青藏高原雨季特征及其对气候增暖的响应  

Characteristics of wet season over the Tibetan Plateau and its response to climate warming

作　　者：余迪 段丽君 温婷婷 申红艳[1,2] 汪青春[1,2] 李红梅 YU Di;DUAN Li-jun;WEN Ting-ting;SHEN Hong yan;WANG Qing-chun;LI Hong-mei(Qinghai Climate Center,Xining 810001,China;Key Laboratory for Preventing and Mitigating Disaster of Qinghai Province,Xining 810001,China)

机构地区：[1]青海省气候中心,青海西宁810001 [2]青海省防灾减灾重点实验室,青海西宁810001

出　　处：《气象与环境学报》2021年第2期12-18,共7页Journal of Meteorology and Environment

基　　金：中国科学院寒旱区陆面过程与气候变化开放基金(LPCC2019009);国家自然科学基金(42065003、41530531、41861013);中国气象局气候变化专项(CCSF201929、CCSF202021)共同资助。

摘　　要：利用青藏高原气象台站逐日观测资料,采用候雨量稳定通过临界阈值的方法对高原雨季起讫期进行客观定量划分,在此基础上,进一步分析增暖背景下雨季起讫期和雨季降水演变特征,并对比增暖前后高原雨季起讫期及不同等级降水的响应特征。结果表明:青藏高原雨季平均开始期为5月第3候、结束期为9月第6候、共持续28候;青藏高原雨季降水集中期为6月中旬至9月中旬,并在7月上旬、下旬和8月下旬出现3个峰值,7月上旬为雨季主峰期;1961-2017年雨季降水量总体呈增加趋势,雨季降水量自东南向西北逐渐递减,高值区位于青藏高原东南部的横断山脉;青藏高原雨季气候于1997年开始增暖,增暖前后雨季起讫期区域间差异较大,增暖后雨季开始期在青藏高原西部明显推迟,其余地区均提前,结束期则总体推迟;气候增暖后中雨以上日数增多,雨季降水极端性显著增强且空间覆盖范围明显扩大。Basing on the daily data from the meteorological stations of the Tibetan Plateau,the characteristics of onsetto-end period and rainfall amount of the wet season were analyzed under the background of climate warming,using the method of pentad rainfall steadily passing the critical thresholds to determine the onset and end of the wet season.The characteristics of the onset-to-end time and the rainfall amount for different grades in the wet season were compared before and after warming periods in Tibetan Plateau. The results show that the wet season in Tibetan Plateau begins on the third pentad in May and ends on the sixth pentad in September. The total duration of the wet season is28 pentads. The precipitation in the wet season concentrates from mid-June to mid-September. The three peaks occur in early July,late July,and late August,respectively. Among them,early July is the main peak in the wet season. The precipitation amounts in the wet season from 1961 to 2017 show an increasing trend in Tibetan Plateau. For spatial distribution,the precipitation amount decreases from southeast to northwest,and the precipitation amount in the Hengduan mountains located in the southeast of the plateau is most. The average temperature in the wet season increases significantly since 1997. There is an obvious difference among regions for the onset-to-end period of the wet season before and after warming. The onset of wet season delays significantly in the west part of the Plateau after warming periods. For most parts of the Plateau,the onset of wet season advances,and the end-date delays for most parts of the Plateau. After warming,the number of days that the precipitation is above the moderate rain grade increases. The extreme precipitation amount in the wet season significantly enhances,and its extent expands.

关 键 词：气候变暖 青藏高原 雨季划分 降水 

分 类 号：P468.024[天文地球—大气科学及气象学]