Changes in nonlinearity and stability of streamflow recession characteristics under climate warming in a large glaciated basin of the Tibetan Plateau

Abstract

Abstract. The accelerated climate warming in the Tibetan Plateau after 1997 has profound consequences in hydrology, geography, and social wellbeing. In hydrology, the change in streamflow as a result of changes in dynamic water storage that originated from glacier melt and permafrost thawing in the warming climate directly affects the available water resources for societies of the most populated nations in the world. In this study, annual streamflow recession characteristics are analyzed using daily climate and hydrological data during 1980–2015 in the Yarlung Zangbo River basin (YRB) of the southern Tibetan Plateau. The recession characteristics are examined in terms of dQ/dt = − aQb and the response/sensitivity of streamflow to changes in groundwater storage. Major results show that climate warming has significantly increased the nonlinearity of the response (b) and streamflow stability [log(a)] in most subbasins of the YRB. These changes in the recession characteristics are attributed to the opposite effects of increases in the available water storage and recession timescale on the recession. Climate warming has increased subbasin water storage considerably due to more recharge from accelerated glacier melting and permafrost thawing after 1997. Meanwhile, the enlarged storage lengthens recession timescales and thereby decreases the sensitivity of discharge to storage. In the recession period when recharge diminished, increased evaporation and the decreased buffering effect of frost soils under warmer temperatures accelerate the initial recession of streamflow. By contrast, enlarged storage and lengthened recession timescales slow down the recession. While reservoir regulations in some basins have helped reduce and even reverse some of these climate warming effects, this short-term remedy can only function before the solid water storage is exhausted should the climate warming continue.

Overview: Cascading spatial, seasonal, and temporal effects of permafrost thaw on streamflow in changing nested Arctic catchments

“…However, an explanation for this difference could be in the length of the dataset, with Sergeant using data from 1970-2000 and our study encompassed data from 1954-2020, an extra 40 years. Other studies agree with our findings of increased β values (e.g., McKenzie et al, 2021b;Ploum et al, 2019;Wang et al, 2022). (1984)(1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995) of βOC = 1.72.…”

“…In the upstream catchments, the thawing active layer will allow for increasing subsurface flow, with spring having the shallowest thickness of the active layer and fall having the deepest thickness of the active layer, while in downstream catchments the thickness of the active layer can already be fluctuating within the areas of discontinuous permafrost, leading some areas to already have deep thickness of active layer as well as with streamflow of different seasons flowing from the upstream catchments creating a blend of spring, summer or fall discharge further obfuscating seasonal recessions. Increasing groundwater flow as found in studies from and Walvoord and Striegl (2007) lead researchers to suggest that this increase leads to more non-linearity in streamflow response and the increased storage capacity lengthens timescales and leads to the increased blending of streamflow seasonalities (Wang et al, 2022;Curran and Biles, 2021).…”

Heterogeneity in Spatiotemporal Variability of High Mountain Asia's Runoff and Its Underlying Mechanisms

“…It motivates many researchers to investigate the response of runoff to changes in climate and cryosphere (Han et al., 2019; Jiang et al., 2022; J. Wang et al., 2021). It is found that there are significant shifts in hydrological regimes including the runoff magnitude, streamflow recession, precipitation‐runoff relationship and water yield around 2000 (H. Li et al., 2022; X. Li et al., 2022; J. Wang et al., 2022), whereas the monotonic trend in runoff is not significant (as shown in our results).…”

“…It is found that there are significant shifts in hydrological regimes including the runoff magnitude, streamflow recession, precipitation-runoff relationship and water yield around 2000 (H. X. Li et al, 2022;J. Wang et al, 2022), whereas the monotonic trend in runoff is not significant (as shown in our results).…”