Impact of Improved Soil Freezing Process on Climate in East Asia Using NCAR CAM Model

An improved frozen soil parameterization scheme is introduced and its effects on climate in East Asia are investigated by using the latest version of general circulation model (GCM) CAM3.1 developed at NCAR. Simulation results show that the improved soil freezing process leads to enhanced heating of the earths surface by the atmosphere over most parts of Eurasia in winter, while it leads to enhanced heating of the atmosphere by the earth's surface in summer, especially the abnormal heating is significantly strengthened over the Tibetan Plateau. The climate in East Asia is very sensitive to the frozen soil parameterization with notable change of the surface air temperature in both winter and summer. With the improved soil freezing process, the simulated Siberian high is enhanced and the East Asia trough moves westward in winter; the East Asian summer monsoon is intensified, and the western Pacific Ocean subtropical high extends northwestward, resulting in increasing rainfall in northern China and the middle and lower reaches of the Yangtze River and decreasing rainfall in South China. These results may have meaningful implications for improving the performance of GCM to simulate the climate in East Asia.