黄土高原不同植被覆盖土地利用等对蒸散发量的影响
2021-12-17李燕张凯瑞
李燕 张凯瑞






摘 要:为实现对黄土高原蒸散发量的动态连续监测,基于蒸散发量(ET)、归一化植被指数(NDVI)、土地利用、气温和降水量数据,采用SEN趋势分析、Hurst指数及偏相关分析法,探究了黄土高原2001—2020年ET时空分布特征、变化趋势、未来持续状态及降水、气温、不同植被覆盖度、不同坡度、不同土地利用下的ET变化规律。结果表明:①黄土高原ET空间分布呈从北向南增大的趋势,高蒸发区集中在渭河平原、六盘山和祁连山区域,ET随坡度、植被覆盖度的增大而增大;②占黄土高原总面积92.02%的区域ET表现为显著增大趋势(显著性水平α<0.01),增速为2~5 mm/a,草地和农用地的ET增速较大,水体、湿地、建筑用地的ET增速较小;③ET与降水和气温均以正相关关系为主。
关键词:蒸散發;植被覆盖;土地利用;黄土高原
中图分类号:S161.4;TP79
文献标志码:A
doi:10.3969/j.issn.1000-1379.2021.12.014
引用格式:李燕,张凯瑞.黄土高原不同植被覆盖/土地利用等对蒸散发量的影响[J].人民黄河,2021,43(12):68-73.
Abstract: In order to achieve the dynamic and continuous monitoring of evapotranspiration in the Loess Plateau, based on evapotranspiration (ET), normalized vegetation index (NDVI), land use data, temperature and precipitation data, this paper adopted SEN trend analysis, R/S analysis and partial correlation analysis and studied the temporal and spatial distribution characteristics, change trend, future continuous state, precipitation and air quality of ET under different vegetation coverage, slope and land use in the Loess Plateau from 2001 to 2020. The results show that: a) the spatial distribution of ET in the Loess Plateau shows an increasing trend from north to south in the past 20 years. b) ET shows a significant increasing trend in a large area during 20 years, and the increasing rate is concentrated in 2-5 mm/a, accounting for 92.02% of the total area of the Loess Plateau. The ETs of grassland and agricultural land increase more, while the ETs of water, wetland and construction land increase less. c) In the future, ET will decrease in most areas of the Loess Plateau, and the persistence in most pixels of Inner Mongolia, Gansu and Qinghai is stronger than that in other areas. d) The relationship between ET and precipitation/air temperature is mainly positive correlation.
Key words: evapotranspiration; vegetation cover; land use; Loess Plateau
蒸散发主要由土壤蒸发和植物蒸腾组成,将部分地表水分输送到大气中[1-3],是干旱与半干旱区水量消耗的主要途径[4-7]。黄土高原地处半湿润、半干旱、干旱区过渡地带,受西风环流、高原季风和东亚季风环流共同影响,干旱事件频繁发生[8-12]。因此,充分认识蒸散发量(ET)和植被覆盖/土地利用的时空变化规律及其响应关系,不仅有利于理解ET对水循环的影响机制,也可为黄土高原水源涵养和水资源合理开发利用提供理论参考。
近年来,专家们从不同角度出发不断对蒸散发开展研究,提出很多种蒸散发量的计算方法[13-16]。……
