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Eddy-correlation measurements of fluxes of CO2 and H2O above a spruce standстатья
Дата последнего поиска статьи во внешних источниках: 19 июля 2016 г.
- Авторы: Ibrom A., Schütz C., Tworek T., Morgenstern K., Oltchev A., Falk M., Constantin J., Gravenhorst G.
- Журнал: Physics and Chemistry of the Earth
- Том: 21
- Номер: 5–6
- Год издания: 1996
- Издательство: Pergamon Press Ltd.
- Местоположение издательства: United Kingdom
- Первая страница: 409
- Последняя страница: 414
- DOI: 10.1016/S0079-1946(97)81133-0
- Аннотация: Atmospheric fluxes of CO2 and H2O above a mature spruce stand (Picea abies (L.) Karst.) have been investigated using the eddy- correlation technique. A closed path sensor adapted to the special requirements of long-term studies has been developed and tested. Field measurements have been performed since April 1995. Estimates of fetch showed a very narrow source area dimension under instable stratification (≤ 200 m). Fetch requirements at night are not met in some directions. Energy balance closure was influenced systematically by the wind direction indicating a substantial attenuation of the vertical wind motion by the tower (up to 40 %). Even for optimal flow directions, energy balance closure was about 88%. Intercomparison of the used ultra sonic anemometer (USAT-3) with a GILL - anemometer showed systematically lower values of vertical wind speed fluctuations (13 %). Average CO2-fluxes ranged between -13 at noon to 3 μmol m−2, s−1 at night in summer. In November and December the stand released CO2 on a daily basis. A preliminary estimate of the cumulative net carbon balance over the observed period of 9 months is 4–5 t, C ha−1.
- Добавил в систему: Ольчев Александр Валентинович