张掖湿地CO_2通量变化特征及光能利用率分析  

Dynamics of CO_2 flux and analysis of light use efficiency over a wetland in Zhangye,China

作　　者：蒋国庆[1,2,3] 王玉洁[4,5] 孙睿[1,2,3] 张蕾[1,2,3] 刘绍民[1,2] 徐自为[1,2] 张强 

机构地区：[1]遥感科学国家重点实验室(北京师范大学/中国科学院遥感应用研究所),北京100875 [2]北京师范大学地理学与遥感科学学院,北京100875 [3]环境遥感与数字城市北京市重点实验室,北京100875 [4]西北区域气候中心,甘肃兰州730020 [5]南京大学大气科学学院,江苏南京210023

出　　处：《干旱区地理》2016年第4期809-816,共8页Arid Land Geography

基　　金：国家自然科学基金(41471349);国家科技支撑计划项目(2013BAC03B02);中央高校基本科研业务费专项(2014k JJCA02)

摘　　要：湿地生态系统储存着大量的碳,在陆地碳循环中扮演着很重要的角色。同时,湿地生态系统本身比较脆弱,特别是干旱地区湿地生态系统,对气候变化非常敏感,容易受到环境因素的影响而改变原有的碳循环模式。干旱区湿地碳循环规律研究不但有助于评估干旱区湿地生态效益,也有助于分析其对气候变化的响应。通过对甘肃省张掖湿地CO_2通量的观测(2012年6月~2014年8月),分析了湿地生态系统CO_2通量的季节变化特征,并结合遥感数据,估算了湿地生态系统的光能利用率,分析了环境因子对CO_2通量和光能利用率的影响。结果表明,湿地CO_2通量的季节变化特征明显,两整年GPP平均值为1.06 kg C m^(-2)·a^(-1),NEE平均值为-0.40 kg C m^(-2)·a^(-1),为明显的碳汇。空气温度和土壤温度与夜间生态系统呼吸都呈显著的指数关系,太阳辐射与湿地白天CO_2通量呈负相关,并且随季节不同,相关性差异较大。结合遥感数据计算得到的光能利用率最大值为1.51 g C·MJ^(-1),生长季平均光能利用率为1.07 g C·MJ^(-1)。光能利用率与温度有一定的相关性,随温度升高,光能利用率呈现增大趋势。Wetland ecosystem stores a large amount of carbon in the soil and plays an important role in the terrestrial carbon cycle. Meanwhile,wetland ecosystem,especially wetland in the arid area,is sensitive to climate change and very fragile. Its carbon cycle is easily influenced by environmental factors and human activity. It is significant to study carbon cycle of wetland ecosystem in the arid area. With CO2 flux observation over a Phragmites-dominated wetland in Zhangye oasis,Gansu province,northwest China（from June,2012 to August,2014）,the seasonal change of CO2 flux and environmental impact factors of the wetland were analyzed first. And combining with fraction of absorbed photosynthetically active radiation（FPAR）from MODIS remote sensing data,light use efficiency（LUE）of the wetland was also estimated. The results showed that there was a distinct seasonal variation of CO2 flux. The mean gross primary productivity（GPP）over two years was 1.06 kg C·m^-2·a^-1and the mean net ecosystem exchange（NEE）over two years was-0.40 kg C·m^-2·a^-1 The wetland was apparently a carbon sink. The night-time ecosystem respiration exponentially increased with air temperature and soil temperature,while there was a negative correlation between daytime CO2 flux values and incident solar radiation,and the relation changed seasonally. The maximum value of LUE was 1.51 g C·MJ^-1 and the average LUE during the growing seasons was 1.07 g C·MJ^-1. LUE was generally related with air temperature,and the value of LUE increased with temperature increasing,which means the higher conversion efficiency of solar energy to dry matter when the air temperature is close to the optimum temperature for vegetation growth.

关 键 词：湿地 涡度相关 CO2通量 温度 辐射 光能利用率 遥感 

分 类 号：Q14[生物学—生态学] X171[生物学—普通生物学]