Seasonal variation of heat balance components over a Japanese red pine forest in snowy northern Japan
✍ Scribed by Kazuyoshi Suzuki; Takeshi Ohta; Hiroshi Miya; Satoshi Yokota
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 214 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0885-6087
No coin nor oath required. For personal study only.
✦ Synopsis
Continuous observations of the meteorological elements and heat ¯uxes 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 ¯oor compared to those above the forest canopy also varied. 2) Under dry canopy conditions, the peaks of each heat balance component occurred at dierent times. The net radiation peaked in June; the latent heat ¯ux peaked in July; the sensible heat ¯ux peaked in May; the heat storage on the ground peaked in March. When the forest ¯oor was snow-covered, the Bowen ratio was more than 1 . 0 and the maximum ratio of sensible heat ¯ux to net radiation occurred. The forest canopy over the snow surface acted as a heat source because the direction of the sensible heat ¯ux was upward above the forest canopy. 3) The seasonal change in evaporation eciency was similar to that in the air temperature above the canopy. When the daily air temperature was below 10 8C, the transpiration was limited. 4) Snowcover on the forest ¯oor also aected the relationships between evaporation eciency and meteorological conditions. This was caused by properties of the snowcover.