1998—2018年北疆天然草地植被覆盖度时空变化及其与气象因子的关系

Temporal and Spatial Variation of Natural Grassland Vegetation Coverage and Its Relationship with Meteorological Factors in Northern Xinjiang from 1998 to 2018

为分析北疆天然草地植被覆盖度在生长季不同月份的时空变化及其与气象因子的关系,采用像元二分模型、变化率分析和相关分析探讨了北疆1998—2018年6—9月天然草地植被覆盖度的时空变化及其与气象因子的关系。结果表明,北疆天然草地植被覆盖度空间上呈现降水较少、气温较高的中部和东部较低,海拔较高、降水较多且相对湿度较高的北部、西部和南部较高,由中部和东部向北部、西部和南部三面波动增加。北疆天然草地植被覆盖度在6、7、8和9月呈降低趋势,月平均值表现为6月>7月>9月>8月。北疆天然草地归一化植被指数7月为增加趋势,6、8和9月为减少趋势,整体上波动较小。6、7和8月北疆月平均天然草地植被覆盖度与降水和相对湿度呈正相关关系,9月与气温和日照时数呈正相关关系。

In order to analyze the temporal and spatial changes of natural grassland vegetation coverage in different months of the growing season in Northern Xinjiang and its relationship with meteorological factors,the pixel dichotomy model,change rate analysis and correlation analysis were used to explore the temporal and spatial changes of natural grassland vegetation coverage and its relationship with meteorological factors in Northern Xinjiang in June,July,August and September from 1998 to 2018.The results showed that the vegetation coverages of natural grassland in Northern Xinjiang were lower in the middle and east with less precipitation and higher temperature,higher in the north,west and south with higher altitude,more precipitation and higher relative humidity,which increased from the middle and east to the north,west and south.In June,July,August and September,the natural grassland vegetation coverage in Northern Xinjiang showed no significant decreasing trend,in which the monthly average natural grassland coverage was June>July>September>August.The normalized difference vegetation index of natural grassland in Northern Xinjiang showed an increasing trend in July and decreasing trend in June,August and September.The monthly average natural grassland vegetation coverages in Northern Xinjiang were mainly positively correlated with precipitation and relative humidity in June,July and August,and were mainly positively correlated with temperature and sunshine hours in September.