FEBRUARY 2014 UPDATE

The NOMADSS field campaign has been successfully completed!

What Is NOMADSS?

The Nitrogen, Oxidants, Mercury, and Aerosol Distributions, Sources, and Sinks (NOMADSS) study is a National Science Foundation (NSF)-sponsored research project that is also incorporated into the broader Southeast Atmosphere Study (SAS). The SAS field campaign involved a wide range of ground-based and airborne measurements directed toward assessing air quality and climate in the Southeastern U.S. during the summer of 2013. The field measurement portion of NOMADSS took place from June 1 to July 15, 2013. During the campaign, research groups from the National Center for Atmospheric Research (NCAR) and from universities across the U.S. made measurements onboard the NSF/NCAR C-130 research aircraft, which was based in Smyrna, Tennessee. A total of 19 research flights were conducted across the Midwestern and Southeastern U.S.

Locations of airborne and ground-based measurements during the SAS field study and mercury point sources in the Eastern U.S.

Using the UW-DOHGS to Measure Mercury

During NOMADSS, the Jaffe Group operated the University of Washington’s aircraft mercury (Hg) instrument--the Detector of Oxidized Hg Species (UW-DOHGS)--onboard the NSF/NCAR C-130. The UW-DOHGS is a dual-channel instrument that allows for simultaneous sampling of total mercury (THg) and gaseous elemental mercury (GEM). Reactive mercury (RM) concentrations are determined by the difference between THg and GEM. This is a state-of-the-art instrument specifically designed for high time resolution measurements from an aircraft platform. The UW-DOHGS was previously operated during the Western Airborne Mercury Observations (WAMO) study (see Lyman and Jaffe, 2011) and the ground-based Reno Atmospheric Mercury Intercomparison Experiment (RAMIX) (see Ambrose et al., 2013).

Jaffe Group post-doctoral researchers Dr. Jesse Ambrose and Dr. Lynne Gratz installed the UW-DOHGS on the NSF/NCAR C-130 during May 2013 at the NCAR Research Aviation Facility (RAF) in Broomfield, Colorado. Then Drs. Ambrose and Gratz joined NOMADSS primary investigator and research group leader, Professor Dan Jaffe, in Smyrna, Tennessee, for six weeks of field work and 149 research flight hours. The UW-DOHGS performed well on all 19 research flights, allowing the Jaffe group to sample mercury near major urban areas and industrial point sources, as well as in the free troposphere over the eastern U.S.

The UW-DOHGS installed on the NSF/NCAR C-130 aircraft.

Scientific Objectives of the Research

Using measurements from the UW-DOHGS, together with other measurements made onboard the NSF/NCAR C-130, the Jaffe Group sought to address the following key scientific objectives during NOMADSS:

• Constrain emissions of mercury from major source regions in the Eastern U.S. What is the spatial distribution of mercury in the boundary layer in the Midwestern and Southeastern U.S.? Are observations consistent with bottom-up emissions inventories? Can we separate U.S. emission sources from global sources?


• Quantify the distribution and chemical transformations of speciated mercury in the free troposphere. How does the speciation of mercury change with increasing height in the free troposphere over the eastern U.S.? How is this speciation affected by atmospheric chemistry and transport? How do mercury concentrations and speciation evolve in the outflow of emission regions?

Our Findings

Dr. Gratz presented some preliminary findings from NOMDASS at the 11th International Conference on Mercury as a Global Pollutant (ICMGP) in Edinburgh, Scotland, in July 2013. Dr. Ambrose presented his initial analyses of power plant mercury emissions inventories and aircraft observations at the American Geophysical Union (AGU) Annual Fall Meeting in San Francisco, California, in December 2013. Professor Jaffe and Drs. Ambrose and Gratz are continuing to analyze the speciated atmospheric mercury measurements from NOMADSS and they expect to publish their findings in the peer-reviewed literature later this year.
For more information, please contact Dan Jaffe at the University of Washington-Bothell. Email: djaffe@u.washington.edu

APRIL 2013 UPDATE

NAAMEX is now merged with the SOAS campaign to become NOMADSS/SAS

Research flights on the NCAR C-130 start in June 2013 to investigate sources and sinks of mercury, nitrogen oxidants, and aerosols. Our group will be measuring total and speciated mercury with the UW Detector of Oxidized HG Species (UW-DOHGS).

AUGUST 2012 UPDATE

The UW-Detector of Oxidized Hg Species (UW-DOHGS) will fly again!

After our sucessful WAMO project (Lyman and Jaffe, 2011) , the National Science Foundation has recommended funding for the North American Airborne Mercury Experiment (NAAMEX). This will be the first ever airborne Hg experiment to examine the US Hg sources from coal burning. The UW-DOHGS instrument will play a critcal role in the sucessful outcome of the experiment. NAAMEX will build on the results from WAMO. This experiment will use the NCAR C-130 aircraft in two 3-week deployments: one based in the Western U.S. and the other in the Eastern U.S. Both will take place in the summer of 2013.

NAAMEX will incorporate a number of high quality measurements, including speciated Hg, CO, O3, NOx, aerosols, HOx, hydrocarbons, halocarbons, and halogens. We will also be fully integrated with multiple models operating in forecast mode and used for post-mission analysis. The experiment is a partnership between the University of Washington, University of Colorado, Georgia Tech, UC-Irvine, and MIT. Dan Jaffe and Lyatt Jaegle are the mission and co-mission leads, respectively.

NAAMEX will be part of a broader aircraft experiment called Nitrogen, Oxidants, Mercury and Aerosol: Distributions, Sources and Sinks (NOMADSS). Details on NOMADSS can be found here.

Click here for: 2012 NAAMEX White Paper

Click here for: NAAMEX C-130 Facilities Request

 

Key Scientific Objectives and Questions

• Constrain emissions of mercury from major source regions in the United States. What is the spatial distribution of mercury in the boundary layer in the western U.S., Midwest, and Eastern U.S.? Are observations consistent with bottom-up emissions inventories? Can we separate U.S. sources from global sources?


• Quantify the distribution and chemical transformations of speciated mercury in the free troposphere. How does the speciation of mercury change with increasing height in the free troposphere over the U.S.? How is this speciation affected by atmospheric oxidation, precipitation, cloud-processing, and stratospheric intrusions? How does the partitioning of mercury evolve in the outflow of emission regions?

For more information: contact Dan Jaffe, University of Washington-Bothell (djaffe@u.washington.edu, 425-352-5357)