Characteristics of Atmospheric Particles and Radiation Over Tibetan Plateau
作者单位：Research Institute for Humanity and NatureKyotoJapan
会议名称：《第四届青藏高原国际学术研讨会》
会议日期：2004年
学科分类：07[理学] 070601[理学-气象学] 0706[理学-大气科学]
摘 要：正In order to help a comprehensive understanding of climate processes over Tibetan Plateau, some basic meteorological components （aerosol optical depth, precipitable water, cloud fraction, cloud optical depth, precipitation and surface downward shortwave radiative flux: DSRF） are collected and analyzed to study their seasonal variations. Most of products used here are from satellite data analysis from International Satellite Cloud Climatology Project （ISCCP）. Data of aerosol optical depth, precipitation and radiative flux are from numerical model simulations, ground-based rain gauges and parameterization inputting ISCCP products, respectively. The area interested is E70-E105, N20-N50. Aerosol optical depth is not seasonally-variable. On average, it is about 0.7. This value is rather high over land. The main component of aerosol species seems to be soil particles. Cloud fraction is particularly high in April and July and vice versa. Clouds are optically thicker （around about 30） in summer, and are not so much in other seasons. These would be caused by Asian monsoon for spring-summer and by high-pressure system for fall-winter. DSRF is dominated by the cloud fraction, cloud optical depth and solar zenith angle. Consequently, the seasonal variation of DSRF is complicatedly combinative with cloud and sun-viewing conditions. Satellite-derived DSRF is compared with ground-based pyranometer to be validated. Detailed analyses including precipitation will be shown at the symposium.