【摘要】 贵州高原具有少日照、多云雨和复杂下垫面的山地特殊气候和地形,准确探究该区域生态系统水分利用效率(WUE)的时空分异特征对进一步了解喀斯特地区碳水循环过程具有重要意义。本文气象站点数据用ANUSPLIN软件进行插值处理,与使用时间序列谐波分析法和质量控制文件重新构建高质量的MODIS-NDVI数据作为CASA模型的输入数据模拟植被NPP,再结合MOD16-ET数据估算WUE。综合利用Theil-Sen Median趋势分析、Mann-Kendall检验和稳定性分析等统计方法,对贵州高原2000—2014年各地貌区、植被类型WUE的时空分异特征进行对比分析。研究表明:(1)研究区近15年来WUE均值和趋势的空间格局都呈西部高于东部的特点, WUE趋势呈显著增加态势(R~2=0.63,P<0.001)。(2)从各地貌区来看,多年WUE均值排序为:断陷盆地>岩溶峡谷>峰丛洼地>非喀斯特地貌>岩溶高原>岩溶槽谷,其中断陷盆地和岩溶峡谷呈显著(P<0.05)增加趋势。(3)从不同植被类型来看, WUE大小呈混交林>阔叶林>耕地>针叶林>草地>灌丛排序。针叶林和灌丛变异系数(CV)值较高,但前者对气候波动的抵挡能力更强,增加速率更快。草地CV值最低,变化速率最慢,不易受气候波动的影响。由于退耕还林等生态工程的实施效果显著,使耕地WUE的变化速率最快。更多还原

【Abstract】 There are special climate and terrain in mountain areas of Guizhou Plateau including less sunshine, more cloud, rain and complex underlying surface. It is important for further understanding the process of carbon and water cycle in Karst area if we accurately explore the spatio-temporal differential characteristics of ecosystem water use efficiency(WUE) in this area. The data of meteorological stations in this paper were handled with interpolation by ANUSPLIN software. Meanwhile, high-quality MODIS-NDVI data had been reconstructed by time series harmonic analysis and quality control file as common input data of the CASA model to simulate NPP and estimated WUE with MOD16-ET data. With statistical method including Theil-Sen Median trend analysis, Mann-Kendall test and stability analysis, the spatial and temporal differential characteristics of WUE in different landform regions and vegetation types of Guizhou Plateau from 2000 to 2014 were compared and analyzed. The following were the results:(1) The spatial pattern for trend and WUE average value in the researching area during past 15 years was higher in western part than eastern and the trend of WUE was increasing significantly(R~2=0.63, P<0.001).(2) From the point of view of various landform regions, the order of WUE average value for many years was: fault depression basin > karst canyon > peak-cluster depression > non-karst landform > karst plateau > karst trough valley, among which fault depression basin and karst canyon showed a significant increase trend(P<0.05).(3) Viewing from different vegetation types, WUE value size ranked as mixed forest > broadleaf forest > cultivated land > coniferous forest > grassland > shrub. Coniferous forest and shrub coefficient variation(CV) were higher, but the former one had stronger resistance to climate fluctuations with faster growth rate. The CV value for grassland was lowest and change rate was slowest which was not easily affected by climate fluctuations. Because of the remarkable effect of ecological projects such as returning farmland to forests, the variation rate of WUE for cultivated land was the fastest.更多还原