Now showing items 1-20 of 293

• #### An adaptive reduction algorithm for efficient chemical calculations in global atmospheric chemistry models ﻿

(Elsevier BV, 2010)
We present a computationally efficient adaptive method for calculating the time evolution of the concentrations of chemical species in global 3-D models of atmospheric chemistry. Our strategy consists of partitioning the ...
• #### Air mass factor formulation for spectroscopic measurements from satellites: Application to formaldehyde retrievals from the Global Ozone Monitoring Experiment ﻿

(Wiley-Blackwell, 2001)
We present a new formulation for the air mass factor (AMF) to convert slant column measurements of optically thin atmospheric species from space into total vertical columns. Because of atmospheric scattering, the AMF depends ...
• #### Air-Sea Exchange in the Global Mercury Cycle ﻿

(American Geophysical Union, 2007)
We present results from a new global atmospheric mercury model coupled with a mixed layer slab ocean. The ocean model describes the interactions of the mixed layer with the atmosphere and deep ocean, as well as conversion ...
• #### Air-snow exchange of HNO3 and NOy at Summit, Greenland ﻿

(Wiley-Blackwell, 1998)
Ice core records of NO3− deposition to polar glaciers could provide unrivaled information on past photochemical status and N cycling dynamics of the troposphere, if the ice core records could be inverted to yield concentrations ...
• #### All-Time Releases of Mercury to the Atmosphere from Human Activities ﻿

(American Chemical Society (ACS), 2011)
Understanding the biogeochemical cycling of mercury is critical for explaining the presence of mercury in remote regions of the world, such as the Arctic and the Himalayas, as well as local concentrations. While we have ...
• #### Ammonia Emissions in the United States, European Union, and China Derived by High-Resolution Inversion of Ammonium Wet Deposition Data: Interpretation with a New Agricultural Emissions Inventory (MASAGE_NH3) ﻿

(Wiley-Blackwell, 2014)
We use the adjoint of a global 3-D chemical transport model (GEOS-Chem) to optimize ammonia $(NH_3)$ emissions in the U.S., European Union, and China by inversion of 2005–2008 network data for $NH^+_4$ wet deposition ...
• #### Annual Distributions and Sources of Arctic Aerosol Components, Aerosol Optical Depth, and Aerosol Absorption ﻿

(Wiley-Blackwell, 2014)
Radiative forcing by aerosols and tropospheric ozone could play a significant role in recent Arctic warming. These species are in general poorly accounted for in climate models. We use the GEOS-Chem global chemical transport ...
• #### Anthropogenic and natural contributions to tropospheric sulfate: A global model analysis ﻿

(Wiley-Blackwell, 1996)
A global three-dimensional model is used to examine the export of anthropogenic sulfur from northern midlatitude continents and to assess the relative importance of anthropogenic and natural sources to sulfate levels in ...
• #### Anthropogenic emissions in Nigeria and implications for atmospheric ozone pollution: A view from space ﻿

(Elsevier BV, 2014)
Nigeria has a high population density and large fossil fuel resources but very poorly managed energy infrastructure. Satellite observations of formaldehyde (HCHO) and glyoxal (CHOCHO) reveal very large sources of anthropogenic ...
• #### Anthropogenic emissions of highly reactive volatile organic compounds in eastern Texas inferred from oversampling of satellite (OMI) measurements of HCHO columns ﻿

(IOP Publishing, 2014)
Satellite observations of formaldehyde (HCHO) columns provide top-down constraints on emissions of highly reactive volatile organic compounds (HRVOCs). This approach has been used previously in the US to estimate isoprene ...
• #### Anthropogenic forcing on tropospheric ozone and OH since preindustrial times ﻿

(Wiley-Blackwell, 1998)
A global three-dimensional model of tropospheric chemistry is used to investigate the changes in tropospheric O3 and OH since preindustrial times as a result of fuel combustion and industry, biomass burning, and growth in ...
• #### Anthropogenic Impacts on Global Storage and Emissions of Mercury from Terrestrial Soils: Insights from a New Global Model ﻿

(Wiley-Blackwell, 2010)
We develop a mechanistic global model of soil mercury storage and emissions that ties the lifetime of mercury in soils to the lifetime of the organic carbon pools it is associated with. We explore the implications of ...
• #### Application of empirical orthogonal functions to evaluate ozone simulations with regional and global models ﻿

(Wiley-Blackwell, 2003)
Empirical orthogonal functions are used together with standard statistical metrics to evaluate the ability of models with different spatial resolutions to reproduce observed patterns of surface ozone (O3) in the eastern ...
• #### Aqueous-Phase Reactive Uptake of Dicarbonyls as a Source of Organic Aerosol Over Eastern North America ﻿

(Elsevier, 2009)
We use a global 3-D atmospheric chemistry model (GEOS-Chem) to simulate surface and aircraft measurements of organic carbon (OC) aerosol over eastern North America during summer 2004 (ICARTT aircraft campaign), with the ...
• #### 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 ...
• #### The Arctic Boundary Layer Expedition (ABLE 3A): July–August 1988 ﻿

(Wiley-Blackwell, 1992)
The Arctic Boundary Layer Expedition (ABLE 3A) used measurements from ground, aircraft, and satellite platforms to characterize the chemistry and dynamics of the lower atmosphere over Arctic and sub-Arctic regions of North ...
• #### The Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) Mission: Design, Execution, and First Results ﻿

(European Geosciences Union, 2010)
The NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission was conducted in two 3-week deployments based in Alaska (April 2008) and western Canada (June–July 2008). Its ...
• #### Asian chemical outflow to the Pacific in spring: Origins, pathways, and budgets ﻿

(Wiley-Blackwell, 2001)
We analyze the Asian outflow of CO, ozone, and nitrogen oxides (NOx) to the Pacific in spring by using the GEOS-CHEM global three-dimensional model of tropospheric chemistry and simulating the Pacific Exploratory Mission-West ...
• #### Asian outflow and trans-Pacific transport of carbon monoxide and ozone pollution: An integrated satellite, aircraft, and model perspective ﻿

(Wiley-Blackwell, 2003)
Satellite observations of carbon monoxide (CO) from the Measurements of Pollution in the Troposphere (MOPITT) instrument are combined with measurements from the Transport and Chemical Evolution Over the Pacific (TRACE-P) ...
• #### Atmosphere-biosphere exchange of CO 2 and O 3 in the central Amazon Forest ﻿

(Wiley-Blackwell, 1990)
Measurements of vertical fluxes for CO2 and O3 were made at a level 10 m above the canopy of the Amazon forest during the wet season, using eddy correlation techniques. Vertical profiles of CO2 and O3 were recorded ...