Commented [AL1]: How about: 1 Aufeis of the Indigirka river basin (Russia): the database “Historical and recent aufeis, Indigirka River basin, Russia“ 2 from historical data and recent Landsat images 3 *Olga Makarieva1,2,, Andrey Shikhov3, Nataliia Nesterova2,4, Andrey Ostashov2 4 1Melnikov Permafrost Institute of RAS, Yakutsk 5 2St. Petersburg State University, St. Petersburg 6 3Perm State University, Perm 7 4State Hydrological institute, St. Petersburg 8 RUSSIA 9 *[email protected] 10 Abstract: A dDetailed spatial geodatabase of aufeis (or naled in Russian) within the 11 Indigirka River watershed (, the basin area 305 000 km2), Russia, was compiled from historical 12 Russian publications (year 1958) the Cadaster of aufeis of the North-East of the USSR published 13 in 1958, topographic maps (year xxx), and Landsat images for (year 2013-2017). The aufeis area 14 sharecoverage varies from 0.26 to 1.15% in different river sub-basins within the Indigirka River 15 watershedstudied area. The 16 dDigitized historical archive (Cadaster, (1958) contains the coordinates and 17 characteristics of 897 aufeises with total area of 2064 km2. The Landsat-based identification of 18 aufeises for 2013-2017 allowed the description ofincluded 1213 aufeises on with a total area of 19 1287 km2. The combined digital database of the aufeis is available at 20 https://doi.pangaea.de/10.1594/PANGAEA.891036. Accordingly, tThe satellite-derived total 21 aufeis area of aufeis is 1.6 times less than in the Cadaster (1958) dataset. At the same 22 timeHowever, more than 600 aufeis identified by from Landsat images analyses are missing in 23 the Cadaster (1958) archive. It is therefore possible implies that the conditions for aufeis 24 formation conditions may have been changed between from the mid-20th century and to the 25 present. 26 About 60% of total area presents 10% of the largest aufeis. Most aufeis are located in the Commented [AL2]: Present or historical? 27 elevation band of 1 100 – 1 300 m. About 60% of total aufeis area are represented by top presents 28 10% of the largest of the largest aufeis. 29 The iInterannual variability of the aufeis area for the period of 2001-2016 was estimated 30 by the example of assessed at the Bolshaya Momskaya naled (aufeis) and the for a group of large 31 aufeis (>xx km2 each) in the basin of the Syuryuktyakh River for the period of 2001-2016. The 32 results of analysis indicate a tendency towards an area decrease in the area of the Bolshaya 33 Momskaya naled in recent years, while no at the same time the reduction Syuryuktyakh Riverin 34 the aufeis area in the basin of the Syuryuktyakh River has not occurredwas observed. The 35 combined digital database of the aufeis is available at 36 https://doi.pangaea.de/10.1594/PANGAEA.891036. 37 38 Keywords: aufies, the Indigirka river, the Map and Cadaster of aufeises, Landsat images, 39 database, interannual variability, the Bolshaya Momskaya naled (aufeis) 40 41 1. Introduction 42 Aufeis (naled in Russian, icings in English) is one of thea glaciation periglacial landforms, 43 standing on the same level with other types o that is characteristic of many streams in cold regions 44 f snow-ice formations and that affecting affects water exchange and economic activity (Alekseev, 45 1987). They are distributedAufeis are found in permafrost regions, for example, such as Alaska 46 (Slaughter, 1982), Siberia (Alekseev, 1987), Canada (Pollard, 2005), Greenland (Yde and 1 47 Knudsen, 2005) and others (Yoshikawa et al., 2007). Intensification of aAufeis formation 48 processes can result in significant economic expenses as; they aufeis may negatively affect 49 engineering constructions’ sustainabilityinfrastructure, and therefore natural resource extraction 50 as well as complicate exploitation of hydro-technical and industrial constructions (Aufeis of 51 Siberia…, 1981). Moreover, the springs that often , feeding aufeis may, in some cases can be the Commented [AL3]: I think you need to list the last name of the author here (not the title) or alternatively, the publisher, and the 52 only source of water supply for inhabited localitiesremote communities (Simakov, publication year. 53 Shilnikovskaya, 1958). 54 In Russia, aufeis are found in the North-East, Transbaikal region, Yakutia, and West Siberia. 55 Sokolov (1975) assessed estimated that the total aufeis water storage in aufeis of Russia to be not 56 less than at least 50 km3, which approximately equals the Indigirka River total annual streamflow. 57 The main hydrological role of aufeis is the seasonal redistribution of the underground 58 groundwater component of river runoff, where the from winter groundwater discharge is released 59 to summer streamflow through melting of aufeis to spring-summer season (Surface water 60 resources, 1972). In most cases, the share of the aufeis component in a river’s annual streamflow 61 accounts for 3-7 %, reaching 25-30 % in particular river basins with an extremely large proportion 62 of aufeis (Reedyk et al., 1995; Kane & Slaughter, 1973; Sokolov, 1975). The most significant 63 water inflow from aufeis melting takes place in May-June (Sokolov, 1975). For example, the share 64 of the aufeis flow accounts for more than 11% from of total annual streamflow at the Indigirka 65 River (gauging station Yurty, basin area 51 100 km2). In May, it aufeis melt may be represent 50 66 % of monthly total streamflow, but decreases in June to 35 % (Sokolov, 1975). 67 It is important to understand how climate change may impact aufeis formation may be Formatted: Indent: First line: 0.49" 68 impacted by climate change. Aufeis are formed by a complex interconnection between river and 69 groundwater. Currently mMany studies have reported the increase of minimum flow in Arctic 70 rivers (Rennermalm and Wood, 2010; Tananaev et al., 2016), including those where aufeis are 71 observed in abundance (Makarieva et al., 2018, in review). The A widely accepted hypothesis for 72 permafrost regions is that a warming climate improves increase the connection between surface- 73 and groundwater in permafrost areas which that in turn leads to the increase of streamflow, both 74 in cold seasons and in annual flow (Bense et al., 2012; Ge et al., 2011; Walvoord et al., 2012; 75 Walvoord and Kurylyk., 2016). The dynamic ofVariation and changes in aufeis extent which can 76 partly be assessed based on the analysis ofusing remote sensing data techniques, where aufeis 77 dynamics can serve as an can be viewed as one indicator of groundwater changes which that are 78 is otherwise difficult to be observe d naturally in remote arctic areas (Topchiev, 2008; Yoshikawa 79 et al., 2007). 80 Projected assessments of change inThe understanding of how aufeis respond to a in warming 81 conditions climate vary. Observations Alekseev (2016) points out that in long-term regime of 82 aufeis in general there are suggests 3, 7 andthree to 11 year up and down cycles of aufeis maximum 83 annual size, whichs, during which they may vary by up to 25-30 % in comparison with average 84 long-term average values (Alekseev, 2016). However, for the last 50-60 years there is a decrease Commented [AL4]: Would be good to include which region this 85 in the volumes of spring discharge,s which feed aufeis , in agreement with other evidences of study represents. 86 current cryosphere degradation (Alekseev, 2016). Some authors expect suggest that degradation 87 of permafrost in the discontinuous and island-like zones will lead to the decrease of the number of Commented [AL5]: Do you mean sporadic permafrost regions? 88 aufeis and in facteven an almost complete disappearance. of them. Meanwhile, in the zone of 89 continuous permafrost in North-East Siberia, a climate warming of 2-3°С being projected for 90 North-East Siberia by the end of the 21th century, will is not projected to not lead to the significant 91 changes in permafrost regimeextent, but will increase number and size volumes of both through- 92 and open taliks by the end of the 21th century (Pomortsev et al., 2010). This Such a scenario may 93 result in dispersion of large aufeis and formation of new small ones aufeis (Pomortsev et al., 2010). 94 The projections of increasing dynamics of aufeis formation under climate change are 95 confirmed by direct observations. Indeed, inIn the aufeis valleys of Ulakhan Taryn and Bulus, 96 (central Yakutia, Russia,) only in four4 out of 10 aufeis seasons in this century aufeis didn’t reach 97 their maximum area, volume and depth (Pomortsev et al., 2007). In Alaska, however, according Commented [AL6]: It is unclear what you are trying to say here. 98 to Yoshikawa et. al (2007), on the contrary, there are no significant changes were documented in 2 99 the area and volume of aufeis over the past few decades or even a century (Yoshikawa et. al, 2007). 100 Yoshikawa et. al (2007) suggested that the formation and melting of ice is less dependent on 101 climate change and more so on the source (spring) water properties such as temperature and 102 volume (discharge). 103 In 1958, Simakov and Shilnikovskaya (1958) compiled and published the mMap (scale 1:2 104 000 000) and the Cadasterinventory of aufeis of the North-East USSR (scale 1:2 000 000). In the 105 last 60 yearsSince then, there has been no update onf the information on aufeis in general in this 106 region, apart from some specific studies. In 1980-1982, the Cataloguean inventory of aufeis of in 107 the zone of the Baikal-Amur Mainline was published (Catalog of Aufeis…, 1980, 1981, 1982). 108 Markov et al. (2017) summarized the results of field studies onf the aufeis in the southern mountain 109 taiga of Eastern Siberia in the period from 1976 to 1983.