Variation of Melt Water and Rainfall Runoff and Their Impacts on Streamflow Changes during Recent Decades in Two Tibetan Plateau Basins

Abstract

To fully understand potential changes in hydrological regime over the Lhasa River Basin (LRB) and the upstream of Niyang River Basin (UNRB) in Tibetan Plateau under global warming, the VIC-glacier model was employed to analyze the responses of rainfall runoff and melt water to recent climate change, and we also quantify their roles in controlling the trend of river streamflow during 1963–2012. The hydrological model was calibrated using the observed streamflow, glacier mass balance, and MODIS snow cover. The simulations indicate that there is a significant increasing trend in glacier runoff for both basins during 1963–2012, especially in the period of 2000s when it exhibits a large increment up to about 45% relative to baseline period. Rainfall runoff suggests a rising tendency whereas snowmelt runoff displays a general decreasing tendency. For both basins, increasing rainfall runoff was identified as the dominant driver for the upward trend in total runoff during 1963–2012. The role of glacier runoff in controlling the trend of total runoff is also obvious, especially in the more glaciated UNRB where increased glacier runoff accounts for up to 41% of the tendency in river discharge. Snowmelt runoff plays a minor role in affecting the trend of total runoff.

Google Earth Engine for Large-Scale Flood Mapping Using SAR Data and Impact Assessment on Agriculture and Population of Ganga-Brahmaputra Basin

“…The river discharge in the Brahmaputra river is highly influenced by the snowmelt at the upper part of the catchment due to global warming [57]. The snow cover area changes under the recent climatic conditions are expected to have a larger effect on the hydrological cycle [58]. Satellite gravimetry was used to understand the contribution of substantial meltwater to the Brahmaputra river and found that summer meltwater contributed 43 ± 8 Gt to the Brahmaputra.…”

Glacial Change and Its Hydrological Response in Three Inland River Basins in the Qilian Mountains, Western China

“…Similar studies showed that the mean proportion ranged from 0.2% to 40.3% in four basins in northern Europe [10], from 14% to 85% around the Gulf of Alaska [9] and from 3.5% to 67.5% around Tienshan [27]. The contribution of glacier runoff to basin runoff also varies throughout the year and is dominated by interannual changes in precipitation and temperature [28]. In some basins in West Asia and South America, the contribution of glacier runoff will be reduced by more than 25% [3] by the end of this century.…”

“…In watersheds where precipitation increases more than glacial meltwater, the contribution of glacial meltwater may be reduced even though the total amount of meltwater increases due to the increase in total runoff in the watershed [22]. However, studies are typically focused on individual highly glacierized regions or large watersheds [3,11,28,31], and it remains unclear how representative these results are in lightly glacierized watersheds or subbasins, especially for arid regions, where even though glacier runoff is relatively small, it is still meaningful for the sustainability of water supplies.…”

Impacts of Climate Change on Blue and Green Water Resources in the Middle and Upper Yarlung Zangbo River, China

“…The Qinghai-Tibet Plateau, which is also known as Asia's "water tower", is the birthplace of many rivers, including the Yangtze, Yellow, and Yarlung Zangbo River, and it is vital to the surrounding areas and the global hydrological cycle. Climate change is a serious issue right now, and the Tibetan Plateau region has received a lot of attention from the international and scientific communities because of its unique geographical location [16][17][18]. According to studies, the rapid melting and retreating of glaciers on the Qinghai-Tibet Plateau due to global warming has resulted in frequent glacial lake outbursts, debris flow disasters, and river floods, all of which have serious consequences for people's production and lives [19][20][21].…”