摘要
该文采用中国气象局月值站点数据和JRA-55资料分析华南前汛期降水特征及其与大气热源的关系。发现4-6月降水中心从南岭地区转移到珠三角地区,同时伴随副高东退北抬。6月降水范围和强度最大,降水空间分布的典型模态是全区变化一致型。降水偏多年副高异常偏西,西南气流强盛,华南地区大气整层被强热源控制,且伴随显著上升气流。菲律宾以东和孟加拉湾西侧被异常冷源控制,伴随强下沉气流,异常冷热源在400 hPa高度达最强。合成和相关分析表明,前汛期菲律宾以东异常冷源加强下沉气流,使副高西伸加强,利于东南气流沿南海北上。孟加拉湾西侧异常冷源加强低空气流反气旋式辐散,从而使冷源东侧的印缅槽加深东进,利于西南暖湿气流北上。来自热带太平洋和热带印度洋的暖湿气流北上在华南地区汇合,而华南地区异常强热源抽吸低空气流辐合上升,从而造成前汛期降水偏多。降水偏少年也可采用相似机理来解释。
This paper uses monthly station data of China Meteorological Administration and JRA-55 data to analyze the characteristics of precipitation in the first rainy season in South China and its relationship with atmospheric heat sources.It was found that the precipitation center shifted from the Nanling region to the Pearl River Delta region from April to June,and at the same time the subtropical high retreated and moved northward.The precipitation range and intensity are the largest in June,and the typical pattern of spatial distribution of precipitation is consistent with changes in the whole region.The subtropical high of precipitation has been abnormally west for many years,the southwest airflow is strong,and the entire atmosphere of South China is controlled by strong heat sources,and it is accompanied by significant updrafts.The east of the Philippines and the west of the Bay of Bengal are controlled by anomalous cold sources.Accompanied by strong downdrafts,the anomalous cold and heat sources are strongest at a height of 400hPa.Synthesis and related analysis show that the abnormal cold source east of the Philippines in the previous flood season strengthened the sinking airflow,which strengthened the westward extension of the subtropical high,which is conducive to the northeast airflow along the South China Sea.The abnormal cold source on the west side of the Bay of Bengal strengthens the anticyclonic divergence of the low-air flow,so that the India-Burma trough on the east side of the cold source moves further eastward,which is conducive to the northward movement of the southwest warm humid air.The warm and humid air currents from the tropical Pacific and the tropical Indian Ocean flow northward and converge in South China,while the convergence of low air currents sucked by the abnormally strong heat source in South China rises,resulting in more precipitation during the previous flood season.The partial precipitation can also be explained by a similar mechanism.
作者
罗小青
巫郎琪
徐建军
李凯
LUO Xiaoqing;WU Langqi;XU Jianjun;LI Kai(South China Sea Institute of Marine Meteorology,Guangdong Ocean University,Zhanjiang 524088,China;College of Ocean and Meteorology,Guangdong Ocean University,Zhanjiang 524088,China;Maritime College,Guangdong Ocean University,Zhanjiang 524088,China)
出处
《中低纬山地气象》
2021年第5期19-27,共9页
Mid-low Latitude Mountain Meteorology
基金
2020年湛江市非资助科技计划项目(200518174546338):华南前汛期降水与大气热源关系探究
广东海洋大学2020年校级教学质量工程项目(580420011):数值天气预报
2021年广东海洋大学大学生创新创业项目(010403032104):El Ni o事件消亡期对流层上层海陆热力差异的演变。
关键词
华南前汛期
降水
大气热源
South China first flood season
recipitation
atmospheric heat sources
