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The Adjoint of CMAQ

Hakami, Amir and Henze, Daven K. and Seinfeld, John H. and Singh, Kumaresh and Sandu, Adrian and Kim, Soontae and Byun, Daewon and Li, Qinbin (2007) The Adjoint of CMAQ. Environmental Science and Technology, 41 (22). pp. 7807-7817. ISSN 0013-936X. doi:10.1021/es070944p.

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An adjoint model for the internationally used Community Multiscale Air Quality (CMAQ) modeling platform of the U.S. EPA is developed. The adjoint version for CMAQ (CMAQ-ADJ) provides the user community with forward (decoupled direct method or DDM) and backward (adjoint) sensitivity analysis capabilities. Current implementation is for gas-phase processes. Discrete adjoints are implemented for all processes with the exception of horizontal advection, for which, because of inherent discontinuities in the advection scheme, the continuous approach is superior. The adjoint of chemistry is constructed by interfacing CMAQ with the kinetic pre-processor, which provides for increased flexibility in the choice of chemical solver and facilitates the implementation of new chemical mechanisms. The adjoint implementation is evaluated both on a process-by-process basis and for the full model. In general, adjoint results show good agreement with brute-force and DDM sensitivities. As expected for a continuous adjoint implementation in a nonlinear scheme, the agreement is not perfect for horizontal transport. Sensitivities of various air quality, public health, and environmental metrics with respect to emissions are calculated using the adjoint method. In order to show applicability to regional climate studies, as an example, the sensitivities of these metrics with respect to local temperatures are calculated.

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Seinfeld, John H.0000-0003-1344-4068
Additional Information:© 2007 American Chemical Society. Received 20 April 2007. Date accepted 4 September 2007. Published online 11 October 2007. Published in print 1 November 2007. This work was supported by National Science Foundation award NSF ITR AP&IM 0205198 and by funding from the Jet Propulsion Laboratory. The work of A.S. and K.S. was also supported by the Houston Advanced Research Council through award H59/2005.
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Houston Advanced Research CouncilH59/2005
Issue or Number:22
Record Number:CaltechAUTHORS:20170320-064605024
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Official Citation:The Adjoint of CMAQ Amir Hakami, Daven K. Henze, John H. Seinfeld, Kumaresh Singh, Adrian Sandu, Soontae Kim, Daewon Byun, and Qinbin Li Environmental Science & Technology 2007 41 (22), 7807-7817 DOI: 10.1021/es070944p
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:75221
Deposited By: Ruth Sustaita
Deposited On:20 Mar 2017 15:01
Last Modified:15 Nov 2021 16:31

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