Climate and hydrological changes in the Ob River Basin during 1936–2017

Abstract

Changes in the hydrological regimes of Arctic rivers could affect the thermohaline circulation of the Arctic Ocean. In this study, we analysed spatiotemporal variations in temperature and precipitation in the Ob River Basin regions during 1936-2017 based on data from the Global Precipitation Climatology Center.Changes in discharge and response to climate change were examined based on monthly observed data during the same period. It is indicated the Ob River Basin experienced significant overall rapid warming and wetting (increased precipitation) in the study period, with average rates of 0.20 C (10 year −1 ) and 5.3 mm (10 year −1 ), respectively. The annual spatial variations of temperature and precipitation showed different scales in different regions. The discharge in spring and winter significantly increased at a rate of 384.1 and 173.1 m 3 /s (10 year −1 ), respectively. Hydrograph separation indicated infiltration and supported that deep flow paths increased the contribution of groundwater to base flow. Meanwhile, the variation of the ratio of Q max /Q min suggested that the basin storage and the mechanism of discharge generation have significantly changed. The hydrological processes were influenced by changes of permafrost in a certain in the Ob RiverBasin. An increase in the recession coefficient (RC) implies that the permafrost degradation in the basin due to climate warming affected hydrological processes in winter. Permafrost degradation affected the Q max /Q min more significantly in the warm season than RC due to the enhanced infiltration that converted more surface water into groundwater in the cold season. The impact of precipitation on discharge, including surface flow and base flow, was more significant than temperature at the annual and seasonal scales in the Ob River Basin. The base flow was more obviously influenced by temperature than surface flow. The results of this study are significant for analyses of the basin water budget and freshwater input to the Arctic Ocean. K E Y W O R D Sdischarge, hydrological processes, impacts, Ob River, temperature and precipitation

Pan‐Arctic Riverine Dissolved Organic Matter: Synchronous Molecular Stability, Shifting Sources and Subsidies

“…Discontinuous permafrost allows even greater groundwater connectivity; in the Yukon watershed (23% continuous permafrost), weathering signatures have shown that inputs from deep groundwater flowpaths dominated during winter but were present in small amounts throughout the year (Douglas et al., 2013), and long‐term increases in groundwater contribution to streamflow have been attributed to deepening flowpaths caused by permafrost degradation (Walvoord & Striegl, 2007). In the Ob', where continuous permafrost coverage is low but sporadic and discontinuous permafrost underlie a quarter of the watershed, groundwater reservoirs join other water sources such as lakes and wetlands in providing baseflow during winter and provide the bulk of solute inputs in its lower latitude, non‐permafrost impacted reaches (Frey et al., 2007; Xu et al., 2020).…”

Opportunities and Challenges Arising from Rapid Cryospheric Changes in the Southern Altai Mountains, China

“…The main rivers in this region include the Irtysh and Ulungur. The Irtysh originates in the SAM, flows northwest into Kazakhstan, and then joins the Ob River near the city of Khanty-Mansiysk, western Siberia, Russia, before draining into the Arctic Ocean [33,39]. The Ulungur is an inland river that originates in western Mongolia and flows south into Altay Prefecture of northern Xinjiang of China, where it then flows northwest and empties into Ulungur Lake [40].…”

Changes of Hydrological Components in Arctic Rivers Based on Multi-Source Data during 2003–2016

“…Nevertheless, a previous study indicated the annual precipitation in the Arctic showed decreasing trends during the last few decades [16]. Meanwhile, a statistically obvious increase in the averaged seasonal and annual precipitation was demonstrated in the Canadian Arctic and Eurasia Arctic [9,17]. It has been noted that the spatiotemporal variations of precipitation over the subregions of the Arctic show inconsistencies [5].…”

“…The hydrological cycle of Arctic terrestrial ecosystems is a key element in the Earth's system [5]. 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]. More specifically, the average annual temperature has increased at almost twice the global rate over recent decades in the Artic regions, which is pronounced to increase by an additional 4-7 • C over the next century [10,11].…”