Editorial Type:
Article
Article Type:
Research Article

Sensitivity of Air–Sea Fluxes to SST Perturbations

Ilya Rivin Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel

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Eli Tziperman Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel

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Print Publication:
01 Oct 1997
DOI:
https://doi.org/10.1175/1520-0442(1997)010<2431:SOASFT>2.0.CO;2
Page(s):
2431–2446
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Abstract

The sensitivity of long-term averaged air–sea fluxes calculated by a 3D atmospheric general circulation model to SST perturbations of an idealized spatial structure is investigated as a function of the SST perturbation amplitude, spatial scale, latitude, and season. This sensitivity is a dominant, yet largely unknown, parameter determining the stability and variability behavior of ocean-only model studies of decadal climate variability.

The air–sea heat-flux anomaly induced by the SST perturbation varies linearly with respect to the SST perturbation amplitude in a wide range of perturbation amplitudes (±3°C). The implied restoring time of the nonglobal SST perturbations by the air–sea fluxes is found to vary from 1.5 to 3 months (for a 50-m oceanic mixed layer and perturbation scale of less than 3.4 × 106 m) depending on the spatial scale, latitude, and season of the SST anomaly. The calculated restoring time for global perturbation is of the order of two years, and the latent heat flux is found to be the air–sea heat-flux component most sensitive to SST perturbations. Both longwave and shortwave radiative fluxes are much less sensitive than latent and sensible turbulent fluxes for nonglobal SST anomalies.

The restoring time is found to be significantly longer for large-scale anomalies than for the small-scale ones, because of the dominant effect of the heat advection by wind over small perturbations. No significant difference is found between the restoring times for SST perturbations in midlatitudes and in the Tropics. SST perturbations are dissipated faster by the air–sea fluxes during the winter than during the summer. The air–sea freshwater flux anomaly is also found to strongly depend on the SST perturbation amplitude, and to vary almost linearly with the SST perturbation in the midlatitudes, but in a nonlinear way in the Tropics. The possible model dependence of the calculated restoring times is analyzed.

* Permanent affiliation: St. Petersburg Branch, P. P. Shirshov Institute of Oceanology, St. Petersburg, Russia.

Corresponding author address: Dr. Eli Tziperman, Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.

Abstract

The sensitivity of long-term averaged air–sea fluxes calculated by a 3D atmospheric general circulation model to SST perturbations of an idealized spatial structure is investigated as a function of the SST perturbation amplitude, spatial scale, latitude, and season. This sensitivity is a dominant, yet largely unknown, parameter determining the stability and variability behavior of ocean-only model studies of decadal climate variability.

The air–sea heat-flux anomaly induced by the SST perturbation varies linearly with respect to the SST perturbation amplitude in a wide range of perturbation amplitudes (±3°C). The implied restoring time of the nonglobal SST perturbations by the air–sea fluxes is found to vary from 1.5 to 3 months (for a 50-m oceanic mixed layer and perturbation scale of less than 3.4 × 106 m) depending on the spatial scale, latitude, and season of the SST anomaly. The calculated restoring time for global perturbation is of the order of two years, and the latent heat flux is found to be the air–sea heat-flux component most sensitive to SST perturbations. Both longwave and shortwave radiative fluxes are much less sensitive than latent and sensible turbulent fluxes for nonglobal SST anomalies.

The restoring time is found to be significantly longer for large-scale anomalies than for the small-scale ones, because of the dominant effect of the heat advection by wind over small perturbations. No significant difference is found between the restoring times for SST perturbations in midlatitudes and in the Tropics. SST perturbations are dissipated faster by the air–sea fluxes during the winter than during the summer. The air–sea freshwater flux anomaly is also found to strongly depend on the SST perturbation amplitude, and to vary almost linearly with the SST perturbation in the midlatitudes, but in a nonlinear way in the Tropics. The possible model dependence of the calculated restoring times is analyzed.

* Permanent affiliation: St. Petersburg Branch, P. P. Shirshov Institute of Oceanology, St. Petersburg, Russia.

Corresponding author address: Dr. Eli Tziperman, Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.

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  • Allen, M. R., and M. K. Davey, 1993: Empirical parameterization of tropical ocean–atmosphere coupling: The inverse Gill problem. J. Climate,6, 509–530.

  • Blackmon, M. L., 1985: Sensitivity of January climate response to the position of Pacific sea-surface temperature anomalies. Coupled Ocean–Atmosphere Models, J. C. J. Nihoul, Ed., Elsevier, 19–28.

  • Bretherton, F. P., 1982: Ocean climate modeling. Progress in Oceanography, Vol. 11, Pergamon Press, 93–129.

  • Bryan, F., 1986: High-latitude salinity effects and interhemispheric thermohaline circulation. Nature,323(25), 301–304.

  • Cai, W., and S. J. Godfrey, 1995: Surface heat flux parameterization and the variability of thermohaline circulation. J. Geophys. Res.,100(C6), 10679–10692.

  • Capotondi, A., and R. Saravanan, 1996: Sensitivity of the thermohaline circulation to surface buoyancy forcing in a two-dimensional ocean model. J. Phys. Oceanogr.,26, 1039–1058.

  • Cess, R. D., and Coauthors, 1990: Intercomparison and interpretation of climate feedback processes in 19 atmospheric general circulation models. J. Geophys. Res.,95, 16601–16615.

  • Chen, F., and M. Ghil, 1995: Interdecadal variability of the thermohaline circulation and high-latitude surface fluxes. J. Phys. Oceanogr.,25, 2547–2568.

  • Chervin, R. M., J. E. Kutzbach, D. D. Houghton, and R. G. Gallimore, 1980: Response of the NCAR general circulation model to prescribed changes in ocean surface temperature. Part I: Midlatitude and subtropical changes. J. Atmos. Sci.,37, 308–332.

  • Delworth, T., S. Manabe, and R. J. Stouffer, 1993: Interdecadal variations of the thermohaline circulation in a coupled ocean–atmosphere model. J. Climate,6, 1993–2011.

  • Frankingoul, C., 1985a: Multivariate analysis of sensitivity studies with atmospheric GCMs. Coupled Atmosphere–Ocean Models, J. C. J. Nihoul, Ed., Elsevier Oceanography Series Vol. 40, Elsevier, 199–209.

  • ——, 1985b: Sea surface temperature anomalies, planetary waves and air-sea feedback in the middle latitude. Rev. Geophys.,23, 357–390.

  • Gill, A. E., 1982: Atmosphere–Ocean Dynamics. Academic Press, 662 pp.

  • Haney, R. L., 1971: Surface thermal boundary conditions for the ocean model. J. Phys. Oceanogr.,1, 241–248.

  • Hoskins, B. J., and D. J. Karoly, 1981: The steady linear response of a spherical atmosphere to thermal and orographic forcing. J. Atmos. Sci.,38, 1179–1196.

  • Kleeman, R., and S. Power, 1995: A simple atmospheric model of surface heat flux for use in ocean modeling studies. J. Phys. Oceanogr.,25, 92–105.

  • Kushnir, Y., 1994: Interdecadal variations in North Atlantic Sea surface temperature and associated atmospheric conditions. J. Climate,7, 141–157.

  • ——, and N.-C. Lau, 1992: The general circulation model response to a North Pacific SST anomaly: Dependence on time scale and pattern polarity. J. Climate,5, 271–283.

  • Kutzbach, J. E., R. M. Chervin, and D. D. Houghton, 1977: Response of the NCAR general circulation model to the prescribed changes in ocean surface temperature. Part I: Mid-latitude changes. J. Atmos. Sci.,34, 1200–1213.

  • Lau, N.-C., and M. J. Nath, 1990: A general circulation model study of the atmospheric response to extratropical SST anomalies observed in 1950–79. J. Climate,3, 969–989.

  • Maier-Reimer, E., U. Mikolajewicz, and K. Hasselmann, 1993: Mean circulation of the Hamburg LSG OGCM and its sensitivity to the thermohaline surface forcing. J. Phys. Oceanogr.,23, 731–757.

  • Manabe, S., R. J. Stouffer, M. J. Spelman, and K. Bryan, 1991: Transient responses of a coupled ocean–atmosphere model to graduate changes of atmospheric CO2 Part I: Annual mean response. J. Climate,4, 785–818.

  • Marotzke, J., 1989: Instabilities and multiple steady states of the thermohaline circulation. Oceanic Circulation Models: Combining Data and Dynamics, D. L. T. Anderson and J. Willebrand, Eds., NATO ASI Series, Vol. C284, Kluwer, 501–511.

  • ——, 1994: Ocean models in climate problems. Ocean Processes in Climate Dynamics: Global and Mediterranean Examples, P. Malanotte-Rizzoli and A. R. Robinson, Eds., Kluwer Academic Publishers, 79–109.

  • Mikolajewicz, U., and E. Maier-Reimer, 1990: Internal secular variability in an ocean general circulation model. Climate Dyn.,4, 145–156.

  • ——, and ——, 1994: Mixed boundary conditions in ocean general circulation models and their influence on the stability of the model’s conveyor belt. J. Geophys. Res.,99, 22633–22644.

  • Moore, A. M., and C. J. C. Reason, 1993: The response of a global general circulation model to climatological surface boundary conditions for temperature and salinity. J. Phys. Oceanogr.,23, 300–328.

  • Nakamura, M., P. H. Stone, and J. Marotzke, 1994: Destabilization of the thermohaline circulation by atmospheric eddy transport. J. Climate,7, 1870–1882.

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

  • Phillips, T. J., and A. J. Semptner Jr., 1984: The seasonal response of the Held–Suarez climate model to prescribed ocean temperature anomalies. Part I: Results of decadal integrations. J. Atmos. Sci.,41, 2605–2619.

  • Power, S. B., and R. Kleeman, 1993: Multiple equilibria in a global OGCM. J. Phys. Oceanogr.,23, 1670–1681.

  • ——, and ——, 1994: Surface heat flux parameterization and the response of ocean general circulation models to high-latitude freshening. Tellus,46, 86–95.

  • ——, A. M. Moore, D. A. Post, N. R. Smith, and R. Kleeman, 1994: Stability of North Atlantic deep water formation in a global ocean general circulation model. J. Phys. Oceanogr.,24, 904–916.

  • ——, R. Kleeman, R. Colman, and B. McAvaney, 1995: Modeling the surface heat flux response to long-lived SST anomalies in the North Atlantic. J. Climate,8, 2161–2180.

  • Rahmstorf, S., and J. Willebrand, 1995: The role of temperature feedback in stabilizing the thermohaline circulation. J. Phys. Oceanogr.,25, 787–805.

  • Randall, D. A., and Coauthors, 1992: Intercomparison and interpretation of surface energy fluxes in atmospheric general circulation models. J. Geophys. Res.,97(D4), 3711–3724.

  • Rivin, I., and E. Tziperman, 1997: Linear versus self-sustained interdecadal thermohaline variability in a coupled box model. J. Phys. Oceanogr.,27, 1216–1232.

  • Schopf, P. S., 1983: On equatorial waves and El Niño. II. Effects of air–sea thermal coupling J. Phys. Oceanogr.,13, 1878–1893.

  • Seager, R., Y. Kushnir, and M. Cane, 1995: An advective atmospheric mixed layer model for ocean modeling purposes: Global simulation of surface heat fluxes. J. Climate,8, 1951–1064.

  • Tziperman, E., R. Toggweiler, Y. Feliks, and K. Bryan, 1994: Instability of the thermohaline circulation with boundary conditions: Is it really a problem for realistic models? J. Phys. Oceanogr.,24, 217–232.

  • Washington, W. M., and J. Meehl, 1989: Climate sensitivity due to increased CO2: Experiments with a coupled atmosphere and ocean general circulation model. Climate Dyn.,4, 1–38.

  • Weaver, A. J., and T. M. C. Hughes, 1994: Rapid interglacial climate fluctuations driven by North Atlantic Ocean circulation. Nature,367, 447–450.

  • ——, E. S. Sarachik, and J. Marotzke, 1991: Freshwater flux forcing of decadal and interdecadal oceanic variability. Nature,353, 836–838.

  • Webster, P. J., 1981: Mechanisms determining the atmospheric response to sea surface temperature anomalies. J. Atmos. Sci.,38, 554–571.

  • Weisse, R., U. Mikolajewicz, and E. Maier-Reimer, 1994: Decadal variability of the North Atlantic in an ocean general circulation model. J. Geophys. Res.,99, 12411–12422.

  • Willebrand, J., 1993: Forcing the ocean with heat and freshwater fluxes. Energy and Water Cycles in the Climate System, E. Raschke, Ed., Springer-Verlag, 215–233.

  • Williamson, D. L., J. T. Kiehl, V. Ramanathan, R. E. Dickinson, and J. J. Hack, 1987: Description of NCAR Community Climate Model (CCM1). NCAR Tech. Note NCAR/TN285+STR, 112 pp. [Available from National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307.].

  • Winton, M., and E. S. Sarachik, 1993: Thermohaline oscillations induced by strong salinity forcing of ocean general circulation models. J. Phys. Oceanogr.,23, 1389–1410.

  • Yin, F. L., and E. S. Sarachik, 1995: Interdecadal thermohaline oscillations in a sector ocean general circulation model: Advective and convective processes. J. Phys. Oceanogr.,25, 2465–2484.

  • Zhang, S., R. J. Greatbatch, and C. A. Lin, 1993: A reexamination of the polar halocline catastrophe and implications for coupled ocean–atmosphere modeling. J. Phys. Oceanogr.,23, 287–299.

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