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Regional and Urban Column CO Trends and Anomalies as Observed by MOPITT Over 16 Years

Hedelius, Jacob K. and Toon, Geoffrey C. and Buchholz, Rebecca R. and Iraci, Laura T. and Podolske, James R. and Roehl, Coleen M. and Wennberg, Paul O. and Worden, Helen M. and Wunch, Debra (2021) Regional and Urban Column CO Trends and Anomalies as Observed by MOPITT Over 16 Years. Journal of Geophysical Research. Atmospheres, 126 (5). Art. No. e2020JD033967. ISSN 2169-897X. doi:10.1029/2020jd033967.

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Atmospheric carbon monoxide (CO) concentrations have decreased since the beginning of the century, and the rate of decrease depends on the region. Depending on how regions are chosen, their boundaries may not always align with where there are differences in trends. To address this, we calculate trends within 0.4° × 0.4° grid cells independently throughout the globe using satellite CO retrievals from the Measurements Of Pollution In The Troposphere (MOPITT) satellite instrument from 2002 to 2017. These trends are found with the caveat that there are large singular biomass burning events somewhere nearly every year, and we include examples of large column CO anomalies during sporadic but large burning events in the North American and Eurasian boreal forests, the Amazon, Africa, and Indonesia. CO trends behave similarly within regions that span about a few thousand kilometers. Using TransCom region definitions, we find average trends between −0.9 and 0.1 ppb year⁻¹ (about −0.9 to 0.1% year⁻¹) for 2002–2017. Over 5‐year subsets, trends in TransCom regions vary between −3.6 and 1.8 ppb year⁻¹. This substantial spatial and temporal variability in trends is in agreement with other studies. With an understanding of regional trends, we compare with trends from urban areas. Generally, CO trends within urban areas are indistinguishable from regional trends. This may be because of a combination of noise in the data, the large footprint for MOPITT, or because anthropogenic CO reduction measures were implemented before the MOPITT record began. We provide case studies for a few cities, such as Los Angeles, and find long‐term variation in the rate of change of column CO.

Item Type:Article
Related URLs:
URLURL TypeDescription‐LARCRelated ItemMOPITT data
https://tccondata.orgRelated ItemTCCON data archive
https://mark4sun.jpl.nasa.govRelated ItemMkIV data
Hedelius, Jacob K.0000-0003-2025-7519
Toon, Geoffrey C.0000-0003-4174-7541
Buchholz, Rebecca R.0000-0001-8124-2455
Iraci, Laura T.0000-0002-2859-5259
Podolske, James R.0000-0003-2771-5375
Roehl, Coleen M.0000-0001-5383-8462
Wennberg, Paul O.0000-0002-6126-3854
Worden, Helen M.0000-0002-5949-9307
Wunch, Debra0000-0002-4924-0377
Additional Information:© 2021 American Geophysical Union. Issue Online: 01 March 2021; Version of Record online: 01 March 2021; Accepted manuscript online: 10 February 2021; Manuscript accepted: 27 October 2020; Manuscript received: 25 September 2020. The authors thank the MOPITT team and TCCON partners for providing high quality CO retrievals to the scientific community. The author thank Jennifer Murphy and Xuesong Zhang for helpful conversations. This study was funded by the Canadian Space Agency Earth System Science Data Analyses program (grant #16SUASCOBF). The Authors declare no conflict of interest. Data Availability Statement: MOPITT data may be obtained from the NASA Earthdata website (‐LARC, last access: October 30, 2020). TCCON data were obtained through the TCCON data archive hosted by CaltechData (, last access: June 19, 2019). Ground‐based MkIV data were obtained through the JPL MkIV website (, last access: June 19, 2019).
Funding AgencyGrant Number
Canadian Space Agency (CSA)16SUASCOBF
Subject Keywords:anthropogenic emissions; biomass burning; carbon monoxide; MOPITT; regional atmospheric trends; TCCON
Issue or Number:5
Record Number:CaltechAUTHORS:20210211-125216415
Persistent URL:
Official Citation:Hedelius, J. K., Toon, G. C., Buchholz, R. R., Iraci, L. T., Podolske, J. R., Roehl, C. M., et al. (2021). Regional and urban column CO trends and anomalies as observed by MOPITT over 16 years. Journal of Geophysical Research: Atmospheres, 126, e2020JD033967.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108005
Deposited By: Tony Diaz
Deposited On:11 Feb 2021 21:41
Last Modified:16 Nov 2021 19:08

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