An intercomparison between the surface heat flux feedback in five coupled models, COADS and the NCEP reanalysis

FRANKIGNOUL C., E. KESTENARE, M. BOTZET, A. F. CARRIL, H. DRANGE, A. PARDAENS, L. TERRAY AND R. SUTTON

CLIMATE DYNAMICS

Springer

Año: 2004 vol. 22 p. 373 - 388

0930-7575

The surface heat flux feedback is estimated inthe Atlantic and the extra-tropical Indo-Pacific, usingmonthly heat flux and sea surface temperature anomalydata from control simulations with five global climatemodels, and it is compared to estimates derived fromCOADS and the NCEP reanalysis. In all data sets, theheat flux feedback is negative nearly everywhere anddamps the sea surface temperature anomalies. At extratropicallatitudes, it is strongly dominated by the turbulentfluxes. The radiative feedback can be positive ornegative, depending on location and season, but it remainssmall, except in some models in the tropicalAtlantic. The negative heat flux feedback is strong in themid-latitude storm tracks, exceeding 40 W m–2 K–1 atplace, but in the Northern Hemisphere it is substantiallyunderestimated in several models. The negative feedbackweakens at high latitudes, although the models do notreproduce the weak positive feedback found in NCEP inthe northern North Atlantic. The main differences arefound in the tropical Atlantic where the heat flux feedbackis weakly negative in some models , as in theobservations, and strongly negative in others where itcan exceed 30 W m–2 K–1 at large scales, in part becauseof a strong contribution of the radiative fluxes, in particularduring spring. A comparison between modelswith similar atmospheric or oceanic components suggeststhat the atmospheric model is primarily responsiblefor the heat flux feedback differences at extra-tropicallatitudes. In the tropical Atlantic, the ocean behaviorplays an equal role. The differences in heat flux feedbackin the tropical Atlantic are reflected in the sea surfacetemperature anomaly persistence, which is too small inmodels where the heat flux damping is large. A goodrepresentation of the heat flux feedback is thus requiredto simulate climate variability realistically.