Gradients of Column CO<sub>2</sub> across North America from the NOAA Global Greenhouse Gas Reference Network Journal Article uri icon



  • Abstract. This study analyzes seasonal and spatial patterns of column carbon dioxide (CO2) over North America calculated from aircraft and tall tower measurements from the NOAA Global Greenhouse Gas Reference Network from 2004 to 2014. Consistent with expectations, gradients between the eight regions studied are larger below 2 km than above 5 km. The 11-year mean CO2 dry mole fraction (XCO2) in the column below ~ 330 hPa (~ 8 km above sea level) from NOAA's CO2 data assimilation model, CarbonTracker (CT2015), demonstrates good agreement with those calculated from calibrated measurements on aircraft and towers. Total column XCO2 was attained by combining modeled CO2 above 330 hPa from CT2015 with the measurements. We find large spatial gradients of total column XCO2 during June to August, and the north and northeast regions have ~ 3 ppm stronger summer drawdown than the south and southwest regions. The spatial gradients of total column XCO2 across North America mainly reflect large-scale circulation patterns rather than regional surface sources and sinks. We have conducted a CarbonTracker experiment to investigate the impact of Eurasian long-range transport. The result suggests that the large summer time Eurasian boreal flux contributes about half of the north-south column XCO2 gradient across North America. Our results confirm that continental-scale total column XCO2 gradients simulated by CarbonTracker are realistic and can be used to evaluate the credibility of spatial patterns from satellite retrievals, such as the long term average spatial patterns from satellite retrievals reported for Europe which show larger spatial difference (~ 6 ppm) and scattered hot spots.;

publication date

  • May 19, 2017

has restriction

  • green

Date in CU Experts

  • June 9, 2021 9:44 AM

Full Author List

  • Lan X; Tans P; Sweeney C; Andrews A; Jacobson A; Crotwell M; Dlugokencky E; Kofler J; Lang P; Thoning K

author count

  • 11

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