摘要
黄河头道拐—潼关区间是黄河泥沙的主要来源区,也是中国植被恢复最快的地区。植被的快速恢复对径流和输沙过程产生了深远影响。本文基于250 m分辨率的归一化植被指数数据(MOD13Q1 NDVI),使用统计分析和趋势分析技术,分析了头道拐—潼关区间不同景观单元植被恢复特点、影响因素以及其对水沙过程的影响,并对头道拐—潼关区间植被未来发展趋势进行了预测。研究结果显示:头道拐—潼关区间82.87%区域的植被呈显著增加趋势(p<0.05),且植被恢复速度最快的区域为半湿润的黄土丘陵沟壑区,坡度和降水量在不同景观单元下对植被恢复的影响不同。随着降水量的增加,头道拐—潼关区间NDVI和年降水量的相关性降低。在植被恢复背景下,黄河中游主要河流径流的主要影响因素仍然是降水量,输沙量同时受到降水量和植被恢复的影响,含沙量与NDVI呈现出较强的负相关关系,而与降水量的相关性较弱。随着植被覆盖度的增加,流域土壤侵蚀量降低,河流输沙量也呈降低趋势,土壤侵蚀量对河流输沙量的贡献率变化于39%~88%之间。基于植被恢复潜力和恢复速度,本文预测头道拐—潼关区间2020年、2030年、2040年以及2050年的NDVI平均值将分别达到0.68、0.75、0.79以及0.80。
The Toudaoguai-Tongguan section is the main source area of sediments in the Yellow River and has the largest vegetation restoration rate in China. Subsequently, the rapid restoration of vegetation has had significant effects on the runoff and sediment transport processes. In this paper, the vegetation restoration characteristics, and the influencing factors and their effects on runoff and sediment processes in different landform units in the Toudaoguai-Tongguan section were analyzed based on the MOD13 Q1 Normalized Difference Vegetation Index(NDVI) data using the statistical and trend analysis techniques. And then, the future vegetation development trend in this area was predicted. The results suggest that the vegetation exhibits a significant increasing trend(p < 0.05) in 82.87% of the study area, and the semi-humid loess hilly and gully zones have the largest vegetation restoration rate. Slope gradient and precipitation have different effects on the vegetation restoration in different landform units. With the increase of precipitation, the correlation between NDVI and annual precipitation in the Toudaoguai-Tongguan section is lessened. In the context of vegetation restoration, precipitation is still the major factor influencing the main river runoffs in the middle reaches of the Yellow River, whereas the sediment load is affected by both precipitation and NDVI, and the sediment concentration exhibits a relatively strong negative correlation with NDVI. With the increase of vegetation coverage, the amount of soil erosion in the watershed decreases, and the river sediment load exhibits a decreasing trend. The contribution rate of the amount of soil erosion to the sediment load varies between 39%-88%. Based on the vegetation restoration potential and vegetation restoration rate, it was predicted that the mean values of NDVI in the Toudaoguai-Tongguan section in 2020, 2030, 2040, and 2050 would be 0.68, 0.75,0.79, and 0.80, respectively.
作者
高海东
吴曌
GAO Haidong;WU Zhao(State Key Laboratory of Eco-hydraulics in Northwest Arid Region,Xi'an University of Technology,Xi'an 710048,China 2.School of Civil Engineering and Architecture,Xi'an University of Technology,Xi'an 710048,China)
出处
《地理学报》
EI
CSSCI
CSCD
北大核心
2021年第5期1206-1217,共12页
Acta Geographica Sinica
基金
国家自然科学基金项目(41877077)。
关键词
植被恢复
趋势分析
黄河中游
水沙过程
vegetation restoration
trend analysis
middle reaches of the Yellow River
runoff and sediment process