基于RS和GIS的云南石林县石漠化时空变化特征分析

Analysis of temporal and spatial changes of rocky desertification based on RS and GIS in Shilin County,Yunnan

为探究云南石林县岩溶地区石漠化的时空变化特征,运用基于RS和GIS的Landsat TM/OLI遥感影像数据解译3个时像的石漠化信息,选取变化方式、变化方向等从时间和空间上揭示石林县2008—2018年间的石漠化转移变化过程,结果为:(1)空间上,潜在和轻度石漠化分布范围最广,强度、极强度石漠化主要分布在西街口镇东北部、鹿阜街道东部及圭山镇西南部;(2)时间上,2008、2013和2018年石漠化面积占全县总国土面积的比例分别为19.98%、23.58%和20.19%,呈先增加后减少的趋势,石漠化恶化得到遏制;(3)变化方式以单变方式为主,其次是返变方式,渐变方式最少;(4)变化方向上,3个研究时段内已石漠化类型中转移最显著的分别是轻度—中度石漠化、轻度—潜在石漠化和中度—轻度石漠化,中度及以下石漠化呈现变化速率快并且转移面积多的特点。石漠化改善和恶化同时存在,恶化面积逐渐减少,2008—2013年石漠化恶化明显,2013—2018年石漠化改善明显,变化面积呈金字塔状并且与变化等级成反比关系。2008—2018年间石林县石漠化总体变化速度呈放缓趋势。

In order to explore the temporal and spatial characteristics of rocky desertification in karst areas in Shi-lin County,Yunnan,Landsat TM/OLI remote sensing image data based on RS and GIS was used to interpret the rocky desertification information of three temporal images.The change mode and direction of change were selected from time and space.The study reveals the process of rocky desertification transfer and change in Shilin County from 2008 to 2018.(1)In terms of space,the distribution of potential and light rocky desertification ranges the widest,and strong and extreme rocky desertification is mainly distributed in the West Street,the northeast of Kou Town,the north of Lufu Street and the southwest of Guishan Town.(2)In terms of time changes,the proportions of rocky desertification area in total land area of the county in 2008,2013 and 2018 were 19.98%,23.58%and 20.19%respectively,a trend of first increasing and then decreasing.The deterioration of rocky desertification was curbed.(3)The change mode was mainly single change mode,followed by reversion mode,with least change.(4)In the change direction,from three research periods and the rocky desertification types,the most significant shifts are mild-moderate rocky desertification,mild-potential rocky desertification,and moderate-mild rocky de-sertification.Moderate and below rocky desertification shows a rapid change,with large transfer area.Both im-provement and deterioration of rocky desertification existed,and the area of deterioration gradually decreased.From 2008 to 2013,rocky desertification deteriorated significantly.From 2013 to 2018,rocky desertification im-proved significantly.The area change is pyramid-shaped and is inversely proportional to the change level.From 2008 to 2018,the overall speed of rocky desertification in Shilin County showed a slowdown.