Page 187 - 《高原气象》2022年第5期

高 原 气 象 41 卷
1280

The Relationship between the Surface Cloud Radiative Effect in

Spring and the Qinhai-Xizang Plateau Vortex in July

CHEN Yihao，FAN Guangzhou
（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，Sichuan，China）

Abstract：The Tibetan Plateau Vortex（TPV）is an important kind of precipitation system over the Qinghai-Xi‐
zang（Tibetan）Plateau in summer，and TPVs can produce disastrous weather in the downstream area when they
move off the Qinghai-Xizang（Tibetan）Plateau. Investigating the influence of early factors on the QXPVs in
mid-summer can provide reference for the forecast of disastrous weather caused by QXPVs. Based on CERES ra‐
diation products，ERA-Interim reanalysis data，and QXPVs’datasets，the relationship between the surface net
cloud radiative effect in Spring and the QXPV in July during 2001 to 2017 was discussed by using correlation
analysis，SVD analysis，composite analysis methods. The results show that when the cloud radiative heating ef‐
fect in the central India in spring is stronger，and the cloud radiative cooling effect in eastern China and the West
Pacific region is weaker（stronger）in the north（south），the QXPVs in July（especially warm QXPVs）are more
frequent，stronger，and easier to move out of the Qinghai-Xizang（Tibetan）Plateau. Cloud radiative heating ef‐
fect in the central India in spring could increase the surface temperature and reduce the stability of the atmo‐
sphere，thereby increasing the mid- and low-level cyclonic circulation of the Indian Peninsula，which is condu‐
cive to the transportation of water vapor from the Bay of Bengal to the Qinghai-Xizang（Tibetan）Plateau and
provides water vapor conditions for the QXPVs；At the same time，the high-level divergence is strengthened，
which in turn causes the intensifying and eastward extension of South Asian High（SAH），and cooperates with
the low-level system to provide dynamic conditions for the QXPVs. The Cloud radiative cooling effect weaker
（stronger）in the north（south）of the eastern China and West Pacific region could increase the temperature gradi‐
ent to the north and south，enhances the low（high）-level convergence（divergence），which is conducive to the
intensifying and westward extension of the West Pacific Subtropical High（WPSH），thereby increasing the trans‐
portation of water vapor from the West Pacific to the inland，and provides water vapor conditions for the QXPVs.
According to the results of SVD analysis，three Cloud Radiative Effect Indexes（CREI）are defined，which have
certain indicative significance for the characteristics of the QXPVs in July. The relationship between the different
CREIs and the circulation field verifies that the CRE of the Indian（eastern China and the Western Pacific region）
in spring mainly affects the water vapor transportation on the southern side of the Qinghai-Xizang（Tibetan）Pla‐
teau and the intensifying of the high-level SAH（WPSH）in July，which affects the favorable conditions for the
generation and development of QXPVs in July.
Key words：Qinghai-Xizang（Tibetan）Plateau；Qinghai-Xizang Plateau Vortex（QXTPVs）；cloud radiative ef‐
fect