Temporal and Spatial variation characteristics of seasonal precipitation over the Ti-betan Plateau and its relationship with sea surface temperature
Ciren Wangmu
Daque
Deji Quzong
Baima Quzha
Zunzhui baima
Abstract：Traditional dynamics studies have focused on how plateaus affect the Asian climate and global atmospher-ic circulation through dynamics and thermal interactions,but there is a lack of systematic assessment of precipitation changes and their hazards on the plateau itself.Therefore,based on the daily precipitation provided by the National Meteorological Information Center,the Sea Surface Temperature(SST)data of NOAA,and the monthly geopotential height field and wind field reanalysis data of NCEP/NCAR,this paper adopts the empirical orthogonal function(EOF),regression analysis,correlation analysis and other methods to explore the temporal and spatial distribution characteristics of precipitation and the related SST and atmospheric circulation on the Tibetan Plateau(TP),so as to provide opinions and suggestions for future disaster prevention,mitigation and ecological environment protection.The results show that:(1)The precipitation on the plateau is more in summer and less in winter,and the precipitation in spring,summer and autumn varies significantly from year to year.(2)In spring of the year El Niño(La Niña),when the Pacific Decadal Oscillation(PDO)is in the positive(or negative)phase or the consitent SST mode in the tropical Indian Ocean is positive(or negative),the corresponding plateau precipitation is bounded by 34°N and less south and more north(or more south and less north).(3)In summer,when the Indian Ocean Dipole(IOD)is in the warm(or cold)phase or the SST in the Niño 1+2 zone is high(or low),it is beneficial(or unfavorable)for precipita-tion,showing a districution of 30°N as the dividing line,more north and less south(or more south and less north).(4)In spring,the 850hPa geopotential height field in the lower layer of the plateau shows positive in the south and nega-tive in the north(or positive in the north and negative in the south),and the Lake Baikal anticyclone(or cyclone)of the 200hPa geopotential height extends to the northeast of the TP,while the southeast is controlled by low(or high)pressure,resulting in more precipitation in the north and less in the south(or more in the south and less in the north)bounded by the Tanggula Mountains.(5)In summer,the southwest side of the plateau at low level is of weakly high(or low)pressure,while the northeast is of weakly low(or high)pressure;and the southwest side of the high-rise pla-teau is located in the front of the top of the Nepal low pressure,and the northeast is behind the bottom of the North China high pressure.As a result,the precipitation in the south of BayanKela Mountain is low(or high)and high(or low)in the north.
Keywords：Tibetan PlateauSeasonal precipitationSpatial and temporal characteristicsSea surface temperature anomaly
Publication Date：2024-11-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：9( 54-62 )