A Climatic Perspective on the Impacts of Global Warming on Water Cycle of Cold Mountainous Catchments in the Tibetan Plateau: A Case Study in Yarlung Zangbo River Basin

Abstract

Global warming has a profound influence on global and regional water cycles, especially in the cold mountainous area. However, detecting and quantifying such changes are still difficult because noise and variability in observed streamflow are relatively larger than the long-term trends. In this study, the impacts of global warming on the catchment water cycles in the Yarlung Zangbo River Basin (YZRB), one of most important catchments in south of the Tibetan Plateau, are quantified using a climatic approach based on the relationship between basin-scale groundwater storage and low flow at the annual time scale. By using a quantile regression method and flow recession analysis, changes in low flow regimes and basin-scale groundwater storage at the Nuxia hydrological station are quantified at the annual time scale during 1961–2000. Results show annual low flows (10th and 25th annual flows) of the YZRB have decreased significantly, while long-term annual precipitation, total streamflow, and high flows are statistically unchanged. Annual lowest seven-day flow shows a significantly downward trend (2.2 m3/s/a, p < 0.05) and its timing has advanced about 12 days (2.8 day/10a, p < 0.1) during the study period. Estimated annual basin-scale groundwater storage also shows a significant decreasing trend at a rate of 0.079 mm/a (p < 0.05) over the study period. Further analysis suggests that evaporation increase, decreased snow-fraction, and increased annual precipitation intensity induced by the rising temperature possibly are the drivers causing a significant decline in catchment low flow regimes and groundwater storage in the study area. This highlights that an increase in temperature has likely already caused significant changes in regional flow regimes in the high and cold mountainous regions, which has alarming consequences in regional ecological protection and sustainable water resources management.

Impact of climate change on the long-term water balance in the Yarlung Zangbo basin

“…We quantified water balance, which is composed of precipitation and evaporation, water yield, groundwater recharge, and soil water content of the entire YZB, indicating that more inflow from precipitation for the whole hydrological system will be consumed by evaporation rather than contributing to runoff, implying that rising temperatures have a greater impact on water balance than increasing precipitation in northern Himalayan. This is consistent with previous findings that global warming likely caused significant changes in the water cycle of cold mountain catchments (Xu et al, 2020). Soil water content can be used as a good indicator to evaluate the degree of dryness and wetness (Chakraborty et al, 2013;Li and Huang, 2021).…”

Detecting and attributing drought‐induced changes in catchment hydrological behaviours in a southeastern Australia catchment using a data assimilation method

“…46.0% decrease) during the period of 1997–2010. The change of annual lowest 7‐day mean flow can be used as the indicator of groundwater storage changes (Gao et al, 2015; Troch et al, 2013; Xu et al, 2020; Zhang et al, 2014). Significant declines in annual lowest 7‐day mean flow and reported groundwater level changes in published literatures are consistent with the findings in this study that SC was larger during the Millennium drought period (1997–2009) than at other times (Figure 5 and Figure 6).…”

“…Many researchers also reported that the catchment groundwater level dropped significantly during the Millennium drought in southern Australia (Gao et al, 2014;Kinal & Stoneman, Petheram et al, 2011;Petrone et al, 2010). The change of annual lowest 7-day mean flow can be used as the indicator of groundwater storage changes (Gao et al, 2015;Troch et al, 2013;Xu et al, 2020;Zhang et al, 2014). Significant declines in annual lowest 7-day mean flow and reported groundwater level changes in published literatures are consistent with the findings in this study that SC was larger during the Millennium drought period (1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009) than at other times (Figure 5 and Figure 6).…”

Understanding the Hydropower and Potential Climate Change Impact on the Himalayan River Regimes—A Study of Local Perceptions and Responses from Himachal Pradesh, India

“…The possible impact of dams on the river flow regimes across the world varies based on the terrain, topography, ecology, and socioeconomic conditions of the region. In the climate change scenarios and impact of global warming, estimated runoff contributions to the total runoff from snow and glacier melt in the Beas at 35%, the Chenab 49%, and the Satluj 60% at present are going to increase with the increase in snow and glaciers melting [46][47][48]. Ali et al [8] suggested the wetter 17.04 ± 20.76% and 15.30 ± 20.16% increase in the annual mean precipitation in the Nathpa Jhakri (1500 MW) and Bhakra Nangal (1300 MW) big storage dams of the Satluj basin, respectively, in the near future was owing to snow and glaciers melting.…”