Abstract
As rapid warming and consequent glaciers retreat across the Tibetan
Plateau (TP), the problem about whether or not atmospheric water supply
could alleviate the depletion of surface water storage need to be
examined. Long-term changes of atmospheric water vapor balance across
the TP is investigated by the ERA5 reanalysis from 1979 to 2018.Annual
accumulated precipitation, water vapor convergence and evaporation
generally keep an equilibrium but with different long-term variation
trends: 0.68mm/a, 0.68mm/a and -0.18mm/a, respectively. Results suggest
that surface water storage will not be well replenished by the water
vapor transported from outside of the TP. For different regions of the
TP, characteristic of water vapor balance and their long-term trends are
completely different. Regions around Yarlung Zangbo Grand Canyon
experiences sharp decrease in water vapor convergence and leads to
decrease in precipitation. Meanwhile, evaporation keeps increasing due
to the warming and melting of glaciers. Loss of surface water storage
should be severe. For the source region of the Three Rivers, decrease in
water vapor convergence overlaps increase in evaporations leads to no
significant changes in total precipitations. Decrease in water
transported from outsides brings risk to the depletion of surface water
storage. Brahmaputra basin, inner TP and Qilian Mountain show
significant wetting trends due to the increases in both convergence of
water vapor flux and evaporation. Above regional characteristics of
water vapor balances across the TP cause by inhomogeneous variation of
atmospheric heat source and changes of atmospheric circulations, which
need to be studied in further.