Three-year changes of surface albedo of degraded grassland and cropland surfaces in a semiarid area

作     者：LIU HuiZhi1↑, TU Gang2,3 & DONG WenJie4 1 State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chi- nese Academy of Sciences, Beijing 100029, China 2 Laboratory of Research for Middle-High Latitude Circulation System and East Asia Monsoon, China Meteorological Administration, Changchun 130062, China 3 Institute of Meteorological Science of Jilin Province, Changchun 130062, China 4 National Climate Center, Beijing 100081, China 

作者机构：State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Laboratory of Research for Middle-High Latitude Circulation System and East Asia Monsoon China Meteorological Administration Changchun China Institute of Meteorological Science of Jilin Province Changchun China National Climate Center Beijing China 

出 版 物：《Chinese Science Bulletin》 (CHINESE SCIENCE BULLETIN)

年 卷 期：2008年第53卷第8期

页      面：1246-1254页

核心收录：

学科分类：09[农学] 0903[农学-农业资源与环境] 090301[农学-土壤学] 

基　　金：the National Basic Research Program of China (973 Program, 2006CB500401) partly by the Chinese Academy of Sciences (Grant No. KZCX2-YW-219) 

主　　题：半干旱地区 表面反照率 土壤湿度 草地退化 

摘      要：Diurnal, seasonal and interannual variations of surface albedo of degraded grassland and cropland surfaces at a semiarid area of Tognyu have been investigated based on the continuous three years observational data from 2003 to 2005. The changes of surface albedo with solar elevation angle and soil moisture have been discussed also. It has been found that surface albedo has almost the same diurnal and seasonal variations on degraded grassland and cropland surfaces in the semiarid area, while sur- face albedo is large in winter and small in summer. The diurnal variation of the surface albedo has re- lationship with the weather condition. The diurnal cycle of the surface albedo likes the U shape curve in sunny day, while it is low-high after the rain, and high-low after the snow. The surface albedo has large variation in cloudy day, while it has no any variation in overcast day. The large difference of the surface albedo can be 0.04 in winter between two land surfaces, because the snow has large effects on the surface albedo in winter. The rainfall is an important factor in summer on the surface albedo, while the difference of the surface albedo is 0.01 only between two land surfaces. The differences of the surface albedo can also be 0.04 in autumn due to vegetation growing. The seasonal-average surface albeo from 2003―2005 is 0.25, 0.22, 0.24, 0.32 respectively in spring, summer, autumn and winter on the degraded grassland surface,while it is 0.25, 0.21, 0.22, 0.33 respectively in spring, summer, autumn and winter on the cropland surface. The surface albedo becomes smaller with the increase of solar elevation angle. When the solar elevation angle is greater than 40°, the surface albedo changes very little and tends to be a constant. The surface albedo has negative exponent functions with soil moisture in the growing season.