Abstract

Accumulation of CO2 impacts climate resulting in an increase of global temperatures. It is vital to know the underlying processes driving the uptake of CO2 emissions by the biosphere and oceans to infer the rate at which CO2 concentrations will increase in the atmosphere. In this paper, we compar... Show moreAccumulation of CO2 impacts climate resulting in an increase of global temperatures. It is vital to know the underlying processes driving the uptake of CO2 emissions by the biosphere and oceans to infer the rate at which CO2 concentrations will increase in the atmosphere. 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 ofatmospheric CO2 observations from: (a) the Greenhouse gases Observing SATellite (GOSAT) instrument, (b) the NOAA/ESRL surface flask network, and (c) the Total Carbon Column Observing Network. Since the inverse model simulations generate CO2 fluxes at ~1 degree, these are then 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) a greater difference between the aircraft and the inverse modeling simulated CO2 concentrations over land regions relative to over ocean basins, and (b) the inverse simulations under-estimate in the winter and over-estimate in the summer. 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. Show less