基于亚米级卫星数据的典型喀斯特小流域石漠化空间格局与演变特征

The Spatial Pattern and Evolution Features of Rocky Desertification in Representative Karst Watershed based on Sub-Meter Satellite Data

关键词:  指数分类法  石漠化等级  演变方向  演变速率

Key words:  index classification  classification of karst rocky desertification  evolution direction  evolution rate

摘要:

[目的]阐明石漠化演变的过程和机制，为下一步石漠化综合治理的方向和重点提供科学依据。[方法]选取契合喀斯特地区景观特点的亚米级卫星数据，使用指数分类法提取2003年和2013年研究区不同等级石漠化信息，对研究区石漠化空间格局和演变特征进行分析。[结果]指数分类法分类精度评价结果显示，Kappa系数大于0.8，且野外验证精度为85%，说明解译结果可信。2003-2013年，研究区石漠化面积从96.55 km²减少至88.97 km²，石漠化面积呈现减少的趋势，总体减少速率为0.76 km²/a；无明显石漠化增加速率最大，为20.11 km²/a，轻度和中度石漠化演变速率为-0.23 km²/a和-0.02 km²/a。虽然不同等级石漠化面积之间均有转化，但是向无明显石漠化转移的面积（7.65 km²）大于向强度石漠化转移的面积（3.04 km²）。演变方向上，石漠化轻度改善的面积最大为10.56 km²。[结论]研究区整体的石漠化状况有所好转，总体上石漠化治理取得一定的成效，但是轻度恶化的面积（6.08 km²）也不容忽视，需要对石漠化治理工程效果进行巩固。

Abstract:

[Objective] The study is aimed to clarify the process and mechanism of the karst rocky desertification,which may provide scientific basis for the direction and the focus of the comprehensive control of karst rocky desertification.[Methods] The sub-meter satellite data matching the landscape characteristics of the karst area was selected. The index classification method was used to extract the rocky desertification information of different grades in the study area in 2003 and 2013.The spatial pattern and evolution characteristics of rock desertification in the study area were analyzed.[Results] The classification accuracy evaluation results of the index classification method showed that the Kappa coefficient was greater than 0.8,and the field verification accuracy was 85%,indicating that the interpretation results were credible. From 2003 to 2013,the area of rocky desertification in the study area decreased from 96.55 km² to 88.97 km²,and the rocky desertification area showed a decreasing trend,with an overall reduction rate of 0.76 km²/a. The increase rate of no obvious rocky desertification was the largest,which was 20.11 km²/a,and the evolution rate of mild and moderate rocky desertification was -0.23 km²/a and -0.02 km²/a. Although there were conversions between different grades of rocky desertification,the area transferred to the area without obvious rocky desertification (7.65 km²) was larger than that transferred to the intensity rocky desertification (3.04 km²). In the direction of evolution,the area of slight improvement of rocky desertification was 10.56 km².[Conclusion] The overall rocky desertification situation in the study area has improved. In general,the rocky desertification control has achieved certain results,but the slightly deteriorated area (6.08 km²) cannot be ignored. It is necessary to consolidate the effect of the rocky desertification control project.