Related Research Areas
Atmospheric Composition

We propose a three year program of research to use the Aura satellite data in combination with the GEOS-Chem model to rigorously evaluate the representation of key processes controlling tropospheric composition in the tropics. This work addresses major goals of the ROSES 2009 NRA NNH09ZDA001N, Atmospheric Composition: Modeling and Analysis, which is "oriented toward understanding the chemical, radiative, and dynamical processes controlling atmospheric composition of the troposphere and stratosphere. It achieves this through the analysis of atmospheric composition observations and their use to rigorously test the theoretical understanding of the atmosphere that is expressed in atmospheric models." Our main objective is to use the synergy provided by the suite of Aura observations and in-situ data to test the theoretical understanding of tropospheric composition represented in the model, and to investigate the underlying causes of discrepancies between model and observation by focusing on individual components of the model that determine tropospheric composition and its variability, both spatial and temporal. The Aura period includes two moderate El Ninos and a La Nina period, and the variability in dynamics and in tropical biomass burning emissions has resulted in significant interannual variability (IAV) in tropospheric composition. Our research has the following components:
1. We propose to use OMI NO2 tropospheric data to evaluate the GFED3 biomass burning inventory in the tropics, and to conduct a source inversion. The results will be used to adjust the CO and aerosol emissions from biomass burning, and we will use TES and MOPITT CO data and MODIS AOD data as an independent test of the inferred emissions, because of concerns over aerosol interference in the NO2 retrieval.
2. Our work to date evaluating the GEOS-Chem model with TES and MLS data revealed discrepancies with CO, some of which appear to be related to problems with the meteorological fields. We propose to compare the GEOS-5 winds fields to those of NCEP and ECMWF in the regions of interest to see if these problems are unique to the GEOS fields. We plan also to compare the CO and NO2 fields to those from a model driven by ECMWF fields. 3. We propose to conduct a detailed analysis of MLS data for CO, ozone and ice water content in the upper troposphere (UT), and to use the MLS data in combination with TES and MOPITT data for the lower troposphere (LT) to evaluate convection and large scale ascent in the GEOS-5 meteorological fields. Characterizing model performance in the LT is a prerequisite for understanding its behavior in the UT. We will analyze the spatial and vertical distribution of convective mass fluxes of air to interpret the model results. 4. We propose to evaluate the ozone simulation with TES data in the LT, and TES and MLS data in the UT, and ozone sonde data. We will analyze the consistency of the TES and OMI/MLS ozone products. We propose to evaluate correlations of CO and ozone in the LT in the model and TES data, and to use the OMI NO2 data to evaluate the model throughout the tropics. For regions/years with significant IAV in ozone, we will analyze the meteorology in detail. We will conduct sensitivity simulations to investigate causes of discrepancies between the model and observation.

Project PI: Jennifer Logan/Harvard University

Harvard University School of Engineering and Applied Sciences 108 Pierce Hall 29 Oxford Street Cambridge MA 02138

Phone: (617) 495-4582



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Started: Sep 03, 2010

Last Activity: Feb 02, 2011


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