Abstract
This paper examines the mean annual cycle, interannual variability, and leading patterns of the tropical Atlantic Ocean simulated in a long-term integration of the climate forecast system (CFS), a state-of-the-art coupled general circulation model presently used for operational climate prediction at the National Centers for Environmental Prediction. By comparing the CFS simulation with corresponding observation-based analyses or reanalyses, it is shown that the CFS captures the seasonal mean climate, including the zonal gradients of sea surface temperature (SST) in the equatorial Atlantic Ocean, even though the CFS produces warm mean biases and underestimates the variability over the southeastern ocean. The seasonal transition from warm to cold phase along the equator is delayed 1 month in the CFS compared with the observations. This delay might be related to the failure of the model to simulate the cross-equatorial meridional wind associated with the African monsoon. The CFS also realistically simulates both the spatial structure and spectral distributions of the three major leading patterns of the SST anomalies in the tropical Atlantic Ocean: the south tropical Atlantic pattern (STA), the North tropical Atlantic pattern (NTA), and the southern subtropical Atlantic pattern (SSA). The CFS simulates the seasonal dependence of these patterns and partially reproduces their association with the El Niño-Southern Oscillation. The dynamical and thermodynamical processes associated with these patterns in the simulation and the observations are similar. The air-sea interaction processes associated with the STA pattern are well simulated in the CFS. The primary feature of the anomalous circulation in the Northern Hemisphere (NH) associated with the NTA pattern resembles that in the Southern Hemisphere (SH) linked with the SSA pattern, implying a similarity of the mechanisms in the evolution of these patterns and their connection with the tropical and extratropical anomalies in their respective hemispheres. The anomalies associated with both the SSA and NTA patterns are dominated by atmospheric fluctuations of equivalent-barotropic structure in the extratropics including zonally symmetric and asymmetric components. The zonally symmetric variability is associated with the annular modes, the Arctic Oscillation in the NH and the Antarctic Oscillation in the SH. The zonally asymmetric part of the anomalies in the Atlantic is teleconnected with the anomalies over the tropical Pacific. The misplaced teleconnection center over the southern subtropical ocean may be one of the reasons for the deformation of the SSA pattern in the CFS.
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References
Breugem WP, Hazeleger W, Haarsma RJ (2006) Multimodel study of tropical Atlantic variability and change. Geophys Res Lett 33:L23706. DOI 10.1029/2006GL027831
Carton JA, Huang B (1994) Warm events in the tropical Atlantic. J Phys Oceanogr 24:888–903
Chang P, Ji L, Li H (1997) A decadal climate variation in the tropical Atlantic Ocean from thermodynamic air–sea interactions. Nature 385: 516–518
Chang P, Fang Y, Saravanan R, Ji L, Seidel H (2006) The cause of the fragile relationship between the Pacific El Niño and the Atlantic Niño. Nature 443:324–328. DOI 10.1038/nature05053
Czaja A, Frankignoul C (2002) Observed impact of Atlantic SST anomalies on the North Atlantic Oscillation. J Clim 15:606–623
Czaja A, van der Vaart P, Marshall J (2002) A diagnostic study of the role of remote forcing in tropical Atlantic variability. J Clim 15: 3280–3290
Davey MK et al. (2002) STOIC: a study of coupled model climatology and variability in tropical ocean regions. Clim Dyn 18:403–420. DOI 10.1007/s00382-001-0188-6
Delworth TL, et al. (2006) GFDL’s CM2 global coupled climate models—part I: formulation and simulation characteristics. J Clim 19:643–674
Deser C, Capotondi A, Sravanan R, Phillips AS (2006) Tropical Pacific and Atlantic climate variability in CCSM3. J Clim 19:2451–2481
Enfield DB, Mayer DA (1997) Tropical Atlantic sea surface temperature variability and its relation to the El Niño-Southern Oscillation. J Geophys Res 102(C1):929–945
Enfield DB, Lee S-K, Wang C (2006) How are large Western Hemisphere warm pools formed? Progr Oceanogr 70(2–4):346–365
Gnanadesikan A, et al. (2006) GFDL’s CM2 global coupled climate models—part II: the baseline ocean. J Clim 19:675–697
Gong DY, Wang SW (1999) Definition of Antarctic oscillation index. Geophys Res Lett 26:459–462
Hall A, Visbeck M (2002) Synchronous variability in the Southern Hemisphere atmosphere, sea ice, and ocean resulting from the annular mode. J Clim 15:3043–3057
Handoh IC, Bigg GR (2000) A self-sustaining climate mode in the tropical Atlantic, 1995–1997: observations and modelling. Q J R Meteorol Soc 126 (564):807–821
Hazeleger W, Haarsma RJ (2005) Sensitivity of tropical Atlantic climate to mixing in a coupled ocean–atmosphere model. Clim Dyn 25 (4):387–399. DOI 10.1007/s00382-005-0047-y
Hong S-Y, Pan H-L (1998) Convective trigger function for a mass-flux cumulus parameterization scheme. Mon Weather Rev 126:2599–2620
Hu Z-Z, Huang B (2006a) Air–sea coupling in the North Atlantic during summer. Clim Dyn 26(2):441–457. DOI 10.1007/s00382-005-0094-4
Hu Z-Z, Huang B (2006b) Physical processes associated with tropical Atlantic SST meridional gradient. J Clim 19 (21):5500–5518
Hu Z-Z, Huang B (2007a) Physical processes associated with tropical Atlantic SST gradient during the anomalous evolution in the southeastern ocean. J Clim 20 (14):3366–3378
Hu Z-Z, Huang B (2007b) The predictive skill and the most predictable pattern in the tropical Atlantic: The effect of ENSO. Mon Weather Rev 135 (5):1786–1806
Hu Z-Z, Huang B, Pegion K (2007c) Low cloud errors over the southeastern Atlantic in the NCEP CFS and their association with lower-tropospheric stability and air-sea interaction. J Geophys Res (Ocean) (in press)
Huang B, Shukla J (1997) Characteristics of the interannual and decadal variability in a general circulation model of the tropical Atlantic Ocean. J Phys Oceanogr 27:1693–1712
Huang B, Shukla J (2005) Ocean–atmosphere interactions in the tropical and subtropical Atlantic Ocean. J Clim 18:1652–1672
Huang B, Schopf PS, Pan Z (2002) The ENSO effect on the tropical Atlantic variability: a regionally coupled model study. Geophys Res Lett 29(21):2039. DOI 10.1029/2002GL014872
Huang B, Schopf PS, Shukla J (2004) Intrinsic ocean–atmosphere variability of the tropical Atlantic Ocean. J Clim 17:2058–2077
Huang B, Hu Z-Z, Jha B (2007) Evolution of model systematic errors in the tropical Atlantic basin from the NCEP coupled hindcasts. Clim Dyn 28 (7/8):661–682. DOI 10.1007/s00382-006-0223-8
Illig S, Gushchina D, Dewitte B, Ayoub A, du Penhoat Y (2006) The 1996 equatorial Atlantic warm event: Origin and mechanisms. Geophys Res Lett 33:L09701. DOI 10.1029/2006GL025632
Jochum M, Murtugudde R (2006) Temperature advection by tropical instability waves. J Phys Oceanogr 36:592–605
Jungclaus JH, Keenlyside N, Botzet M, Haak H, Luo J-J, Latif M, Marotzke J, Mikolajewicz U, Roeckner E (2006) Ocean circulation and tropical variability in the coupled model ECHAM5/MPI-OM. J Clim 19:3952–3972
Kalnay E, Kanamitsu M, Kistler R, Collins W, Deaven D, Gandin L, Iredell M, Saha S, White G, Woollen J, Zhu Y, Chelliah M, Ebisuzaki W, Higgins W, Janowiak J, Mo KC, Ropelewski C, Wang J, Leetmaa A, Reynolds R, Jenne R, Joseph D (1996) The NCEP/NCAR 40-year reanalysis project. Bull Am Meteorol Soc 77:437–471
Mitchell TP, Wallace JM (1992) On the annual cycle in equatorial convection and sea surface temperature. J Clim 5:1140–1156
Mo KC (2000) Relationships between low-frequency variability in the Southern Hemisphere and sea surface temperature. J Clim 13:3599–3610
Mo KC, Häkkinen S (2001) Interannual variability in the tropical Atlantic and linkages to the Pacific. J Clim 14(12):2740–2762
Mo KC, Higgins RW (1998) The Pacific-South American modes and tropical convection during the Southern Hemisphere winter. Mon Weather Rev 126: 1581–1596
Mo KC, White GH (1985) Teleconnections in the Southern Hemisphere. Mon Weather Rev 113:22–37
North GR, Bell TL, Cahalan RF, Moeng FJ (1982) Sampling errors in the estimation of empirical orthogonal functions. Mon Weather Rev 110: 699–706
Okumura Y, Xie S-P (2004) Interaction of the Atlantic equatorial cold tongue and the African monsoon. J Clim 17:3589–3602
Pacanowski RC, Griffies SM (1998) MOM 3.0 manual, NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey, USA 08542, 668 pp
Press WT, Teukolsky SA, Vetterling WT, Flannery BP (1992) Numerical Recipes in fortran, the art of scientific computing, 2nd Edn. Cambridge University Press, Cambridge, pp 1–963
Richman MB (1986) Rotation of principal component. J Climatol 6: 293–335
Ruiz-Barradas A, Carton JA, Nigam S (2000) Structure of interannual-to-decadal climate variability in the Tropical Atlantic sector. J Clim 13:3285–3297
Saha S, Nadiga S, Thiaw C, Wang J, Wang W, Zhang Q, van den Dool H, Pan H-L, Moorthi S, Behringer D, Stokes D, Pena M, Lord S, White G, Ebisuzaki W, Peng P, Xie P (2006) The NCEP climate forecast system. J Clim 19(5):3483–3517
Saravanan R, Chang P (2000) Interaction between tropical Atlantic variability and El Niño-Southern Oscillation. J Clim 13:2177–2194
da Silva A, Young CC, Levitus S (1994) Atlas of Surface Marine Data 1994. Vol. 1: Algorithms and Procedures. NOAA Atlas NESDIS 6, U. S. Department of Commerce, Washington, DC, 83 pp
Smith TM, Reynolds RW (2003) Extended reconstruction of global sea surface temperatures based on COADS data (1854–1997). J Clim 16: 1495–1510
Sterl A, Hazeleger W (2003) Coupled variability and air–sea interaction in the South Atlantic. Clim Dyn 21:559–571
Thompson DWJ, Wallace JM (2000) Annular modes in the extratropical circulation. Part I: Month-to-month variability. J Clim 13:1000–1016
Thompson DWJ, Wallace JM, Hegerl G (2000) Annular modes in the extratropical circulation. Part II: Trends. J Clim 13:1018–1036
Venegas SA, Mysak LA, Straub DN (1997) Atmosphere–ocean coupled variability in the South Atlantic. J Clim 10:2904–2920
Visbeck M, Hall A (2004) Reply. J Clim 17:2255–2258
Wang W, Saha S, Pan H-L, Nadiga S, White G (2005) Simulation of ENSO in the new NCEP coupled forecast system model. Mon Weather Rev 133: 1574–1593
Woodruff SD, Slutz RJ, Jenne RL, Steurer PM (1987) A comprehensive ocean–atmosphere data set. Bull Am Meteor Soc 68:1239–1250
Wu L, Zhang Q, Liu Z (2004) Toward understanding tropical Atlantic variability using coupled modeling surgery. In: Wang C, Xie S-P, Carton JA (eds) Earth’s climate: The ocean–atmosphere interaction. Geophysical monograph, no. 147, Am Geophys. Union, Washington DC, pp 157–170
Xie S-P (1999) A dynamic ocean–atmosphere model of the tropical Atlantic decadal variability. J Clim 12:64–70
Xie P, Arkin PA (1996) Analyses of global monthly precipitation using gauge observations, satellite estimates, and numerical model predictions. J Clim 9:840–858
Xie S-P, Carton JA (2004) Tropical Atlantic variability: Patterns, mechanisms, and impacts. In: Wang C, Xie S-P, Carton JA (eds) Earth’s Climate: The Ocean–Atmosphere Interaction. Geophysical Monograph, No. 147, Amer Geophys. Union, Washington DC, pp 121–142
Xie S-P, Philander SGH (1994) A coupled ocean–atmosphere model of relevance to the ITCZ in the eastern Pacific. Tellus 46A:340–350
Xie S-P, Miyama T, Wang Y, Xu H, de Szoeke SP, Small RJO, Richards KJ, Mochizuki T, Awaji T (2007) A regional ocean-atmosphere model for eastern Pacific climate: toward reducing tropical biases. J Clim 20: 1504–1522
Zebiak SE (1993) Air–sea interaction in the equatorial Atlantic region. J Clim 6:1567–1586
Acknowledgments
The authors appreciate the comments and suggestions of B. Klinger and D. Straus which significantly improved the manuscript. This work was supported by the NOAA CLIVAR Program (NA04OAR4310115 and NA07OAR431031) and the GEC-hri project (NASA Grant NNX06AF30G, Mason project 201152-1).
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Hu, ZZ., Huang, B. & Pegion, K. Leading patterns of the tropical Atlantic variability in a coupled general circulation model. Clim Dyn 30, 703–726 (2008). https://doi.org/10.1007/s00382-007-0318-x
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DOI: https://doi.org/10.1007/s00382-007-0318-x