Historical and recent aufeis in the Indigirka River basin (Russia)

Abstract

Abstract. A detailed spatial geodatabase of aufeis (or naled in Russian) within the Indigirka River watershed (305 000 km2), Russia, was compiled from historical Russian publications (year 1958), topographic maps (years 1970–1980s) and Landsat images (year 2013–2017). Identification of aufeis by late spring Landsat images was performed with a semi-automated approach according to Normalized Difference Snow Index (NDSI) and additional data. After this, a cross-reference index was set for each aufeis field to link and compare historical and satellite-based aufeis datasets. The aufeis coverage varies from 0.26 % to 1.15 % in different sub-basins within the Indigirka River watershed. The digitized historical archive (Cadastre, 1958) contains the coordinates and characteristics of 896 aufeis fields with a total area of 2064 km2. The Landsat-based dataset included 1213 aufeis fields with a total area of 1287 km2. Accordingly, the satellite-derived total aufeis area is 1.6 times less than the Cadastre (1958) dataset. However, more than 600 aufeis fields identified from Landsat images are missing in the Cadastre (1958) archive. It is therefore possible that the conditions for aufeis formation may have changed from the mid-20th century to the present. Most present and historical aufeis fields are located in the elevation band of 1000–1200 m. About 60 % of the total aufeis area is represented by just 10 % of the largest aufeis fields. Interannual variability of aufeis area for the period of 2001–2016 was assessed for the Bolshaya Momskaya aufeis and for a group of large aufeis fields (11 aufeis fields with areas from 5 to 70 km2) in the basin of the Syuryuktyakh River. The results of this analysis indicate a tendency towards an area decrease in the Bolshaya Momskaya aufeis in recent years, while no reduction in Syuryuktyakh River aufeis area was observed. The combined digital database of the aufeis is available at https://doi.org/10.1594/PANGAEA.891036.

Warming temperatures are impacting the hydrometeorological regime of Russian rivers in the zone of continuous permafrost

“…The assessment of aufeis area conducted for the Indigirka River basin based on recent Landsat imagery analysis has shown that the number of aufeis fields increased by 35 %, but the total area decreased by 1.6 times (Makarieva et al, 2019a) in comparison with the data by Simakov and Shilnikovskaya (1958). The current aufeis area share for the studied watersheds in the Indigirka River basin ranges from 0.26 % to 0.80 % (Makarieva et al, 2019a), though historical estimations are higher. For example, Tolstikhin (1974) estimates that relative aufeis area averages 0.4 % to 1.3 %, reaching 4 % in the basins of some rivers.…”

“…Approximately 85 % of the total terrestrial runoff to the Arctic Ocean is supplied by rivers draining from Russia (Aagaard and Carmack, 1989). Moreover, Makarieva et al (2019b) have shown that most runoff of the Indigirka River is generated in mountainous areas and not from the coastal plains. Therefore, the analysis of this database, including the mountainous upstreams of the Yana and Indigirka rivers, is particularly timely.…”

Catalogue and Atlas of giant aufeis of the North-East of Russia

“…The aufeis accumulates 26 km 3 of ground water in the free water exchange zone (36 % of their total dynamic reserves). The total volume of aufeis is about 30 km 3 , which corresponds to 25 mm of water layer at the area of 1.2 million km 2 [5]. Aufeis is the climate regulator of underground and river flow.…”

“…The developed Catalogue contains the coordinates and characteristics of 896 aufeis with a total area of 2064 km 2 in the Indigirka River basin [3,10], 385 aufeis with a total area of 738 km 2 in the Yana River basin, 1765 aufeis with a total area of 1945 km 2 in the Kolyma River basin, and 1599 aufeis with a total area of 2434 km 2 in Chukotka (Fig. 2).…”

“…Aufeis is a peculiar form of seasonal glaciation that is typical for almost the entire permafrost region and consists of large ice masses in river valleys that are formed as a result of layer-by-layer freezing of ground water spilled onto the surface. Aufeis-taryns are especially widespread in the North-East of the Asian continent where they are of gigantic size: the area of aufeis fields is measured in tens of square kilometres, and the ice thickness reaches 10-12 m. Systematic study of aufeis began in the 1930 and currently there is a new wave of research interest to aufeis [1,2,3,4].…”