Abstracts for the 6th International GAME Conf.

3-5 December 2004

Kyoto Japan

Flux variation in a Siberian taiga forest near Yakutsk from 1986 to 2000 estimated by a one-dimensional model with routine data

YAMAZAKI Takeshi (1), OHTA Takeshi (2), SUZUKI Rikie (3), OHATA Tetsuo (4)

Energy and water fluxes are estimated and their variations are investigated in a larch forest site near Yakutsk using a one-dimensional model with daily basis routine data. Estimated period is 1986 to 2000 including the period before start of tower observation (1997) on the left bank of Lena River. The land surface model includes three submodels; vegetation, snow cover, and soil. It can calculate water and energy fluxes above and within forest, if meteorological data over the forest are given as input. The data used in this study is Baseline Meteorological Data in Siberia (BMDS) Version 3; it consists of daily data of main meteorological elements. Procedure is as follows: 1) preparing equations between routine Yakutsk data and larch tower data, 2) estimating past meteorological data over taiga by the equations, and 3) estimating fluxes using the one-dimensional model. Date of leaf-out start is parameterized with soil temperature and daily maximum air temperature; it corresponds to green-up time obtained from satellite NDVI data. Monthly deviation of net radiation, Rn, is 10 Wm-2, maximum is 20 Wm-2. Monthly deviation of latent heat flux, lE, is less than 10 Wm-2, its warm season average is less than 5 Wm-2. Although magnitude of lE is almost zero in December and January, it is several Wm-2 and sensible heat flux, H, sometimes becomes negative in cold season except these two month. The evapotranspiration (E) normalized by potential evaporation (Ep), E/Ep is from 0.37 to 0.44 in warm season, it tends to be large when the leaf-out starts early. The amount of evapotranspiration in warm season can be estimated from Ep in an error of 5 mm using this relationship.

Submittal Information

Name : Date :
    YAMAZAKI Takeshi
    26-Jul-04-12:13:20
Organization : Theme :
    Institute of Observational Research for Global Change, JAMSTEC
    Theme 5
Address : Presentation :
    3173-25, Showa-machi, Kanazawa-ku, Yokohama
    Only poster
Country : Abstract ID :
    Japan
    T5YT26Jul04121320
Phone : Fax :
    +81-45-778-5646
    +81-45-778-5706
E-mail :
    yamaz@jamstec.go.jp