The Role of Mesoscale Convective Systems in Precipitation in the Tibetan
Plateau region
Abstract
Mesoscale convective systems (MCSs) have been identified as an important
source of precipitation in the Tibetan Plateau (TP) region. However, the
characteristics and structure of MCS-induced precipitation are not well
understood. Infrared satellite imagery has been used for MCS tracking,
but cirrus clouds or cold surfaces can cause misclassifications of MCS
in mountain regions. We therefore combine brightness temperatures from
IR imagery with satellite precipitation data from GPM and track MCSs
over the TP, at the boundary of the TP (TPB) and in the surrounding
lower-elevation plains (LE) between 2000 and 2019. We show that MCSs are
less frequent over the TP than earlier studies have suggested and most
MCSs over land occur over the Indo-Gangetic Plain (LE) and the south of
the Himalayas (TPB). In the LE and TPB, MCSs have produced 10 % to 55
% of the total summer precipitation (10 % to 70 % of summer extreme
precipitation), whereas MCSs over the TP account for only 1 % to 10
\% to the total summer precipitation (1 % to 30 % of
the total summer extreme precipitation). Our results also show that MCSs
that produce the largest amounts of convective precipitation are
characterized by longevity and large extents rather than by high
intensities. These are mainly located south of the TP, whereas
smaller-scale convection makes a greater contribution to total and total
extreme precipitation over the TP. These results highlight the
importance of convective scale modeling to improve our understanding of
precipitation dynamics over the TP.