摘要
In this paper,the rainfall features in southwestern China are studied using daily rainfall station data.The rainfall features are distinct along the eastern and western edges of the Hengduan Mountains and over the mountains,especially in terms of rainfall frequency.The rainfall amounts and frequencies are much higher along the eastern and western edges than over the mountains,particularly during spring,which is partly contributed by the number and duration of rainfall events.The differences are more obvious in the nocturnal rainfall than in the daytime rainfall.The rainfall differences over the three regions could be affected by the large-scale environment.By analyzing reanalysis data,the large-scale circulations linked to the different rainfall features over southwestern China,and the interactions of these circulations with the topography are also discussed.
在复杂地形的影响下,我国西南地区降水的区域特征明显。为进一步深入分析我国横断山脉及周边地区降水的区域差异,利用1961-2013年的逐日降水资料分析发现,在横断山脉的东西两侧以及山脉上,降水量和降水频次的分布差异显著。山脉两侧降水量和降水频次高于横断山脉上,且区域差异在2-5月最为突出。降水频次的区域差异较降水量更为明显,且夜间降水的差异较白天发生降水更大,这与大尺度环流与地形的相互作用密切相关。
基金
jointly supported by the National Key R&D Program of China [grant number 2018YFC1507603]
the National Natural Science Foundation of China [grant number41875112 and 41675075]
