| Project/Area Number |
11490001
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
広領域
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| Research Institution | Hokkaido University |
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Principal Investigator |
ISHIKAWA Nobuyoshi Hokkaido Univ., Inst. Of Low Temp. Sci., Asso, Prof., 低温科学研究所, 助教授 (70002277)
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| Co-Investigator(Kenkyū-buntansha) |
ATKAHASHI Hidenori Hokkaido Univ., Grad. School of Environ. Earth Sci., Asso. Prof., 大学院・地球環境科学研究科, 助教授 (20001472)
ISHII Yoshiyuki Hokkaido Univ., Inst. Of Low Temp. Sci., Assist. Prof., 低温科学研究所, 助手 (40222955)
KODAMA Yuji Hokkaido Univ., Inst. Of Low Temp. Sci., Assist. Prof., 低温科学研究所, 助手 (70186708)
TANAKA Yumiko Hokkaido Univ., Univ. Forest, Academy Staff, 農学部付属演習林, 教務職員 (60221397)
HIRANO Takashi Hokkaido Univ., Grad. School of Agri. Asso. Prof., 大学院・農学研究科, 助教授 (20208838)
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| Project Period (FY) |
1999 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥7,200,000 (Direct Cost: ¥7,200,000)
Fiscal Year 2002: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2001: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2000: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1999: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | water balance / heat balance / CO_2 concentration / turbulent heat flux / evapo-transpiration / soil respiration / runoff / chemical content / 水循環 / 炭酸ガス濃度 / 酵素同位体 / 蒸発散量 / 乱流変動法 / 物質循環 / 落葉広葉樹林 / 熱収支 / 酸性度 / 顕熱 / 樹冠 |
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| Research Abstract |
For understanding the effects of forest and snow cover on the water, CO_2 and chemical cycles were examined at two different experimental watersheds from 1999 to 2003 including three snow cover seasons. One watershed located at the northern part of Hokkaido where the annual temperature range was -30℃ to 25℃ and the maximum snow depth was more than 2m. The other was at the southern part of Hokkaido, where the temperature range was -25℃ to 25℃ and the snow depth was below 50cm. Vegetations of both sites are mixed forests of evergreen needle leaf trees and deciduous broad-leaved trees with bamboo bush undergrowth. Observation items are radiative heat flux, turbulent heat flux, evapo-transpiration, CO_2 concentration above canopy and forest floor, chemical contents of river water, snowmelt water, groundwater and precipitation.
The main observational results are : 【○!1】Evapo-transpiration above canopy showed remarkable seasonal variation and even in mid-summer it occupied 30-40% of the net radiation , which was smaller compared with other reports. 【○!2】The absorbed CO_2 by broad-leaved forest was 2680-2200kgC/ha/yr, which qualitatively consists with the growth rates of trees. Soil respiration was 4100-3900kg/C/ha/yr and showed daily and seasonal variations according to the change of soil temperature. 【○!3】CO_2 concentration at the bottm of snow cover in mid-winter sometime exceeded 1200ppm. CO_2 in the atmosphere just above the snow cover showed no daily variation in the mid-winter but clear daily variation appeared after March. 【○!4】During snow melting season the runoff ratio of water was 80-85%, however the chemical balance showed that the outflow of iron exceeded more than two times of the inflow, which suggested the inflow of snow-free season reserved in the watershed for a while and drained in the snowmelt season.
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