Key Investigator: Gerald Livingston
Global climate change is a growing concern. It may be brought about by an increase in the concentration of gases in the atmosphere that absorb and re-radiate heat energy from the learth. One of these "greenhouse gases" is methane (CH4). The concentration of methane in the atmosphere has increased rapidly during the last 100 years and continues to increase approximately 1% per year.
Knowledge of the natural sources and sinks of methane is limited. Prior to 1986, estimates of the annual production of methane and the variation in production among the ecological zones on the earth was based on incomplete data and/or guesswork. In 1986, a research effort was initiated to determine the emission of methane from a northern high latitude ecosystem;the tundra region in Alaska north of the Brooks Range. The three year program included collection of gas samples from sites typical of the wet and dry conditions of the tundra (Fig. 1) , the acquisition of Landsat satellite digital data (Fig. 2) concurrent with the collection of ground data, and the generation of regional estimates. A classification of the Landsat data was generated and the different land cover types in the tundra were identified. These land cover types were related to variation in methane production based on the measurements taken on the ground. The results were the first "map" of methane production for the region (Fig. 3) , and the first regional esti-mates for methane that included an estimate of the error.
It is hoped that this research will be expanded to other regions with the ultimate goal of modelling and monitoring methane production on a global scale. Such information is essential to understand the role of methane in global temperatures and global climate.
COLLABORATORS: Pennsylvania State University; University of Alaska, Fairbanks; University of New Hampshire.
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