Deposition flux of NOィイD22ィエD2 in natural vegetation

• Project/Area Number: 10460142
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 生物資源科学
• Research Institution: Tokyo University of Agriculture & Technology
• Principal Investigator: AOKI Masatoshi TOKYO UNIVERSITY OF AGRICULTURE AND TECHNOLOGY, Faculty of Agriculture, Professor, 農学部, 教授 (60081569)
• Project Period (FY): 1998 – 1999
• Project Status: Completed (Fiscal Year 1999)
• Budget Amount: ¥9,400,000 (Direct Cost: ¥9,400,000); Fiscal Year 1999: ¥3,800,000 (Direct Cost: ¥3,800,000); Fiscal Year 1998: ¥5,600,000 (Direct Cost: ¥5,600,000)
• Keywords: NOィイD22ィエD2 absorption from air / Deposition flux / Deposition velocity / red pine plantation / crop fields / meteorological factors / seasonal transition / annual total deposition / NO_2 フラックス / アカマツ群落 / コムギ畑 / NO_2濃度 / 日射量 / 窒素成分量

Research Abstract

The objective of the study is to find out the deposition flux (FィイD2NO2ィエD2) and amount of NOィイD22ィエD2 deposition in natural vegetation. The results are the following:
1. The long-term measurement system of NOィイD22ィエD2 flux and deposition velocity (KN02) is developed and tested in red pine plantation of about 15m tall and crop fields.
2. NOィイD22ィエD2 flux and deposition velocity in crop fields (soybean, wheat, maize and paddy rice) and pine plantation showed systematic diurnal transition with the maximum at around noon. The diurnal transition was affected strongly by solar radiation.
3. Deposition velocities (KィイD2NO2ィエD2) of NO2 in crop fields were smaller than those of 03 (KOィイD23ィエD2.
4. KィイD2NO2ィエD2 in crop fields were in the range of 0. 5-1 cm/s, while the values of KィイD2NO2ィエD2 in red pine forest were 1-2cm/s in May-June and Oct.-Nov. But in July - Sept., the values in the pine forest became 5-10 times larger than that of crop fields.
5. Montly means of FィイD2NO2ィエD2 and KィイD2NO2ィエD2 were affected strongly by air temperature.
6. The extremely large values in June-Sept. will not be explained by the stomata conductance of red pine leaf, and then the possibility of chemical reaction with terphene and DMS in and above the pine forest is expected.
7. Monthly average FィイD2NO2ィエD2 were 0, 0, 47, 80, 106, 106, 399, 1726, 480, 106, 96, 4, respectively from January to December.
8. Deposition amount in a year was estimated as about 3.2 and 0.9 kgNOィイD22ィエD2/mィイD12ィエD1/year, respectively in the pine plantation and in wheat-soybean crop field, and the value of pine forest was 3.6 times larger than the wheat-soybean crop field.