Editorial Type:
Article
Article Type:
Research Article

Response of Freshwater Flux and Sea Surface Salinity to Variability of the Atlantic Warm Pool

Chunzai Wang NOAA/Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida

Search for other papers by Chunzai Wang in
Current site
Google Scholar
PubMed Close
,
Liping Zhang Cooperative Institute for Marine and Atmospheric Studies, University of Miami, and NOAA/Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida, and Physical Oceanography Laboratory, Ocean University of China, Qingdao, China

Search for other papers by Liping Zhang in
Current site
Google Scholar
PubMed Close
, and
Sang-Ki Lee Cooperative Institute for Marine and Atmospheric Studies, University of Miami, and NOAA/Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida

Search for other papers by Sang-Ki Lee in
Current site
Google Scholar
PubMed Close
Print Publication:
15 Feb 2013
DOI:
https://doi.org/10.1175/JCLI-D-12-00284.1
Page(s):
1249–1267
Restricted access

Abstract

The response of freshwater flux and sea surface salinity (SSS) to the Atlantic warm pool (AWP) variations from seasonal to multidecadal time scales is investigated by using various reanalysis products and observations. All of the datasets show a consistent response for all time scales: A large (small) AWP is associated with a local freshwater gain (loss) to the ocean, less (more) moisture transport across Central America, and a local low (high) SSS. The moisture budget analysis demonstrates that the freshwater change is dominated by the atmospheric mean circulation dynamics, while the effect of thermodynamics is of secondary importance. Further decomposition points out that the contribution of the mean circulation dynamics primarily arises from its divergent part, which mainly reflects the wind divergent change in the low level as a result of SST change. In association with a large (small) AWP, warmer (colder) than normal SST over the tropical North Atlantic can induce anomalous low-level convergence (divergence), which favors anomalous ascent (decent) and thus generates more (less) precipitation. On the other hand, a large (small) AWP weakens (strengthens) the trade wind and its associated westward moisture transport to the eastern North Pacific across Central America, which also favors more (less) moisture residing in the Atlantic and hence more (less) precipitation. The results imply that variability of freshwater flux and ocean salinity in the North Atlantic associated with the AWP may have the potential to affect the Atlantic meridional overturning circulation.

Corresponding author address: Dr. Chunzai Wang, NOAA/Atlantic Oceanographic and Meteorological Laboratory, 4301 Rickenbacker Causeway, Miami, FL 33149. E-mail: chunzai.wang@noaa.gov

Abstract

The response of freshwater flux and sea surface salinity (SSS) to the Atlantic warm pool (AWP) variations from seasonal to multidecadal time scales is investigated by using various reanalysis products and observations. All of the datasets show a consistent response for all time scales: A large (small) AWP is associated with a local freshwater gain (loss) to the ocean, less (more) moisture transport across Central America, and a local low (high) SSS. The moisture budget analysis demonstrates that the freshwater change is dominated by the atmospheric mean circulation dynamics, while the effect of thermodynamics is of secondary importance. Further decomposition points out that the contribution of the mean circulation dynamics primarily arises from its divergent part, which mainly reflects the wind divergent change in the low level as a result of SST change. In association with a large (small) AWP, warmer (colder) than normal SST over the tropical North Atlantic can induce anomalous low-level convergence (divergence), which favors anomalous ascent (decent) and thus generates more (less) precipitation. On the other hand, a large (small) AWP weakens (strengthens) the trade wind and its associated westward moisture transport to the eastern North Pacific across Central America, which also favors more (less) moisture residing in the Atlantic and hence more (less) precipitation. The results imply that variability of freshwater flux and ocean salinity in the North Atlantic associated with the AWP may have the potential to affect the Atlantic meridional overturning circulation.

Corresponding author address: Dr. Chunzai Wang, NOAA/Atlantic Oceanographic and Meteorological Laboratory, 4301 Rickenbacker Causeway, Miami, FL 33149. E-mail: chunzai.wang@noaa.gov
Save
Cover Journal of Climate
Journal of Climate

  • Adler, R. F., and Coauthors, 2003: The version-2 Global Precipitation Climatology Project (GPCP) monthly precipitation analysis (1979–present). J. Hydrometeor., 4, 1147–1167.

    • Search Google Scholar
    • Export Citation

  • Broecker, W. S., 1997: Thermohaline circulation, the Achilles heel of our climate system: Will man-made CO2 upset the current balance? Science, 278, 1582–1588.

    • Search Google Scholar
    • Export Citation

  • Carton, J. A., and B. S. Giese, 2008: A reanalysis of ocean climate using Simple Ocean Data Assimilation (SODA). Mon. Wea. Rev., 136, 2999–3017.

    • Search Google Scholar
    • Export Citation

  • Compo, G. P., and Coauthors, 2011: The Twentieth Century Reanalysis project. Quart. J. Roy. Meteor. Soc., 137, 1–28.

  • Foltz, G. R., and M. J. McPhaden, 2008: Seasonal mixed layer salinity balance of the tropical North Atlantic Ocean. J. Geophys. Res., 113, C02013, doi:10.1029/2007JC004178.

    • Search Google Scholar
    • Export Citation

  • Gibson, J. K., P. Kållberg, S. Uppala, A. Nomura, A. Hernandez, and E. Serrano, 1997: ERA description. ECMWF Re-Analysis Project Rep. 1, 71 pp.

  • Gill, A. E., 1980: Some simple solutions for heat-induced tropical circulation. Quart. J. Roy. Meteor. Soc., 106, 447–462.

  • Ishii, M., M. Kimoto, K. Sakamoto, and S. I. Iwasaki, 2006: Steric sea level changes estimated from historical ocean subsurface temperature and salinity analyses. J. Oceanogr., 62, 155–170.

    • Search Google Scholar
    • Export Citation

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

  • Katsumata, K., and H. Yoshinari, 2010: Uncertainties in global mapping of Argo drift data at the parking level. J. Oceanogr., 66, 553–569.

    • Search Google Scholar
    • Export Citation

  • Kõhl, A., D. Dommenget, K. Ueyoshi, and D. Stammer, 2006: The global ECCO 1952 to 2001 ocean synthesis. ECCO Tech. Rep. 40, 44 pp. [Available online at http://www.ecco-group.org/ecco1/report/report_40.pdf.]

  • Krebs, U., and A. Timmermann, 2007: Tropical air–sea interactions accelerate the recovery of the Atlantic meridional overturning circulation after a major shutdown. J. Climate, 20, 4940–4956.

    • Search Google Scholar
    • Export Citation

  • Magana, V., J. A. Amador, and S. Medina, 1999: The midsummer drought over Mexico and Central America. J. Climate, 12, 1577–1588.

  • Mapes, B. E., P. Liu, and N. Buenning, 2005: Indian monsoon onset and the Americas midsummer drought: Out-of-equilibrium response to smooth seasonal forcing. J. Climate, 18, 1109–1115.

    • Search Google Scholar
    • Export Citation

  • Peixoto, J. P., and A. H. Oort, 1992: Physics of Climate. American Institute of Physics, 520 pp.

  • Richter, I., and S.-P. Xie, 2010: Moisture transport from the Atlantic to the Pacific basin and its response to North Atlantic cooling and global warming. Climate Dyn., 35, 551–566.

    • Search Google Scholar
    • Export Citation

  • Romanova, V., M. Prange, and G. Lohmann, 2004: Stability of the glacial thermohaline circulation and its dependence on the background hydrological cycle. Climate Dyn., 22, 527–538.

    • Search Google Scholar
    • Export Citation

  • Rosati, A., M. Harrison, A. Wittenberg, and S. Zhang, 2004: NOAA/GFDL ocean data assimilation activities. Proc.CLIVAR Workshop on Ocean Reanalysis, NCAR, Boulder, CO, 25–26.

  • Seager, R., N. Naik, and G. A. Vecchi, 2010: Thermodynamic and dynamic mechanisms for large-scale changes in the hydrological cycle in response to global warming. J. Climate, 23, 4651–4668.

    • Search Google Scholar
    • Export Citation

  • Thorpe, R. B., J. M. Gregory, T. C. Johns, R. A. Wood, and J. F. B. Mitchell, 2001: Mechanisms determining the Atlantic thermohaline circulation response to greenhouse gas forcing in a non-flux-adjusted coupled climate model. J. Climate, 14, 3102–3116.

    • Search Google Scholar
    • Export Citation

  • Trenberth, K. E., and C. J. Guillemot, 1995: Evaluation of the global atmospheric moisture budget as seen from analyses. J. Climate, 8, 2255–2272.

    • Search Google Scholar
    • Export Citation

  • Vellinga, M., and P. Wu, 2004: Low-latitude freshwater influences on centennial variability of the Atlantic thermohaline circulation. J. Climate, 17, 4498–4511.

    • Search Google Scholar
    • Export Citation

  • Wang, C., 2007: Variability of the Caribbean low-level jet and its relations to climate. Climate Dyn., 29, 411–422.

  • Wang, C., and D. B. Enfield, 2001: The tropical Western Hemisphere warm pool. Geophys. Res. Lett., 28, 1635–1638.

  • Wang, C., and D. B. Enfield, 2003: A further study of the tropical Western Hemisphere warm pool. J. Climate, 16, 1476–1493.

  • Wang, C., and S.-K. Lee, 2007: Atlantic warm pool, Caribbean low-level jet, and their potential impact on Atlantic hurricanes. Geophys. Res. Lett., 34, L02703, doi:10.1029/2006GL028579.

    • Search Google Scholar
    • Export Citation

  • Wang, C., D. B. Enfield, S.-K. Lee, and C. W. Landsea, 2006: Influences of the Atlantic warm pool on Western Hemisphere summer rainfall and Atlantic hurricanes. J. Climate, 19, 3011–3028.

    • Search Google Scholar
    • Export Citation

  • Wang, C., S.-K. Lee, and D. B. Enfield, 2007: Impact of the Atlantic warm pool on the summer climate of the Western Hemisphere. J. Climate, 20, 5021–5040.

    • Search Google Scholar
    • Export Citation

  • Wang, C., S.-K. Lee, and D. B. Enfield, 2008a: Atlantic warm pool acting as a link between Atlantic multidecadal oscillation and Atlantic tropical cyclone activity. Geochem. Geophys. Geosyst., 9, Q05V03, doi:10.1029/2007GC001809.

    • Search Google Scholar
    • Export Citation

  • Wang, C., S.-K. Lee, and D. B. Enfield, 2008b: Climate response to anomalously large and small Atlantic warm pools during the summer. J. Climate, 21, 2437–2450.

    • Search Google Scholar
    • Export Citation

  • Xie, P., and P. A. Arkin, 1997: Global precipitation: A 17-year monthly analysis based on gauge observations, satellite estimates, and numerical model outputs. Bull. Amer. Meteor. Soc., 78, 2539–2558.

    • Search Google Scholar
    • Export Citation

  • Yin, J., M. E. Schlesinger, N. G. Andronova, S. Malyshev, and B. Li, 2006: Is a shutdown of the thermohaline circulation irreversible? J. Geophys. Res., 111, D12104, doi:10.1029/2005JD006562.

    • Search Google Scholar
    • Export Citation

  • Yu, L., and R. A. Weller, 2007: Objectively analyzed air–sea heat flux for the global ice-free oceans (1981–2005). Bull. Amer. Meteor. Soc., 88, 527–539.

    • Search Google Scholar
    • Export Citation

  • Zaucker, F., and W. S. Broecker, 1992: The influence of atmospheric moisture transport on the fresh water balance of the Atlantic drainage basin: General circulation model simulations and observations. J. Geophys. Res., 97, 2765–2773.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 354 122 6
PDF Downloads 208 52 4