Assessment of IASI CO and MOPITT CO Data Assimilation in CAM-Chem.

Friday, 19 December 2014
Jerome Barre1, David P Edwards2, Avelino F Arellano3, Benjamin Gaubert1, Helen Marie Worden1, Jeffrey L Anderson4 and Arthur P Mizzi5, (1)National Center for Atmospheric Research, Boulder, CO, United States, (2)Natl Ctr Atmospheric Research, Boulder, CO, United States, (3)University of Arizona, Tucson, AZ, United States, (4)NCAR, Boulder, CO, United States, (5)NCAR/MMM/FL2, Boulder, CO, United States
An Ensemble Adjustement Kalman Filter (DART) system has been developed to assimilate simultaneously meteorological and chemical variables in the global scale chemistry-climate model CAM-Chem. Comparisons of Terra/MOPITT carbon monoxide (CO) and IASI/Metop CO observation assimilations will be presented. Data assimilation impacts due to both different instrument capabilities (i.e. vertical sensitivity and global coverage) will be discussed. For example, using a multispectral retrieval approach, MOPITT has enhanced measurement sensitivity toward the surface compared to IASI. Conversely, IASI spatial sampling covers the globe in one day while it takes four days for MOPITT. Impacts of these two different nadir sounder properties will be compared using data assimilation. Effects of a combined data assimilation experiment and synergies between the two instruments in the middle and the lowermost troposphere will be shown.