大气科学2017，Vol.41Issue(4)：857-868,12.DOI:10.3878/j.issn.1006-9895.1701.16226
ENSO位相转换对华北雨季降水的影响
Effects of ENSO Phase-Switching on Rainy-Season Precipitation in North China
摘要
Abstract
The changing characteristics of Niio3.4 index during 1961-2014 corresponding to much more (less) RSPNC (rainy-season precipitation in North China) were statistically analyzed using RSPNC station data and NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research) reanalyzed data,etc.It was found that most of the years with much more RSPNC were coincident with the ENSO phase-switching years from E1 Ni(n)o to La Ni(n)a,and most of the years with much less RSPNC corresponded to the years when the sea surface temperature anomalies over the central and eastern tropical Pacific changed from negative to positive for E1 Ni(n)o phase.In the years with much more RSPNC,days with regional mean rainfall more than 10 mm over North China during July and August accounted for about 25％ of the total days,and days with regional mean rainfall between 4-10 mm also accounted for about 25％ of the total.Both are far more than that in the years with much less RSPNC.The earlier than normal northward shift of the NWPSH (northwestern Pacific subtropical high),the evident maintenance of NWPSH at the location more north than its normal position,and the northward shift of the East Asian subtropical jet stream were major reasons for the frequent and heavy rainfall in July and August in the years with much more RSPNC.Compared with the E1 Ni(n)o decaying years,the years when ENSO switched from E1 Ni(n)o to La Ni(n)a had stronger positive geopotential height anomaly over 500 hPa near the Japan Sea during July and August,which was more in accordance with the typical circulation pattern in higher RSPNC years.In addition,compared with the E1 Ni(n)o decaying years,the years when ENSO switched from El Ni(n)o to La Ni(n)a had stronger Walker circulation during July and August.As a result,the East Asian subtropical jet stream shifted northward more significantly,which was also in favor of more precipitation over North China.The phenomenon inspired us to pay close attention to the changing speed of ENSO event in the past and future,which might be helpful for forecasting rainy-season precipitation in North China.关键词
华北雨季/ENSO/位相转换Key words
Rainy-season in North China/ENSO/Phase-switching分类
天文与地球科学引用本文复制引用
赵树云,陈丽娟,崔童..ENSO位相转换对华北雨季降水的影响[J].大气科学,2017,41(4):857-868,12.基金项目
国家重点基础研究发展计划(2015CB453203),国家自然科学基金面上项目41275073,中国气象局气候研究开放课题青年基金2016年度资助项目 National Basic Research Program of China (Grant 2015CB453203),National Natural Science Foundation of China (Grant 41275073),LCS Open Funds for Young Scholars (2016) （2015CB453203）
