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Precipitation Over China: CMIP5 Model Simulations vs. Reality

Paper Reviewed
Chen, L. and Frauenfeld, O.W. 2014. A comprehensive evaluation of precipitation simulations over China based on CMIP5 multimodel ensemble projections. Journal of Geophysical Research: Atmospheres 19: 5767-5786.

Authors Chen and Frauenfeld (2014) write that "precipitation is a key component in the climate system and represents a crucial link between the atmosphere, hydrosphere and biosphere," noting "climate change and the associated precipitation variability produce substantial impacts on both natural environments and human society." Against this backdrop the pair of researchers set out to evaluate precipitation simulations for all of China, as well as for individual sub-regions, based on 20 General Circulation Models from the CMIP5 archive with simulations for both the 20th and 21st centuries; and in so doing they "employ a suite of model evaluation statistics to provide a comprehensive assessment of model performance." And what did their evaluation reveal?

The two researchers report that (1) "uncertainties in climate models are still evident," that (2) "the models overestimate the magnitude of seasonal and annual precipitation in most regions of China, especially along the eastern edge of the Tibetan Plateau," that they (3) "underestimate summer precipitation over southeastern China," that (4) "CMIP5's overestimation of annual precipitation is greater than CMIP3," that (5) "there is a wide spread among individual models, with the greatest uncertainties in simulating summer precipitation," that (6) "there is poor agreement in precipitation trends over the southeast and northeast regions," and that (7) "in general, multi-model means cannot capture the amplitude of observed multi-decadal precipitation variability." Given such, Chen and Frauenfeld conclude that "due to the uncertainties in CMIP5, future precipitation projections should be interpreted with caution."

Posted 2 October 2014