Sciences and Exploration Directorate

Sarah A Strode


Sarah A Strode's Contact Card & Information.
Phone: 301.614.5547
Org Code: 614
Mail Code 614
Greenbelt, MD 20771

Brief Bio

Sarah Strode received her Ph.D in Atmospheric Science from the University of Washington. Her thesis work focused on the air-sea exchange and global transport of mercury. Sarah came to Goddard in 2009. Her research focuses on the interactions between atmospheric chemistry and climate, trends in atmospheric pollutants, and global transport of trace gases. She uses GEOS-5 Chemistry Climate Model (GEOSCCM) and the Global Modeling Initiative (GMI) Chemical Transport Model to analyze the trace gas distributions and trends seen in satellite, aircraft, and ground-based observations.  She is also involved in the Atmospheric Tomography Mission (ATom) and the Chemistry-Climate Modeling Initiative (CCMI).

Research Interests

Trends in Atmospheric Pollutants

Earth Science: Atmospheric Chemistry

Atmospheric concentrations of pollutants such as ozone and carbon monoxide (CO) are changing over time due to human activities and air pollution regulations.  I use global atmospheric models along with satellite and surface observations to investigate what causes the observed trends and variability in atmospheric pollutants.  I am also interested in using models to predict how observations from future missions will help constrain pollutant trends.

Oxidizing Capacity of the Troposphere

Earth Science: Atmospheric Chemistry

The hydroxyl radical (OH) is the primary sink for many atmospheric pollutants and for some greenhouse gases such as methane.  Consequently, the amount of OH in the troposphere affects air quality and climate by controlling the lifetime of these gases.  My research uses models to quantify the impact of CO concentrations, overhead ozone, water vapor, and other factors on concentrations of OH.

Chemistry-Climate Modeling

Earth Science: Climate

Climate change can alter the emissions and chemistry of reactive trace gases, while changes in reactive greenhouse gases such as ozone and methane impact the climate.  Chemistry-climate models allow us to simulate the coupled chemistry-climate system to better understand the feedbacks between atmospheric chemistry and climate.

Current Projects

Atmospheric Chemistry Modelling for ATom

Atmospheric Chemistry

Dr. Strode is participating in the modeling effort for the Atmospheric Tomography Mission (ATom), which seeks to understand the production and loss of ozone as well as methane oxidation in the remote atmosphere.  She is working with the GMI chemical transport model for this effort.  She also provided chemistry forecast briefings for the ATom team.

Trends and Variability in Surface Ozone over the United States

Atmospheric Chemistry

Pollution controls on ozone precursors have led to reductions in summertime surface ozone pollution over the eastern United States.  Trends in other seasons and regions of the country are more complex, as they are affected by processes such as atmospheric transport as well as local emissions.  On top of the long-term trends, there is also substantial year-to-year variability in surface ozone due to meteorology.  I am using the GMI chemical transport model to investigate the causes of the observed variability and trends in surface ozone over the United States.  Model simulations allow us to separate the role of changing emissions from that of meteorology.

Trends in Carbon Monoxide

Atmospheric Chemistry

Space-based observations of carbon monoxide (CO) show negative trends in several regions of the atmosphere [Worden et al., 2013].  I am using multiple model simulations from the Chemistry Climate Modeling Initiative (CCMI) to explore whether models can reproduce and explain the observed trends.

Simulation of Methane Isotopes

Atmospheric Chemistry

Biogenic and thermogenic sources of methane differ in their isotopic ratios.  Consequently, the isotopic composition of atmospheric methane provides valuable information on methane sources.  Dr. Strode is conducting 3-dimensional model simulations of the isotopic composition of atmospheric methane that can be compared to observations.  The goal of this study is to obtain stronger constraints on the contribution of different methane sources.

Ozone in cloudy versus clear sky conditions

Atmospheric Chemistry

Convection impacts ozone concentrations by lifting ozone-poor air from the surface, but can also lift pollutants that lead to additional ozone formation aloft.  Dr. Strode is using satellite observations in conjunction with the GEOSCCM to investigate differences in ozone between cloudy and clear regions of the atmosphere.


Associate Research Scientist

Morgan State University - NASA GSFC

December 2021 - Present

Contributes to development and evaluation of the GEOSCCM

Scientist II

USRA - NASA GSFC, Code 614

August 2011 - November 2021

  • Contributed to the ATom campaign by providing chemical transport modeling of the mission period and chemical forecasts during the mission
  • conducted research on trace gases as part of the Atmospheric Chemistry and Dynamics Laboratory
  • Investigated trends and variability in atmospheric composition by using models to analyze satellite, surface, and suborbital observations
  • contributed to model intercomparison studies

Atmospheric Constituent Scientist


September 2009 - August 2011

  • Contributed to atmospheric modeling efforts of the Global Modeling and Assimilation Office (GMAO)
  • Updated trace gas emissions for the GEOS-5 Chemistry Climate Model

Project Scientist

O'Brien and Gere - Blue Bell, PA

July 2008 - June 2009

  • Prepared greenhouse gas inventories
  • Contributed to human health risk assessments


Ph.D: Atmospheric Science; University of Washington, Seattle, WA (2008)
Dissertation Topic: “Mercury in the Atmosphere and Ocean: Sources, Transport, and Global Impacts”
: Atmospheric Science; University of Washington, Seattle, WA (2005)
B.A.: Chemistry and Mathematics, Washington University in St. Louis, St. Louis, MO (2002)

Professional Service

Reviewer for several scientific journals including: Nature Communications, Journal of Geophysical Research, Geophysical Research Letters, Atmospheric Chemistry and Physics, Atmospheric Environment, and Environmental Science and Technology, and Environmental Pollution

Selected Publications


2021. "Description of the NASA GEOS Composition Forecast Modeling System GEOS‐CF v1.0." Journal of Advances in Modeling Earth Systems 13 (4): [10.1029/2020ms002413] [Journal Article/Letter]

2021. "Mapping Yearly Fine Resolution Global Surface Ozone through the Bayesian Maximum Entropy Data Fusion of Observations and Model Output for 1990–2017." Environmental Science & Technology acs.est.0c07742 [10.1021/acs.est.0c07742] [Journal Article/Letter]

2020. "Aircraft observations since the 1990s reveal increases of tropospheric ozone at multiple locations across the Northern Hemisphere." Science Advances 6 (34): eaba8272 [10.1126/sciadv.aba8272] [Journal Article/Letter]

2020. "Strong sensitivity of the isotopic composition of methane to the plausible range of tropospheric chlorine." Atmospheric Chemistry and Physics 20 (14): 8405-8419 [10.5194/acp-20-8405-2020] [Journal Article/Letter]

2020. "Abrupt decline in tropospheric nitrogen dioxide over China after the outbreak of COVID-19." Science Advances 6 (28): eabc2992 [10.1126/sciadv.abc2992] [Journal Article/Letter]

2020. "Attribution of Chemistry-Climate Model Initiative (CCMI) ozone radiative flux bias from satellites." Atmospheric Chemistry and Physics 20 (1): 281-301 [10.5194/acp-20-281-2020] [Journal Article/Letter]

2019. "Disentangling the Drivers of the Summertime Ozone‐Temperature Relationship Over the United States." Journal of Geophysical Research: Atmospheres 124 (19): 10503-10524 [10.1029/2019jd030572] [Journal Article/Letter]

2019. "Trends in global tropospheric ozone inferred from a composite record of TOMS/OMI/MLS/OMPS satellite measurements and the MERRA-2 GMI simulation." Atmospheric Chemistry and Physics 19 (5): 3257-3269 [10.5194/acp-19-3257-2019] [Journal Article/Letter]

2019. "Global changes in the diurnal cycle of surface ozone." Atmospheric Environment 199 323-333 [10.1016/j.atmosenv.2018.11.028] [Journal Article/Letter]

2018. "Changes in Global Tropospheric OH Expected as a Result of Climate Change Over the Last Several Decades." Journal of Geophysical Research: Atmospheres 123 (18): 10,774-10,795 [10.1029/2018jd028388] [Journal Article/Letter]

2018. "Forecasting carbon monoxide on a global scale for the ATom-1 aircraft mission: insights from airborne and satellite observations and modeling." Atmospheric Chemistry and Physics 18 (15): 10955-10971 [10.5194/acp-18-10955-2018] [Journal Article/Letter]

2018. "How well can global chemistry models calculate the reactivity of short-lived greenhouse gases in the remote troposphere, knowing the chemical composition." Atmospheric Measurement Techniques 11 (5): 2653-2668 [10.5194/amt-11-2653-2018] [Journal Article/Letter]

2017. "A Model and Satellite-Based Analysis of the Tropospheric Ozone Distribution in Clear Versus Convectively Cloudy Conditions." Journal of Geophysical Research: Atmospheres [10.1002/2017jd027015] [Journal Article/Letter]

2017. "A cloud-ozone data product from Aura OMI and MLS satellite measurements." Atmospheric Measurement Techniques 10 (11): 4067-4078 [10.5194/amt-10-4067-2017] [Journal Article/Letter]

2017. "Global atmospheric chemistry – which air matters." Atmospheric Chemistry and Physics 17 (14): 9081-9102 [10.5194/acp-17-9081-2017] [Journal Article/Letter]

2016. "Variability of O3 and NO2 profile shapes during DISCOVER-AQ: Implications for satellite observations and comparisons to model-simulated profiles." Atmospheric Environment 147 133-156 [10.1016/j.atmosenv.2016.09.068] [Journal Article/Letter]

2016. "The effect of future ambient air pollution on human premature mortality to 2100 using output from the ACCMIP model ensemble." Atmos. Chem. Phys. 16 (15): 9847-9862 [10.5194/acp-16-9847-2016] [Journal Article/Letter]

2016. "Interpreting space-based trends in carbon monoxide with multiple models." Atmos. Chem. Phys. 16 (11): 7285-7294 [10.5194/acp-16-7285-2016] [Journal Article/Letter]

2016. "The description and validation of the computationally Efficient CH4–CO–OH (ECCOHv1.01) chemistry module for 3-D model applications ." Geoscientific Model Development 9 799-822 [doi:10.5194/gmd-9-799-2016] [Journal Article/Letter]

2015. "Implications of carbon monoxide bias for methane lifetime and atmospheric composition in chemistry climate models." Atmospheric Chemistry and Physics 15 11789–11805 [10.5194/acp-15-11789-2015] [Journal Article/Letter]

2015. "Trends and variability in surface ozone over the United States." Journal of Geophysical Research: Atmospheres 120 [10.1002/2014JD022784] [Journal Article/Letter]

2015. "Use of North American and European air quality networks to evaluate global chemistry-climate modeling of surface ozone." Atmos. Chem. Phys. 15 10581-10596 [10.5194/acp-15-10581-2015] [Journal Article/Letter]

2014. "Multi-decadal aerosol variations from 1980 to 2009: a perspective from observations and a global model." Atmos. Chem. Phys. 14 (7): 3657-3690 [10.5194/acp-14-3657-2014] [Journal Article/Letter]

2013. "Detection of carbon monoxide trends in the presence of interannual variability." Journal of Geophysical Research-Atmospheres 118 ( 21): 12257-122 [10.1002/2013JD020258] [Journal Article/Letter]

2013. "Evaluation of ACCMIP outgoing longwave radiation from tropospheric ozone using TES satellite observations." Atmos. Chem. Phys. 13 (8): 4057-4072 [10.5194/acp-13-4057-2013] [Journal Article/Letter]

2013. "Three decades of global methane sources and sinks." Nature Geosci 6 (10): 813-823 [10.1038/ngeo1955] [Journal Article/Letter]

2013. "The Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP): overview and description of models, simulations and climate diagnostics." Geosci. Model Dev. 6 (1): 179-206 [10.5194/gmd-6-179-2013] [Journal Article/Letter]

2013. "Preindustrial to present-day changes in tropospheric hydroxyl radical and methane lifetime from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)." Atmos. Chem. Phys. 13 (10): 5277-5298 [10.5194/acp-13-5277-2013] [Journal Article/Letter]

2013. "Tropospheric ozone changes, radiative forcing and attribution to emissions in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)." Atmos. Chem. Phys. 13 (6): 3063-3085 [10.5194/acp-13-3063-2013] [Journal Article/Letter]

2013. "Analysis of present day and future OH and methane lifetime in the ACCMIP simulations." Atmos. Chem. Phys. 13 (5): 2563-2587 [10.5194/acp-13-2563-2013] [Journal Article/Letter]

2013. "Pre-industrial to end 21st century projections of tropospheric ozone from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)." Atmos. Chem. Phys. 13 (4): 2063-2090 [10.5194/acp-13-2063-2013] [Journal Article/Letter]

2012. "Emission and transport of cesium-137 from boreal biomass burning in the summer of 2010." JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 117 [10.1029/2011JD017382] [Journal Article/Letter]

2010. "Vertical transport of anthropogenic mercury in the ocean." Global Biogeochem. Cycles 24 GB4014 [10.1029/2009GB003728] [Journal Article/Letter]

2009. "Interannual variability of long-range transport as seen at the Mt. Bachelor Observatory." Atmos. Chem. Phys. 9 557-572. [Journal Article/Letter]

2009. "Impact of mercury emissions from historic gold and silver mining: Global modeling." Atmos. Environ. 43 2012-2017. [Journal Article/Letter]

2008. "Fate and Transport of Atmospheric Mercury from Asia." Environ. Chem. 5 121 [10.1071/EN08010] [Journal Article/Letter]

2008. "Trans-Pacific transport of mercury." J. Geophys. Res. 113 D15305 [10.1029/2007JD009428] [Journal Article/Letter]

2007. "Air -sea exchange in the global mercury cycle." Global Biogeochemical Cycles 21 GB1017 [10.1029/2006GB002766] [Journal Article/Letter]