Abstracts for the 5th International GAME Conf.

3-5 October 2001

Aichi Trade Center

Nagoya Japan

Surface energy/water balance in the tundra region estimated by a one-dimensional land surface model ---An examination of transpiration by CO2 flux

Kumiko TAKATA (1), Hironori YABUKI (2), Toshiyuki SATO (3), Manfred BOELTER (4), Seita EMORI (5), Yuji KODAMA (6), Tetsuo OHATA (7)

The surface energy/water balance at Tiksi in the tundra region is calculated for 1998-2000 using a one-dimensional land surface model, MATSIRO, and compared with the observed seasonal cycle. The calculated snow-covered duration agrees well with the observation, and the observed variation in radiation components are reproduced including the day-to-day variations. The calculated latent heat flux is lower than those estimated by Bowen ratio method, while the calculated sensible heat flux is higher than that. 78 % of the total evapotranspiration averaged for two years is ground evaporation, 2 % is interception evaporation, 1 % is transpiration, and 19 % is sublimation from snow surface. Transpiration is calculated from the stomatal resistance estimated by photosynthetic processes in MATSIRO. The CO2 assimilation rate of photosynthesis is 112 gCO2/m^2/year in this experiment. On the other hand, CO2 flux by soil respiration estimated from soil temperature data at Tiksi is 273 gCO2/m^2/summer (Boelter et al., 2000). Assuming that CO2 assimilation rate by vegetation equilibrates with CO2 release due to soil respiration, the CO2 assimilation rate calculated by MATSIRO is low. It is also lower than the net primary production (NPP) estimated from the satellite observation in Tundra regions, 350 gCO2/m^2/year. We are going to estimate the CO2 assimilation rate from measured dry weight of vegetation, and examine the calculated and observed latent and sensible heat fluxes.

Submittal Information

Name : Date :
    Kumiko TAKATA
    31-May-01-20:17:16
Organization : Theme :
    Frontier Research System for Global Change
    Theme 2
Address : Presentation :
    3173-25 Showa-machi, Kanazawa-ku, Yokohama 236-0001
    Only poster
Country : Abstract ID :
    JAPAN
    T2KT31May01201716
Phone : Fax :
    +81-45-778-5544
    +81-45-778-5706
E-mail :
    takata@jamstec.go.jp