Dr. Róisín Commane, Research Associate, Harvard School of Engineering and Applied Sciences, Cambridge, MA (Note: Starting in July 2018 Commane will be an Assistant Professor, Columbia University, New York, NY, and affiliated with Columbia University’s Lamont-Doherty Earth Observatory)
Research interests: Using airborne gas concentration data, atmospheric transport models, and ecosystem models to understand surface processes affecting atmospheric chemistry. This includes measuring carbon dioxide (CO2) and methane (CH4) from Arctic ecosystems and measuring continental pollution (from, for example, fires and aerosols) over remote oceans.
Research highlights: Dr. Róisín Commane likely has more frequent flyer miles than you. As part of the joint NASA/Harvard University Atmospheric Tomography Mission (ATom), Dr. Commane just completed her fourth series of global flights aboard NASA’s four-engine DC-8 research aircraft. Flying as high as 40,000 feet to skimming the surface at 500 feet (check out the amazing videos of low-level flights over Arctic sea ice and the open ocean on the ATom Twitter feed), ATom instruments collected data about chemical components of the atmosphere between 85° north and south latitude.
To say these flights were frill-free might be an understatement. Flights often lasted 10 hours or longer and the aircraft, which was built in 1969 and acquired by NASA in 1985, is a flying laboratory with instruments receiving priority over people (or soundproofing—headsets are recommended to “save your ears,” according to the ATom daily schedule mission planning page). A typical “day” for Commane during the recently-completed fourth and final ATom deployment might begin well before local sunrise for flight preparations and end after sunset several time zones later, a schedule that was repeated throughout the almost one-month series of flights conducted between April 24 and May 21, 2018.
The “T” in “ATom” stands for tomography. Tomography is a technique for imaging by sections or sectioning using any kind of penetrating wave (magnetic resonance imaging, or MRI, is a type of tomography that uses strong magnetic fields and radio waves to create high resolution images of soft tissue in the human body that can be looked at slice by slice). ATom uses 24 aircraft-mounted instruments to sample slices of the atmosphere and analyze the chemical composition of these slices. These data are used to study the impact of human-produced air pollution on greenhouse gasses and on chemically reactive gasses in the atmosphere, especially over remote ocean areas. Data from ATom are helping to validate and improve satellite and model atmospheric data as well as the algorithms used to produce these data. Between the summer of 2016 and this past spring, Commane participated in ATom flights that sampled the atmosphere in all seasons.
Commane is a co-investigator for the Harvard University-develped Quantum Cascade Laser System (QCLS) instrument. The QCLS measures atmospheric concentrations of carbon monoxide (CO), methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2). She uses a range of tools, including airborne gas concentration data, atmospheric transport models, and ecosystem models, to develop a better understanding of processes occurring on Earth’s surface that affect atmospheric chemistry. She is particularly interested in the different chemical signatures created by fires occurring in Africa and how these fires affect the chemical composition of the atmosphere over the Atlantic Ocean. She also is examining how clouds in the Arctic can hide the chemical signature of fires and make them more difficult to detect.
ATom is closely linked to satellite missions designed to measure atmospheric chemistry, and provides unique complementary data for missions including the Orbiting Carbon Observatory-2 (OCO-2), launched in 2014, the Global Ozone Monitoring Experiment–2 (GOME-2) instrument aboard the European Space Agency’s (ESA) MetOp-A and MetOp-B satellites, the TROPOspheric Monitoring Instrument (TROPOMI) aboard the ESA Copernicus Sentinel-5 Precursor satellite, and the Japan Aerospace Exploration Agency’s Greenhouse Gases Observing Satellite (GOSAT).
ATom researchers, in turn, use satellite data to extend the data collected from their airborne observations to a global scale and deliver a single, large-scale, contiguous in situ dataset that can be used for evaluating and improving computer models designed to forecast atmospheric conditions. One such model is the Goddard Earth Observing System Model, Version 5 (GEOS-5), which is located at NASA’s Goddard Space Flight Center in Greenbelt, MD.
Much of the ATom data collected by Commane and her colleagues are being archived at the Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC). ORNL DAAC is the Earth Observing System Data and Information System (EOSDIS) DAAC responsible for archiving and distributing NASA Earth observing data related to biogeochemical dynamics, ecology, and environmental processes.
While Commane and her ATom research colleagues are still finalizing mission data and digging into science questions, she notes that they have been really impressed at how well the GEOS-5 atmospheric forecast has predicted pollution. In looking specifically at comparisons between GEOS-5 model predictions and observed concentrations of atmospheric CO, for example, she points out that some events, like Siberian forest fires, were completely missed by the model due to Arctic clouds masking the fires. Overall, though, she and her colleagues found that the model accurately predicted both the location and magnitude of atmospheric pollution plumes.
The real strength of ATom, observes Commane, will be when all the mission data are final and complete, giving the research community data representing all four seasons that can be used to evaluate and improve atmospheric chemistry models on a global scale. For a frequent flyer like Commane, these data are a price worth paying for her long days in the air.
Representative data products used:
- Data from ORNL DAAC:
- ATom main dataset page
- ATom: Merged Atmospheric Chemistry, Trace Gases, and Aerosols (doi:10.3334/ORNLDAAC/1581); Commane contributed CO2, CH4, CO, and N2O data for this collection
- ATom: Observed and GEOS-5 Simulated CO Concentrations with Tagged Tracers for ATom-1 ( doi:10.3334/ORNLDAAC/1604); Commane contributed CO data for this collection
- 2, CO, and CH4 Concentrations (doi:10.3334/ORNLDAAC/1419) from the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE); Commane contributed airborne platform CO2, CH4, and CO data for this collection
- CARVE Level 4 Gridded Footprints from the Weather Research and Forecasting (WRF) Stochastic Time-Inverted Lagrangian Transport (STILT) model (doi:10.3334/ORNLDAAC/1431)
- Arctic-Boreal Vulnerability Experiment (ABoVE) airborne CO2 and CH4 concentrations
- ATom main dataset page
- Moderate Resolution Imaging Spectroradiometer (MODIS) Snow Cover 8-Day Level 3 Global 500m Grid, Version 6 from the Aqua (MYD10A2; doi:10.5067/MODIS/MYD10A2.006) and Terra (MOD10A2; doi:10.5067/MODIS/MOD10A2.006) Earth observing satellites; available through the National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC)
- CO total column Measurements Of Pollution In The Troposphere (MOPITT) data; available through the Atmospheric Science Data Center (ASDC)
- GEOS-5 model Forward Processing (FP) CO fields; available through the Global Modeling and Assimilation Office (GMAO) at NASA’s Goddard Space Flight Center
Read about the research:
NASA ATom website: https://www.nasa.gov/content/earth-expeditions-atom
Strode, S.A., Liu, J., Lait, L., Commane, R., Daube, B., Wofsy, S., Conaty, A., Newman, P. & Prather, M. (in review, 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, Discussion Papers. doi:10.5194/acp-2018-150
Commane, R., Lindaas, J., Benmergui, J., Luus, K.A., Chang, R.Y.-W., Daube, B.C., Euskirchen, E.S., Henderson, J.M., Karion, A., Miller, J.B., Miller, S.M., Parazoo, N.C., Randerson, J.T., Sweeney, C., Tans, P., Thoning, K., Veraverbeke, S., Miller, C.E. & Wofsy, S.C. (2017). Carbon dioxide sources from Alaska driven by increasing early winter respiration from Arctic tundra. Proceedings of the National Academy of Sciences, 114(21): 5361-5366. doi:10.1073/pnas.1618567114
For more information
- Atmospheric Tomography Mission (ATom)
- Quantum Cascade Laser System (QCLS) instrument
- Orbiting Carbon Observatory-2 (OCO-2)
- Global Ozone Monitoring Experiment–2 (GOME-2)
- TROPOspheric Monitoring Instrument (TROPOMI)
- Greenhouse Gases Observing Satellite (GOSAT)
- Goddard Earth Observing System Model, Version 5 (GEOS-5)