甘肃岷县漳县MS6.6地震前后岷县植被覆盖度动态变化

利用Landsat8遥感影像数据,应用像元二分模型估算了岷县植被覆盖度,分析了岷县漳县地震前后岷县植被覆盖度动态变化,并结合高程和坡度数据,研究了地形因素对植被受损和恢复的影响,结果表明:3个时段岷县植被覆盖度以中高和高植被覆盖度为主,反映出研究区植被覆盖状况良好。①空间分布上来看,中高和高植被覆盖度主要分布在岷县西南和东南部的高海拔地区,低植被覆盖区由岷县县城所在地向西北方向两侧沿居民地延展;②2013-2014年平均植被覆盖度下降了0.09,受损面积达到96.53%,主要为高植被覆盖度植被受损,植被受损在高程上主要分布在2 344~3 283 m,坡度5°~35°范围是植被受损的主要区域;③2014-2017年平均植被覆盖度回升至0.43,恢复面积达2 901.93 km^2,以高植被覆盖度植被恢复为主,其次为低植被覆盖度;植被恢复在高程2 031~2 970 m,呈增长趋势,随后开始下降,在坡度0°~25°范围内植被恢复面积呈增加趋势,随后降低。

Vegetation Cover Dynamic Changes of Minxian Before and After Minxian-Zhangxian MS6.6 Earthquake in Gansu Province

Using the Landsat8 remote sensing image data, the imidiate pixel model was used to estimate the vegetation coverage of Minxian county before and after the Minxian-Zhangxian MS6.6 earthquake, and combined with elevation and slope data, the effects of topographic factors on vegetation damage and restoration were studied. The results showed that: The vegetation coverage of Minxian County in the three periods was mainly medium and high vegetation coverage, reflecting the good vegetation coverage in the study area. ① In terms of spatial distribution, the mediumhigh and high-vegetation coverage is mainly distributed in the high-altitude areas in the southwest and southeast of Jixian County, and the low-vegetation coverage area is extended along the residential areas from the location of the Jixian County to the northwest. ② From 2013 to 2014, the average vegetation coverage decreased by 0.09, and the damaged area reached 96.53%, mainly due to the damage of vegetation with high vegetation coverage. Vegetation damage is mainly distributed in the elevation of 2 344~3 283 m, and the slope of 5°~35° is the main area of vegetation damage. ③From 2014 to 2017, the average vegetation coverage rose to 0.43, and the restored area reached 2 901.93 km2. Vegetation restoration was dominated by vegetation restoration with high vegetation coverage, followed by low vegetation coverage. The vegetation restoration showed an increasing trend at an elevation of 2 031~2 970 m, and then began to decline. The vegetation restoration area showed an increasing trend at a slope of 0°~25°, and then decreased.