HR: 1330h
AN: A52C-0817    [PDF]
TI: Seasonal Change Of CO2 Flux At Tundra Vegetation In Interior Alaska
AU: * Nojiri, A
EM: gev13036@cc.okayama-u.ac.jp
AF: Graduate School of Natural Science and Technology, 2-1-1 Tsushima-naka, Okayama, 700-8530 Japan
AU: Harazono, Y
EM: Y.Harazono@uaf.edu
AF: International Arctic Research Center / University of Alaska Fairbanks, 930 Koyukuk Dr., Fairbanks, AK 99775 United States
AU: Ohtaki, E
EM: ohtaki@cc.okayama-u.ac.jp
AF: Graduate School of Natural Science and Technology, 2-1-1 Tsushima-naka, Okayama, 700-8530 Japan
AU: Iwata, T
EM: iwata@cc.okayama-u.ac.jp
AF: Graduate School of Natural Science and Technology, 2-1-1 Tsushima-naka, Okayama, 700-8530 Japan
AB: CO2 flux and micrometeorology have been measured to reveal the responses of forest at permafrost to climate change since October in 2002. The vegetation was black spruce and tussock tundra located in the campus (147$\deg$51'W, 64$\deg$51N) of the University of Alaska Fairbanks, Alaska. There have been significant gaps of flux measurements in the interior Alaska where it is generally warmer in summer and has different climate conditions. CO2 uptake started in March when the tussock tundra was still under snow cover. CO2 uptake increased after spring thaw in mid April that ranged -0.3mg/m2/s and increased gradually until early May (DOY135). After that, daily maximum CO2 uptake kept almost upper-limit level of -1mg/m2/s during summer (June and July). Day-length was longer at the site so the nighttime CO2 respiration was defined as CO2 efflux when PAR was less than 10 mol/m2/s. Averages of CO2 respiration were 0.042mg/m2/s in mid April (DOY100-109), 0.021mg/m2/s in mid May (DOY130-139), 0.15mg/m2/s in mid June (DOY160-169), and 0.15mg/m2/s in mid July (DOY190-199), respectively. Air temperature in mid summer did not changed remarkably and daily average temperature in June and July were almost the same as between 10 and 20. These were caused by lower solar radiation and higher level of precipitation in 2003 summer than the normal year. Observed CO2 flux was limited period and the CO2 budget over tussock tundra in interior Alaska was a source from spring to summer in 2003. Long term CO2 budget study is demanded to reveal whether anthropogenic or natural variation is major effect on climate change, thus it is important to continue the flux measurements and to reveal the relationships between the atmosphere and the vegetation.
DE: 0315 Biosphere/atmosphere interactions
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting