Land Use and Climate Changes and Their Impacts on Runoff in the Yarlung Zangbo River Basin, China

Abstract

Impacts of land use and climate change on runoff were investigated by studying the runoff in the Yarlung Zangbo River basin, China. Trends in precipitation, mean air temperature, and runoff were analysed by non‐parametric Mann‐Kendall tests. Land‐use changes were examined with land‐use transition matrix and geographic information system tools. Land‐use and climate changes showed several characteristics, including increased reforestation, decreased grassland, retreat of glaciers and increased desertification. Human activity caused great impact, especially within densely populated regions and cities. Reforestation and degradation of grasslands were more frequent than deforestation and cultivation of grasslands. Annual mean air temperature, precipitation and runoff showed increasing trends between 1974 and 2000. The impacts of land use and climate change on runoff had different effects depending on region and season. In the season of freezing, climate change clearly affected runoff within regions that experienced precipitation. Altered evapotranspiration accounted for about 80 per cent of runoff changes, whereas land‐use changes appear to have had greatest impact on runoff changes within regions that have inconsistent relationships between runoff and climate change. It was demonstrated that afforestation leads to increased runoff in dry seasons. It was estimated that glacier snow melt has caused annual runoff to increase at least 6·0 mm/10yr, 2·1 mm/10yr and 1·7 mm/10yr in Regions 1, 3 and 4, respectively, whereas evapotranspiration caused annual runoff to decrease at least 7·4 mm/10yr in Region 2. Copyright © 2012 John Wiley & Sons, Ltd.

Trend Analyses of Extreme Precipitation Events in the Yarlung Zangbo River Basin, China Using a High-Resolution Precipitation Product

“…The annual precipitation for the whole basin has an increasing trend, which is in accordance with the results of You et al [41] and Liu et al [18]. The number of rain days at the basin scale shows a significant increasing trend.…”

Elevation-Dependent Vegetation Greening of the Yarlung Zangbo River Basin in the Southern Tibetan Plateau, 1999–2013

“…The upstream region is defined as the area between Chemayungdung Glacier and Lizi, and is located within a cold and dry temperate steppe climate zone with a multi-year average precipitation of <300 mm. The midstream region is defined as the area between Lizi and Paizhen, and has a temperate forest-grassland climate with a multi-year average precipitation of 300-600 mm, while the downstream region is defined as the area between Paizhen and Pasighat, and belongs to a warm and humid subtropical climate zone with a multi-year average precipitation reaching 4000 mm [32]. Both temperature and precipitation exhibited an increasing trend from the headwater region downstream to the low reaches of the basin.…”

“…In this paper, we investigate the pattern of EDVG in the Yarlung Zangbo River (YZR) basin, an important alley to transport moisture from the Indian Ocean to the inner Tibetan Plateau [32], during the past 15 years (1999-2013) and examine how EDW and precipitation affect this pattern. Using NDVI (normalized difference vegetation index) as an indicator of vegetation greenness [33][34][35], we aim to address three research questions: (1) does NDVI's temporal increasing/decreasing trend depend on elevation?…”

Effects of soil management techniques on soil water erosion in apricot orchards

“…If a soil has characteristics (Stanchi et al, 2015) that prohibit infiltration of water (e.g. crusting, slacking, lack of macro pores) the runoff coefficient will be higher (Liu et al, 2014). However, if the soil has a rough surface (Gao et al, 2015), runoff will be delayed by ponding water, allowing water to infiltrate and reducing the soil erosion on such sites.…”