用浙江省常规气象观测资料、NCEP/NCAR再分析格点资料和NOAA提供的OLR资料,分析总结了浙江省高温天气气候特点及2013年盛夏异常高温情况,在此基础上重点对2013年盛夏7-8月浙江省出现的异常高温天气成因进行了分析。结果表明:浙江省高温日数以7月最多、8月次之;空间分布上呈西多东少、内陆多沿海少的特点。2013年盛夏浙江省出现了近60余年最严重的高温热浪天气,高温日数异常偏多,部分市县极端最高气温屡破历史记录。盛夏期间高层南亚高压的持续稳定加强东伸,导致副热带高压的加强西伸,异常偏强偏西的副热带高压持续稳定控制浙江省,是浙江省异常高温产生的主要原因。浙江省中低层下沉气流偏强且盛行暖脊影响,上空OLR值异常偏高,整层水汽含量异常偏少,有利于浙江省异常高温的产生。极涡偏向西半球,影响浙江省的冷空气偏弱,台风北上活动影响轻,对于浙江省高温缓解作用有限,促使浙江省异常高温过程频繁且间隔时间短。

Based on the Zhejiang conventional observation data,the datasets from the NCEP/NCAR reanalysis and NOAA-OLR, the climate characteristics of high temperature weather and the high temperature case of 2013 in Zhejiang have been summarized,particularly the abnormal high temperature weather causes between July and August of 2013 in Zhejiang are analyzed. The results show that high temperature days of Zhejiang appeared most frequently in July,followed by August. There were more high temperature days in the west region and less ones in the east coast. In summer of 2013,large sections of Zhejiang province were hit by heat wave. It was the worst heat wave in recent 60 years. The High temperature days of Zhejiang in the summer of 2013 were much more than that in the summer of the perennial average. The history records of extreme maximum temperature were broken in part cities and countries frequently. The high-level South Asia high pressure steadily strengthen the eastward,subtropical high strengthen the westward,sustained and stable control in Zhejiang Province was the main causes of abnormal high temperature produced in Zhejiang province. Low-level downdraft partial strong and popular among warm ridge,OLR value anomaly on the high side and the whole layer moisture content abnormal less was beneficial to the abnormal temperature of Zhejiang province. The polar vortex leaned tothe Western Hemisphere leads to weakening of the cold air which influences Zhejiang province and less influence of typhoon made abnormal high temperature more frequent and its interval shorter.