Page 36 - 《高原气象》2022年第1期
P. 36
高 原 气 象 41 卷
34
Impacts of Spring Soil Moisture Anomalies in Qinghai-Xizang
Plateau on the Summer Precipitation Variability in China
DING Xu ,LAI Xin ,FAN Guangzhou 2
1
2
(1. Meteorological Center of Xinjiang Air Traffic Management Bureau,Urumqi 830016,China;
2. School of Atmospheric Sciences,Plateau Atmosphere and Environment Key Laboratory of Sichuan Province,Joint Laboratory of
Climate and Environment Change,Chengdu University of Information Technology,Chengdu 610225,China)
Abstract:Using 1979-2014 Global Land Data Assimilation System-the Community surface parameter data set,
China regional daily observation data grid data set(CN05. 1)and ERA-interim reanalyze atmospheric circulation
data. To study the relationship between the abnormal soil moisture in the Qinghai-Xizang Plateau in May and the
surface heat flux in June and the precipitation change in July. The results show that:(1)From 1979 to 2014,the
average soil moisture in the 0~10 cm layer area in May was abnormally high years were:2000,2001,2004,
2005,2006,2013;the abnormal low years were:1994,1995,1996,1998,1999. Soil moisture increased after
2000. Soil moisture increased after 2000. The soil moisture in the higher Tibetan Plateau,the Three Rivers
Source Region,and the southern Tibetan valley is significantly higher than in the lower years. The results passed
the 90% confidence test.(2)There is a clear correlation between the abnormality of soil moisture in spring and
the distribution of summer precipitation in China. When the soil is wet(dry),from high latitude to low latitude,
the relevant area is "+ - + -"("- + - +")banded distribution.(3)The soil is moist in May,and the sensible heat
flux in the east and the latent heat flux in the west increase in June. Their combined effect strengthens the conver‐
gent circulation of the lower atmosphere and the divergence circulation of the upper layer,so that the East Asia
region is controlled by the strong anticyclone circulation above 850 hPa. The 500 hPa and above in the northeast
of the plateau is an anticyclone circulation,and the south and west are cyclonic circulations. This circulation
field configuration makes the South Asian high pressure move eastward and the Western Pacific subtropical high
pressure.(4)In July,the Huanghuai area on the north side of the Pacific High has a vertical upward movement.
The warm and moist air flow converges with the dry and cold air flow on the west side of the northeast cold vor‐
tex. High-level divergence and low-level convergence are conducive to precipitation in Huanghuai area. The east‐
ern northwestern and northern China regions are controlled by anticyclonic circulation,with strong sinking move‐
ment,dry and cold air,and insufficient water vapor transport,which is unfavorable for precipitation.
Key words:Qinghai-Xizang Plateau;soil moisture;surface thermal conditions;atmospheric circulation;pre‐
cipitation