Editorial Type:
Article
Article Type:
Research Article

Physical Response of the Tropical–Subtropical North Atlantic Ocean to Decadal–Multidecadal Forcing by African Dust

Amato T. Evan Department of Environmental Sciences, University of Virginia, Charlottesville, Virginia

Search for other papers by Amato T. Evan in
Current site
Google Scholar
PubMed Close
,
Gregory R. Foltz NOAA/Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida

Search for other papers by Gregory R. Foltz in
Current site
Google Scholar
PubMed Close
, and
Dongxiao Zhang JISAO, University of Washington, and NOAA/Pacific Marine Environmental Laboratory, Seattle, Washington

Search for other papers by Dongxiao Zhang in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Sep 2012
DOI:
https://doi.org/10.1175/JCLI-D-11-00438.1
Page(s):
5817–5829
Restricted access

Abstract

Dust storms are a persistent feature of the tropical North Atlantic and vary over a wide range of temporal scales. While it is well known that mineral aerosols alter the local radiative fluxes, far less is understood about the oceanic response to such forced changes to the radiative budget, particularly on long time scales. This study uses an observation-based climatology of dust surface forcing and an ocean general circulation model to examine the influence of anomalous atmospheric dust cover over the tropical North Atlantic on upper ocean temperature and circulation during 1955–2008. It is found that surface temperature anomalies from the model experiments are forced primarily by local radiation-induced changes to the surface heat budget. The subsurface temperature anomalies are additionally influenced by upper ocean circulation anomalies, which are the response to dust-forced steric changes in dynamic height. The results herein suggest that on decadal time scales dust-forced variability of ocean surface and subsurface temperatures are of a magnitude comparable to observed variability. On longer time scales dust-forced sea surface temperature anomalies vary in phase with the Atlantic multidecadal oscillation, implying that tropical North Atlantic multidecadal variability is related to changes in dust emissions from West Africa.

Corresponding author address: Amato T. Evan, Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22904. E-mail: aevan@virginia.edu

Abstract

Dust storms are a persistent feature of the tropical North Atlantic and vary over a wide range of temporal scales. While it is well known that mineral aerosols alter the local radiative fluxes, far less is understood about the oceanic response to such forced changes to the radiative budget, particularly on long time scales. This study uses an observation-based climatology of dust surface forcing and an ocean general circulation model to examine the influence of anomalous atmospheric dust cover over the tropical North Atlantic on upper ocean temperature and circulation during 1955–2008. It is found that surface temperature anomalies from the model experiments are forced primarily by local radiation-induced changes to the surface heat budget. The subsurface temperature anomalies are additionally influenced by upper ocean circulation anomalies, which are the response to dust-forced steric changes in dynamic height. The results herein suggest that on decadal time scales dust-forced variability of ocean surface and subsurface temperatures are of a magnitude comparable to observed variability. On longer time scales dust-forced sea surface temperature anomalies vary in phase with the Atlantic multidecadal oscillation, implying that tropical North Atlantic multidecadal variability is related to changes in dust emissions from West Africa.

Corresponding author address: Amato T. Evan, Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22904. E-mail: aevan@virginia.edu
Save
Cover Journal of Climate
Journal of Climate

  • Adcroft, A., J.-M. Campin, P. Heimbach, C. Hill, and J. Marshall, cited 2002: MITgcm release 1 manual (online documentation). [Available online at http://mitgcm.org/sealion/online_documents/manual.pdf.]

  • Boyer, T. P., S. Levitus, H. E. Garcia, R. A. Locamini, C. Stephens, and J. Antonov, 2005: Objective analyses of annual, seasonal, and monthly temperature and salinity for the World Ocean on a 0.25° grid. Int. J. Climatol., 25, 931–945, doi:10.1002/joc.1173.

    • Search Google Scholar
    • Export Citation

  • de Boyer Montégut, C., G. Madec, A. S. Fischer, A. Lazar, and D. Iudicone, 2004: Mixed layer depth over the global ocean: An examination of profile data and a profile-based climatology. J. Geophys. Res., 109, C12003, doi:10.1029/2004JC002378.

    • Search Google Scholar
    • Export Citation

  • Deser, C., M. A. Alexander, and M. S. Timlin, 2003: Understanding the persistence of sea surface temperature anomalies in midlatitudes. J. Climate, 16, 57–72.

    • Search Google Scholar
    • Export Citation

  • Engelstaedter, S., I. Tegen, and R. Washington, 2006: North African dust emissions and transport. Earth Sci. Rev., 79, 73–100.

  • Evan, A. T., and S. Mukhopadhyay, 2010: African dust over the northern tropical Atlantic: 1955–2008. J. Appl. Meteor. Climatol., 49, 2213–2229.

    • Search Google Scholar
    • Export Citation

  • Evan, A. T., and Coauthors, 2008: Ocean temperature forcing by aerosols across the Atlantic tropical cyclone development region. Geochem. Geophys. Geosyst., 9, Q05V04, doi:10.1029/2007GC001774.

    • Search Google Scholar
    • Export Citation

  • Evan, A. T., D. J. Vimont, A. K. Heidinger, J. P. Kossin, and R. Bennartz, 2009: The role of aerosols in the evolution of tropical North Atlantic ocean temperature anomalies. Science, 324, 778–781.

    • Search Google Scholar
    • Export Citation

  • Evan, A. T., G. R. Foltz, D. Zhang, and D. J. Vimont, 2011: Influence of African dust on ocean–atmosphere variability in the tropical Atlantic. Nat. Geosci., 4, 762–765, doi:10.1038/ngeo1276.

    • Search Google Scholar
    • Export Citation

  • Foltz, G. R., and M. J. McPhaden, 2006: The role of oceanic heat advection in the evolution of tropical North and South Atlantic SST anomalies. J. Climate, 19, 6122–6138.

    • Search Google Scholar
    • Export Citation

  • Foltz, G. R., and M. J. McPhaden, 2008a: Impact of Saharan dust on tropical North Atlantic SST. J. Climate, 21, 5048–5060.

  • Foltz, G. R., and M. J. McPhaden, 2008b: Trends in Saharan dust and tropical Atlantic climate during 1980–2006. Geophys. Res. Lett., 35, L20706, doi:10.1029/2008GL035042.

    • Search Google Scholar
    • Export Citation

  • Gent, P. R., and J. C. McWilliams, 1990: Isopycnal mixing in ocean circulation models. J. Phys. Oceanogr., 20, 150–155.

  • Giannini, A., R. Saravanan, and P. Chang, 2003: Oceanic forcing of Sahel rainfall on interannual to interdecadal time scales. Science, 302, 1027–1030.

    • Search Google Scholar
    • Export Citation

  • Huneeus, N., and Coauthors, 2010: Global dust model intercomparison in AeroCom phase I. Atmos. Chem. Phys. Discuss., 10, 23 781–23 864, doi:10.5194/acpd-10-23781-2010.

    • Search Google Scholar
    • Export Citation

  • Husar, R. B., J. M. Prospero, and L. L. Stowe, 1997: Characterization of tropospheric aerosols over the oceans with the NOAA advanced very high resolution radiometer optical thickness operational product. J. Geophys. Res., 102 (D14), 16 889–16 910.

    • Search Google Scholar
    • Export Citation

  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77, 437–471.

  • Kaufman, Y. J., I. Koren, L. A. Remer, D. Tanré, P. Ginoux, and S. Fan, 2005: Dust transport and deposition observed from the Terra-Moderate Resolution Imaging Spectroradiometer (MODIS) spacecraft over the Atlantic Ocean. J. Geophys. Res., 110, D10S12, doi:10.1029/2003JD004436.

    • Search Google Scholar
    • Export Citation

  • Kok, J. F., 2011: A scaling theory for the size distribution of emitted dust aerosols suggests climate models underestimate the size of the global dust cycle. Proc. Natl. Acad. Sci. USA, 108, 1016–1021.

    • Search Google Scholar
    • Export Citation

  • Large, W. G., J. C. McWilliams, and S. C. Doney, 1994: Oceanic vertical mixing: A review and a model with a nonlocal boundary layer parameterization. Rev. Geophys., 32, 363–403, doi:10.1029/94RG01872.

    • Search Google Scholar
    • Export Citation

  • Mahowald, N. M., 2007: Anthropocene changes in desert area: Sensitivity to climate model predictions. Geophys. Res. Lett., 34, L18817, doi:10.1029/2007GL030472.

    • Search Google Scholar
    • Export Citation

  • Mahowald, N. M., and Coauthors, 2010: Observed 20th century desert dust variability: Impact on climate and biogeochemistry. Atmos. Chem. Phys., 10, 10 875–10 893, doi:10.5194/acp-10-10875-2010.

    • Search Google Scholar
    • Export Citation

  • Marshall, J., A. Adcroft, C. Hill, L. Perelman, and C. Heisey, 1997a: A finite volume, incompressible Navier–Stokes model for studies of the ocean on parallel computers. J. Geophys. Res., 102 (C3), 5753–5766.

    • Search Google Scholar
    • Export Citation

  • Marshall, J., C. Hill, L. Perelman, and A. Adcroft, 1997b: Hydrostatic, quasi-hydrostatic, and nonhydrostatic ocean modeling. J. Geophys. Res., 102, 5733–5752.

    • Search Google Scholar
    • Export Citation

  • Martínez Avellaneda, N. M., N. Serra, P. J. Minnett, and D. Stammer, 2010: Response of the eastern subtropical Atlantic SST to Saharan dust: A modeling and observational study. J. Geophys. Res., 115, C08015, doi:10.1029/2009JC005692.

    • Search Google Scholar
    • Export Citation

  • Miller, R. L., 2012: Adjustment to radiative forcing in a simple coupled ocean–atmosphere model. J. Climate, in press.

  • Miller, R. L., and I. Tegen, 1998: Climate response to soil dust aerosols. J. Climate, 11, 3247–3267.

  • Myhre, G., A. Grini, J. M. Haywood, F. Stordal, B. Chatenet, D. Tanré, J. K. Sundet, and I. S. A. Isaksen, 2003: Modeling the radiative impact of mineral dust during the Saharan Dust Experiment (SHADE) campaign. J. Geophys. Res., 108, 8579, doi:10.1029/2002JD002566.

    • Search Google Scholar
    • Export Citation

  • Prospero, J. M., and P. J. Lamb, 2003: African droughts and dust transport to the Caribbean: Climate change implications. Science, 302, 1024–1027.

    • Search Google Scholar
    • Export Citation

  • Rayner, N. A., D. E. Parker, E. B. Horton, C. K. Folland, L. V. Alexander, D. P. Rowell, E. C. Kent, and A. Kaplan, 2003: Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century. J. Geophys. Res., 108, 4407, doi:10.1029/2002JD002670.

    • Search Google Scholar
    • Export Citation

  • Santer, B., and Coauthors, 2001: Accounting for the effects of volcanoes and ENSO in comparisons of modeled and observed temperature trends. J. Geophys. Res., 106 (D22), 28 033–28 059.

    • Search Google Scholar
    • Export Citation

  • Schollaert, S. E., and J. T. Merrill, 1998: Cooler sea surface west of the Sahara Desert correlated to dust events. Geophys. Res. Lett., 25, 3529–3532.

    • Search Google Scholar
    • Export Citation

  • Trenberth, K. E., and D. J. Shea, 2006: Atlantic hurricanes and natural variability in 2005. Geophys. Res. Lett., 33, L12704, doi:10.1029/2006GL026894.

    • Search Google Scholar
    • Export Citation

  • Wong, S., A. E. Dessler, N. M. Mahowald, P. R. Colarco, and A. da Silva, 2008: Long-term variability in Saharan dust transport and its link to North Atlantic sea surface temperature. Geophys. Res. Lett., 35, L07812, doi:10.1029/2007GL032297.

    • Search Google Scholar
    • Export Citation

  • Wong, S., A. E. Dessler, N. M. Mahowald, P. Yang, and Q. Feng, 2009: Maintenance of lower tropospheric temperature inversion in the Saharan air layer by dust and dry anomaly. J. Climate, 22, 5149–5162.

    • Search Google Scholar
    • Export Citation

  • Yoshioka, M., N. M. Mahowald, A. J. Conley, W. D. Collins, D. W. Fillmore, C. S. Zender, and D. B. Coleman, 2007: Impact of desert dust radiative forcing on Sahel precipitation: Relative importance of dust compared to sea surface temperature variations, vegetation changes, and greenhouse gas warming. J. Climate, 20, 1445–1467.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 172 73 20
PDF Downloads 101 40 11