Abstract
The hydrological cycle of the Arctic river basin holds an important position in the Earth’s system, which has been significantly disturbed by global warming. This study analyzed recent changes in the hydrological components of two representative Arctic river basins in Siberia and North America, the Lena River Basin (LRB) and Mackenzie River Basin (MRB), respectively. The trends were diagnosed in hydrological components through a comparative analysis and estimations based on remote sensing and observational datasets during 2003–2016. The results showed that the annual precipitation decreased at rates of 1.9 mm/10a and 18.8 mm/10a in the MRB and LRB, respectively. In contrast, evapotranspiration (ET) showed increasing trends, with rates of 9.5 mm/10a and 6.3 mm/10a in the MRB and LRB, respectively. Terrestrial water storage (TWS) was obviously decreased, with rates of 30.3 mm/a and 18.9 mm/a in the MRB and LRB, respectively, which indicated that more freshwater was released. Contradictive trends of the runoffs were found in the two basins, which were increased in the LRB and decreased in the MRB, due to the contributions of the surface water and base flow. In addition, the mean annual cycles of precipitation, ET, TWS, runoff depth, surface flow and base flow behaved differently in both magnitudes and distributions in the LRB and MRB, the trends of which will likely continue with the pronounced warming climate. The current case studies can help to understand the recent changes in the Arctic hydro-climatology and the consequence of global warming in Arctic river basins.
Highlights
The global hydrological cycle has been disturbed by recent climate changes [1,2,3,4,5,6]
The climate over the Arctic region has been significantly altered during the past few decades, which has directly influenced the hydrological cycle in different ways [8,9]
The precipitation in high latitudes plays an important role in the Arctic hydrologic system, which is likely to intensify the hydrological cycle [15] in a way that it is linked with ET and related with the river discharge and terrestrial water storage (TWS) changes in the Arctic region [16,17,18]
Summary
The global hydrological cycle has been disturbed by recent climate changes [1,2,3,4,5,6]. Detailed investigations of recent changes in the hydrological cycle, including precipitation, ET, TWS change and runoff, have seldom been systematically discussed for different Arctic river basins, especially in Siberia and North America. Due to the inconsistent monitoring combined with the barriers of data transparency and accessibility, quantifying the variations of the hydrological components by in situ measurements is still a major challenge over the Arctic region To overcome such bottlenecks, remote sensing provides a reliable method to estimate the hydrological components over high-latitude regions and has great potential for advancing our understanding of the water balance dynamics and their relationship with climate change at the regional scale [12,39,40,41].
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