Lake volume and groundwater storage variations in Tibetan Plateau's endorheic basin

Abstract

The Tibetan Plateau (TP), the highest and largest plateau in the world, with complex and competing cryospheric‐hydrologic‐geodynamic processes, is particularly sensitive to anthropogenic warming. The quantitative water mass budget in the TP is poorly known. Here we examine annual changes in lake area, level, and volume during 1970s–2015. We find that a complex pattern of lake volume changes during 1970s–2015: a slight decrease of −2.78 Gt yr−1 during 1970s–1995, followed by a rapid increase of 12.53 Gt yr−1 during 1996–2010, and then a recent deceleration (1.46 Gt yr−1) during 2011–2015. We then estimated the recent water mass budget for the Inner TP, 2003–2009, including changes in terrestrial water storage, lake volume, glacier mass, snow water equivalent (SWE), soil moisture, and permafrost. The dominant components of water mass budget, namely, changes in lake volume (7.72 ± 0.63 Gt yr−1) and groundwater storage (5.01 ± 1.59 Gt yr−1), increased at similar rates. We find that increased net precipitation contributes the majority of water supply (74%) for the lake volume increase, followed by glacier mass loss (13%), and ground ice melt due to permafrost degradation (12%). Other term such as SWE (1%) makes a relatively small contribution. These results suggest that the hydrologic cycle in the TP has intensified remarkably during recent decades.

Quantitative comparison of river inflows to a rapidly expanding lake in central Tibetan Plateau

“…The glacier melt run‐off accounted around 8% for Zhagenzangbu and 11.5% for Zhajiazangbu during 1981–2012. This further confirms the arguments that precipitation‐induced run‐off rather than the glacier meltwater was the main cause for the substantial expansion of Lake Siling Co during the recent decades (Tong et al, ; G. Zhang et al, ).…”

“…Lake inflow ( Q in ) equals the channel flow upstream of the lake location. The lake outflow Q out can be estimated as where k lake is outflow coefficient (1/day), V (m 3 ) is actual active storage with V = A lake ⋅ H , A lake (m 2 ) is the area of the lake, and H (m) is the active storage depth; based on the findings from G. Zhang et al (), the changes of lake areas in Zhagenzangbu and Alizangbu are slight; here, the lake area is assumed to be stable; the maximum value is set to 50 m; and V max is the maximum active storage capacity. The exponent α (−) is dependent on the active storage capacity, indicating that the lower the active storage depth, the higher the exponent will be.…”

Climatic and associated cryospheric, biospheric, and hydrological changes on the Tibetan Plateau: a review

“…Zhang et al . () investigated that glacier mass loss contributes 13% and ground ice melt due to permafrost degradation contributed 12% in annual changes in lake area, level, and volume during 1970s–2015 in TP. Nevertheless, glacial volume changes and the synchronized environmental implications of glacial recession need additional study.…”

Impact of amplified evaporation due to lake expansion on the water budget across the inner Tibetan Plateau

“…() further examined that the spatial patterns of precipitation variability match the observed lake changes, and numerous lakes not connected with glaciers showed comparable growth rates with other glacier‐fed lakes (Phan et al ., ; Song et al ., ), suggesting that precipitation increases dominate the plateau‐scale lake growths. Basin‐scale water balance or land surface modelling also confirmed the primary role of precipitation and evaporation changes on the TP lake variations in recent years (Li et al ., ; Zhou et al ., ; Zhang et al ., ). A consensus among these studies can be reached that the wetting climate strongly drove the recent lake water gains, whereas increased meltwater runoff from glacier supply lakes in the endorheic ITP and the effects may vary with different basins, for example, relatively more influences from glacier meltwater were observed for the lakes in the Tanggula Mountains and Kunlun Mountains (Song and Sheng, ; Qiao and Zhu, ).…”

“…Albeit the field survey and lake bathymetry data are rather limited, modelling the lake hydrograph from time series of area and water level measurements can provide an effective approach to quantify the change of lake water volume (Duan and Bastiaanssen, ; Lei et al ., ; Song et al ., ). The increased lake water mass contributed a large proportion to the GRACE‐derived terrestrial water storage gains (Song et al ., ; Zhang et al ., ). These expanded TP lakes mostly belong to endorheic drainage systems with minimal human impacts, thus their dynamics represent a mixed effect of climate (precipitation, temperature and evaporation), groundwater discharge and cryospheric (snow, ice and permafrost) changes.…”