宁都县植被覆盖度变化及其对地形因子的响应分析

Analysis on Vegetation Coverage Change and Its Response to Topographic Factors in Ningdu County

为研究南方红壤区植被覆盖度变化及其对地形因子的响应,以宁都县为例,基于Landsat系列遥感影像和像元二分模型提取了研究区2010、2017年两期植被覆盖度,结合宁都县DEM数据提取了高程、坡度和坡向地形因子,分析了2010—2017年植被覆盖度动态变化及其与不同地形因子的相关关系.结果表明:①相比2010年,宁都县2017年植被覆盖度整体上是增加的;②2010—2017年区域植被覆盖度改善总面积大于退化总面积;③地形因子显著影响植被覆盖度变化,宁都县不同年份的植被覆盖度均随高程的增加先升高后降低,随着坡度的增加而增加且在平坡地到斜坡地(0°~8°)和急坡地到险坡地(25°以上)之间受坡度影响较大,整体上不同时期向阳坡区域植被覆盖度均比向阴坡的植被覆盖度要高.

In order to study the vegetation coverage change and its response to topographical factors in the southern red soil region,the paper extracted the vegetation coverage of the studied area in the periods of 2010 and 2017 based on Landsat series remote sensing images and dimidiate pixel model by taking Ningdu County as an example. Combining with the data of elevation,slope and aspect terrain factor extracted from DEM,it analyzed the dynamic changes of vegetation coverage in the period of 2010-2017 and its correlation with different terrain factors. The outcomes show that a) comparing with 2010,the vegetation coverage of the county in 2017 is increased as a whole;b) from 2010 to 2017,the regional vegetation coverage,the total area of improvement is larger than the total area of degradation and;c) the vegetation coverage is significantly affected by topographical factors. The vegetation coverage of the county in different years is increased first and then decreased with the increase of elevation. The vegetation coverage is increased with the increased of slope,from flat slope land to slope land( 0° ~ 8°)and from steep slope land to dangerous slope land( above 25°),the vegetation coverage is greatly affected by the slope. On the whole,the vegetation coverage of sunny slope is higher than that of shady slope in different periods.