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Magnitude and seasonality of wetland methane emissions from the Hudson Bay Lowlands (Canada)
(European Geosciences Union, 2011)
The Hudson Bay Lowlands (HBL) is the second largest boreal wetland ecosystem in the world and an important natural source of global atmospheric methane. We quantify the HBL methane emissions by using the GEOS-Chem chemical ...
Intercontinental influence of NOx and CO emissions on particulate matter air quality
(Elsevier BV, 2011)
Anthropogenic emissions of nitrogen oxides (NOx ≡ NO + NO2) and carbon monoxide (CO) affect particulate matter (PM) air quality on an intercontinental scale by changing background concentrations of oxidants (OH, ozone, ...
Sources of carbonaceous aerosols and deposited black carbon in the Arctic in winter-spring: implications for radiative forcing
(European Geosciences Union, 2011)
We use a global chemical transport model (GEOS-Chem CTM) to interpret observations of black carbon (BC) and organic aerosol (OA) from the NASA ARCTAS aircraft campaign over the North American Arctic in April 2008, as well ...
Legacy Impacts of All-Time Anthropogenic Emissions on the Global Mercury Cycle
(Wiley-Blackwell, 2013)
Elevated mercury (Hg) in marine and terrestrial ecosystems is a global health concern because of the formation of toxic methylmercury. Humans have emitted Hg to the atmosphere for millennia, and this Hg has deposited and ...
Estimating North American background ozone in U.S. surface air with two independent global models: Variability, uncertainties, and recommendations
(Elsevier BV, 2014)
Accurate estimates for North American background (NAB) ozone (O3) in surface air over the United States are needed for setting and implementing an attainable national O3 standard. These estimates rely on simulations with ...
Arctic Air Pollution: New Insights from POLARCAT-IPY
(American Meteorological Society, 2014)
Given the rapid nature of climate change occurring in the Arctic and the difficulty for climate models to quantitatively reproduce observed changes such as sea ice loss, it is important to improve understanding of the ...
Monitoring high-ozone events in the US Intermountain West using TEMPO geostationary satellite observations
(Copernicus GmbH, 2014)
High-ozone events, approaching or exceeding the National Ambient Air Quality Standard (NAAQS), are frequently observed in the US Intermountain West in association with subsiding air from the free troposphere. Monitoring ...
Interannual Variability in Tropical Tropospheric Ozone and OH: The Role of Lightning
(Wiley-Blackwell, 2013)
Nitrogen oxide radicals (NOx) produced by lightning are natural precursors for the production of the dominant tropospheric oxidants, OH and ozone. Observations of the interannual variability (IAV) of tropical ozone and of ...
Present and future nitrogen deposition to national parks in the United States: critical load exceedances
(Copernicus GmbH, 2013)
National parks in the United States are protected areas wherein the natural habitat is to be conserved for future generations. Deposition of anthropogenic nitrogen (N) transported from areas of human activity (fuel combustion, ...
Sources and Processes Contributing to Nitrogen Deposition: An Adjoint Model Analysis Applied to Biodiversity Hotspots Worldwide
(American Chemical Society (ACS), 2013)
Anthropogenic enrichment of reactive nitrogen (Nr) deposition is an ecological concern. We use the adjoint of a global 3-D chemical transport model (GEOS-Chem) to identify the sources and processes that control Nr deposition ...