Академическое издательство «Гео»

Keywords: atmospheric circulation, cyclones, anticyclones, NCEP/NCAR reanalysis, accumulative positive temperatures, ablation, glacier.



GEOGRAPHY AND NATURAL RESOURCES, 2016, № 5, p. 15-19

Atmospheric circulation mechanisms and their association with the processes of glacier meltdown of the Baikal Range

O.P. Osipova* and E.Yu. Osipov**

*V. B. Sochava Institute of Geography SB RAS,
664033, Irkutsk, Ulan-Batorskaya str., 1, Russia, olga@irigs.irk.ru
**Limnological Institute SB RAS, 664033, Irkutsk, Ulan-Batorskaya str., 3, Russia, eduard@lin.irk.ru

On the basis of data from monthly bulletins of the Irkutsk Center for Hydrometeorology and Environmental Monitoring for June–August 2001–2013, we investigated the association of the atmospheric circulation with potential summer ablation of the glaciers of the Baikal Range. As the indicator of ablation, we used the accumulated positive temperatures calculated for the mean height of the glacier zone. The summer seasons were classified into three groups: with high, low and moderate ablation. The maximum and minimum values of accumulated positive temperatures, respectively, were 1152 (the year 2002) and 787 °C (2013). The HYSPLIT model was used to identify the prevailing directions of air masses over the study area: westerly, southwesterly, northerly, and northwesterly. We assessed the contribution from the meridional component of the atmospheric circulation which has been enhanced over the course of the last decade. According to the dynamics of A. L. Kats’ zonal and meridional circulation indices, there occur summer seasons with a maximal (2007 and 2010) and minimal (2003 and 2012) intensity of the zonal circulation as well as inter-annual variations in the meridional circulation. Results of a comprehensive analysis of ground-level and altitudinal synoptic maps, isobaric fields of absolute and relative topography, and the temperature regime over the glacier zone (NCEP/NCAR) revealed synoptic conditions contributing to an increase/decrease in glacier meltdown in the region under consideration. A study is made of the dynamics of frontal activity, the types of advection and of the warm wet air masses over the Baikal Range during summer seasons. A change in the frequency of all the circulation mechanisms used in this study involves a change in weather conditions and climatic regime, which favor an enhancement or a decrease in ablation for glaciers and has influence on the evolution of the entire glacier zone of the Baikal Range.

Keywords: atmospheric circulation, cyclones, anticyclones, NCEP/NCAR reanalysis, accumulative positive temperatures, ablation, glacier.

DOI: 10.21782/GiPR0206-1619-2016-5(15-19)

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