Remote-Sensing-Based Analysis of Spatiotemporal Variation of ET and Related Parameters in Xilingol Steppe, China
Remote-Sensing-Based Analysis of Spatiotemporal Variation of ET and Related Parameters in Xilingol Steppe, China
复制标题
DOI：
10.15244/pjoes/129964
复制
发表时间：
2021-02
影响因子：
1.8
通讯作者：
Qiaofeng Zhang;L. Di;Guixiang Liu;Liying Guo;Hongbo Yu
中科院分区：
文献类型：
--
作者：
Qiaofeng Zhang;L. Di;Guixiang Liu;Liying Guo;Hongbo Yu
蒸散量是干旱半干旱地区生态需水的主要来源，是评估干旱半干旱地区生态水量平衡和干旱状况的重要指标。利用年、季尺度的遥感数据和气候资料，研究了锡林郭勒草原蒸散的时空变化特征，并确定了影响蒸散的主要参数。结果表明，锡林郭勒草原年蒸散量自东北向西南逐渐减小，2000-2014年波动在200 mm/a左右。空间平均蒸散量的季节变化顺序为夏、秋、冬、春，分别占全年蒸散量的35%、23%、22%和20%。草甸草原、典型草原和桑迪植被草原的蒸散量最大，出现在夏季，荒漠草原的蒸散量最大，出现在冬季，占全年蒸散量的39%。春、夏、秋三季降水量和植被指数是影响蒸散的主要参数。而在冬季，ET与气温呈正相关，与降水呈负相关。结果表明，实际蒸散量的时空特征和影响因子具有明显的季节性，年蒸散量的特征主要由生长季节（春秋季）决定。此外，植被生长与ET和日照时数直接相关，而不是其他参数。结合自然条件，可以推断草甸和典型草原的干旱状况可能是由于降水分布不均和生长季ET需求量高造成的，而年降水量少和冬季蒸发量高是荒漠草原水分短缺的主要原因。
Evapotranspiration (ET), as the main ecological water consumer, is crucial to assess the ecological water budget and dry conditions in arid and semi-arid areas. The objective of this study was to characterize the spatiotemporal variations of ET and determine the major parameters affecting ET by using remote sensing data and climate data at annual and seasonal scales in Xilingol steppe, China. The results of this study showed that the annual ET gradually reduced from northeast to southwest in the Xilingol steppe, with the values fluctuating around 200 mm per year during 2000-2014. The seasonal value of the spatially averaged ET was in reducing order from summer, fall, and winter to spring, accounting for approximately 35%, 23%, 22%, and 20% of the annual ET, respectively. The largest ET appeared in summer in meadow steppe, typical steppe, and sandy vegetation steppe, while in the desert steppe, it occurred in winter, accounting for 39% of the annual ET. Precipitation and NDVI are the major parameters positively affecting ET in spring, summer, and fall. However, in winter, ET was positively correlated with temperature and negatively correlated with precipitation. The results indicated that the spatiotemporal characteristics and the affecting parameters of the actual ET vary seasonally and that the characteristics of the annual ET are mainly determined by the growing season (spring-fall). Moreover, vegetation growth is directly correlated with ET and sunshine hours rather than other parameters. Combining with the natural conditions, the conclusions can be deduced that the dry conditions in the meadow and typical steppes are probably caused by uneven precipitation distribution and high ET demands during the growing season, while the low annual precipitation combined with high winter evaporation is the main reason for water scarcity in the desert steppe.