资源环境科技发展态势分析平台

Reactive nitrogen (N-r) is an essential nutrient to plants and a limiting element for growth in many ecosystems, but it can have harmful effects on ecosystems when in excess. Satellite-derived surface observations are used together with a dry deposition model to estimate the dry deposition flux of the most abundant short-lived nitrogen species, NH3 and NO2, over North America during the 2013 warm season. These fluxes demonstrate that the NH3 contribution dominates over NO2 for most regions (comprising similar to 85% of their sum in Canada and similar to 65% in the U.S.), with some regional exceptions (e.g. Alberta and northeastern U.S.). Nationwide, similar to 51t of N from these species were dry deposited in the U.S., approximately double the similar to 28 t in Canada over this period. Forest fires are shown to be the major contributor of dry deposition of N-r from NH3 in northern latitudes, leading to deposition fluxes 2-3 times greater than from expected amounts without fires.