渭河流域植被WUE遥感估算及其时空特征  

Estimating the Spatio-temporal Characteristic of Vegetation Water Use Efficiency over Weihe River Basin

作　　者：位贺杰 张艳芳[3] 董孝斌[1,2] 鲁纳川 王雪超[1,2] 

机构地区：[1]北京师范大学地表过程与资源生态国家重点实验室,北京100875 [2]北京师范大学资源学院,北京100875 [3]陕西师范大学旅游与环境学院,西安710119

出　　处：《自然资源学报》2016年第8期1275-1288,共14页Journal of Natural Resources

基　　金：国家自然科学基金项目(41271549);国家科技支撑计划项目(2012BAD14B03);中央高校基本科研业务费专项资金(2014KJJCB33)~~

摘　　要：论文基于估算NPP的CASA模型和估算ET的三角形模型对水分限制因子算法进行改进的基础上,构建了由NPP子模型和ET子模型组成的WUE遥感估算模型,以2010年相关MODIS影像和气象参量为数据源,实现了渭河流域WUE的估算,并对WUE的时空特征及其与年内气温、降雨的关系进行了分析。研究表明:1)WUE模拟结果与通量观测数据以及生态系统模型模拟结果均具有一定的可比性,各模型模拟结果存在差异可能与WUE定义、模拟区域、使用数据源以及使用植被覆盖分类底图等存在差异有关;2)渭河流域WUE年内分布呈现微"双峰"型格局,以8月最高,春、夏、秋、冬四季WUE分别为0.57、1.05、0.66、0.12 g C·m-2·mm-1,呈现夏季>秋季>春季>冬季的特征;3)渭河流域WUE空间分布呈现子午岭、黄龙山、六盘山以及秦岭北坡等林区高,西安市建成区、子流域上游低植被覆盖区以及局部旱作农业区低的分异特征;4)渭河流域尺度上,WUE随年内气温和降雨的变化均呈现5阶段的变化特征,但变化形式存在差异。Water Use Efficiency（WUE） can be used to describe the relationship between＂water loss＂and＂carbon fixation＂of plants in the process of photosynthesis, which is an important variable to link ecosystem carbon and water cycles. Estimating WUE with remote sensing data can enhance our ability to reveal how global change affects water and carbon cycles. Based on triangle model and CASA model which is used to estimate evapotranspiration（ET） and net primary production（NPP）, this paper constructs the WUE remote sensing estimation models with improved water limiting parameters. Using the constructed model, this paper acquires the WUE of vegetation over the Weihe River Basin in 2010 based on MODIS imagery and meteorological data. Then this paper studies the relationship between WUE and temperature or precipitation. Results are shown as follows： 1） The results of WUE estimated by different WUE models are different because these models are based on different definitions of WUE, different simulation areas, different data sources or different vegetation classifications.2） The monthly variation of WUE roughly shows a double peak pattern over the Weihe River Basin in 2010 with the highest value in August. The seasonal WUE shows that the maximum value is in summer（1.05 g C·m^-2·mm^-1）, followed by autumn（0.66 g C·m^-2·mm^-1）, spring（0.57 g C·m^-2·mm^-1） and winter（0.12 g C·m^-2·mm^-1）. 3） The spatial distribution of WUE shows that the high value pixels are in the forest region of Ziwuling, Huanglong Mountain, Liupan Mountain and the northern slope of Qinling, while the low value pixels are in the built- up regions of Xi＇an city, low vegetation coverage regions of upper basin and some dry farming areas. 4） With the increase of temperature, the change of WUE can be divided into five stages,which are essentially invariant, slightly increased, rapid increased, stable and declined. With the increase of precipitation, the change of WUE over the Weihe River Basin also can be divided

关 键 词：水分生产效率(WUE) 净初级生产力(NPP) 蒸散发(ET) 渭河流域 

分 类 号：Q948[生物学—植物学]