EDDY-CORRELATION MEASUREMENTS OF METHANE FLUXES USING A TUNABLE DIODE-LASER AT THE KINOSHEO LAKE TOWER SITE DURING THE NORTHERN WETLANDS STUDY (NOWES)

As part of the Canadian Northern Wetlands Study (NOWES) measurements o f methane flux were made at the Kinosheo Lake tower site for a 1-month period during the 1990 summer intensive. The measurements were made w ith a diode-laser-based methane sensor using the eddy correlation tech nique. Measurements of the methane fluxes were made at two levels, 5 o r 18 m. Approximately 900 half-hour average methane flux measurements were obtained. Weak temporal and diurnal trends were observed in the d ata. Fluxes averaged over the study period showed an overall methane e mission of 16 mg CH4 m(-2) d(-1) with a daytime average of 20 mg CH4 m (-2) d(-1) and a nighttime average of 9 mg CH4 m(-2) d(-1). The effect of emission footprint was evident in the data. A strong relationship between the daily average methane flux and wet bog temperature at 20-c m depth was observed.