Understanding Terrestrial Water Storage Declining Trends in the Yellow River Basin

Abstract

Under dual impacts from climate change and human activities, the Yellow River Basin (YRB) of China suffers from droughts and water scarcity. Understanding variations of terrestrial water storage (TWS) over the YRB is significant and beneficial to regional water resources management and sustainable development. This study investigates TWS variations in the YRB using data sets from two solutions (RL05 and RL06) of the Gravity Recovery and Climate Experiment (GRACE) satellites, as well as from global land surface models (the NOAH model and Catchment Land Surface Model [CLSM]) and hydrology and water resources model (PCR‐GLOBWB). Annual terrestrial water storage anomalies (TWSA) variation patterns were tracked by introducing a weighed centroid analysis concept. Human water use was analyzed, and its importance to TWS changes was evaluated by using the random forest algorithm. Conclusions can be briefly summarized as follows: (1) The declining trend of TWS in the YRB from the RL06 solution is more negative than that from RL05; the TWS trend from the PCR‐GLOBWB model is more consistent with GRACE than with the NOAH model and CLSM at the basin level, and the three models all underestimate the declining trend of TWS in the midstream relative to the GRACE solutions. (2) Spatial weighed centroids of annual GRACE TWSA moved toward the headwater of the YRB during the 2003–2015 period, suggesting a wide gap of TWS between the upstream and downstream YRB; the TWSA time series well correlate with the long‐term accumulation of climatic water balance, but the connections became weak in the 2010–2015 period. (3) Groundwater withdrawals have been controlled according to the Water Resources Bulletin, but the stress may be partly shifted to surface water; the increasing trend of ecological and industrial surface water use is significant, following the agriculture water use. (4) For the entire YRB, groundwater use accounts for the majority of feature importance in modeling TWSA time series, and the contribution of climate factors is the least. Agricultural water use ranks first relative to other sectors for the YRB, followed by the ecological and industrial use. This study provides a first comparison of TWSA between the latest Center for Space Research (CSR) GRACE RL06 solution and the previous RL05 solution in the YRB. The results are expected to present a comprehensive picture of TWS variations in the YRB and the impacts from climate and human factors.

Historical and future climates over the upper and middle reaches of the Yellow River Basin simulated by a regional climate model in CORDEX

“…The black dash lines mark the rough boundaries of three topographic regions: upper (altitudes greater than 2000 m), middle (between 1000 and 2000 m), and lower (less than 1000 m) reaches. SR denotes the source region of the YR significantly since 1986 (Cong et al 2010) and terrestrial water storage in the YRB has therefore dramatically declined over recent years (Jing et al 2019). Water scarcity, driven by growing demand and persistent droughts, has more serious implications for water and food security than was recognized until recently (Wang et al 2019).…”

Groundwater Prediction Using Machine-Learning Tools

“…In addition to these techniques, a range of machine-learning techniques have been applied to the problem, including MLP in [12,[19][20][21][22][23], SVR in [19,24] and recently RFs in [25,26]. The use of XGB is rare in the scheme of groundwater prediction, and is found in only a few studies such as [27,28].…”

Spatial Variations in Terrestrial Water Storage with Variable Forces across the Yellow River Basin

“…Previous studies have evaluated the changes in TWS based on GRACE data, reaching a consistent conclusion that the TWS decreased in the past ten years, with significant spatial variations across the YRB [26][27][28]. Therefore, studies on the impact of climate change and human activities on TWS variations have gained more attention [29][30][31]. Many studies have shown that the rise in temperature and precipitation, the melting of glaciers, and the degradation of permafrost led to increased TWS in the source area of the YRB [32][33][34].…”

“…Many studies have shown that the rise in temperature and precipitation, the melting of glaciers, and the degradation of permafrost led to increased TWS in the source area of the YRB [32][33][34]. For the middle reaches of the YRB, the essential area of the Loess Plateau with a large population density, vegetation restoration, mining, and human water use were the major factors for the decreased TWS [29,31,35,36]. Additionally, some studies have also indicated that reservoir operation caused a significant change in the TWS in the YRB [30,37].…”