摘要
针对叶尔羌河流域这一生态脆弱区,基于像元二分法利用MODIS NDVI数据计算该研究区典型正常年份2016年6-9月生长季植被指数(植被覆盖度),分析探讨了该流域植被覆盖度与土地利用/覆盖状况及高程、坡度、坡向等地貌状况主要要素之间的耦合关联关系。结果表明:叶尔羌河下游地区地形起伏较小,植被覆盖状况和土地利用/覆盖类型均具有明显的地带状与分层分布特征,植被覆盖度仅与距离水源地的远近相关性显著,与高程、坡度等其他地貌因子无明显相关性;而叶尔羌河中上游地区植被覆盖状况复杂,植被覆盖度与高程、坡度和坡向三因子总体耦合度较高。高程对植被覆盖状况的影响尤为显著,具有明显的垂直地带性;同时,随着高程增加,坡度对植被覆盖度的影响则表现出一定的垂直周期地带变化特性,以及随着坡向的变化植被覆盖度呈现出由阴坡、半阴坡较高(4 000m以下地区)按"顺时针"向阳坡、半阳坡较高(4 000m以上地区)逐渐转移。
Exploring the relationship and interaction between Fractional Vegetation Cover(FVC) and geomorphologic status in the Yarkant River basin being a vulnerable and sensitive ecological area is very significant to protect its ecological environment and rationally utilize its natural resources.In this paper,based on the MODIS NDVI data in June,July,August and September of 2016,we generated a composite image of Maximum NDVIs and then calculated its vegetation indices(FVCs)of these typic growing seasons of this typical year over the Yarkant River basin by using apixel dichotomy technique;sequentially,the consistency between the FVCs and the land use/cover status was studied,and the coupling features between the FVCs and the main geomorphologic factors,i.e.,elevation,slope grade,and slope aspect were analyzed.The results show that,given the flat and/or gently undulating topography and limited water resources,etc.in the lower Yarkant River region,there exist obvious zonalities with gradual change belt features,so the FVCs are only significantly correlated with the distances from water sources but no remarkable relationship with elevation,slope grade and slope aspect.However,in the upper-middle drainage basin of the Yarkant River,the complicated vegetation cover conditions occur,which thus results in the higher coupling degrees between the FVCs and the three key geomorphologic factors,and among them,the elevation plays the most significant role in the vegetation coverage status with an obvious vertical zonality.Meanwhile,the effect of slope grades on the FVCs presents a phenomenon of vertical periodic zonality variation characteristics with elevation increasing,while the effect of slop aspects shows an interesting tendency,namely,a clockwise gradual transition appears from the shady-slope and/or half shady-slope areas(below 4 000 m)to the sunny slope and/or half sunny slope areas(above 4 000 m).Additionally,there are a series of transitional types of FVCs in the areas with high FVCs from the shady-slope to the sunny slope.
作者
于涛
杨延梅
冯建中
白林燕
张沛
雒艺欣
YU Tao;YANG Yanmei;FENG Jianzhong;BAI Linyan;ZHANG Pei;LUO Yixin(College of River and Ocean Engineering,Chongqing Jiaotong University,Chongqing 400074,China;Agricultural Information Institute,Chinese Academy of Agricultural Sciences,Beijing 100081,China;Institute of Remote Sensing and Digital Earth,Chinese Academy of Sciences,Beijing 100094,China)
出处
《测绘科学》
CSCD
北大核心
2019年第9期61-72,共12页
Science of Surveying and Mapping
基金
中国科学院“西部之光”人才项目（YBXM-2014-05）
中国科学院战略性先导科技专项（A类）（XDA19030302）
国家自然科学基金项目（41771392）
中国农业科学院农业信息研究所科技创新工程项目“智慧农业关键技术研究与应用”（CAAS-ASTIP-2017-AII2017）
关键词
叶尔羌河
植被覆盖度
地貌因子
耦合关系
Yarkant River
FVC
geomorphologic factors
coupling relationship
