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STUDY TITLE: Use of Satellite Data for Offshore Air Quality Applications

REPORT TITLE: Evaluation of NASA's Remote-Sensing Capabilities in Coastal Environments (BOEM 

2020-047)

CONTRACT NUMBER: M17PG00026

SPONSORING OCS REGION: Headquarters

APPLICABLE PLANNING AREAS: Central, Western, and Eastern Gulf of Mexico (GOM) FISCAL YEARS 

OF PROJECT FUNDING: 2018–2020

COMPLETION DATE OF REPORT: September 2020

COSTS: FY 2018: $307,000; FY 2019: $247,300; FY 2020: $0; 

CUMULATIVE PROJECT COST: $554,300

PROJECT MANAGER: A. M. Thompson

AFFILIATION: NASA Goddard Space Flight Center

ADDRESS: 8800 Greenbelt Road, Greenbelt, MD 20771

OBJECTIVES: The primary goal of this inter-agency agreement is to evaluate the feasibility of using 

satellite data in the offshore environments for

(1) Estimating ground level concentrations of criteria National Ambient Air Quality Standards (NAAQS), 

precursors, and visibility pollutants; monitoring long term trends of these pollutants where there are no 

monitors in the GOM and Pacific Outer Continental Shelf (OCS) Regions; and estimating background 

concentration data in the Alaska and Atlantic OCS Regions before oil and gas or renewables 

development

(2) Validating the satellite data with offshore monitoring in a field campaign.

DESCRIPTION: The purpose of this inter-agency agreement is to work with NASA’s Atmospheric 

Chemistry and Dynamics Laboratory at Goddard Space Flight Center to assess the utility of satellite data 

for air quality applications, specifically through estimating and monitoring of offshore ground level 

concentrations of criteria NAAQS, precursors, and visibility pollutants in the GOM, Pacific, Alaska, and 

Atlantic OCS Regions to support the Bureau of Ocean Energy Management’s (BOEM) requirements 

under the Outer Continental Shelf Lands Act (OCSLA) and National Environmental Policy Act (NEPA), as 

well as assessing the use of satellite data to improve and validate BOEM’s existing emissions inventories 

and photochemical modeling. The exploration and development of oil and gas resources on the OCS in 

the GOM and Alaska, as well as potential renewable energy and alternate use projects, will require 

BOEM to validate information on the concentrations of air pollutants emitted offshore for a variety of 

NEPA-related decision documents and for maintaining compliance with OCSLA. This study will improve 

BOEM’s ability to characterize the impacts of offshore pollutant dispersion.

This inter-agency agreement consisted of two parts:

(1) Examine using satellite data to estimate offshore ground level concentrations of criteria NAAQS, 

precursors, and visibility pollutants; estimate background concentration data in the Alaska and Atlantic 

OCS Regions before oil and gas or renewable development; and monitor long term trends of these 

concentrations. BOEM envisions conducting a scoping study to assess whether current satellite data can 

provide the necessary information to estimate offshore NAAQS, precursors, and visibility pollutants.

(2) Validate the satellite data with offshore monitoring in a field campaign through the use of air 

concentration sensors on wave gliders, sail drones, or drones, and possibly through air concentration 
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monitors on vessels. “Ground truthed” data should be sufficiently representative to properly validate the 

satellite data spatially and temporally in the GOM and then extend to other offshore regions. All sensors 

and monitors should be calibrated according to appropriate US Environmental Protection Agency 

(USEPA) methodology. A field campaign protocol may be developed beforehand to explain approach, 

monitors used, monitor calibration, location, and timeframe.

SIGNIFICANT CONCLUSIONS: This work represents the first of a two-part study set up by NASA and 

BOEM in 2017. The study summarizes a three-year investigation on the feasibility of using satellite 

remote sensing to monitor emissions of oil and gas operations over the OCS to determine if they have 

negative impacts on coastal air quality (AQ). The target pollutant is nitrogen dioxide (NO2), for which 

BOEM conducts regular emissions surveys. The major data source for this report is a May 2019 

oceanographic cruise (“SCOAPE” = Satellite Coastal and Oceanic Atmospheric Pollution Experiment) 

conducted in the GOM off Louisiana with the Research Vessel Point Sur, loaded with a suite of trace-gas 

analyzers and a direct-sun remote sensor Pandora spectrometer that measures column NO2. The 

SCOAPE cruise, augmented by in situ NO2 and Pandora measurements at Cocodrie (Louisiana; 29.25° 

N, 90.66° W) showed that

(1) under cloud-free conditions, satellites can detect elevated column NO2 amounts near isolated large 

platforms and from clusters of smaller operations;

(2) satellite (the European Space Agency’s TROPOspheric Monitoring Instrument [TROPOMI]) total 

column (TC) NO2 agrees well with TC NO2 from ground-based Pandora spectrometers (to 11–18%), with 

the satellite biased low when pollution levels are higher;

(3) in general, NO2 measured by in situ instruments and in column amounts by Pandora or TROPOMI is

greater over coastal Louisiana than over the OCS; and

(4) the extent to which Pandora or satellite measurements correlate with surface NO2 is highly variable.

STUDY RESULTS: It is recommended that BOEM and NASA continue to work together on collecting 

ground-truth NO2 data and on interpreting remote-sensing data for BOEM’s AQ requirements. Specific 

recommendations include the following:

(1) BOEM and NASA should work together to analyze the 2019 SCOAPE data more thoroughly, 

including conducting studies with tracers, ancillary satellite data, trajectories, and appropriate chemical 

transport model output to more firmly establish the magnitude of oil and natural gas influences on GOM 

AQ. Because remote-sensing measurements (satellite- and ground-based) do not provide ambient NO2 

concentrations, these studies must be conducted to determine the column-surface NO2 relationship.

(2) Coastal monitoring along the GOM with NASA and USEPA using Pandora Spectrometer Instrument 

and other instruments would establish better statistics and contribute to ongoing improvements in Ozone 

Monitoring Instrument (OMI) (mature algorithm) and the still-evolving TROPOMI. Co-location with 

BOEM’s coastal project, aiming to begin in late 2020 at a remote unpolluted location in Louisiana, would 

greatly benefit BOEM. Daily overpass comparisons of OMI and TROPOMI TC NO2 with a Pandora 

instrument would give BOEM more complete statistics than the 5- week exploratory dataset of April–May 

2019. Comparisons of the in situ and column NO2 amounts, along with other pollutants being measured, 

would further our understanding of the relationship of chemical transformation and interactions with 

dynamical processes in the boundary layer.

STUDY PRODUCTS: Thompson AM. 2020. Evaluation of NASA's remote-sensing capabilities in coastal 

environments. Sterling (VA): U.S. Department of the Interior, Bureau of Ocean Energy Management. OCS 

Study BOEM 2020-047. 33 p.

Thompson AM, Kollonige DE, Stauffer RM, Abuhassan N, Kotsakis AE, Swap RJ, Wecht HE. 2020.

Satellite and shipboard views of air quality along the Louisiana coast: the 2019 SCOAPE (Satellite 

Coastal and Oceanic Atmospheric Pollution Experiment) cruise. EM. 2020(Oct):28–33. 

https://pubs.awma.org/flip/EM-Oct-2020/emoct20.pdf.