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河西走廊东部植被指数变化及其对气候变化的响应

Changes in Vegetation Index and Its Response to Climate Change in Eastern Hexi Corridor

  • 摘要: 研究植被覆盖对气候变化的响应,对干旱区气候资源的利用和生态环境保护具有重要意义。以河西走廊东部2001~2020年逐月NASA GIMMS(National Aeronautics and Space Administration, Global Inventory Modelling and Mapping Studies)归一化植被指数(Normalized Difference Vegetation Index, NDVI)和气温、降水、日照、蒸发资料为基础,运用差值法和线性趋势法对比分析了21世纪00年代(2001~2010年)和21世纪10年代(2011~2020年)NDVI与气温、降水量、日照时数、蒸发量的时空变化特征,然后采用相关系数法和多元线性回归法探讨了NDVI对气候变化的响应程度。结果表明:河西走廊东部21世纪10年代全区域及各地NDVI呈显著增长趋势,21世纪00年代凉州区、古浪县NDVI呈减少趋势,全区域及其他各地呈增长趋势,21世纪10年代NDVI比21世纪00年代明显偏大。河西走廊东部全区域及各地两个年代气温基本呈上升趋势;21世纪10年代降水基本呈增多趋势、21世纪00年代降水基本呈减少趋势;两个年代日照时数基本呈减少趋势;两个年代蒸发量基本呈增多趋势,两个年代相比21世纪10年代比21世纪00年代气温、降水、蒸发量在增大,日照时数在减少。年NDVI与气温、降水量基本呈正相关,气温、降水量对NDVI具有明显正贡献;年NDVI与日照时数、蒸发量相关性的正负差异较大,总体来看,日照时数对NDVI具有负贡献,蒸发量对NDVI具有正贡献。河西走廊东部NDVI变化对气候变化的响应非常敏感。本研究建立的年NDVI与年气候要素的回归模型,可用于预测NDVI的未来发展趋势。

     

    Abstract: The response of vegetation cover to climate change was studied, which was of great importance to the utilization of climate resources and ecological environment protection in arid areas. Herein, we used the data of the monthly NASA GIMMS (National Aeronautics and Space Administration, Global Inventory Modelling and Mapping Studies) normalized difference vegetation index (Normalized Difference Vegetation Index, NDVI) and the values of temperature, precipitation, sunshine, and evaporation in eastern Hexi Corridor from the period of 2001 to 2020. Based on this data, the characteristics of temporal and spatial change in NDVI and the temperature, precipitation, sunshine hours, and evaporation during the 2000s (2001–2010) and 2010s (2011–2020) were analyzed using the difference method and linear trend method. Subsequently, the response degree of NDVI to climate change was explored using correlation coefficients and multiple linear regression. The results showed that the NDVI values during the 2010s in the whole region and various regions showed a prominent growth trend, whereas the NDVI values during the 2000s showed a decreasing trend in Liangzhou and Gulang and an increasing trend in the whole region and other regions. Overall, the results imply that the NDVI was considerably higher during the 2010s than during the 2000s. The temperature values for the two time periods demonstrated an upward trend; precipitation showed an increasing trend in the 2010s and a decreasing trend in the 2000s. The sunshine hours of the two periods generally showed a decreasing trend, and the evaporation of the two periods also exhibited a decreasing trend. By comparing the results obtained from the two periods, it was found that the temperature, precipitation, and evaporation values increased and sunshine hours decreased to a greater extent in the 2010s than in the 2000s. The annual NDVI values were positively correlated with temperature and precipitation, and both temperature and precipitation had a positive contribution to NDVI. By contrast, the correlation of annual NDVI with sunshine duration and evaporation was quite different. In general, sunshine duration had a negative contribution to NDVI, while evaporation had a positive contribution to NDVI. The response of NDVI to climate change was extremely sensitive in eastern Hexi Corridor. The regression models of annual NDVI and annual climate elements were established in this study. These models could predict future development trends of NDVI.

     

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