ИСТИНА

A negative glacier mass balance is determined by temperature anomalies during the ablation and the lack of winter precipitations. However, it is difficult to confirm or to deny these seemingly obvious conclusions because of the lack of systematic meteorological observations in the mountains. The only source of long-period series of meteorological data in the glacial areas of the Greater Caucasus are the results of the global and regional reanalysis performed by numerical weather prediction models. In this work a widely known reanalysis NCEP/NCAR is used, because it covers a significant period of time (1948-2014 years). Statistical verification of the reanalysis data was performed for the summer season using a seasonal meteorological measurements in different areas of Mount Elbrus in 1960, 2007 and 2013. This verification showed that the reanalysis successfully reproduces the temperature and humidity conditions of Elbrus and its surroundings. This fact allows us to use reanalysis data for reproducing meteorological regime of the Central Caucasus in the last 65 years. It is shown that the air temperature and humidity characteristics in the high-altitude areas of Elbrus were changing slowly. However, an intensive melting of glaciers in the period 2000-2010 is observed. According to the reanalysis, verified by the observations, a possible reason of the increased layer of glacier ablation could be an anomaly of the radiation balance. The value of the balance for the period 2001-2010 exceeded the average climatic value (1961-1990) on 5%. This result could be important because 85-88% of ablation energy on the Greater Caucasus is exactly the radiation balance. It is interesting that the increase of the radiation balance during 2001-2010 period occurred due to the growth of the downward flux of the long-wave radiation.