UC Berkeley

Until recently, European regulatory agencies and photochemical modelers had to use biogenic hydrocarbon emission models that were based almost entirely on the results of investigations in North America. Field studies of biogenic hydrocarbon emissions have been conducted in North America and Europe for more than two decades but it is only recently that there has been an attempt at multi-disciplinary (plant physiologists, micrometeorologists, atmospheric scientists, landscape ecologists) field studies. Whereas past studies involved a few scientists with similar backgrounds, recent studies have been much more multi-disciplinary efforts involving more scientists. In North America, investigations of biogenic hydrocarbon emissions have been important, but relatively minor, components of regional studies such as the Southern Oxidant Study in the United States and the BOREAS experiment in Canada. None of these studies approach the level of participation in biogenic emission studies that occurred in the BEMA program. The BEMA project also addressed another issue that is gaining interest in North America, seasonality. Variation in emission rates through the year need to be incorporated into models and longer field campaigns need to be incorporated into future experimental programs to better determine seasonality of hydrocarbon emissions. The BEMA study has provided valuable insight into hydrocarbon emissions in the Mediterranean ecosystem. Both the similarities and differences between this ecosystem and typical North America ecosystems help us to understand biogenic hydrocarbon emissions.