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Seasonal variation of heat balance components over a Japanese red pine forest in snowy northern Japan
Author(s) -
Suzuki Kazuyoshi,
Ohta Takeshi,
Miya Hiroshi,
Yokota Satoshi
Publication year - 1999
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/(sici)1099-1085(199910)13:14/15<2409::aid-hyp885>3.0.co;2-5
Subject(s) - latent heat , sensible heat , environmental science , canopy , snow , bowen ratio , atmospheric sciences , forest floor , tree canopy , albedo (alchemy) , heat flux , flux (metallurgy) , evaporation , meteorology , heat transfer , ecology , geography , geology , soil water , soil science , chemistry , art , biology , art history , thermodynamics , physics , performance art , organic chemistry
Continuous observations of the meteorological elements and heat fluxes were made for more than one and a half years above and in a red pine forest. We obtained the following results from these observations: 1) During the spring thaw, the albedo above the forest decreased as snow depth decreased and reached a minimum value after the snow disappeared. Due to seasonal variation in the canopy structure, the ratios of insolation and wind speed at the forest floor compared to those above the forest canopy also varied. 2) Under dry canopy conditions, the peaks of each heat balance component occurred at different times. The net radiation peaked in June; the latent heat flux peaked in July; the sensible heat flux peaked in May; the heat storage on the ground peaked in March. When the forest floor was snow‐covered, the Bowen ratio was more than 1·0 and the maximum ratio of sensible heat flux to net radiation occurred. The forest canopy over the snow surface acted as a heat source because the direction of the sensible heat flux was upward above the forest canopy. 3) The seasonal change in evaporation efficiency was similar to that in the air temperature above the canopy. When the daily air temperature was below 10 °C, the transpiration was limited. 4) Snowcover on the forest floor also affected the relationships between evaporation efficiency and meteorological conditions. This was caused by properties of the snowcover. Copyright © 1999 John Wiley & Sons, Ltd.