Half-century evolution of the debris cover on the Djankuat Glacier, the Caucasus

Cover Page

Cite item

Full Text

Open Access Open Access
Restricted Access Access granted
Restricted Access Subscription Access

Abstract

The ongoing degradation of the Djankuat Glacier is also reflected in the expansion of the debris cover on the ice surface. During the 56 years since the start of direct measurements in 1968, the debris-covered glacier area has grown from 2% to 20%. The layer of superficial moraine changes the structure of the heat balance of the glacier surface, significantly affecting ice ablation. A thin (< 7 cm) cover can lead to increased melting of sub-debris ice, whereas as the debris layer thickens further, melting progressively weakens until complete vanishing after the debris cover thickness exceeds 1.5 m. Based on the results of a field survey of the debris cover in 2022, another, fourth map of the debris thickness was compiled, continuing a series of similar maps as of 1983, 1994 and 2010. The mean debris thickness varies greatly by altitudinal belts, and currently it reaches on average 60 cm throughout the glacier, which is more than twice the average all-glacier value for 1983. Thus, all the 4 debris surveys conducted over the years indicate that the hydrological role of the debris cover has always come down to an unambiguous effect of a general melt-rate weakening for the glacier as a whole. The total volume of moraine material increased 4-fold over the 39-year-long period 1983–2022, up to 275 thousand m3, despite the fact that the glacier area has significantly decreased over the same period by more than 1.5 times for both the physical surface and its orthogonal projection. The acceleration of debris mass growth over the last decade is demonstrated. Activation of denudation processes due to progressive deglaciation of the rock revetment above the firm basin causes a more intensive influx of colluvial material to the glacier. Together with the rise of the kinematic equilibrium line, this leads to an increase in the upper boundary of the debris-covered surface on the glacier.

About the authors

V. V. Popovnin

Lomonosov Moscow State University

Email: begemotina81@gmail.com
Moscow, Russia

A. S. Gubanov

Lomonosov Moscow State University

Moscow, Russia

References

  1. Алейников А.А., Золотарёв Е.А., Поповиин В.В. Распознавание ледораздела на перемётных ледниковых комплексах (Джантуганское плато на Кавказе) // Вестник МГУ. Сер. 5. География. 2002. № 3. С. 36–43.
  2. Золотарёв Е.А., Поповиин В.В. Гипсометрия ледника Джанкуат: изменения после МГД (с 1968 по 1984 г.) // Материалы гляциологических исследований. 1993. Вып. 77. С. 58–66.
  3. Каталог ледников России // Электронный ресурс. https://sites.google.com/view/glaciersrussia/ Дата обращения: 18.07.2025.
  4. Ледник Джанкуат / Ред. И.Я. Боярский. Л.: Гидрометеоиздат, 1978. 184 с
  5. Поповнин В.В., Резепкин А.А., Тиелидзе Л.Г. Разрастание поверхностной морены на языке ледника Джанкуат за период прямого гляциологического мониторинга // Криосфера Земли. 2015. Т. XIX. № 1. С. 89–98.
  6. Резепкин А.А., Поповиин В.В. О влиянии поверхностной морены на состояние ледника Джанкуат (Центральный Кавказ) к 2025 г. // Лёд и Снег. 2018. Т. 58. № 3. С. 307–321. https://doi.org/10.15356/2076-6734-2018-3-307-321
  7. Ходаков В.Г. Расчёт абляции льда под слоем морены // Материалы гляциологических исследований. 1972. Вып. 20. С. 105–108.
  8. Anderson L.S., Armstrong W.H., Anderson R.S., Buri P. Debris cover and the thinning of Kennicott Glacier, Alaska: in situ measurements, automated ice cliff delineation and distributed melt estimates // The Cryosphere. 2021. V. 15. P. 265–282. https://doi.org/10.5194/tc-15-265-2021
  9. Bozhinskiy A.N., Krass M.S., Popovnin V.V. Role of debris cover in the thermal physics of glaciers // Journal of Glaciology. 1986. V. 32. № 111. P. 255–266.
  10. Kunmar P., Mehta M., Basu T., Pant S., Mondal T.S., Rana A.S., Kumar V. Surface ablation variability and dirt cone development: A case study of the Parkachik and Durung-Drung Glaciers, Zanskar Himalaya, India // Physics and Chemistry of the Earth. 2025 (in press).
  11. Miles E.S., Steiner J.F., Buri P., Immerzeel W.W., Pelliciotti F. Controls on the relative melt rates of debris-covered glacier surfaces // Environment Research Letters. 2022. V. 17. P. 064004. https://doi.org/10.1088/1748-9326/ac6966
  12. Moeller R., Moeller M., Kukla P.A., Schneider C. Impact of supraglacial deposits of tephra from Grimsvötn volcano, Iceland, on glacier ablation // Journal of Glaciology. 2016. V. 62. № 235. P. 933–943. https://doi.org/10.1017/jog.2016.82
  13. Nakawo M., Rana B. Estimate of ablation rate of glacier ice under a supraglacial debris layer // Geografiska Annaler: Series A. Physical Geography. 1999. V. 81. № 4. P. 695–701. https://doi.org/10.1111/1468-0459.00097
  14. Nakawo M., Young G.J. Field experiments to determine the effect of a debris layer on the ablation of glacier ice // Annals of Glaciology. 1981. № 2. P. 85–91. https://doi.org/10.3189/172756481794352432
  15. Ostrem G. Ice melting under a thin layer of moraine, and the existence of ice cores in moraine ridges // Geografiska Annaler. 1959. V. 41. P. 228–230.
  16. Ostrem G., Brugman M. Glacier mass-balance measurements. Nat. Hydrology Res. Inst. (NHRI) Publ. NHRI Sci. Rep. Saskatoon, Canada. 1991. № 4. 224 p.
  17. Popovnin V.V., Rozova A.V. Influence of sub-debris thawing on ablation and runoff of the Djankuat Glacier in the Caucasus // Nordic Hydrology. 2002. V. 33. № 1. P. 75–94. https://doi.org/10.2166/nh.2002.0005
  18. Popovnin V.V., Naruse R. A 34-year-long record of mass balance and geometric changes of the Djankuat Glacier, Caucasus // Bulletin of Glacial. Reesearch. 2005. V. 22. P. 113–125.
  19. Postnikova T., Rybak O., Gubanov A., Zekollari H., Huss M., Shahgedanova M. Debris cover effect on the evolution of Northern Caucasus glaciers // Frontiers in Earth science. 2023. V. 11. P. 1256696. https://doi.org/10.3389/feart.2023.1256696
  20. Pratap B., Dobhal D.P., Mehta M. Influence of debris cover and altitude on glacier surface melting: A case study on Dokriani Glacier, Central Himalaya, India. // Annals of Glaciology. 2015. V. 56. P. 9–16. https://doi.org/10.3189/2015AoG70A971
  21. Reznichenko N., Davies T., Shulmeister J., McSaveney M. Effects of debris on ice-surface melting rates: an experimental study // Journal of Glaciology. 2010. V. 56. P. 384–394. https://doi.org/10.3189/002214310792447725
  22. Richardson J.M., Brook M.S. Ablation of debris-covered ice: some effects of the 25 September 2007 Mt Ruapehu eruption // Journal of Royal Society of New Zealand. 2010. V. 40. P. 45–55.
  23. Rowan A.V., Egholm D.L., Quincey D.J., Hubbard B., King O., Miles E.S., Miles K.E., Hornsey J. The role of differential ablation and dynamic detachment in driving accelerating mass loss from a debris-covered Himalayan glacier // Jornal of Geophys. Research. Earth Surace. 2021. V. 126. P. 1–20. https://doi.org/10.1029/2020JF005761ol
  24. Scherler D., Bookhagen B., Strecker M.R. Spatially variable response of Himalayan glaciers to climate change affected by debris cover // National Geoscience. 2011. № 4. P. 156–159. https://doi.org/10.1038/NGEO1068
  25. Tielidze L.G., Bolch T., Wheate R.D., Kutuzov S.S., Lavrentiev I.I., Zemp M. Supra-glacial debris cover changes in the Greater Caucasus from 1986 to 2014 // The Cryosphere. 2020. V. 14. P. 585–598.
  26. Verhaegen Y., Rybak O., Popovnin V.V., Huybrechts P. Quantifying supraglacial debris-related melt-altering effects on the Djankuat Glacier, Caucasus, Russian Federation // Journal of Geophys. Research: Earth Surface. 2024. V. 129. № 4. P. e2023JF007542.

Supplementary files

Supplementary Files
Action
1. JATS XML
Download

Copyright (c) 2025 Russian Academy of Sciences

Согласие на обработку персональных данных

 

Используя сайт https://journals.rcsi.science, я (далее – «Пользователь» или «Субъект персональных данных») даю согласие на обработку персональных данных на этом сайте (текст Согласия) и на обработку персональных данных с помощью сервиса «Яндекс.Метрика» (текст Согласия).