Features of spring flood formation in the south mountain taiga zone of East Siberia (Mogot experimental plot case-study)
Zhuravin S.A. (1), Vasilenko N.G. (1)
(1) State Hydrological Institute, St.Petersburg, Russia
Main goal of the presentation is to consider factors of energy and water circulation determining spring flood formation in the south mountain taiga zone of East Siberia. The analysis is based on the observation data obtained at the Mogot experimental plot for 1976-1985. This experimental plot is situated at the south slope of the Stanovoi ridge near Tynda city.
Spring floods in this area are not high, except cases when monsoon rains overlap the spring flood recession. But energy and water exchange during this transfer period are very complex and there are numerous problems to adopt available hydrological models to these conditions correct.
The detailed observations made it possible to consider the following processes and phenomena:
- heat fluxes in the soil during seasonal-thawing soil layer freezing, soil moisture content and ice intrusion into the soil, changes of different soil type properties for this period;
- changes in snow structure and moisture losses in catchments during winter and spring seasons, e.g. evaporation from snow surface, infiltration of melting snow water into the frozen soils;
- heat and water fluxes during the spring flood formation period, quantitative correlation of heat and water balance components for the periods of snow melting and spring flood formation.
In particular, it was found that soil moisture content forming during autumn season is at approximately 50-60 mm in upper soil layer 20 cm that is much more its field capacity. Further transformation this moisture into the ice resulting to the substantial changes soil properties (soil density decreases, for example, up to 30-63% if compared with thawed soils). Winter precipitation as a rule not exceeds 10-30% from year precipitation. Evaporation from snow surface is at approximately 15 mm during winter season (10-20% from snow water equivalent). The main sources of snow melting energy are net radiation (B) and sensible heat flux (L). Summer period is the only period when sensible heat flux dominates in the heat balance (up to 50-60% from B). Losses by evaporation are at about 23-42% from B, while losses by snow melting are 12-17% from B.
Obtained results made it possible improve understanding of regional features processes spring flood formation, assess variations of heat and water balance components, determine information necessary for the development and validation of hydrological models adopting to the specific natural conditions permafrost regions.
Submittal Information
Name :
Date :
Zhuravin S.A.
25-Jul-01-16:54:35
Organization :
Theme :
State Hydrological Institute, St.Petersburg, Russia
