摘要
内陆河流域植被覆盖度的敏感性是预测未来生物多样性变化的重要指标,是植被应对气候变暖的重要反馈。分析了2000—2015年MODIS-NDVI数据反演的植被覆盖度时空动态变化趋势,结合平均气温、降水量、日照时数、相对湿度、地面温度和蒸发量数据,研究了流域及各生态功能区的植被覆盖度与气候因子的相关性,探讨植被覆盖度变化过程中的气候因素制约方式,了解不同时空尺度下内陆河流域植被覆盖度在全球暖湿化过程中对气候的响应。结果表明:(1)石羊河流域平均植被覆盖度较低,上游的植被覆盖度59.4%,下游13.6%; 2000—2015年,流域植被呈现改善趋势的面积远远大于退化的面积,盆地绿洲区植被覆盖度增加趋势最明显。流域植被总体恢复较好,但高海拔地区、城市和民勤绿洲的周边地区植被有不同程度的退化。(2) 2000—2015年,石羊河流域各气候因子对植被覆盖度表现为不显著的相关关系,其中与降水量呈正相关的面积最大,与蒸发量呈负相关的面积最大;从上游到下游,植被生长与热量的相关程度逐渐变弱,与水分的相关程度则逐渐增强。(3)石羊河流域的植被覆盖度与气候因子的样条函数存在极显著的线性相关,水原涵养区和荒漠区的植被覆盖度对气候因子的响应较高;绿洲区的植被覆盖度对气候因子的响应相对较低。地面温度的变化是影响石羊河流域植被覆盖度空间格局变化的主要气候制约因素。
The sensitivity of vegetation coverage in inland river basin is an important index to predict the change of future biodiversity, as well as a significant feedback of vegetation to global warming. Based on mean temperature, precipitation, sunshine hours, relative humidity, surface temperature and evapora- tion data, we analysis the correlation between vegetation coverage inversion and climatic factors, dis- cuss the process of climatic factors with the changes of vegetation coverage, and investigate the re- sponse of vegetation coverage to climate change in the process of global warming in different spatial and temporal scales. The results show that: (l) the average vegetation coverage was low in Shiyang River Basin, the vegetation coverage in upper reaches was better than in downstream, was 59.4% and 13.6% respectively. The improved vegetation area is far greater than the degraded one and the vegetation cover- age in oasis area increased obviously from 2000 to 2015. The overall trend of vegetation restoration was good but the vegetation in high altitude district and the surrounding area of Minqin oasis were degraded with different degree. (2) During 2000--2015, the relation between vegetation and the climatic factors of Shiyang River Basin were not significant. The area with positive correlation with precipitation and the ar- ea with negative correlation with evaporation were both the largest. The correlation between vegetation growth and heat gradually weakened at the same time the correlation between vegetation growth and wa- ter gradually strengthened. (3) There was a significant linear correlation between spline function and cli- matic factors of Shiyang River Basin. There is a higher response to climate factors in water conservation and desert area, a lower response in oasis area. The ground temperature is the crucial factor, which would result in the spatial and temporal patterns of vegetation coverage.
作者
李丽丽
王大为
韩涛
Li Lili;Wang Dawei;Hart Tao(College of Earth Environmental Sciences,Lanzhou University,Lanzhou 730000,China;Northwest Regional Climate Center,Lanzhou 730020,China)
出处
《中国沙漠》
CSCD
北大核心
2018年第5期1108-1118,共11页
Journal of Desert Research
基金
甘肃省青年科技基金计划项目(1506RJYA188)
甘肃省气象局气象科研项目(GSMAMs2016-18)
甘肃省气象局人才专项"石羊河流域综合治理生态效果气象评价"
中国气象局风云四号卫星应用示范项目"西北干旱区沙尘监测评估系统"
关键词
植被覆盖度
气候因子
相关性
制约因素
石羊河
vegetation coverage
climatic factor
correlation
constraints
Shiyang River