Aura Ozone Monitoring Instrument (OMI) Collection 4 Formaldehyde Products

• Published in: Earth and space science (Hoboken, N.J.) Vol. 12; no. 2
• Main Authors: Ayazpour, Zolal, González Abad, Gonzalo, Nowlan, Caroline R., Sun, Kang, Kwon, Hyeong‐Ahn, Chan Miller, Christopher, Chong, Heesung, Wang, Huiqun, Liu, Xiong, Chance, Kelly, O’Sullivan, Ewan, Zhu, Lei, Vigouroux, Corinne, De Smedt, Isabelle, Stremme, Wolfgang, Hannigan, James W., Notholt, Justus, Sun, Xiaoyu, Palm, Mathias, Petri, Cristof, Strong, Kimberly, Röhling, Amelie N., Mahieu, Emmanuel, Smale, Dan, Té, Yao, Morino, Isamu, Murata, Isao, Nagahama, Tomoo, Kivi, Rigel, Makarova, Maria, Jones, Nicholas, Sussmann, Ralf, Zhou, Minqiang
• Format: Journal Article
• Language: English
• Published: Hoboken John Wiley & Sons, Inc 01.02.2025; American Geophysical Union (AGU)
• Subjects: Aerosols; Aldehydes; Algorithms; atmospheric composition; Climate change; Correlation coefficient; Datasets; Earth sciences & physical geography; Emissions; Formaldehyde; Methane; Monitoring instruments; Oxidation; Ozone; Physical, chemical, mathematical & earth Sciences; Physique, chimie, mathématiques & sciences de la terre; remote sensing; satellite validation; Satellites; Sciences de la terre & géographie physique; VOCs; Volatile organic compounds
• ISSN: 2333-5084; 2333-5084
• DOI: 10.1029/2024EA003792

This study presents the ozone monitoring instrument (OMI) Collection 4 formaldehyde (HCHO) retrieval developed with the Smithsonian Astrophysical Observatory's (SAO) Making Earth System Data Records for Use in Research Environments (MEaSUREs) algorithm. The retrieval algorithm updates and makes improvements to the NASA operational OMI HCHO (OMI Collection 3 HCHO) algorithm, and has been transitioned to use OMI Collection 4 Level‐1B radiances. This paper describes the updated retrieval algorithm and compares Collection 3 and Collection 4 data products. The OMI Collection 4 HCHO exhibits remarkably improved stability over time in comparison to the OMI Collection 3 HCHO product, with better precision and the elimination of artificial trends present in the Collection 3 during the later years of the mission. We validate the OMI Collection 4 HCHO data product using Fourier‐Transform Infrared (FTIR) ground‐based HCHO measurements. The climatological monthly averaged OMI Collection 4 HCHO vertical column densities (VCDs) agree well with the FTIR VCDs, with a correlation coefficient of 0.83, root‐mean‐square error (RMSE) of 2.98×1015 $2.98\times 1{0}^{15}$ molecules cm−2 ${\text{cm}}^{-2}$, regression slope of 0.79, and intercept of 8.21×1014 $8.21\times 1{0}^{14}$ molecules cm−2 ${\text{cm}}^{-2}$. Additionally, we compare the monthly averaged OMI Collection 4 HCHO VCDs to OMPS Suomi NPP, OMPS NOAA‐20, and TROPOMI HCHO VCDs in overlapping years for 12 geographic regions. This comparison demonstrates high correlation coefficients of 0.98 (OMPS Suomi NPP), 0.97 (OMPS NOAA‐20), and 0.90 (TROPOMI). Key Points We present the ozone monitoring instrument (OMI) Collection 4 formaldehyde (HCHO) product, retrieved using the SAO retrieval algorithm OMI Collection 4 HCHO product is well‐correlated with the ground‐based Fourier‐Transform Infrared Spectrometers (FTIR) HCHO measurements OMI Collection 4 HCHO provides a stable long‐term data record and shows strong agreement with OMPS and TROPOMI HCHO products