Aufeis impact on the hydrological cycle in the North-Eastern Russia

Nataliia Nesterova,Vladimir Alexeev,Anastasiya Zemlyanskova,Olga Makarieva,Andrey Shikhov,Andrey Ostashov

doi:10.5194/egusphere-egu22-172

Abstract

&lt;p&gt;Aufeis are produced annually in the rivers valleys in permafrost environment as the result of layer-by-layer freezing of groundwater flowing to the surface. Aufeis are widespread in the territory of the North-East of Eurasia (including the basins of large rivers in permafrost, such as the Yana, Indigirka, Kolyma, Anadyr, Penzhina Rivers and rivers of the Chukchi Peninsula (total area about 2 mln. km&lt;sup&gt;2&lt;/sup&gt;). &amp;#160;They comprise an important water resource of the study region.&lt;/p&gt;&lt;p&gt;Based on the analysis of Landsat satellite images for the period 2013-2019 the number and total maximum area were estimated. As Landsat images do not always allow correctly assess the maximum area of aufeis, it was adjusted to get the maximum value before the beginning of ablation period for the assessment of aufeis resources. Total number of giant aufeis (&gt;0.1 km&lt;sup&gt;2&lt;/sup&gt;) formed by groundwater reaches 6217 with maximum area of about 4500 km&lt;sup&gt;2&lt;/sup&gt; (in average 0.22 % of studied area). For each aufeis field the assessment of maximum ice reserves was conducted. &amp;#160;&lt;/p&gt;&lt;p&gt;The aufeis resources of the North-East are at least 10.6 km&lt;sup&gt;3 &lt;/sup&gt;or 5 mm of aufeis runoff. The aufeis resources vary from 0.4 to 4.25 km&lt;sup&gt;3 &lt;/sup&gt;(or 3.7 &amp;#8211; 11 mm) for individual basins of large rivers. The greatest aufeis resources in absolute values are found in the Indigirka River basin. The contribution of aufeis runoff to streamflow in different seasons was calculated for 58 hydrological gauges (area 523 &amp;#8211; 526000 km&lt;sup&gt;2&lt;/sup&gt;). Aufeis annual runoff varies from 0.3 to 29 mm (0.1 &amp;#8211; 22%, average 3.8%) with the share in winter runoff amount about 6 &amp;#8211; 712 % (average 112%) and the spring freshet 0.2 &amp;#8211; 43% (average 7.1%).&lt;/p&gt;&lt;p&gt;The influence of aufeis and glaciers on the water balance is compared &amp;#8211; in general, the aufeis runoff exceeds the glacial runoff. The response of aufeis to climate change depends on different factors of the natural system. The dynamics of aufeis formation is directly related to the winter runoff, which changes are observed in different parts of the cryolithozone. The presented results are relevant for studying the impact of climate change on the hydrological cycle and its components in the permafrost regions of the Northern Hemisphere.&lt;/p&gt;&lt;p&gt;The study was carried out with the support of RFBR (19-55-80028, 20-05-00666) and St. Petersburg State University (project 75295879).&lt;/p&gt;

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