| Project/Area Number |
62840011
|
|---|
| Research Category |
Grant-in-Aid for Developmental Scientific Research
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
気象・海洋・陸水学
|
|---|
| Research Institution | Okayama University |
|---|
Principal Investigator |
OHTAKI Eiji College of Liberal Arts and Sciences, Okayama Univ., Professor, 教養部, 教授 (40033120)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
今岡 護 柳本商事, 技術部, 係長補佐
MISAWA Kiyoshi Yanaco Kogyo, section chief, ガスクロ室, 室長
IMAOKA Mamoru Yanagimoto Shyoji, associate chief clerk
|
|---|
| Project Period (FY) |
1987 – 1988
|
| Project Status |
Completed (Fiscal Year 1988)
|
| Budget Amount *help |
¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 1988: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1987: ¥3,300,000 (Direct Cost: ¥3,300,000)
|
|---|
| Keywords | Carbon Dioxide Flux / Eddy Correlation Technique / Aerodynamic Technique / ガスクロマトグラフ / 二酸化炭素 / フラックス |
|---|
| Research Abstract |
It is well known that the carbon dioxide contents of the atmosphere is increasing. The source of this increasing carbon dioxide has been assumed to be the combustion of fossil fuels, and the ocean and land biota have been considered as the major sink for carbon dioxide. Recently, biologists pointed out that the land biota is not a sink and may be a source of carbon dioxide as large as the fossil fuel source. It is thus considered that a larger portion of atmospheric carbon dioxide may be absorbed by the ocean than previously assumed, but this is not proved by direct measurements. This research project is intending to examine a so called missing carbon sink by the meteorological techniques.
The field experiments have elucidated problems as follows. The power spectral density of carbon dioxide followed a -5/3 power law in high frequency ranges. This frequency dependency of carbon dioxide fluctuations is basically similar to those of temperature and humidity. The cospectrum of carbon dioxide and vertical wind velocity had negative components for whole frequency ranges analyzed, representing downward transport of carbon dioxide by the turbulent eddies over the ocean. The carbon dioxide flux due to the mean flow showed positive, and its value was about twice of the turbulent eddy flux. This means that the flux direction of carbon dioxide over the ocean is mainly controlled by the transport direction of fluxes of sensible heat and latent heat, The upward flux of carbon dioxide may occur when the air layer over the ocean is in unstable stratification. It is noted that the total flux of carbon dioxede, which is the summation of turbulent eddy flux term and mean flow flux term, increased with increasing fluxes of sensible heat, latent heat and momentum over the ocean.
|
