为研究伏牛山地区植被覆盖的变化情况,利用1991、2002和2011年三期TM卫星遥感影像,基于NDVI的像元二分模型,对整体植被变化趋势进行研究,并比较三期变化;同时结合数字高程模型对不同海拔的植被覆盖变化做对比分析;最后,分析气象因子的变化趋势.研究结果表明:(1)从分布上看,研究区整体植被覆盖状况较好.植被覆盖度随海拔的上升先增加后降低,临界点在海拔1 700-1 800m之间.(2)从变化上看,21年以来,植被覆盖度呈增加趋势.海拔高度1 650m以下区域的植被覆盖度变化情况最为明显,这是由于人类活动主要集中在海拔较低的区域,而海拔高于1 650m的区域变化较小,受人类活动的影响较小.(3)从21年温度和降水变化来看,研究区域内植被覆盖度和温度的变化趋势并不一致,而和降水量变化的趋势有较高的一致性,具体表现为随降水量的增加,植被覆盖较好的Ⅳ级(F≥0.7)植被覆盖度区域面积增加.
As a significant part of global ecosystem and climate system, vegetation coverage is the key and of the utmost importance on the research of mountain geographical systematic change. Besides, the evolved environmental change is another aspect of the study for its practical use. As is well known, vegetation cover is sensitive to climate change, and in return, the change of vegetation also influences climate. Therefore, the study on the response of mountain vegetation coverage towards climate, especially the dynamic response on surrounding environment is helpful and serves as guideline on the understanding of climate change in a larger and broader area. It is also believed that vegetation coverage can not only reflect surface vegetation, but also works as a dynamic monitor of ecosystem. It can simultaneously reflect the real-time state of ecosystem and point out questions in time. As a natural result, the study on vegetation cover change is important in global change research for its high accuracy and quick respond. The normalized difference vegetation index (NDVI) is the most common index since it can reflect large scale vegetation coverage, which is a real helper on the process of related reserches. This paper hence adopted the case of Funiu Mountain as an example. Because the mountain is located in the west mountain area of Henan Province, a place of the richest vegetation inside the overall province. In order to study the vegetation cover change in Funiu Mountain, this paper started from 3 TM satellite remote sensing images during 1991--2011 and surveyed the trend of overall vegetation cover change based on the method of NDVI dimidiate pixel model, then a comparative analysis oncow, rage change of different altitudes was conducted combined with the three sensing images and digital elewtion model. At last, this paper analyzed the changing trend of climatic factors. The results are as follows: (1) In the aspect of spatial distribution, overall vegetation cover in the study area is good, and vegettion cov