摘要
为了更为全面的认识中美半干旱区域陆气交换过程中地表能量水分循环机制,选取分别位于亚欧大陆和北美大陆上2个不同的典型半干旱区(中国北方半干旱带和北美半干旱区)作为研究区域,从地表通量交换的分析入手,以期全面深入认识半干旱区气候变化的物理机制和特点,进一步分析认识其干旱化趋势。结果表明,感热通量冬季最小,夏季次之;高净辐射、低土壤含水量的季节感热通量一般较高。在40°N以北的测站,降水较多的季节潜热通量较大。1979-2008年30年间,中国东部、东北部的半干旱地区气候变干,且在年代际尺度上可能具有持续干旱化趋势;北美各站点感热通量的长期变化趋势与温度变化的趋势相符,潜热通量和降水有较好的一致性,但站点并没有一致的变干或变湿趋势。中美半干旱区感热的年际变化和趋势明显受温度和平均土壤含水量的影响。潜热通量的年际变化和降水呈正相关,同时也受到温度变化的影响。
To study the long-term climate trends and the characteristics of land-atmosphere interaction in the semi-arid regions,is conducive to the understanding of drought formation mechanism. It provides scientific basis for the effective organization of the orderly human activities,alleviation the process of drought and improvement of the ecological environment in arid and semi-arid region. The surface flux is the most critical factor in the landatmosphere interaction. In order to analysis and understand the land-atmosphere interaction in semi-arid region,this paper proposes to start from the analysis of the exchange of the surface fluxes by analyzing the practical observation data in the two typical semi-arid region of China and Northern America. The analysis result shows that the sensible heat flux is the minimum in winter,followed by summer,then spring or autumn. The sensible heat flux is generally higher in seasons with high net radiation and low soil moisture. Data collected by the monitoring stations in the north of 40°N indicates that latent heat flux is larger in seasons with much precipitation. From1979 to 2008,the 30 years witnessed the drying out of climate in semi-arid regions in eastern and northeastern part of China. As time goes,this trend is expected to continue. According to the monitoring stations in Northern America,long-term changes of resonating heat go hand in hand with temperature changes while latent heat and precipitation are in good consistency. Interannual variability of sensible heat flux in semi-arid regions of Central America is significantly affected by temperature changes and the average soil moisture content. There is a positive correlation between the interannual change of latent heat flux and that of rainfall. Besides,latent heat flux is also influenced by temperature change.
出处
《高原气象》
CSCD
北大核心
2014年第5期1262-1271,共10页
Plateau Meteorology
基金
国家重点基础研究发展计划项目(2011CB952004)
关键词
半干旱区
地表热通量
降水
土壤含水量
Semi-arid regions
Surface heat flux
Precipitation
Soil moisture
