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Modeling the Tibetan Plateau Summer Monsoon
Duan, A., Hu, J. and Xiao, Z. 2013. The Tibetan Plateau summer monsoon in the CMIP5 simulations. Journal of Climate 26: 7747-7766.

The authors write that "the Tibetan Plateau (TP) monsoon is characterized by the remarkable seasonal alternations in wind and precipitation fields that occur over and around the plateau between winter and summer, with the most significant circulation differences in the surface pressure system," citing Tang et al. (1979). And they add that simulating monsoon systems "is one of the most challenging problems for atmospheric general circulation models (AGCMs) and coupled general circulation models (CGCMs)."

What was done
In the words of Duan et al., "the extensive integrations produced for CMIP5 from the historical runs of 15 CGCMs and AMIP runs from eight AGCMs were used to evaluate the performance of state-of-the-art GCMs in simulating the climatology, annual cycle, interannual variability and trend of the TPSM [Tibetan Plateau Summer Monsoon]."

What was learned
The three researchers report that (1) "no single model consistently performed well in all aspects of the simulation," that (2) "a large bias still exists in the climate mean summer precipitation intensity," that (3) "the observed seesaw pattern in the interannual variability of the TPSM and EASM [East Asian Summer Monsoon] can be reproduced by only a few models," that (4) the simulated tropospheric warming trend of recent decades "was significantly larger than in the observational data," and that (5) "the observed cooling trend in the upper troposphere and the decline of the Tibetan high were not simulated by most of the GCMs."

What it means
Duan et al. conclude that "significant scope still exists for improving the simulation by GCMs of TPSM precipitation and regional climate change, especially in very mountainous areas."

Tang, M.C. 1979. On climate characteristics of the Xizang Plateau monsoon. Acta Geographica Sinica 34: 33-42.

Reviewed 11 December 2013