scope:

Description of Driving Event:

In situ airborne measurements of the turbulent flux and mean values of O3, CO and CH4 were obtained in the boundary layer over selected wetland systems in Alaska. These measurements were obtained in July-August 1988 as part of the NASA Global Tropospheric Experiment Program's Arctic Boundary Layer Expedition. The flux measurements obtained from this study provide information on the source/sink distribution of O3 and CH4 over the Yukon-Kuskokwim Delta (YKD) and Alaskan North Slope (ANS) regions of Alaska. The source/sink distribution over the YKD is qualitatively correlated with surface vegetation type, identified from multispectral scanner imagery. Direct measurements of the spiral variation in the CH4 source strength were obtained over the YKD. The CH4 source strength over the YKD ranged from 2.5 to 85 MG M-2 D-1 during a flux survey flight which spanned a considerable portion of the YKD, a spatially averaged, seasonally adjusted source strength of 51 MG M-2 D-1 was established for the YKD. Indirect CH4 flux estimates obtained over tundra were estimated to be 44 TG/A based on:

1. the spatially averaged source strength obtained over the YKD

2. current estimates of the global coverage of tundra

3. assuming a similarity between other tundra areas and that of the YKD.