Mapping groundwater storage variations with GRACE: a case study in Alberta, Canada

Huang, Jianliang; Pavlić, Goran; Rivera, Alfonso; Palombi, Dan; Smerdon, Brian

Mapping groundwater storage variations with GRACE: a case study in Alberta, Canada | Cartographier les variations de stock d’eau souterraine avec GRACE: un cas d’étude en Alberta, Canada Mapeo de las variaciones de almacenamiento de aguas subterráneas con Grace: un caso de estudio en Alberta, Canadá 利用GRACE绘制地下水储存量变化图:加拿大亚伯达省的研究实例 Mapeamento de variações do armazenamento de água subterrânea com GRACE: estudo de caso em Alberta, Canadá

2016

Huang, Jianliang | Pavlić, Goran | Rivera, Alfonso | Palombi, Dan | Smerdon, Brian

The applicability of the Gravity Recovery and Climate Experiment (GRACE) to adequately represent broad-scale patterns of groundwater storage (GWS) variations and observed trends in groundwater-monitoring well levels (GWWL) is examined in the Canadian province of Alberta. GWS variations are derived over Alberta for the period 2002–2014 using the Release 05 (RL05) monthly GRACE gravity models and the Global Land Data Assimilation System (GLDAS) land-surface models. Twelve mean monthly GWS variation maps are generated from the 139 monthly GWS variation grids to characterize the annual GWS variation pattern. These maps show that, overall, GWS increases from February to June, and decreases from July to October, and slightly increases from November to December. For 2002–2014, the GWS showed a positive trend which increases from west to east with a mean value of 12 mm/year over the province. The resulting GWS variations are validated using GWWLs in the province. For the purpose of validation, a GRACE total water storage (TWS)-based correlation criterion is introduced to identify groundwater wells which adequately represent the regional GWS variations. GWWLs at 36 wells were found to correlate with both the GRACE TWS and GWS variations. A factor f is defined to up-scale the GWWL variations at the identified wells to the GRACE-scale GWS variations. It is concluded that the GWS variations can be mapped by GRACE and the GLDAS models in some situations, thus demonstrating the conditions where GWS variations can be detected by GRACE in Alberta.

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