六盘山贫困区生长季植被覆盖变化及其对水热条件的响应

Vegetation cover change and its response to water and heat conditions in the growing season in Liupanshan poverty-stricken area

利用MODIS13,MODIS11和国家气象站点监测数据,以六盘山集中连片贫困区为研究区,采用最大值合成法、像元二分模型和偏相关分析等方法,分析了该区域生长季植被覆盖时空变化趋势,以及对地表温度和土壤湿度对植被生长的交互作用。结果表明:2001—2018年间,六盘山贫困区生长季植被覆盖度由0.28提升到0.45,且呈现出由东南向西北递减的格局;研究时段内表现为整体改善、局部退化的态势。其中,改善区占51.91%,无显著变化区占44.22%,退化区占3.87%;植被生长与地表温度和土壤湿度的年内变化紧密相关,空间上呈现出协同正相关、协同负相关、反向相关3大类型,但以协同正相关占主导地位;交互作用分析表明,土壤湿度对该区域植被生长的影响大于地表温度的影响,土壤水分条件是影响该区域植被生长的主导因子,土壤水分条件的改善对研究区生态环境建设与修复至关重要。

Based on the MODIS13Q1,MODIS11Q2 data and national meteorological station monitoring data and using the methods of maximum value synthesis,the average two pixel model and partial correlation analysis,the authors analyzed the temporal and spatial variation trend of vegetation coverage in the growing season and the interaction of land surface temperature and soil moisture on vegetation growth.The results are as follows:①From 2001 to 2018,the vegetation coverage of Liupanshan poverty-stricken area increased from 0.28 to 0.45,and showed a decreasing pattern from southeast to northwest.②During the research period,there existed a trend of overall improvement and local degradation:the improved area accounted for 51.91%,the area without significant change accounted for 44.22%,and the degraded area accounted for 3.87%.③The growth of vegetation is closely related to the annual change of land surface temperature and soil moisture.There are three types of spatial correlation:positive correlation,negative correlation and reverse correlation,but the positive correlation is dominant.④The interaction analysis shows that the influence of soil moisture on vegetation growth is greater than that of land surface temperature.Soil moisture condition is the dominant factor affecting the vegetation growth in this area.The improvement of soil moisture condition is very important for the construction and restoration of ecological environment in the study area.