Two Air Quality Regimes in Total Column NO2 over the Gulf of Mexico in
May 2019: Shipboard and Satellite Views
Abstract
The Satellite Coastal and Oceanic Atmospheric Pollution Experiment
(SCOAPE) cruise in the Gulf of Mexico (GOM) was conducted in May 2019 by
NASA and the Bureau of Ocean Energy Management to determine the
feasibility of using satellite data to measure air quality (AQ) in a
region of concentrated oil and natural gas (ONG) operations. SCOAPE
featured nitrogen dioxide (NO2) instrumentation
(Pandora, Teledyne API analyzer) at Cocodrie, LA (29.26°, -90.66°), and
on the Research Vessel Point Sur operating off the Louisiana
coast with measurements of ozone, carbon monoxide (CO) and volatile
organic compounds (VOC). The findings: (1) both satellite and Pandora
NO2 observations revealed two AQ regimes over the GOM,
the first influenced by tropical air in 10-14 May, the second influenced
by flow from urban areas on 15-17 May; (2) Comparisons of OMI v4 and
TROPOMI v1.3 TC (total column) NO2 data with all Pandora
NO2 column observations on the Point Sur averaged
13% agreement with the largest difference during 15-17 May
(~20%). At Cocodrie, LA, at the same time, the
satellite-Pandora agreement was ~5%. (3) Three
new-model Pandora instruments displayed a TC NO2
precision of 0.01 Dobson Units (~5%); (4) Regions of
smaller and older operations displayed high methane
(CH4) readings, presumably from leakage; VOC were also
detected at high concentrations. Given an absence of regular AQ data in
and near the GOM, SCOAPE data constitute a baseline against which future
observations can be compared.