A23B-0292
Impact of Using Assimilated Data for Evaluating Performance of Active CO2 Optical Depth Measurements

Tuesday, 15 December 2015
Poster Hall (Moscone South)
Susan A Kooi1, Fenton W Harrison2, Bing Lin2, Syed Ismail2, Edward V Browell3, Melissa M Yang2 and Yonghoon Choi1, (1)Science Systems and Applications, Inc. Hampton, Hampton, VA, United States, (2)NASA Langley Research Center, Hampton, VA, United States, (3)STARSS II Affiliate, Hampton, VA, United States
Abstract:
NASA has recently conducted multiple DC-8 flight campaigns of candidate instruments for the future Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission. For each campaign, the precision and accuracy of the remote measurements of atmospheric CO2 differential absorption optical depths from the candidate instruments were evaluated with respect to corresponding CO2 optical depths derived from in situ profiles of atmospheric state variables including atmospheric CO2 mixing ratios, temperature (T), pressure (p), and humidity (q) and radiative transfer calculations using the HITRAN spectroscopic database in combination with recent measurements of spectral line parameters. To enable this evaluation, the DC-8 flights were designed to include multiple overpasses of a comparison location where the aircraft performed a spiral ascent or descent and captured the in situ profiles using a suite of onboard instruments. However large segments of some flights took place far from spiral locations and therefore had no coincident in situ measurements of the atmospheric state (CO2, T, p, q). For these situations meterological analysis data from the Goddard Modeling and Assimilation Office (GMAO) GEOS-5 gridded data have been used to assimilate atmospheric state profiles for use in the CO2 optical depth derivation. We use the location of the DC-8 spirals to identify all of the GMAO GEOS-5 gridded profiles that would compare with each spiral and report their differences with respect to the DC-8 in situ profiles. We show how these differences affect the in situ derived CO2 optical depth for the three campaigns and the impacts of these differences on the precision and accuracy evaluations of the remote CO2 measurements.