THREE-DIMENSIONAL VARIATION OF ATMOSPHERIC CO2: A COMPARISON OF AIRCRAFT MEASUREMENTS WITH INVERSE MODEL SIMULATIONS
Eugene Cody1, Abhishek Chatterjee2.
1Haskell Indian Nations University, Lawrence, KS, 2Institute for Mathematics Applied to Geoscience, University Corporation for Atmospheric Research, Boulder, CO.
In this paper, we compare vertical profiles of carbon dioxide concentrations from aircraft measurements to simulated CO2 concentrations from an atmospheric inverse model simulation. The inverse model simulations are based on assimilation of atmospheric CO2 observations from the Greenhouse Gases Observing Satellite (GOSAT) instrument, the NOAA/ESRL surface flask network, and the Total Carbon Column Observing Network. Since the inverse model simulations generate CO2 fluxes at approximately 1 degree, these are fed into an atmospheric transport model to simulate the atmospheric CO2 concentrations. The independent set of aircraft measurements are obtained from a suite of NOAA/ESRL and the HIAPER pole-to-pole flight campaigns (HIPPO-3 and HIPPO-5 field phases). Both qualitative and quantitative analyses are used to evaluate the quality of the simulated CO2 concentrations from the inverse modeling approach. Results show a greater difference between the aircraft and the inverse modeling simulated CO2 concentrations near the surface (1,000 - 800 hPa) relative to higher levels in the atmosphere (< 800 hPa) and over land regions relative to over ocean basins. Both of these differences can be attributed to the greater variability and heterogeneity in the CO2 signal near the land surface, which does not get simulated well by the inverse modeling approach. Future work will examine possible ways to improve the inverse model simulations in order to obtain better agreement with the aircraft data.