Analysis of the spatio-temporal variability of terrestrial water storage in the Great Artesian Basin, Australia Jiabao Yan, Shaofeng Jia, Aifeng Lv, Rashid Mahmood and Wenbin Zhu ABSTRACT The Great Artesian Basin (GAB) in Australia, the largest artesian basin in the world, is rich in groundwater resources. This study analyzed the spatio-temporal characteristics of terrestrial water storage (TWS) in the GAB for 20032014 using satellite (Gravity Recovery and Climate Experiment, GRACE) data, hydrological modelsoutputs, and in situ data. A slight increase in TWS was observed for the study period. However, there was a rapid increase in TWS in 2010 and 2011 due to two strong La Nina events. Long-term mean monthly TWS changes showed remarkable agreements with net precipitation. Both GRACE derived and in situ groundwater disclosed similar trend patterns. Groundwater estimated from the PCR-GLOBWB model contributes 26.8% (26.4% from GRACE) to the total TWS variation in the entire basin and even more than 50% in the northern regions. Surface water contributes only 3% to the whole basin but more than 60% to Lake Eyre and the Cooper River. Groundwater, especially deeper than 50 meters, was insensitive to climate factors (i.e., rainfall). Similarly, the groundwater in the northern Cape York Peninsula was inuenced by some other factors rather than precipitation. The time-lagged correlation analysis between sea surface height and groundwater storage indicated certain correlations between groundwater and sea level changes. Jiabao Yan Shaofeng Jia (corresponding author) Aifeng Lv Rashid Mahmood Wenbin Zhu Institute of Geographic Science and Natural Resources Research/Key Laboratory of Water Cycle and Related Land Surface Processes, Chinese Academy of Sciences, Beijing 100101, China E-mail: jiasf@igsnrr.ac.cn Jiabao Yan University of Chinese Academy of Sciences, Beijing 100049, China Key words | Great Artesian Basin, groundwater, spatio-temporal variability, terrestrial water storage INTRODUCTION Groundwater plays a vital role in the indigenous industrial, domestic, and environmental water uses. In order to utilize groundwater resources precisely, the spatio-temporal characteristics of different components of terrestrial water storage (TWS) should be comprehensively understood. For a long time, the detection of regional water storage change has been mainly dependent on in situ observation and mod- elling approaches. Due to the limited spatial coverage of observing sites, it is a big challenge for large scale analysis and evaluation. Although hydrological models can estimate large scale water storage variations, the lack of observa- tional data is the main limit to using these models. Since the launch of the Gravity Recovery and Climate Experiment (GRACE) satellite in 2002, an unprecedented satellite-based approach to estimating TWS has been spring- ing up. The GRACE products have widely been used in hydrology, including water balance research (Syed et al. ; Swenson & Wahr ), evapotranspiration (ET) esti- mates (Syed et al. ; Billah et al. ; Wan et al. ), extreme weather analysis (Long et al. a; Thomas et al. ; Abelen et al. ), and groundwater storage (GWS) change (Döll et al. ; Famiglietti ; Chen et al. ; Richey et al. ). Previous studies mostly focused on the worlds large basins (Famiglietti ; Getirana et al. ; Long et al. ; Zhang et al. ) and groundwater over-exploitation areas (Rodell et al. ; Munier et al. ; Feng et al. ; Huang et al. ). Most of these areas are located in the north- ern hemisphere. There are a few studies for the whole of Australia (Brown & Tregoning ; van Dijk et al. ; Seoane et al. ; Wang et al. ), the MurrayDarling Basin (Leblanc et al. , ; Brown & Tregoning ; 324 © IWA Publishing 2017 Water Science & Technology: Water Supply | 17.2 | 2017 doi: 10.2166/ws.2016.136 Downloaded from https://iwaponline.com/ws/article-pdf/17/2/324/410326/ws017020324.pdf by guest on 29 May 2020