ИСТИНА

Glacier thickness and volume estimations are key parameters for many glaciological applications. Furthermore, the thermal state and internal structure of glaciers are linked with local climate conditions. Ongoing glacier recession affects local river discharge and contributes to global sea level rise. However, direct measurements of ice thickness are still sparse because of its high costs and labor intensity, especially in remote glacierized areas in Central Asia. In this region, there are two glaciers with very detailed legacy data on ice thickness and thermal regime – Abramov glacier in the Pamir Alay Mountains and Gregoriev ice cap in the inner Tien-Shan. During a recent field campaign, we conducted GPR measurements along 24 and 27 km of profiles on Abramov and Gregoriev glaciers, respectively, with a 20 MHz VIRL-7 monopulse radar. Ice thickness maps were constructed for the investigated parts of the glaciers and the internal structure mapped. Obtained radar data shows the presence of a core of temperate ice on Gregoriev ice cap which was previously considered cold based and a predominantly temperate structure of Abramov glacier. Maximal measured ice thickness reaches 220 m on Abramov glacier and 110 m on Gregoriev ice cap. This research allows to assess changes of Abramov glacier thickness and provides a first estimate of the total volume of Gregoriev ice cap, the biggest glacier in Tien-Shan of this morphological type. Furthermore, this data will contribute to the glacier thickness database (GlaThiDa) for future improvement of glacier thickness modelling.