Boreal forest fires in 1997 and 1998: a seasonal comparison using transport model simulations and measurement data
Forest fire emissions have a strong impact on the concentrations of\ntrace gases and aerosols in the atmosphere. In order to quantify\nthe influence of boreal forest fire emissions on the atmospheric\ncomposition, the fire seasons of 1997 and 1998 are compared in this\npaper. Fire activity in 1998 was very strong, especially over Canada\nand Eastern Siberia, whereas it was much weaker in 1997. According\nto burned area estimates the burning in 1998 was more than six times\nas intense as in 1997. Based on hot spot locations derived from ATSR\n( Along Track Scanning Radiometer) data and official burned area\ndata, fire emissions were estimated and their transport was simulated\nwith a Lagrangian tracer transport model. Siberian and Canadian forest\nfire tracers were distinguished to investigate the transport of both\nseparately. The fire emissions were transported even over intercontinental\ndistances. Due to the El Nino induced meteorological situation, transport\nfrom Siberia to Canada was enhanced in 1998. Siberian fire emissions\nwere transported towards Canada and contributed concentrations more\nthan twice as high as those due to Canada's own CO emissions by fires.\nIn 1998 both tracers arrive at higher latitudes over Europe, which\nis due to a higher North Atlantic Oscillation (NAO) index in 1998.\nThe simulated emission plumes are compared to CMDL ( Climate Monitoring\nand Diagnostics Laboratory) CO2 and CO data, Total Ozone Mapping\nSpectrometer ( TOMS) aerosol index ( AI) data and Global Ozone Monitoring\nExperiment (GOME) tropospheric NO2 and HCHO columns. All the data\nshow clearly enhanced signals during the burning season of 1998 compared\nto 1997. The results of the model simulation are in good agreement\nwith ground-based as well as satellite-based measurements.