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| DOI：10.13522/j.cnki.ggps.2020390 |
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| Response of the Normalized Difference Vegetation Index to Water Storage in Terrestrial Basin of the Yellow River Basin: Taking 2002-2015 as an Example |
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YUAN Ruiqiang, QING Song
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1.College of Geographical Science, Inner Mongolia Normal University, Hohhot 010022, China;2.Key Laboratory of Remote Sensing and Geographic Information System, Hohhot 010022, China
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| Abstract: |
| 【Background】Vegetation is one of most important components in the terrestrial ecosystem, connecting atmosphere, soil and hydrological processes. Spatiotemporal changes in vegetation could affect the balance of energy and water cycling; measuring and analyzing the factors that have a long-term impact on vegetation dynamics has been in increase globally as they are crucial to helping protect ecological system functions and sustain regional development.【Objective】The objective of this paper is to analyze the spatiotemporal change in the normalized difference vegetation index (NDVI) in the Yellow river Basin, and elucidate its response to change in terrestrial water storage anomaly (TWSA).【Method】The analysis was based on the GIMMS NDVI and GRACE TWSA retrieved from remote sensing data, and the Theil-sen trend analysis, M-K trend test and correlation analysis were used to analyze the change of NDVI in response to TWSA from 2002 to 2015 in the basin.【Result】The average annual NDVI during the crop growth season in the studied period was 0.42, but rising at an annual rate of 0.35%. The NDVI varied significantly over space, decreasing from the southeast to the northwest. Areas showing significant increase in NDVI are in Shaanxi, Shanxi and southern Gansu, all in the middle reach of the river. In contrast, areas showing significant decline in NDVI are in the southern areas in the lower reach of the river. Overall, NDVI has seen an increase in most areas and its response to TWSA varied significantly over space, with a positive correlation found in the Three River Source region, southern Gansu and Ningxia, as well as eastern Inner Mongolia.【Conclusion】TWSA showed a strong positive correlation with the vegetation in the upstream and middle reaches of the river, but a weak or even negative correlation in the middle and lower reaches of the river. This difference appeared to be caused by variation in hydrothermal conditions along the river as TWSA in areas with scarce precipitation in the middle and upper reaches of the river has a greater impact on vegetation. Apart from this, anthropogenic activities also played a role in their relationship. |
| Key words: vegetation index (NDVI); terrestrial water storage anomaly (TWSA); temporal and spatial changes; correlation analysis; Yellow River Basin |
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