一种表征南海季风强度的指标及其与华南降水的关系  

An Index to Characterize the Intensity of the South China Sea Monsoon and Its Relationship with Precipitation in South China

作　　者：赵玮 陆尔[1] 龚理卿 王睆 刘佳 方陆俊 ZHAO Wei;LU Er;GONG Liqing;WANG Huan;LIU Jia;FANG Lujun(Key Laboratory of Meteorological Disaster,Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CICFEMD),Nanjing University of Information Science and Technology,Nanjing 210044;Meteorological Bureau of Shenzhen Municipality,Shenzhen 518040;Hangzhou Meteorology Service,Hangzhou 310051)

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/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心,南京210044 [2]深圳市气象局,深圳518040 [3]杭州市气象局,杭州310051

出　　处：《大气科学》2020年第1期1-12,共12页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金项目41991281;国家重点研发计划专项项目2018YFC1507704~~

摘　　要：风场强度与方向的季节性变化是季风区最显著的气象要素变化特征之一。Lu and Chan(1999)利用大气低层风场,定义了一个表征南海季风强度的指数,为简单起见,只用了经向风分量,研究表明该指数与华南夏季降水有很好的相关。为了进一步验证和改进该指数,本文利用逐月NCEP/NCAR(National Centers for Environmental Prediction/National Center for Atmospheric Research)风场再分析资料以及华南地区的基准、基本气象站降水资料,将设计指数时允许的实际风的投影方向从规定的正北方向(即经向风),拓展为允许偏转的其他方向,以此建立改进的指数。为了更好地反应改进后的指数与华南降水的月异常之间的关系,本文引入了广义线性模型及正态分布和Gamma分布两类假设,来建立两者非线性的回归关系。结果证明,实际风在自正北方向逆时针旋转11.3°的方向上的投影与华南降水具有最好的相关性,采用这一方向上的投影可以对原指数加以改进;中国南海季风所覆盖的风场与华南降水的月异常之间有显著的非线性关系,而对降水采用Gamma分布假设的广义线性模型能够比正态分布假设得到更符合实际的回归结果。Seasonal change in wind strength and direction is one of the most significant characteristics of meteorological elements in the monsoon region.Lu and Chan(1999)defined an index to characterize the monsoon intensity in the South China Sea(SCS)by using the low-level wind field.For simplicity,only the meridional component was used.The study shows that the index has a good correlation with the summer rainfall in South China(SC).To modify and verify thisindex,by using the monthly mean NCEP/NCAR(National Centers for Environmental Prediction/National Center forAtmospheric Research)reanalysis data and the daily precipitation data of the national reference or basic synoptic stationsin SC,the authors analyzed the wind projection in different directions,not the restricted southerly direction,so that theperformance of the index can be improved.To quantify the relationship between the monthly mean wind projectioncomponent intensity of the SCS in different directions and the monthly precipitation in SC,the generalized linear modelsand two forms of the probability distribution hypothesis,namely,normal distribution,and gamma distribution,have beenused.Results show that the wind projection component intensity of the SCS in the northwest(11.3°)direction has a bettercorrelation with the summer precipitation in SC then original index.Moreover,a significant nonlinear relationshipbetween precipitation in SC and the improved index has been observed.The generalized linear model with gammadistribution hypothesis for precipitation can obtain better realistic regression results than the generalized linear modelwith normal distribution hypothesis.

关 键 词：中国南海季风 华南降水 非线性 广义线性回归模型 

分 类 号：P461[天文地球—大气科学及气象学]