Analysis of the spatial-temporal change of the vegetation index in the upper reach of Han River Basin in 2000–2016

Abstract

Abstract. Han River is the water source region of the middle route of South-to-North Water Diversion in China and the ecological projects were implemented since many years ago. In order to monitor the change of vegetation in Han River and evaluate the effect of ecological projects, it is needed to reveal the spatial-temporal change of the vegetation in the upper reach of Han River quantitatively. The study is based on MODIS/Terra NDVI remote sensing data, and analyzes the spatial-temporal changes of the NDVI in August from 2000 to 2016 at pixel scale in the upper reach of Han River Basin. The results show that, the area with increasing NDVI between 0 and 0.005 per year accounts for 62.07 % of the area of upper reach of Han River Basin, and the area with changing rate between −0.005 and 0 per year accounts for 26.65 % of the research area. The area with significant decreasing trend only accounts for 2.76 %, while area significant increasing trend accounts for 13.47 %, and the area with increasing NDVI is much larger than the area with reducing NDVI. The vegetation index of each county is evaluated and found that, the areal proportion with significant decreasing trend in Hantai is the biggest, reaching 35.57 %. The areal proportion with significant increasing trend in Zhenba County, Ziyang County, Xunyang County, Zhashui County, Shangzhou District, Shanyang County and Yun County is larger than the others, and the areal proportions are more than 20 %. The largest areal proportion with significant increasing trend is in Shangzhou District and it reaches 31.11 %. On the whole, the area ratio in all districts and counties with increasing NDVI is much larger than the area ratio with decreasing NDVI.

Evaluation of the Coupled Coordination of the Water–Energy–Food–Ecology System Based on the Sustainable Development Goals in the Upper Han River of China

“…A significant tributary in the middle course of the Yangtze River is the Han River; it originates from Panzhong Mountain, Ningqiang County, Hanzhong City, with a main stream length reaching 15,332 km, an 873 mm yearly precipitation total, and a 159,000 km 2 basin, as shown in Figure 1, where the mean annual rainfall is from 700 mm to 1700 mm [23]. The Han River Basin is in a subtropical monsoon zone, with a mild and humid climate and abundant water; however, the distribution is uneven over the year, and the runoff from May to October accounts for about 75% of the annual runoff, with large inter-annual variations, which makes it the most varied river among the major tributaries of the Yangtze River [24].…”

Investigation of vegetation dynamics with a focus on agricultural land cover and its relation with meteorological parameters based on the remote sensing techniques: a case study of the Gavkhoni watershed

“…In particular, its two primary parameters, temperature and precipitation, significantly influence the distribution of vegetation types within terrestrial ecosystems and contribute to their temporal and spatial diversity. These effects occur on both global and local scales (Chang et al, 2014;Luan et al, 2018;Raynolds et al, 2008;Zhong et al, 2010). Precipitation is a particularly important climate parameter, having a significant influence over vegetation dynamics within arid and semi-arid ecosystems (Martiny et al, 2006;Rousta et al, 2014).…”

Classification of Geomorphic Units and Their Relevance for Nutrient Retention or Export of a Large Lowland Padma River, Bangladesh: A NDVI Based Approach

“…NDVI has been used for monitoring the vegetation and ecosystem dynamics of large rivers [57][58][59][60][61]. Relationships between seasonal vegetation and discharge variation of large rivers can be verified by the seasonal correlation between NDVI and discharge [62].…”