青藏高原三江源和河湾区夏季降水变化特征及对高原夏季风的响应.pdf

doi:10.3878/j.9895.2207.22089SSandTheir ResponsetotheTibetanPlateauSummerMonsoon.ChineseJournalof AtmosphericSciences(inChinese),47(3):881-892.LI Hongli,WANG Bin,et al.2023.Variations in Summer Precbitation over the Three-River Headwaters Region and the Yarlung Zangbo River BasinYANGHao,杨浩，李红莉，王斌，等.2 0 2 3.青藏高原三江源和河湾区夏季降水变化特征及对高原夏季风的响应1.大气科学，47(3)：8 8 1-8 92.May20232023年5月ChinessciencesVol.47No.学科第47 卷第3期青藏高原三江源和河湾区夏季降水变化特征及对高原夏季风的响应杨浩1，2李红莉1王斌1张文刚1崔春光11中国气象局武汉暴雨研究所中国气象局流域强降水重点开放实验室/暴雨监测预警湖北省重点实验室，武汉430 2 0 52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，南京2 10 0 44摘要本文利用198 12 0 2 0 年观测数据和ERA5再分析资料，将青藏高原腹地三江源和东南重要水汽通道河湾区作为典型研究区域，分析了降水不同时间尺度变化特征及其典型强弱年对高原季风环流系统的响应，结果表明：（1）三江源和河湾区降水的季节变化均呈双峰型分布，峰值出现在7 月初和8 月下旬。夏季降水在2 1世纪初发生年代际转折，尤其是三江源降水量在近2 0 年增加明显。两个高原季风指数DPMI（D y n a m i c Pl a t e a uMonsoonIndex）和ZPMI（Zh o u Pl a t e a u M o n s o o n I n d e x）的夏季风爆发时间均超前于河湾区和三江源降水的明显增加期。三江源夏季降水年际变化与两个高原夏季风指数有较好的相关性。三江源与河湾区虽然相邻很近，但三江源夏季降水受高原季风影响程度远大于河湾区。当高原夏季风增强（减弱）时，三江源降水量偏多（少）。（2）三江源降水偏多年，南亚高压偏东偏强，低层高原主体低压异常，有利于西南风和东南风在三江源区域交汇，南方暖湿空气能够深入高原腹地导致水汽辐合偏强。河湾区降水偏多年，河湾区及整个高原主体附近高度场并没有明显异常，河湾区的水汽输送主要有两条路径，一条来自孟加拉湾沿高原南坡的西南路径，另一条来自中亚地区穿过高原上空的西北路径，两条路径在高原东侧汇合继续向东输送。关键词降水高原夏季风大气环流三江源河湾区文章编号号10 0 6-98 95(2 0 2 3)0 3-0 8 8 1-12中图分类号P461文献标识码马Adoi:10.3878/j.issn.1006-9895.2207.22089Variations in Summer Precipitation over the Three-River HeadwatersRegion and the Yarlung Zangbo River Basin and Their Responseto the Tibetan Plateau Summer MonsoonYANGHao,ol-2,LI Honglil,WANG Bin,ZHANG Wengang,and CUI Chunguang1 China Meteorological Administration Basin Heavy Rainfall Key Laboratory/Hubei Key Laboratory for Heavy Rain Monitoring and WarningResearch,Institute of Heavy Rain,China Meteorological Administration,Wuhan 4302052 Key Laboratory of Meteorological Disaster(KLME),Ministry of Education/Collaborative Innovation Center on Forecast and Evaluation of收稿日期2022-05-27；网络预出版日期2022-12-01作者简介杨浩，男，198 6 年出生，副研究员，主要从事极端天气气候研究。E-mail:通讯作者崔春光，E-mail:资助项目第二次青藏高原综合科学考察研究项目2 0 19QZKK0105，湖北省自然科学基金项目2 0 2 2 CFD120，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联合开放课题KLME202106Funded bySecond Tibetan Plateau Scientific Expedition and Research(STEP)Program(Grant 2019QZKK0105),Hubei Natural ScienceFoundation(Grant 2022CFD120),Key Laboratory of Meteorological Disaster(KLME),Ministry of Education&CollaborativeInnovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)(Grant KLME202106)882Vol.4747卷大气科学Chinese Journal of Atmospheric SciencesMeteorological Disasters(CIC-FEMD),Nanjing University of Information Science&Technology,Nanjing 210044Abstract Based on precipitation and ERA5 reanalysis datasets from 1981 to 2020,this study analyzed the variationcharacteristics of precipitation at different time scales over the Three-River Headwaters region(TRHR)and the YarlungZangbo River basin(YZRB)and their responses to the Tibetan Plateau summer monsoon.Results are shown as follows:(I)The seasonal variation in precipitation over the TRHR and YZRB shows a bimodal distribution,and the peaks appearin early July and late August.The interdecadal transitions in summer precipitation occur in the early 21st century,especially the TRHR precipitation increases significantly during the recent 20 years.The onset time of summer monsoonin the Dynamic Plateau Monsoon Index(DPMI)and the Zhou Plateau Monsoon Index(ZPMI)is earlier than theprecipitation increase period over the TRHR and YZRB.The interannual variation in summer precipitation over theTRHR correlates well with two plateau summer monsoon indices.Although the TRHR is close to the YZRB,the summerprecipitation of the TRHR is considerably more affected by the Tibetan plateau monsoon than YZRB.When the TibetanPlateau summer monsoon strengthens(weakens),the TRHR precipitation is more(less).(2)In wet TRHR years,theSouth Asian High is stronger and more eastward,while the pressure at low-level over the main body of the plateau islower than in dry years.These situations are conducive to the intersection of southwest and southeast winds over theTRHR so that the warm and humid air from the South can go deep into the hinterland of the plateau,resulting in strongerwater vapor convergence.In wet YZRB years,there is no obvious anomaly in the pressure field near the YZRB or theTibetan Plateau.The water vapor transport over YZRB mainly has two paths.One is the southwest path from the Bay ofBengal along the south slope of the plateau,and the other is the northwest path from Central Asia and through the plateau.The two paths converge on the east side of the plateau and continue to transport eastward.KeywordsPrecipitation,Tibetan Plateau summer monsoon,Atmospheric circulation,Three-River Headwaters region,Yarlung Zangbo Riverbasin1引言青藏高原（以下简称高原）降水对亚洲水文循环具有重要影响，东亚和南亚的主要水系（长江、黄河、雅鲁藏布江）均发源于此，因其在水循环中的重要作用被冠以“亚洲水塔”的称号（Xuetal.,2008;Sunetal.,2020）。大量研究已经证实了高原气候变暖的事实（Yangetal.,2014;Zhangetal.,2021a）。高原范围广阔而且降水空间分布具有明显差异（Youetal.,2008;Luetal.,2015），降水趋于增多还是减少一直存在较大的争议（黄浠等，2016;赤曲等，2 0 2 0），最新研究指出高原降水整体上呈增加趋势（李晓英等，2 0 16;Shangetal.，2021）。三江源地区位于高原腹地的青海省南部