摘要:
为了研究三峡库区近50年的林地变化及气候响应,该文以TM、SPOT、MSS影像和地形图等多种信息源为基础,通过一种新的自动提取方法获取了2002年三峡库区的各类型林地资源现状分布,并通过人工修改达到了精度要求.通过人工解译找动态图斑的方法获取了近50年三峡库区其他各期(2000、1995、1986、1973和1953年)的林地资源分布图,并对近50年三峡库区各种林地的变化过程作了分析.以全国1915个站点的气象数据为基础,通过插值获取三峡库区的气候要素资料,并对三峡库区林地变化的气候响应做了阐述.结果表明:三峡库区的各种林地在近50年经历了剧烈减少—缓慢减少—较大减少—不断恢复的发展过程.三峡库区的年均气温对林地变化的响应不明显,而年降水量与林地面积变化呈正相关,但是年降水量的变化相对于林地面积的变化在时间上具有滞后性和某个时段上的反常性.
Abstract:
In order to make a detailed analysis of forestland changes and their climate responses during the last 50 years, the authors obtained information for the year 2002 of the distribution of forestland by the application of a new auto-extraction method with relatively high precision. The authors took TM, SPOT and MSS images as well as topographic maps, assisted by manual revision, as our fundamental information sources. And the forestland distribution maps of previous periods (years of 2000, 1995, 1986, 1973 and 1953) were also obtained by the manual interpretation method, which was carried out in the way of searching for dynamic spots. Meanwhile, analysis was made on the process of the dynamic changes of forestland during the last 50 years. Moreover, on the basis of data collected from 1 915 stations throughout China, the meteorological data in the Three Gorges Reservoir Area were obtained by the interpolation method and also the climate responses to the changes of forestland were analyzed.Resultsshow that each kind of forestland area in the Three Gorges Reservoir Area has experienced a process of sharp reduction--mild reduction--relatively great reduction--slow restoration during the last 50 years. The response of the annual average temperature to the forestland changes is not significant. However, the changes of annual average rainfall are closely related with those of the forestlands, although its changes lag behind the forestland changes and have abnormality in certain period.
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