Simulation of the Precipitation and Its Variation During the 20th Century Using the BCC Climate Model (BCC_CSM1.0)

The precipitation of the late 19th and 20th century (1870—2005) is simulated using Beijing Climate Center's Climate System Model (BCC_CSM1.0) under specified external forcing of solar constant, greenhouse gases, sulfate aerosols and volcanic ashes. The simulated precipitation and its variations are validated, showing that the BCC_CSM1.0 can pretty well simulate the basic climate state of global precipitation, the seasonal transition, the intra-seasonal oscillation of tropical precipitation and the inter-annual variation. The simulation shows there is an increasing trend in global land precipitation and in the extreme precipitation events during 1901—2005. The result consists with the CMAP and CRU analysis data which is based on observations in general, but there are still some discrepancies between the simulated and observed precipitation in the spatial distribution and temporal evolution. The simulation ability of the model needs improvement in some aspects. The simulated seasonal transition of the main rain belt in east part of China is faster than the observation. And the simulated precipitation over northeast part of Tibet Plateau and nearby region is heavier than observation especially in summer. The simulated intra-seasonal oscillation of the tropical precipitation is weaker than the observation. The simulated inter-annual variability is larger than the observation, which mainly occurs in the tropical region where the precipitation is large. The mean precipitation of global land, Eurasia, Asia, east part of China, the south part of the Yangtze River and North China during 1901—2005 from BCC_CSM1.0 is consistent with corresponding CRU data. In most of the above regions the simulated precipitation is lower than the observation. The simulated precipitation trend of global land, east part of China, the south part of the Yangtze and North China from BCC_CSM1.0 is consistent with that from CRU data. The simulated precipitation of global land for 1901—2005 has obvious increasing trend which is more significant than that from CRU data. But for the other regions mentioned, the precipitation trend simulation result is unsatisfactory and needs further improvement.