Favorable climatic regime for maintaining the present-day geometry of the Gregoriev Glacier, Inner Tien Shan

• Main Authors: K. Fujita, N. Takeuchi, S. A. Nikitin, A. B. Surazakov, S. Okamoto, V. B. Aizen, J. Kubota
• Format: Article
• Language: English
• Published: Copernicus Publications 2011-07-01
• Series: The Cryosphere
• Online Access: http://www.the-cryosphere.net/5/539/2011/tc-5-539-2011.pdf

We conducted 2 yr (2005–2007) of in situ meteorological and glaciological observations on the Gregoriev Glacier, a flat-top glacier within the Inner Tien Shan, Kyrgyzstan. Relative carrier-phase GPS surveys reveal a vertical lowering at the summit of the glacier. Based on snow density data and an energy-mass balance model, we estimate that the annual precipitation and summer mean temperature required to maintain the glacier in the current state are 289 mm and −3.8 °C at the glacier summit (4600 m a.s.l.), respectively. The good agreement between dynamically derived precipitation and the long-term observed precipitation at a nearby station in the Tien Shan (296 mm at 3614 m a.s.l. for the period 1930–2002) suggests that the glacier has been in a near steady-state in terms of mass supply. The glacier mass-balance, reconstructed based on meteorological data from the Tien Shan station for the past 80 yr, explains the observed fluctuations in glacier extent, particularly the negative mass balance in the 1990s.