VARIATIONS OF CLOUD FRACTION OVER EAST ASIA UNDER GLOBAL WARMING CONDITIONS IN THE PAST 20 YEARS

Based on the variation of cloud fraction revealed by D2 Cloud Climatic Data of the InternationalSatellite Cloud Climatology Project and trend analysis methods, the trend of different types of cloud fractionover East Asia during 1984-2006 is obtained. The analysis focuses on the relationship between temperatureand different cloud fraction under the background of globe warming. The result shows a fluctuatingdecreasing tendency in the total cloud fraction, high-level cloud and low-level cloud over East Asia with thedecrement being 2.24%, 1.65% and 1.68%, respectively, while the mid-level cloud increases by 1.07%. Inaddition, there are great regional differences in cloud fraction. Temperature and water-vapor contentvariation caused by the greenhouse effects over East Asia is the primary reason for the variation of cloudfraction. Over the Tibetan Plateau, the Bay of Bengal and the Intertropical Convergence Zone, thetemperature is negatively correlated with high-level cloud, but positively correlated with mid- and low-levelcloud. However, over the West Pacific and the ocean east and north of Japan, the temperature is negativelycorrelated with low-level cloud but positively correlated with high-level cloud.