Eric M. Leibensperger

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[1] We investigate the effects on U.S. ozone air quality from 2000–2050 global changes in climate and anthropogenic emissions of ozone precursors by using a global chemical transport model (GEOS-Chem) driven by meteorological fields from the NASA Goddard Institute for Space Studies general circulation model (NASA/GISS GCM). We follow the Intergovernmental(More)
[1] We use observations from two aircraft during the ICARTT campaign over the eastern United States and North Atlantic during summer 2004, interpreted with a global 3-D model of tropospheric chemistry (GEOS-Chem) to test current understanding of regional sources, chemical evolution, and export of NOx. The boundary layer NOx data provide top-down(More)
We show that the frequency of summertime midlatitude cyclones tracking across eastern North America at 40–50 N (the southern climatological storm track) is a strong predictor of stagnation and ozone pollution days in the eastern US. The NCEP/NCAR Reanalysis, going back to 1948, shows a significant long-term decline in the number of summertime mid-latitude(More)
We calculate decadal aerosol direct and indirect (warm cloud) radiative forcings from US anthropogenic sources over the 1950–2050 period. Past and future aerosol distributions are constructed using GEOS-Chem and historical emission inventories and future projections from the IPCC A1B scenario. Aerosol simulations are evaluated with observed spatial(More)
UNLABELLED Multiple linkages connect air quality and climate change. Many air pollutant sources also emit carbon dioxide (CO2), the dominant anthropogenic greenhouse gas (GHG). The two main contributors to non-attainment of U.S. ambient air quality standards, ozone (O3) and particulate matter (PM), interact with radiation, forcing climate change. PM warms(More)
We use GEOS-Chem chemical transport model simulations of sulfateeammonium aerosol data from the NASA ARCTAS and NOAA ARCPAC aircraft campaigns in the North American Arctic in April 2008, together with longer-term data from surface sites, to better understand aerosol sources in the Arctic in winterespring and the implications for aerosol acidity. Arctic(More)
We investigate the climate response to changing US anthropogenic aerosol sources over the 1950–2050 period by using the NASA GISS general circulation model (GCM) and comparing to observed US temperature trends. Time-dependent aerosol distributions are generated from the GEOS-Chem chemical transport model applied to historical emission inventories and future(More)
We have obtained Spitzer Space Telescope IRS 5.5 35 μm spectra of 59 main sequence stars that possess IRAS 60 μm excess. The spectra of five objects possess spectral features that are well-modeled using micron-sized grains and silicates with crystalline mass fractions 0% 80%, consistent with T-Tauri and Herbig AeBe stars. With the exception of η Crv, these(More)
We applied a multiple linear regression model to understand the relationships of PM2.5 with meteorological variables in the contiguous US and from there to infer the sensitivity of PM2.5 to climate change. We used 2004–2008 PM2.5 observations from ∼1000 sites (∼200 sites for PM2.5 components) and compared to results from the GEOS-Chem chemical transport(More)
Anthropogenic emissions of nitrogen oxides (NOx h NO þ NO2) and carbon monoxide (CO) affect particulate matter (PM) air quality on an intercontinental scale by changing background concentrations of oxidants (OH, ozone, H2O2) and thus increasing the oxidation rate of sulfur dioxide (SO2) to sulfate and NOx to nitrate. We conduct sensitivity simulations with(More)