Mogot, Russia, 1976-1985, 2000-2002
Location and Scale
The hydrological polygon “Mogot” (55.60; 124.90) of the Baikal-Amur expedition of State Hydrological Institute is located in the middle part of the southern slope of the Stanovoi and Tukuringra ridges in the Amur River basin, approximately 60 km north from Tynda (Russia).
The polygon includes the several watersheds: the Nelka River (basin area 30.8 km2) and three tributaries – Zakharyonok (5.8 km2), Filiper (4.5 km2) and Onyx Creek (3 km2). Additional observations were also made in the nearby watershed area of the Tsyganka River (basin area 150 km2).
All observational data are systematized and presented in Vasilenko (2013). The dates includes:
1. Daily precipitation for the period 1976-1985 – according to the network of precipitation gauges and pluviographs (from 5 to 22). In the period from 2000 to 2002 – 1 precipitation gauge and 1 pluviograph;
2. Solar radiation for 2 sites: for the main site in 1977-1985; for additional areas - in 1979-1982; 2000-2002 - in the warm period of the year; in 7 terms – in the warm period, in 4 terms – in the cold;
3. Heat balance for 2 gradient sites: for the main site continuously in the periods from 1977 to 1985 and from August 2000 to June 2002; for additional sites in the 1979-1982; in the warm period – in 7 terms daily, in 4 terms – in the cold period;
4. Daily water discharge and water levels for 5 gauges;
5. Meteorological characteristics (air temperature and humidity, wind speed, atmospheric pressure, dew point, cloud cover, soil/snow surface temperature) – in 7 terms in the period 1976-1985 and 2000-2002;
6. The soil water equivalent in a layer of 0-20 cm at 20 points of the routes and at 11 reference sites in the warm period (1976-1985), once a decade; on one route in the period from August 2000 to September 2001;
7. The snow water equivalent on routes for the period 1976-1985 and in 2000-2002 – once at the end of the month;
8. Freezing – thawing of the active layer of soil on various landscapes – 1 time in 5-10 days from the beginning of thawing of the active layer to its complete freezing in 1976-1985 and 2000-2001;
9. Hydrochemical composition of river waters in different phases of the hydrological regime in 1978-1982;
10. Evaporation from the water surface at one site in 1977-1984;
11. Evaporation from the soil – 4 sites in 1976-1985.
The climate of the region is extremely continental with large annual and daily air temperature amplitudes. The influence of the Far Eastern monsoons is great in the summer. The average annual air temperature is -7.5 °C. The duration of the period with negative temperatures amounts up to 195-220 days per year. During warm period (April-September) more than 80% of the annual precipitation is registered ( about 560 mm). Snow cover appears in late September - early October, and remains until early May. The maximum water equivalent in snow is registered in March-April and varies significantly every year (from 42 to 160 mm for the period 1976-1985).
Complex base: crystalline shales, Precambrian gneiss, broken by granite intrusions. The polygon is located in the area of continuous permafrost with a depth of 100-250 m and temperatures of -1-3°C. Soils are represented by various combinations of permafrost mountain taiga soils with a shortened profile, abundance of gravelly inclusions of all horizons and low level of the humus-accumulated horizon. The soil layer remains in a frozen condition for 7-8 months a year.
The natural conditions of the territory are typical for low-mountain mid-taiga landscapes of the southern slope of the Stanovoi ridge. These landscapes are characterized by a combination of low mountains and excessively moist inter-mountain lower areas. The polygon relief is represented by rounded and flat watersheds, steep slopes of shadow exposure and more flattened slopes of light exposure.
Vegetation / Land Use
The researched area is covered mainly by larch woodlands, the forestry area of the Nelka River basin is 80%, and the forestry area of tributaries – up to 90%. The main representatives of vegetation are Dahurian larch and white birch. The vegetation cover includes blueberry, cowberry, green mosses and reindeer lichen. Within the area of the valley bottom the swamps are widely spread, covered with a thick (up to 40 cm) moss layer.
According to the results of the hydrological polygon “Mogot” studies and descriptions, the landscapes of the Nelka River basin can be summarized as follows:
1. The heads of watersheds are located at altitudes of more than 850 m and are characterized by well-drained soils. Vegetation is represented by sparse larch. The top layer consists of a dry layer of lichens with transition to loam and sandy loam.
2. The shady slopes located within the elevations of 650-850 m, are composed of soil pattern consisting of the layer formed by forest litter. The soil organic layer thickness is more than 20 cm, the depth of the seasonal thaw depth reaches 120 cm.
3. The sun exposed slopes, also located within the range of altitudes from 650 to 850 m, are characterized by the presence of a higher amount of solar radiation. Landscape have the highest melting depth, reaching 160 cm, and the least developed vegetation, consisting of the cowberry larch and secondary birch forests. The thickness of the organic layer is 15-20 cm, the soil column primarily consists of sandy loam, common at depths of 40-160 cm.
4. River valleys are common at altitudes less than 650 m. They are waterlogged blueberry larch forests, sphagnum moss, with some areas covered by blueberry-sedge plant complex. A distinctive feature of this landscape is the presence of peat layer and thick moss cover.
The hydrological polygon “Mogot” was established in February 1976. The bservations were made from 1977 to 1985. The work program changed from year to year while maintaining the overall focus and composition of observations. The observations were discontinued and the polygon was closed in December 1985. The observations were resumed at a limited number of points in August 2000. The polygon has been closed again since July 1, 2002.
Hydrological Knowledge Gained
The study of heat and moisture exchange and the water regime of small watersheds in the permafrost zone of the southern mountainous regions of Eastern Siberia (Vasilenko, Zhuravin, 1997, 1998, 1999; Vasilenko, 2004, 2013; Sokolov, Vuglinsky, 1997; Suzuki et al., 2006a,b,c; 2013; Zhang et al., 2004; Yamazaki et al., 2006), the study of the influence of deforestation on the hydrological regime (Vasilenko, 2013).
Georgiadi and Zolotokrylin (2007) showed that in the conditions of intermittent permafrost, the contribution of snow and rain to the formation of spring flooding is close to each other. Flood runoff losses are determined by the duration of snowmelt. In case of rain floods, the water output during the thawing of the permafrost is 2-3 % of the total runoff. The values of the subsurface runoff are determined. Vasilenko (2013) developed methods for calculating the maximum flow of spring floods and rain floods in the BAM region. She proposed a comprehensive situational analysis of hydrological processes instead of factor-by-factor analysis, which takes into account the most likely combinations of natural conditions.
The use of observational data for the development of parameters of the hydrological model for the main landscape is given in the works Zhang et al. (2004), Yamazaki et al. (2006), Suzuki et al. (2013), Nesterova et al. (2018).
Vasilenko N.G. Hydrology of the BAM Zone Rivers : Field Researchers. — SPb. : Nestor-Historia, 2013. — 672 р. (in Russian)
Vasilenko N. & Zhuravin S. (1997). Peculiarities of energy balance formation in the layer of seasonal thawing in East Siberia // Proc. Third Int. Study Conference on GEWEX in Asia and GAME, 26–28 March 1997. Cheju, Korea. Preprint Volume, 76.
Vasilenko N. & Zhuravin S. (1998) Experimental study of heat balance and heat exchange in the seasonal melt layer of soils in the permafrost zone (case-study in Stanovoi Ridge) // Research Report of IHAS. № 4. / Ed. by T. Ohata and T. Hiyama. Proc. Second Int. Workshop on Energy and Water Cycle in GAME-Siberia, Moscow, Russia, June 1997. Nagoya University Press, 1998. P. 72–78.
Vasilenko N.G. & Zhuravin S.A. (1999). Peculiarities of water and heat regimes of seasonal thawing soil layer in mountain regions of permafrost zone (East Siberia case-study). // Proc. Third Int. Scientific Conference on the Global Energy and Water Cycle jointly with the Fourth Study Conference on GEWEX Asian Monsoon Experiment (GAME), 16–19 June 1999. Beijing, China (Preprint Volume). P. 285–286.
Vasilenko N.G. (2004). Water balance of small Russian catchments in the southern mountainous Taiga Zone: “Mogot” case-study. IAHS Publ. 2004. № 290. P. 65–77. Georgiadi A. G., Zolotokrylin A. N. (2007) Heat and water exchange in permafrost landscapes of Eastern Siberia and its factors. Tver, Triada, 576 p. (in Russian)
Nesterova N. V., Makarieva O. M., Vinogradova T. A., Lebedeva L. S. (2018) Modelling runoff formation processes at the BAM zone based on the data of the Mogot research site / / Water Management of Russia, No. 1, pp.18-36 (in Russian)
Sokolov B. L. and V. S. Vuglinsky (1997) Energy and Water Exchange in Mountain Taiga in the South of East Sibe- ria // State Hydrological Institute, St. Petersburg (in Russian)
Suzuki K., J. Kubota, T. Ohata and V. Vuglinsky (2006a) Influence of Snow Ablation and Frozen Ground on Spring Runoff Generation in the Mogot Experimental Watershed, Southern Mountainous Taiga of Eastern Siberia // Nordic Hydrology, Vol. 37, 2006, pp. 21-29.
Suzuki K., et al. (2006b) Transport of Organic Carbon from the Mogot Experimental Watershed in the Southern Mountainous Taiga of Eastern Siberia // Nordic Hydrology, Vol. 37, No. 3, 2006, pp. 303-312. http://dx.doi.org/10.2166/nh.2006.015
Suzuki K., et al. (2006c) Snow Ablation in an Open Field and Larch Forest of the Southern Mountainous Region of Eastern Siberia // Hydrological Sciences Journal, Vol. 51, No. 3, 2006, pp. 465-480. http://dx.doi.org/10.1623/hysj.51.3.465
Suzuki K. (2013) Estimation of Snowmelt Infiltration into Frozen Ground and Snowmelt Runoff in the Mogot Experimental Watershed in East Siberia // International Journal of Geosciences, Vol. 4 No. 10, pp. 1346-1354. doi: 10.4236/ijg.2013.410131.
Zhang Y., K. Suzuki, T. Kadota and T. Ohata (2004) Sublimation from Snow Surface in Southern Mountain Taiga of Eastern Siberia // Journal of Geophysical Research, Vol. 109, doi: 10.1029/2003JD003779 Yamazaki Y., J. Kubota, T. Ohata, V. Vuglinsky and T. Mizuyama (2006) Seasonal Changes in Runoff Characteristics on a Permafrost Watershed in the Southern Mountainous Region of Eastern Siberia // Hydrological Processes, Vol. 20, No. 3, pp. 453-467. http://dx.doi.org/10.1002/hyp.5914