Terrestrial Water Storage Climatology for Canada from GRACE Satellite Observations in 2002–2014

Abstract. Quantifying terrestrial water storage (TWS) and its dynamic changes has been a key subject in water-related research and resources management. The Gravity Recovery and Climate Experiment (GRACE) satellite mission has been providing opportunities to observe monthly TWS since 2002. This study characterizes the TWS climatology over Canada, using GRACE observations, for the period of 2002–2014. The results show that the landmass has maximum/minimum TWS in April/September, with a maximum seasonal variation of 111 mm, or 1,104 km3, of water. The west coastal region has the largest seasonal variations of over 800 mm, followed by east Canada. The southern Prairies and the Arctic have the smallest seasonal variations of less than 100 mm. The results also revealed significant long-term water loss in the Yukon, the Arctic Cordillera, and western Hudson Bay, and water gain in eastern Canada, the Prairies, and some regions over the northwest Mackenzie River Basin and southern Arctic. The water loss is likely a result of glacier and permanent snow shrinkage in the Yukon and the Arctic Cordillera, and precipitation decrease in western Hudson Bay. The water gain is likely due to precipitation increase. The results will help us better understand the water cycle and climate change impact and improve water resources management.