非典型大西洋尼诺对中国东部前、后汛期降水的影响  

Impacts of non-canonical Atlantic Nino on eastern China precipitation in the early and late rainy seasons

作　　者：杨萌洲 袁潮霞 YANG Mengzhou;YUAN Chaoxia(Key Laboratory of Meteorological Disaster of Ministry of Education(KLME),Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD),Institute for Climate and Application Research(ICAR),Nanjing University of Information Science&Technology,Nanjing 210044,China;Application Laboratory,Japan Agency of Marine-Earth Science and Technology,Yokohama 2360001,Japan)

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心/气候与应用前沿研究院,江苏南京210044 [2]日本海洋研究开发机构应用实验室,日本横滨2360001

出　　处：《大气科学学报》2024年第2期260-272,共13页Transactions of Atmospheric Sciences

基　　金：国家自然科学基金资助项目(42088101);国家重点研发计划项目(2022YFF0801702)。

摘　　要：采用1979—2020年共42 a的降水观测和再分析资料,使用多变量EOF、傅立叶滤波、线性回归、T-N波通量等方法,研究了非典型大西洋尼诺(Non-Canonical Atlantic Ni1o,NCA)对中国东部夏季前、后汛期降水的影响及物理机制。结果显示,NCA在前汛期引起中国南方降水增加,但在后汛期导致华南沿海地区降水减少而北方降水增加。这是由于在前汛期,NCA的暖海温异常位于热带北大西洋,可通过“风-蒸发-海表温度”正反馈引起拉尼娜,进而激发西北太平洋异常反气旋,其西北侧的异常西南气流有助于将暖湿水汽输送至我国南方,导致前汛期南方降水增加。在后汛期,NCA的暖海温异常南移至赤道大西洋,通过调节沃克环流增强拉尼娜,使得西北太平洋异常反气旋进一步增强并覆盖华南地区,导致华南降水减少而北方降水增加。此外,与NCA相关的东传罗斯贝波列在前/后汛期位于副热带/中高纬地区,其在我国东部引起的环流异常也有助于NCA在前/后汛期影响我国南/北方降水。Exploring the potential predictability of seasonal precipitation in Eastern China beyond the preceding winter El Nino-Southern Oscillation(ENSO)has long been a significant challenge.This study investigates the influences of the non-canonical Atlantic Ni o(NCA)on precipitation patterns in Eastern China during the early and late rainy seasons using observational and reanalysis data from 1979 to 2020.Results indicate that the NCA leads to increased precipitation in southern China during the early rainy season,while it decreases precipitation along the southern coast but increases precipitation in northern China during the late rainy season.This is because,in the early rainy season,warm sea surface temperature(SST)anomalies associated with the NCA in the North Tropical Atlantic trigger La Ni a through the“wind-evaporation-SST”feedback,inducing an anomalous anticyclone over the western North Pacific.The southwesterly flow along the northwest flank of this anomalous anticyclone transports warm and moist air into southern China,resulting in increased precipitation.Conversely,during the late rainy season,NCA-related warm SST anomalies migrate southward to the equatorial Atlantic,modifying the Walker circulation,reinforcing La Ni a,and intensifying the anomalous anticyclone over the western North Pacific.This enhanced anticyclone covers the southern coastal region of China,reducing precipitation there,while further northward moisture transport along the enhanced anticyclone increases precipitation in northern China.Additionally,NCA influences Eastern China’s precipitation by stimulating different mid-high-latitude Rossby waves in the early and late rainy seasons.In the early rainy season,the Rossby wave is primarily triggered by anomalous warm SST in the North Tropical Atlantic,propagating from northern Africa to the Qinghai-Tibet Plateau and eventually reaching the Yangtze River basin.Although the SST anomalies in the Tropical North Atlantic weaken during the late rainy seasons,the North Atlantic Oscillation can st

关 键 词：非典型大西洋尼诺(NCA) 中国东部 前、后汛期 降水 

分 类 号：P461.2[天文地球—大气科学及气象学]