Impacts of the Tibetan Plateau Winter/Spring Snow Depth and Surface Heat Source on Asian Summer Monsoon: A Review

The climate effect of the Tibetan Plateau (TP) snow depth and surface heat source are two major topics of the TP climate dynamics. Numerous results from data analysis and numerical modeling have confirmed that both the TP snow depth and surface heat source can be utilized as the precursors of the Asian summer monsoon anomaly. This paper provides an overall review on relevant studies, and the differences and similarities between impacts of these two factors on the East Asian and South Asian summer precipitation are further discussed. It is shown that East Asian summer precipitation has two typical spatial patterns on both the interannual and interdecadel timescales, i.e., the triple pattern and the North and South reversed-phase pattern. On the interannual and interdecadel timescales, the triple rainfall pattern is mainly affected by the TP surface heat source, and decadal changes in the South flood-North drought rainfall pattern over eastern China is also largely affected by the surface heat source. However, the impact of the TP snow depth seems to be opposite to that of the surface heat source. Particularly, the TP winter snow depth has a better predictive meaning for the Indian summer monsoon rainfall than the TP surface heat source on both timescales. Statistically, there is no robust relationship between the TP winter snow depth and spring surface heat source on both their spatial distributions and time series. A better ground observation network and improved model performance over the TP are imperative to obtain more insights of the potential physical progresses and mechanisms for the impacts of the TP snow depth and surface heat source on the Asian summer monsoon.