Title: Spatial distributions of X_CO2 seasonal cycle amplitude and phase over northern high-latitude regions

Abstract

Satellite-based observations of atmospheric carbon dioxide (CO₂) provide measurements in remote regions, such as the biologically sensitive but undersampled northern high latitudes, and are progressing toward true global data coverage. Recent improvements in satellite retrievals of total column-averaged dry air mole fractions of CO₂ (X_CO2) from the NASA Orbiting Carbon Observatory 2 (OCO-2) have allowed for unprecedented data coverage of northern high-latitude regions, while maintaining acceptable accuracy and consistency relative to ground-based observations, and finally providing sufficient data in spring and autumn for analysis of satellite-observed X_CO2 seasonal cycles across a majority of terrestrial northern high-latitude regions. Here, we present an analysis of X_CO2 seasonal cycles calculated from OCO-2 data for temperate, boreal, and tundra regions, subdivided into 5° latitude by 20° longitude zones. We quantify the seasonal cycle amplitudes (SCAs) and the annual half drawdown day (HDD). OCO-2 SCAs are in good agreement with ground-based observations at five high-latitude sites, and OCO-2 SCAs show very close agreement with SCAs calculated for model estimates of X_CO2 from the Copernicus Atmosphere Monitoring Services (CAMS) global inversion-optimized greenhouse gas flux model v19r1 and the CarbonTracker2019 model (CT2019B). Model estimates of X_CO2 from the GEOS-Chem CO₂ simulation version 12.7.2 with underlying biospheric fluxes frommore » CarbonTracker2019 (GC-CT2019) yield SCAs of larger magnitude and spread over a larger range than those from CAMS, CT2019B, or OCO-2; however, GC-CT2019 SCAs still exhibit a very similar spatial distribution across northern high-latitude regions to that from CAMS, CT2019B, and OCO-2. Zones in the Asian boreal forest were found to have exceptionally large SCA and early HDD, and both OCO-2 data and model estimates yield a distinct longitudinal gradient of increasing SCA from west to east across the Eurasian continent. In northern high-latitude regions, spanning latitudes from 47 to 72° N, longitudinal gradients in both SCA and HDD are at least as pronounced as latitudinal gradients, suggesting a role for global atmospheric transport patterns in defining spatial distributions of X_CO2 seasonality across these regions. GEOS-Chem surface contact tracers show that the largest X_CO2 SCAs occur in areas with the greatest contact with land surfaces, integrated over 15–30d. The correlation of X_CO2 SCA with these land surface contact tracers is stronger than the correlation of X_CO2 SCA with the SCA of CO₂ fluxes or the total annual CO₂ flux within each 5° latitude by 20° longitude zone. This indicates that accumulation of terrestrial CO₂ flux during atmospheric transport is a major driver of regional variations in X_CO2 SCA.« less

Authors:

Jacobs, Nicole ^[1]; Simpson, William R.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-8596-7290"

Graham, Kelly A. ^[2]; Holmes, Christopher  ^[2];

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• Search DOE PAGES for ORCID "0000-0002-2727-0954"

Hase, Frank ^[3]; Blumenstock, Thomas  ^[3];

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Tu, Qiansi ^[3]; Frey, Matthias  ^[4];

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Dubey, Manvendra K.  ^[5];

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• Search DOE PAGES for ORCID "0000-0002-3492-790X"

Parker, Harrison A. ^[6]; Wunch, Debra  ^[7];

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Kivi, Rigel  ^[8];

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• Search DOE PAGES for ORCID "0000-0001-8828-2759"

Heikkinen, Pauli ^[8]; Notholt, Justus ^[9]; Petri, Christof  ^[9];

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• Search DOE PAGES for ORCID "0000-0002-7010-5532"

Warneke, Thorsten ^[9]

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+ Show Author Affiliations

1. Univ. of Alaska, Fairbanks, AK (United States)
2. Florida State Univ., Tallahassee, FL (United States)
3. Karlsruhe Inst. of Technology (KIT) (Germany). Institute of Meteorology and Climate Research
4. Karlsruhe Inst. of Technology (KIT) (Germany). Institute of Meteorology and Climate Research; National Institute for Environmental Studies (NIES), Tsukuba (Japan)
5. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
6. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); California Institute of Technology (CalTech), Pasadena, CA (United States)
7. Univ. of Toronto, ON (Canada)
8. Finnish Meteorological Inst. (FMI), Sodankylä (Finland)
9. Univ. of Bremen (Germany). Inst. of Environmental Physics (IUP)

Publication Date:

Tue Nov 16 00:00:00 EST 2021

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); National Aeronautics and Space Administration (NASA); National Science Foundation (NSF)

OSTI Identifier:

1969231

Report Number(s):

LA-UR-21-20427
Journal ID: ISSN 1680-7324

Grant/Contract Number:  

89233218CNA000001; NNH17ZDA001N-OCO2; 1602883; 80NSSC17K0361

Resource Type:

Accepted Manuscript

Journal Name:

Atmospheric Chemistry and Physics (Online)

Additional Journal Information:

Journal Name: Atmospheric Chemistry and Physics (Online); Journal Volume: 21; Journal Issue: 22; Journal ID: ISSN 1680-7324

Publisher:

Copernicus Publications, EGU

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; Earth sciences; Carbon cycle; Remote sensing; Arctic; TCCON; COCCON; Solar-FTS; OCO2; Climate; Climate-carbon feedbacks; CO23 seasonal cycle