NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Evaluating Model Performance of an Ensemble-based Chemical Data Assimilation System During INTEX-B Field MissionWe present a global chemical data assimilation system using a global atmosphere model, the Community Atmosphere Model (CAM3) with simplified chemistry and the Data Assimilation Research Testbed (DART) assimilation package. DART is a community software facility for assimilation studies using the ensemble Kalman filter approach. Here, we apply the assimilation system to constrain global tropospheric carbon monoxide (CO) by assimilating meteorological observations of temperature and horizontal wind velocity and satellite CO retrievals from the Measurement of Pollution in the Troposphere (MOPITT) satellite instrument. We verify the system performance using independent CO observations taken on board the NSFINCAR C-130 and NASA DC-8 aircrafts during the April 2006 part of the Intercontinental Chemical Transport Experiment (INTEX-B). Our evaluations show that MOPITT data assimilation provides significant improvements in terms of capturing the observed CO variability relative to no MOPITT assimilation (i.e. the correlation improves from 0.62 to 0.71, significant at 99% confidence). The assimilation provides evidence of median CO loading of about 150 ppbv at 700 hPa over the NE Pacific during April 2006. This is marginally higher than the modeled CO with no MOPITT assimilation (-140 ppbv). Our ensemble-based estimates of model uncertainty also show model overprediction over the source region (i.e. China) and underprediction over the NE Pacific, suggesting model errors that cannot be readily explained by emissions alone. These results have important implications for improving regional chemical forecasts and for inverse modeling of CO sources and further demonstrate the utility of the assimilation system in comparing non-coincident measurements, e.g. comparing satellite retrievals of CO with in-situ aircraft measurements. The work described above also brought to light several short-comings of the data assimilation approach for CO profiles. Because of the limited vertical resolution of the measurement, the retrievals at different altitudes are correlated which can lead to problems with numerical error and overall efficiency. This has resulted in a manuscript that is about to be submitted to JGR:
Document ID
20100011379
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Arellano, A. F., Jr.
(National Center for Atmospheric Research Boulder, CO, United States)
Raeder, K.
(National Center for Atmospheric Research Boulder, CO, United States)
Anderson, J. L.
(National Center for Atmospheric Research Boulder, CO, United States)
Hess, P. G.
(National Center for Atmospheric Research Boulder, CO, United States)
Emmons, L. K.
(National Center for Atmospheric Research Boulder, CO, United States)
Edwards, D. P.
(National Center for Atmospheric Research Boulder, CO, United States)
Pfister, G. G.
(National Center for Atmospheric Research Boulder, CO, United States)
Campos, T. L.
(National Center for Atmospheric Research Boulder, CO, United States)
Sachse, G. W.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 24, 2013
Publication Date
January 1, 2007
Publication Information
Publication: Journal of Atmospheric Chemistry and Physics
Publisher: European Geosciences Union
Volume: 7
Subject Category
Meteorology And Climatology
Funding Number(s)
CONTRACT_GRANT: NNG06GB27G
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available