Simulated and projected climate extremes in the Zhujiang River Basin, South China, using the regional climate model COSMO-CLM



This study presents a detailed analysis of simulated and projected climate extremes in the Zhujiang River Basin (ZRB). Daily output from the regional climate model COSMO-CLM (CCLM), driven by the ECHAM5 general circulation model, is used. The hindcast simulation covers the period from 1961 to 2000 while the projection concentrates on the near future period from 2011 to 2050. Spatio-temporal statistical characteristics are investigated for three temperature and three precipitation indicators. The six simulated annual and monthly indicators are statistically compared with synoptic observations. The analysis is based on daily values of 195 grid points and 192 meteorological stations.

The findings are presented and interpreted in terms of the model's capability. Compared to observations, slightly higher values for temperature indicators and slightly lower values for precipitation indicators are simulated. With the resulting good similarities in the spatial variation and trends, we conclude that CCLM is able to satisfyingly reproduce climate extreme for the simulated period. Therefore, our analyses show that CCLM can be used to project climate extremes in the ZRB for the period from 2011 to 2050. The projected changes indicate warmer and wetter conditions in the northern and southern regions, especially in winter and spring. This includes more intense rainfall events, which might potentially increase the risk of flooding in the central parts of the basin in these seasons. Warmer and dryer conditions can be expected in the western and eastern parts of the region, especially in summer and fall. These lower precipitation amounts but warmer temperatures will probably increase the evapotranspiration, which potentially leads to a higher risk of drought. Regarding these findings in climate extremes, adverse consequences in various sectors, such as agriculture, water, and energy should be anticipated.