Abstract
Total evaporation from the vast terrain of the Tibetan Plateau (TP) may
strongly influence downwind regions. However, the ultimate fate of this
moisture remains unclear. This study tracked and quantified
TP-originating moisture. The results show that the TP moisture
participation in downwind regions’ precipitation is the strongest around
the eastern edge of the TP and then weakens gradually toward the east.
Consequently, TP moisture in the composition of precipitation over the
central-eastern TP is the largest of over 30%. 44.9-46.7% of TP annual
evaporation is recycled over the TP, and about 2/3 of the TP evaporation
is reprecipitated over terrestrial China. Moisture cycling of TP origin
shows strong seasonal variation, with seasonal patterns largely
determined by precipitation, evaporation and wind fields. High levels of
evaporation and precipitation over the TP in summer maximize local
recycling intensity and recycling ratios. Annual precipitation of TP
origin increased mainly around the northeastern TP during 2000-2020.
This region consumed more than half of the increased TP evaporation.
Further analyses showed that changes in reprecipitation of TP origin
were consistent with precipitation trends in nearby downwind areas: when
intensified TP evaporation meets intensified precipitation, more TP
moisture is precipitated out. The model estimated an annual
precipitation recycling ratio (PRR) of 26.9-30.8% in forward moisture
tracking. However, due to the non-closure issue of the atmospheric
moisture balance equation, the annual PRR in backward tracking can be
~6% lower.