Increased Water Storage in the Qaidam Basin, the North Tibet Plateau from GRACE Gravity Data

Abstract

Groundwater plays a key role in maintaining the ecology and environment in the hyperarid Qaidam Basin (QB). Indirect evidence and data from sparse observation wells suggest that groundwater in the QB is increasing but there has been no regional assessment of the groundwater conditions in the entire basin because of its remoteness and the severity of the arid environment. Here we report changes in the spatial and temporal distribution of terrestrial water storage (TWS) in the northern Tibetan Plateau (NTP) using Gravity Recovery and Climate Experiment (GRACE) data. Our study confirms long-term (2003–2012) TWS increases in the NTP. Between 2003 and 2012 the TWS increased by 88.4 and 20.6 km3 in the NTP and the QB, respectively, which is 225% and 52% of the capacity of the Three Gorges Reservoir, respectively. Soil and water changes from the Global Land Data Assimilation System (GLDAS) were also used to identify groundwater storage in the TWS and to demonstrate a long-term increase in groundwater storage in the QB. We demonstrate that increases in groundwater, not lake water, are dominant in the QB, as observed by groundwater levels. Our study suggests that the TWS increase was likely caused by a regional increase in precipitation and a decrease in evaporation. Degradation of the permafrost increases the thickness of the active layers providing increased storage for infiltrated precipitation and snow and ice melt water, which may also contribute to the increased TWS. The huge increase of water storage in the NTP will have profound effects, not only on local ecology and environment, but also on global water storage and sea level changes.

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

“…Glacial retreat has resulted in hydrological changes, including greater river discharges, elevated lake levels, recurrent glacial lake upsurges, flooding, and increased debris flows from glacial, and water resources. These changes have been the focus of many studies (Lemke et al ., ; Yao et al ., ; Li et al ., ; Zhang et al ., ; Cuo et al ., ; Yang et al ., ; Jiao et al ., ). In the 1990s, an increased river runoff (>5.5%) from TP caused by glacier retreat was observed, which is even greater in northwestern China (Yao et al ., ).…”

“…Adjacent to the southern boundary of TP, obvious decrease in total water storage was observed during 2002–2012 (Figure ). Melting of glacial ice and snow caused the decrease in total water storage along the Yarlung Tsangpo River (Jiao et al ., ).…”

“…Spatial distribution of changing rates of total water storage (mm month −1 ) in the TP from 2003 to 2012 (modified from Jiao et al , ).…”

“…Because of its high sensitivity to climate change, TP changes are considered as an indicator of global warming effects (Yao et al ., ). Substantial glacial recession, snow melt, and permafrost degradation have occurred on the TP due to temperature increases which have led to modifications in the hydrological cycle and changes in water resources throughout the region (Jiao et al ., ).…”

An innovative method to estimate regional-scale hydraulic diffusivity using GRACE data

“…However, these measurements are not cost-effective and provide hydraulic parameters only at a small spatial scale. For regions of global or continental scale (Luckey et al 1986, Lemieux et al 2008, Fan et al 2013 or very remote areas with no or limited data (Jiao et al 2015a), there is no reliable and efficient way to estimate the hydraulic properties. Since the successful launch of two Gravity Recovery and Climate Experiment (GRACE) satellites in March 2002, the GRACE mission has measured the Earth's gravitational field more accurately.…”