Interannual tropospheric aerosol variability in the late twentieth century and its impact on tropical Atlantic and West African climate by direct and semidirect effects
A new high-resolution global tropospheric aerosol dataset with monthly resolution is generated using version 4 of the Community Atmosphere Model (CAM4) coupled to a bulk aerosol model and forced with recent estimates of surface emissions for the period 1961-2000 to identify tropospheric aerosol-indu...
Published in: | Journal of Climate |
---|---|
Other Authors: | , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
American Meteorological Society
2012
|
Subjects: | |
Online Access: | http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-012-022 https://doi.org/10.1175/JCLI-D-12-00029.1 |
id |
ftncar:oai:drupal-site.org:articles_12432 |
---|---|
record_format |
openpolar |
spelling |
ftncar:oai:drupal-site.org:articles_12432 2023-09-05T13:21:41+02:00 Interannual tropospheric aerosol variability in the late twentieth century and its impact on tropical Atlantic and West African climate by direct and semidirect effects Mahajan, Salil (author) Evans, Katherine (author) Truesdale, John (author) Hack, James (author) Lamarque, Jean-Francois (author) 2012-12-01 application/pdf http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-012-022 https://doi.org/10.1175/JCLI-D-12-00029.1 en eng American Meteorological Society Journal of Climate http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-012-022 doi:10.1175/JCLI-D-12-00029.1 ark:/85065/d7xs5w5b Copyright 2012 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be "fair use" under Section 107 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Law (17 USC, as revised by P.L. 94-553) does not require the Society's permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statements, requires written permission or license from the AMS. Additional details are provided in the AMS Copyright Policies, available from the AMS at 617-227-2425 or amspubs@ametsoc.org. Permission to place a copy of this work on this server has been provided by the AMS. The AMS does not guarantee that the copy provided here is an accurate copy of the published work. Text article 2012 ftncar https://doi.org/10.1175/JCLI-D-12-00029.1 2023-08-14T18:39:37Z A new high-resolution global tropospheric aerosol dataset with monthly resolution is generated using version 4 of the Community Atmosphere Model (CAM4) coupled to a bulk aerosol model and forced with recent estimates of surface emissions for the period 1961-2000 to identify tropospheric aerosol-induced interannual climate variations. The surface emissions dataset is constructed from phase 5 of the Coupled Model Intercomparison Project (CMIP5) decadal-resolution surface emissions dataset to include reanalysis of tropospheric chemical composition [40-yr Reanalysis of Tropospheric Chemical Composition (RETRO)] wildfire monthly emissions data. A four-member ensemble run is conducted using the spectral configuration of CAM4, forced with the new tropospheric aerosol dataset and prescribed with observed sea surface temperature, sea ice, and greenhouse gases. CAM4 only simulates the direct and semidirect effects of aerosols on the climate. The simulations reveal that variations in tropospheric aerosol levels can induce significant regional climate variability on the interannual time scales. Regression analyses over tropical Atlantic and Africa suggest that increasing dust aerosols can cool the North African landmass and shift convection southward from West Africa into the Gulf of Guinea in the spring season. Further, it is found that carbonaceous aerosols emanating from the southwestern African savannas can significantly cool the region and increase the marine stratocumulus cloud cover over the southeast tropical Atlantic Ocean by aerosol-induced diabatic heating of the free troposphere above the low clouds. Experiments conducted with CAM4 coupled to a slab ocean model suggest that present-day aerosols can cool the tropical North Atlantic and shift the intertropical convergence zone southward and can reduce the ocean mixed layer temperature beneath the increased marine stratocumulus clouds in the southeastern tropical Atlantic. Article in Journal/Newspaper North Atlantic Sea ice OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) Journal of Climate 25 23 8031 8056 |
institution |
Open Polar |
collection |
OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) |
op_collection_id |
ftncar |
language |
English |
description |
A new high-resolution global tropospheric aerosol dataset with monthly resolution is generated using version 4 of the Community Atmosphere Model (CAM4) coupled to a bulk aerosol model and forced with recent estimates of surface emissions for the period 1961-2000 to identify tropospheric aerosol-induced interannual climate variations. The surface emissions dataset is constructed from phase 5 of the Coupled Model Intercomparison Project (CMIP5) decadal-resolution surface emissions dataset to include reanalysis of tropospheric chemical composition [40-yr Reanalysis of Tropospheric Chemical Composition (RETRO)] wildfire monthly emissions data. A four-member ensemble run is conducted using the spectral configuration of CAM4, forced with the new tropospheric aerosol dataset and prescribed with observed sea surface temperature, sea ice, and greenhouse gases. CAM4 only simulates the direct and semidirect effects of aerosols on the climate. The simulations reveal that variations in tropospheric aerosol levels can induce significant regional climate variability on the interannual time scales. Regression analyses over tropical Atlantic and Africa suggest that increasing dust aerosols can cool the North African landmass and shift convection southward from West Africa into the Gulf of Guinea in the spring season. Further, it is found that carbonaceous aerosols emanating from the southwestern African savannas can significantly cool the region and increase the marine stratocumulus cloud cover over the southeast tropical Atlantic Ocean by aerosol-induced diabatic heating of the free troposphere above the low clouds. Experiments conducted with CAM4 coupled to a slab ocean model suggest that present-day aerosols can cool the tropical North Atlantic and shift the intertropical convergence zone southward and can reduce the ocean mixed layer temperature beneath the increased marine stratocumulus clouds in the southeastern tropical Atlantic. |
author2 |
Mahajan, Salil (author) Evans, Katherine (author) Truesdale, John (author) Hack, James (author) Lamarque, Jean-Francois (author) |
format |
Article in Journal/Newspaper |
title |
Interannual tropospheric aerosol variability in the late twentieth century and its impact on tropical Atlantic and West African climate by direct and semidirect effects |
spellingShingle |
Interannual tropospheric aerosol variability in the late twentieth century and its impact on tropical Atlantic and West African climate by direct and semidirect effects |
title_short |
Interannual tropospheric aerosol variability in the late twentieth century and its impact on tropical Atlantic and West African climate by direct and semidirect effects |
title_full |
Interannual tropospheric aerosol variability in the late twentieth century and its impact on tropical Atlantic and West African climate by direct and semidirect effects |
title_fullStr |
Interannual tropospheric aerosol variability in the late twentieth century and its impact on tropical Atlantic and West African climate by direct and semidirect effects |
title_full_unstemmed |
Interannual tropospheric aerosol variability in the late twentieth century and its impact on tropical Atlantic and West African climate by direct and semidirect effects |
title_sort |
interannual tropospheric aerosol variability in the late twentieth century and its impact on tropical atlantic and west african climate by direct and semidirect effects |
publisher |
American Meteorological Society |
publishDate |
2012 |
url |
http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-012-022 https://doi.org/10.1175/JCLI-D-12-00029.1 |
genre |
North Atlantic Sea ice |
genre_facet |
North Atlantic Sea ice |
op_relation |
Journal of Climate http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-012-022 doi:10.1175/JCLI-D-12-00029.1 ark:/85065/d7xs5w5b |
op_rights |
Copyright 2012 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be "fair use" under Section 107 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Law (17 USC, as revised by P.L. 94-553) does not require the Society's permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statements, requires written permission or license from the AMS. Additional details are provided in the AMS Copyright Policies, available from the AMS at 617-227-2425 or amspubs@ametsoc.org. Permission to place a copy of this work on this server has been provided by the AMS. The AMS does not guarantee that the copy provided here is an accurate copy of the published work. |
op_doi |
https://doi.org/10.1175/JCLI-D-12-00029.1 |
container_title |
Journal of Climate |
container_volume |
25 |
container_issue |
23 |
container_start_page |
8031 |
op_container_end_page |
8056 |
_version_ |
1776202274659368960 |