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Emission-Induced Nonlinearities in the Global Aerosol System: Results from the ECHAM5-HAM Aerosol-Climate Model

Stier, Philip and Feichter, Johann and Kloster, Silvia and Vignati, Elisabetta and Wilson, Julian (2006) Emission-Induced Nonlinearities in the Global Aerosol System: Results from the ECHAM5-HAM Aerosol-Climate Model. Journal of Climate, 19 (16). pp. 3845-3862. ISSN 0894-8755. https://resolver.caltech.edu/CaltechAUTHORS:STIjc06

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Abstract

In a series of simulations with the global ECHAM5-HAM aerosol-climate model, the response to changes in anthropogenic emissions is analyzed. Traditionally, additivity is assumed in the assessment of the aerosol climate impact, as the underlying bulk aerosol models are largely constrained to linearity. The microphysical aerosol module HAM establishes degrees of freedom for nonlinear responses of the aerosol system. In this study’s results, aerosol column mass burdens respond nonlinearly to changes in anthropogenic emissions, manifested in alterations of the aerosol lifetimes. Specific emission changes induce modifications of aerosol cycles with unaltered emissions, indicating a microphysical coupling of the aerosol cycles. Anthropogenic carbonaceous emissions disproportionately contribute to the accumulation mode numbers close to the source regions. In contrast, anthropogenic sulfuric emissions less than proportionally contribute to the accumulation mode numbers close to the source regions and disproportionately contribute in remote regions. The additivity of the aerosol system is analyzed by comparing the changes from a simulation with emission changes for several compounds with the sum of changes of single simulations, in each of which one of the emission changes was introduced. Close to the anthropogenic source regions, deviations from additivity are found at up to 30% and 15% for the accumulation mode number burden and aerosol optical thickness, respectively. These results challenge the traditional approach of assessing the climate impact of aerosols separately for each component and demand for integrated assessments and emission strategies.


Item Type:Article
Additional Information:© 2006 American Meteorological Society Received: 22 November 2004; Accepted: 12 October 2005 This work was supported by the German climate research program DEKLIM. Review comments by two anonymous reviewers as well as by Stefan Kinne, Erich Roeckner, and Martin Schultz greatly improved this manuscript. SPECIAL SECTION: CLIMATE MODELS AT THE MAX PLANCK INSTITUTE FOR METEOROLOGY (MPI-M)
Issue or Number:16
Record Number:CaltechAUTHORS:STIjc06
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:STIjc06
Alternative URL:http://dx.doi.org/10.1175/JCLI3772.1
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3804
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:15 Sep 2006
Last Modified:02 Oct 2019 23:06

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