Precipitation in high-mountain regions is characterized by a strong heterogeneity due to complex interaction between atmospheric circulation and steep topography, however, extremely rare network of high elevation stations hampers the adequate high resolution regional climate modeling. In this study we present new data of precipitation directly measured in high-mountain catchment, on the continental glacier (East Sayan Range, south of East Siberia) during the summer periods of 2015–2017 using automatic weather station. The precipitation record was compared with near located weather stations and ERA Interim and NCEP/NCAR reanalysis data. Precipitation mode similar to the glacier site was found at the stations located west and northwest, while ERA Interim and NCEP/NCAR reanalysis data underestimated the precipitation by 40 % and 70 %, respectively. Atmospheric circulation patterns in days with precipitation were analyzed by using mean sea level pressure, geopotential height at 700 and 500 hPa and classification of macro scale atmospheric processes of the Northern Hemisphere by Dzerdzeevskii. Summer precipitation was mostly associated with meridional southern group of large scale circulation the Northern Hemisphere, while at synoptic scale it basically fell in cyclonic (49 % of precipitation) and low-gradient cyclonic (30 %) baric fields. Six typical atmospheric circulation patterns over the East Sayan were identified for days with precipitation. The sources and atmospheric moisture transfer to the glacier was defined by using the HYSPLIT trajectory model. The most of summer precipitation (70 %) was related with western cyclones, while about 25 % of rainfalls (mainly of moderate to strong intensity) was originated from the south-east (Pacific monsoon influence).
Precipitation, both in solid and liquid form, is an important component of mass balance in high-mountain glaciarized basins. It affects the formation of snow cover, accumulation, ablation, and energy balance (e.g. albedo in case of summer snowfalls) of glaciers. For example, it was found that summer balance of the glaciers of south-east Siberia is largely associated with atmospheric circulation processes of different scales (Osipova and Osipov, 2018). At the same time some persistent processes in the atmosphere significantly affects the precipitation anomalies in Eastern Siberia and Mongolia (Antokhina et al., 2016). However, understanding of fundamental nature of such relationship is limited by the lack of more or less continuous observational data from high-mountain catchments. Obtaining such meteorological time series will contribute to more reliable spatially distributed climate models, which are a useful tool for predicting climate changes and their effects on the environment, including hazardous events (e.g. catastrophic floods).
Location of the Glacier #18 (purple circle) and 11 regional weather stations (blue circles) in the East Sayan Range area
The high mountains of the south of Eastern Siberia are distinguished by an extremely rare network of conventional meteorological stations and complete absence of automatic stations. The severe topography and atmospheric circulation determine here the heterogeneity of precipitation, both spatial and seasonal. Recently, spatiotemporal inhomogeneity of precipitation of warm period has been found in the northern part of the Baikal mountain region and moisture sources identified (Osipova and Osipov, 2019a). In 2015–2017, for the first time, we obtained meteorological series of observations from the East Sayan mountains using automatic station and evaluated the main components of the surface energy balance of the glacier during summer periods (Osipova and Osipov, 2019b). In this study, we focused on the analysis of the precipitation record from the East Sayan glacier basin and its correlation with regional weather stations, reanalysis data and multiscale atmospheric circulation processes which determine the transportation and precipitation of moisture on the glacier.
The study Glacier #18 is located in central part of the East Sayan Range
(Fig. 1a and b). East Sayan, East Siberia, of length about 1000 km is located inside the Asian continent, far from the oceans. There are some
high-mountain massifs with summits more than 3000 m, such as Peak Topografov
(3015 m a.s.l.) and Munku-Sardyk (3491 m a.s.l.), located in central and
south-eastern parts of the range, respectively. East Sayan is one of the
centers of mountain glaciation in southern Siberia. There are about 270 small glaciers with total area of about 20 km
The automatic weather station was installed in the lower part of accumulation area of the glacier (52.5
Precipitation records from the glacier, weather stations Orlik and
Verkhnyaya Gutara
In order to study precipitation regime over broader (regional) area we used
the daily precipitation data from 11 regional weather stations of “Rosgidromet network” (Fig. 1a),
The 131 d precipitation record obtained from the glacier is shown in Fig. 2. The precipitation mainly fell in liquid form (90 %). In total, 100 of 131 d (80 %) were precipitated. Extreme precipitation (
The comparison of precipitation regime (over the study period) on the glacier and 11 meteorological stations is presented in Fig. 3. On the glacier, rainfalls of low intensity (
Precipitation regime on the glacier #18 and 11 nearest weather
stations (abbreviations correspond to those in Fig. 1) during the observation period 2015–2017
Over the study period we defined 8 precipitation-bearing ECMs (3, 4b, 6, 8a, 9a, 10b, 12a, 12bs and 13s), however only one stands out very well (ECM 13s). This ECM is most typical in the Northern Hemisphere for summer period and belongs to the meridional southern group of circulation. It is characterized by cyclonic circulation over the Arctic, by absence of blockings and by 3 to 4 intrusions of southern cyclones (from low latitudes to high). It was characterized by both the largest number of days with precipitation (75 %) and precipitated water (81 %). On a regional scale, days with precipitation were associated with 3 types of baric fields (Fig. 4): cyclonic (24 % days and 49 % of precipitation), low-gradient cyclonic (44 % and 30 %) and anticyclonic (32 % and 21 %). It should be noted that the precipitation on the glacier in anticyclonic field was mostly associated with eastern periphery of anticyclones. At the same time, cyclones with atmospheric fronts were observed nearby the study area and could affect the precipitation. The low-gradient cyclonic pressure field was of the greatest duration and dominated by precipitation of low intensity (up to 10 mm). However, the greatest amount of precipitation (more intense and even extreme) fell in cyclonic field.
Relationship between types of baric field over the East Sayan and
the number of precipitation days
Frequency analysis of 5 d backward trajectories arriving at the glacier showed the main directions of moisture-bearing air masses (Fig. 5). In July 2016 (24 d with precipitation and 174 mm of precipitated water) western and north-western transport prevailed. Cyclonic circulation was observed over the Arctic, the Pacific maximum was clearly pronounced, and the study area was in the low pressure field. In August 2016 (25 d and 168 mm) multidirectional trajectories of moisture-bearing flows were observed, but the northern component prevailed. High pressure was over the European Russia, and anticyclone field prevailed over the study area. In July 2017 (26 d and 222 mm) western air transport bringing the moisture was dominant, however south-western and north-western components were also presented. The study area was characterized by low pressure field. In August 2017 (17 d and 118 mm) north-western directions were prevailed, while the East Sayan was in high pressure field. In general, the most of trajectories (79 %) began west of the glacier (south-western and north-western quadrants) and they accounted for 70 % of precipitated water. However, it should be noted that trajectories originated from the south-east quadrant (14 %) had a large proportion in total precipitation (25 %), mainly due to rainfalls of moderate and high intensity.
Frequency maps of 5 d backward trajectories for July and August of 2016–2017 (days with precipitation).
Based on the precipitation record firstly obtained from high-mountain glacier and synoptic analysis we defined six regional (East Sayan) synoptic patterns for all days with precipitation (Fig. 6). These are characterized by:
(1) Mediterranean cyclones regenerated on the Mongolian branch of the polar front (ES01), (2) polar front cyclones coming from the north, north-west and north-east (ES02), (3) anticyclones centred over Lake Baikal and Far East and large depression over the North Siberia (ES03), (4) anticyclones over the West Mongolia and cyclonic circulation over the Arctic (ES04), (5) low-gradient pressure field over the East Sayan and high pressure over the Arctic (ES05), and (6) low-gradient pressure field over the East Sayan with low pressure over the Arctic (ES06). The maximum precipitation was attributed to ES06, while the minimum to ES03 and ES05. It should be noted that although the total duration of ES01 and ES02 was only 20 d they contributed 41 % of total precipitation. These both types were characterized by extreme precipitation events. In both extreme events (17 July 2016 and on 11 July 2017) heavy rainfalls were associated with cyclones. In the first event it was a Mediterranean cyclone regenerated on the Mongolian branch of polar front (ES01), while in the second one it was a
northern cyclone (ES02). Such kind of extreme precipitation events, which
falls in short time in mountains catchments, can provoke intensive snow/ice
melting and drastic increase of water level in mountain rivers. In turn it
may case catastrophic floods in foothills, one of which happened in 2019 summer on the north-east slope of the East Sayan (Floods in Irkutsk region, 2020;
Synoptic patterns allocated for days with precipitation on the glacier (maps of 700 hPa surface). For each type, the duration (in d) and total amount of precipitation (in mm and %) are indicated. Black arrows indicate leading airflows in low troposphere (700 hPa level) over the study area.
Firstly, using automatic weather station during three summer periods (2015–2017), we obtained the 131 d precipitation record from the high-mountain glacier (No. 18), located on the East Sayan Range, south of East Siberia. The record was correlated with different scale atmospheric circulation mechanisms. Rainfall mode similar to that on the glacier was found at weather stations located west and northwest, while ERA Interim and NCEP/NCAR reanalysis data underestimate precipitation in the high-mountain catchment by 40 % and 70 %, respectively. Most of summer rainfalls in glacial zone were associated with the meridional southern group of large scale circulation (Dzerdzeevskii's classification for the Northern Hemisphere) characterized by cyclonic circulation over the Arctic and intrusions of southern cyclones (ECM 13s). On a regional scale, days with precipitation were associated with three types of baric fields, cyclonic (49 % of precipitation), low-gradient cyclonic (30 %) and anticyclonic (21 %). The most of summer precipitation (70 %) came to the glacier from west, while about 25 % of total precipitation (mainly of moderate to strong intensity) was originated from the south-east (Pacific monsoon). Six atmospheric circulation patterns over the East Sayan were identified for days with precipitation over the study period. The maximum precipitation was found for type ES06 (low-gradient pressure field over the East Sayan with low pressure over the Arctic), with regenerated Mediterranean cyclones and polar front cyclones contributing 41 % of total precipitation, including extreme precipitation events.
The original observation database of precipitation on the glacier is the intellectual property of Limnological Institute SB RAS (contact the authors of this paper for data requests). Data of elementary circulation mechanisms (ECMs) of the Northern Hemisphere by Dzerdzeevskii with daily resolution is accessible at
EYO designed this study, performed field measurements of precipitation on the glacier and wrote the original draft. OPO performed the analysis of weather stations data and atmospheric circulation patterns.
The authors declare that they have no conflict of interest.
This article is part of the special issue “19th EMS Annual Meeting: European Conference for Applied Meteorology and Climatology 2019”. It is a result of the EMS Annual Meeting: European Conference for Applied Meteorology and Climatology 2019, Lyngby, Denmark, 9–13 September 2019.
We thank Andrey Fedotov, Konstantin Vershinin, Ilya Enushchenko and Vladimir Isaev who participated in field works. The authors gratefully acknowledge the NOAA Air Resources Laboratory (ARL) for the provision of the HYSPLIT transport and dispersion model and/or READY website (
This research has been supported by the Russian Foundation for Basic Research (grant no. 19-05-00668).
This paper was edited by Renato R. Colucci and reviewed by Nina Kononova, Natalia Kichigina, and one anonymous referee.