极端干旱区荒漠-湿地生态系统小气候特征与碳通量变化季节对比  

Contrastive analysis of microclimate and CO_2 flux in different season in Xihu desert wetland of extreme arid region

作　　者：缑倩倩[1,2] 屈建军[1,2] 韩致文[1,2] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所沙漠与沙漠化重点实验室,甘肃兰州730000 [2]中国科学院寒区旱区环境与工程研究所敦煌戈壁荒漠生态与环境研究站,甘肃敦煌736200

出　　处：《干旱区地理》2014年第6期1119-1127,共9页Arid Land Geography

基　　金：国家科技支撑计划课题"敦煌生态修复关键技术研究与示范"(2012BAC08B07)资助

摘　　要：甘肃敦煌荒漠-湿地具有极干旱区湿地生态系统和荒漠生态系统的典型性和代表性,在中国乃至世界上都具有重要的特殊性,然而目前关于该区小气候特征以及碳通量变化的研究基本属于空白。利用2012年夏季与冬季甘肃敦煌西湖实验观测资料,从中分别选取资料较好的5个连续晴天,对比分析了该地区荒漠-湿地生态系统冬夏两季局地气候、辐射特征以及碳通量的日变化。结果表明:(1)西湖地区两个季节湍流混合都比较充分,全天以上升气流为主,两季节温差较大,表层土壤温湿度对气温以及太阳加热作用敏感,冬季波动幅度小于夏季;(2)冬夏季辐射各分量具有典型日变化特征,但冬季各分量明显低于夏季,且该地区向下和向上长波辐射比同季节同纬度高海拔地区高;(3)西湖地区生态系统碳吸收的日最大值出现在上午11∶00前后,CO2浓度随着时间的推移逐渐降低,两个季节均表现为"碳汇",冬季的碳汇作用较弱一些。The Xihu desert wetland, Dunhuang, Gansu Province, China is quite important and peculiar in China or even in the world. However, until now, little research has been focused on the microclimate and CO2 flux characteris- tic in this area. This paper reports the characteristics of daily variations of microclimate and COs flux in the Dun- huang Xihu desert wetland by analyzing the data observed in the Xihu desert wetland of Dunhuang for summer and winter continuous fine weather in 2012. Results indicated a level of turbulent mixing in agreement with the observa- tions in Xihu region for summer and winter weather, justifying their reliability, and there existed updraft prevails in this re^- ion in the two seasons. The temperature and humidity of topsoil were both sensitive to the air temperature and solar heating in summer and winter, but the variation amplitude in winter was less than that in summer. The components of the ground surface radiation in the Xihu desert wetland of Dunhuang in summer and winter both showed typical daily variation, but it was lower in winter, and the ground upward longwave radiation and atmospheric longwave radiation were higher than that in other high altitudes. The maximum value of carbon absorption both ap- peared at about 11 o＇ clock every day in the two seasons. The concentration of carbon dioxide both gradually de- creased as time went on, therefore, the desert wetland ecosystem was a carbon sink during the observation period in summer and winter, but it was weaker as a carbon sink in winter.

关 键 词：近地层 小气候特征 能量平衡 碳通量 对比分析 敦煌 极端干旱区 

分 类 号：P463.2[天文地球—大气科学及气象学]