Abstracts for the 6th International GAME Conf.

3-5 December 2004

Kyoto Japan

Heat and water exchange of the snowpack and permafrost during the snowmelt season in a larch forest in eastern Siberia

Tetsu Hashimoto (1), Takeshi Ohta (2), Tae Toba (2), Trofim Chr. Maximov (4)

In the Lena River basin which is one of the three largest basins in Siberia, the period during and after snowmelt is a very important hydrological event. Taiga zone of the Lena River basin; the boreal forest, snowmelt processes and the timing of the snow disappearance can affect the timing of the thaw in the phenology of trees, and the change in the heat exchange processes between land and atmosphere. To clarify the features of the heat and water balances in the snowpack and their effects on the permafrost under the snowpack during the period from pre-melt to the disappearance of the snowpack , for the taiga forest in the middle reaches of the Lena River basin, observation of the snow water equivalent, snowmelt rates, water vapor flux at the snow surface, and meteorological elements were made in 1998. The snow temperature reached 0 degree only at the snow surface in the pre-melt period, and reached 0 degree in all layers of the snowpack in the melt period. The heat available to the snowpack included the net all-wave radiation and the sensible heat flux. The net all-wave radiation contributed more than 60% of the available heat in both periods. The main released heat was the latent heat flux in the pre-melt period and the heat for melt in the melt period, which accounted for 67 and 72% of the all released heat, respectively. From the snow water equivalent and surface snowmelt rates 44 and 81% of the meltwater in the snowpack was estimated to flow out to the permafrost in the pre-melt and melt periods, respectively. The contribution of evaporation to snow ablation was as much as 37% in the pre-melt period and 6% in the melt period. In the pre-melt period, the meltwater was thought to flow down through flow fingers. The meltwater infiltrated the frozen permafrost and raised the temperature of the frozen soil by releasing the fusion heat of refreezing in both periods.

Submittal Information

Name : Date :
    Tetsu Hashimoto
    31-Jul-04-16:02:15
Organization : Theme :
    Education and Research Center for Biological Resources, Faculty of Life and Environmental Science, Shimane University
    Theme 1
Address : Presentation :
    Nishikawatsu-cho 1060, Matsue City, Shimane, 690-8504
    Only poster
Country : Abstract ID :
    Japan
    T1TH31Jul04160215
Phone : Fax :
    +81-852-32-6592
    +81-852-32-6079
E-mail :
    tetsu@life.shimane-u.ac.jp