Changes of hydrothermal structure of Austre Grønfjordbreen and Fridtjovbreen Glaciers in Svalbard

• Published in: Ice and Snow
• Main Authors: E. Vasilenko V., A. Glazovsky F., I. Lavrentiev I., Yu. Macheret Ya., Е. Василенко В., А. Глазовский Ф., И. Лаврентьев И., Ю. Мачерет Я.
• Format: Article in Journal/Newspaper
• Language: Russian
• Published: IGRAS 2015
• Subjects: Hydrothermal structure;radio-echo sounding of glaciers;Svalbard;water content in glaciers; Вода в ледниках;гидротермическая структура;радиозондирование ледников;Шпицберген; Svalbard; Nordenskiöld Land; Fridtjovbreen; Austre Grønfjordbreen; Annals of Glaciology; Antarctic and Alpine Research; Arctic; Polar Research; The Cryosphere
• Online Access: https://ice-snow.igras.ru/jour/article/view/19; https://doi.org/10.15356/2076-6734-2014-1-5-19

The results of ground-based RES studies (20 MHz) at the Austre Grønfjordbreen and Fridtjovbreen glaciers on Nordenskiöld Land, Svalbard, spring 2010–2012, were compared with previous airborne RES data (620 MHz) of 1979 to understand the hydrothermal structure and its changes with time for these twinned glaciers. Temperature measurements in 9 shallow ice bore holes (down to 20 m) of spring 2013, and other RES and bore-hole data (1977–2005) were also considered. Both glaciers now are polythermal ones. The ratio of cold/temperate ice volumes in Austre Grønfjordbreen is 83 and 17 per cent, and in Fridtjovbreen is 26 and 74 per cent. The water content in temperate ice estimated from radio wave velocity is ca. 2–5%. Total water content in temperate ice of Austre Grønfjordbreen is estimated as 1,8–4,5∙10−3 km3, and in Fridtjovbreen as 74–85∙10−3 km3. Over the past 33 years (1979–2012) the average thickness of the cold ice in Austre Grønfjordbreen decreased by about 34 m, and thickness of temperate ice by 9 m. In Fridtjovbreen the cold ice has thinned by 87 m, but the temperate ice became thicker by 48 m. These differences in hydrothermal structure changes of the neighboring glaciers with common climatic history are attributed to the additional effect of Fridtjovbreen surge in 1991–1997 resulted in its additional internal heating. Приведены результаты радиозондирования ледников Восточный Гренфьорд и Фритьоф на западе Земли Норденшельда (Шпицберген), полученные весной 2010–2013 гг. Установлено, что сейчас оба лед‐ ника – политермические. В леднике Восточный Гренфьорд доля холодного и тёплого льда равна соответ‐ ственно 83 и 17%, а в леднике Фритьоф – 26 и 74%. Содержание воды в тёплом льде, оцененное по ско‐ рости распространения радиоволн, составляет 2–5%. Её объём в леднике Восточный Гренфьорд равен около 1,8÷4,5∙10−3 км3, а в леднике Фритьоф – 74÷85∙10−3 км3. Сравнение с данными 1979 г. показало, что за последние 33 года средняя толщина холодного льда в леднике Восточный Гренфьорд уменьшилась при‐ мерно на ...