Planning, implementation, and scientific goals of the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC⁴RS) field mission

Abstract

The Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) field mission based at Ellington Field, Texas, during August and September 2013 employed the most comprehensive airborne payload to date to investigate atmospheric composition over North America. The NASA ER‐2, DC‐8, and SPEC Inc. Learjet flew 57 science flights from the surface to 20 km. The ER‐2 employed seven remote sensing instruments as a satellite surrogate and eight in situ instruments. The DC‐8 employed 23 in situ and five remote sensing instruments for radiation, chemistry, and microphysics. The Learjet used 11 instruments to explore cloud microphysics. SEAC4RS launched numerous balloons, augmented AErosol RObotic NETwork, and collaborated with many existing ground measurement sites. Flights investigating convection included close coordination of all three aircraft. Coordinated DC‐8 and ER‐2 flights investigated the optical properties of aerosols, the influence of aerosols on clouds, and the performance of new instruments for satellite measurements of clouds and aerosols. ER‐2 sorties sampled stratospheric injections of water vapor and other chemicals by local and distant convection. DC‐8 flights studied seasonally evolving chemistry in the Southeastern U.S., atmospheric chemistry with lower emissions of NOx and SO2 than in previous decades, isoprene chemistry under high and low NOx conditions at different locations, organic aerosols, air pollution near Houston and in petroleum fields, smoke from wildfires in western forests and from agricultural fires in the Mississippi Valley, and the ways in which the chemistry in the boundary layer and the upper troposphere were influenced by vertical transport in convective clouds.

Inconsistency of ammonium–sulfate aerosol ratios with thermodynamic models in the eastern US: a possible role of organic aerosol

“…We implemented this crude kinetic limitation of ammonia uptake by SNA aerosol into the GEOS-Chem chemical transport model (CTM) version 9-02, previously applied by Kim et al (2015) to simulation of aerosol observations from the NASA SEAC 4 RS aircraft campaign over the Southeast in summer-fall 2013 (Toon et al, 2016). The simulation includes detailed oxidant-aerosol chemistry as described by Kim et al (2015) and Travis et al (2016).…”

Biogenic isoprene emissions driven by regional weather predictions using different initialization methods: case studies during the SEAC<sup>4</sup>RS and DISCOVER-AQ airborne campaigns

“…NASA's Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC 4 RS, Toon et al, 2016, https://espo.nasa.gov/ home/seac4rs/content/SEAC4RS) was conducted in AugustSeptember 2013. More than 20 research flights were executed, including 10 September DC-8 flights over the southeastern US primarily focusing on the attribution and the quantification of trace gas pollution and their distributions as a result of deep convection.…”

High-resolution inversion of methane emissions in the Southeast US using SEAC<sup>4</sup>RS aircraft observations of atmospheric methane: anthropogenic and wetland sources

“…Observations of atmospheric methane reviewed by Brandt et al (2014) have implied that the US national inventory reported by the Environmental Protection Agency (EPA) may be greatly underestimated. Here we use aircraft observations from the NASA SEAC 4 RS aircraft campaign over the Southeast US (Toon et al, 2016), together with a newly gridded version of the EPA inventory , in a fine-resolution inversion with detailed error characterization to better quantify methane emissions over this major source region.…”