Grant-in-Aid for Scientific Research on Priority Areas (B)
|Allocation Type||Single-year Grants |
Science and Engineering
|Research Institution||Hokkaido University |
OHATA Tetsuo Institute of low Temperature Science, Hokkaido University, Professor, 低温科学研究所, 教授 (90152230)
ISHII Yoshiyuki ILTS, Hokkaido University, Lecturer, 低温科学研究所, 助手 (40222955)
KODAMA Yuji ILTS, Hokkaido University, Lecturer, 低温科学研究所, 助手 (70186708)
ISHIKAWA Nobuyoshi ILTS, Hokkaido University, Assoc. Professor, 低温科学研究所, 助教授 (70002277)
MIZOGUCHI Masaru Tokyo University, Assoc. Professor, 農学部, 助教授 (00181917)
NOMURA Mutumi Hokkaido University, Lecturer, 北方生物圏フィールド科学センター, 助手 (20271629)
山崎 剛 東北大学, 理学研究科, 助教授 (80220317)
|Project Period (FY)
1999 – 2001
Completed (Fiscal Year 2002)
|Budget Amount *help
¥45,400,000 (Direct Cost: ¥45,400,000)
Fiscal Year 2001: ¥8,600,000 (Direct Cost: ¥8,600,000)
Fiscal Year 2000: ¥16,500,000 (Direct Cost: ¥16,500,000)
Fiscal Year 1999: ¥20,300,000 (Direct Cost: ¥20,300,000)
|Keywords||tundra / water cycle / snow cover / permafrost / evaporation / runoff / heat balance / thaw depth|
The following are the main results.
(1) Concerning Tiksi site in tundra region, hydrometeorological data (AWS, flux, basin hydrology) from the sumner of 1997 to spring of 2002 has been accumulated As for Yakutsk, similar data for forest/grass surface has been accumulated for two years since year 2000. This is the longest tundra observational data which has been taken, except the case of Alaska.
(2) As for Tiksi facing Arctic Ocean, following finding were obtained.
(a) Characteristics of evaporation is the most important process understanding the regional water cycle in this region. The summer evaporation (June - August) was estimated to be 110-165 mm for the 4 years period. Seasonal and interaanual variation of summer evaporation has strong correlation with solar radiation. This is sue to the moist grand surface layer due to shallow thawed layer. (The lowest volumetric soil moisture just below the surface was 30% during the 4 year period). However, since the solar radiation and precipitat
ion which moisten the surface, both favorable for evaporation, has negative correlation, the range of variation is suppressed. The evaporation amount obtained here is similar to the value measured at tundra regions of North America continents.
(b) The beat flux terms (sensible and latent heat) has certain relation with wind direction depending on the air masses(pressure pattern) since it is located at the northern edge of the continent.
(c) Construction of numerical model for water and energy flow in the drainage has been accorpolished Sensitivity of hydrothermal conditions and flow to climate change such as warming will be made in the near future.
(3) As for the forested region of taiga, comparative analysis of the alas regions have been advanced and following results have been obtained.
(a) In the larch forest values of heat/water exchange at the surface showed similar value disregarding the difference in stand density, age etc.
(b) The grass land in this area is formed both naturally and artificially. The large old alas seem to show low evaporation values during the summer and new alas seem to show high evaporation. This seemed to correspond to the alas development diagram developed by Russian scientists.
(c) One dimensional heat/water exchange modal developed by T. Yamazaki was revised by observational data and long term heat/water exchange data was developed. Less