Convective cloud systems and warm-pool sea surface temperatures : coupled interactions and self-regulation

Questions regarding the upper limits on tropical sea surface temperatures and the processes determining those limits have recently come under renewed interest and debate. We present results from an analysis of the relationship between observed sea surface temperature (SST) and organized deep convection in the tropics that has produced new and important findings relevant to this issue. First, the analysis reveals that the highest observed tropical SSTs are generally associated with diminished convection. Second, the maximum convective activity occurs, on average, at an SST of about 29.5°C. Third, at SSTs of about 29°C and greater, intense deep convection is associated with ocean surface cooling of approximately 0.1°C per month, while suppressed deep convection is associated with a similar degree of ocean surface warming. These three findings, together with results from simplified model analyses, emphasize the importance of the cooling mechanisms associated with deep convection in determining the observed upper limits on tropical SST. Implications of the observed relationship between deep convection and SST on the temporal correlations between these fields is discussed, as is the convective cloud system's relative influence on the solar and evaporative heat flux components of the surface energy budget.

[1]  W. Liu,et al.  Thermal forcing on the tropical Pacific from satellite data , 1990 .

[2]  R. Somerville,et al.  Global Monitoring of Net Solar Irradiance at the Ocean Surface: Climatological Variability and the 1982-1983 El Niño. , 1991 .

[3]  V. Ramanathan,et al.  Thermostat and global warming , 1992, Nature.

[4]  Richard W. Reynolds,et al.  A Real-Time Global Sea Surface Temperature Analysis , 1988 .

[5]  R. Houze,et al.  The Structure and Evolution of Convection in a Tropical Cloud Cluster , 1979 .

[6]  C. Gautier,et al.  A Satellite-derived Climatology of the ITCZ , 1993 .

[7]  J. Kiehl,et al.  Comparison of the observed and calculated clear sky greenhouse effect: Implications for climate studies , 1992 .

[8]  S. Gadgil,et al.  Ocean–atmosphere coupling over monsoon regions , 1984, Nature.

[9]  G. Paltridge.  Cloud‐radiation feedback to climate , 1980 .

[10]  Taketo Maruyama,et al.  Power Spectra of Large-Scale Disturbances over the Tropical Pacific , 1968 .

[11]  N. Graham,et al.  Comparison of the Highly Reflective Cloud and Outgoing Longwave Radiation Datasets for Use in Estimating Tropical Deep Convection. , 1993 .

[12]  S. Gadgil,et al.  Systematic Bias in the NOAA Outgoing Longwave Radiation Dataset , 1992 .

[13]  R. Houze.  Observed structure of mesoscale convective systems and implications for large-scale heating , 1989 .

[14]  J. Bjerknes,et al.  A possible response of the atmospheric Hadley circulation to equatorial anomalies of ocean temperature , 1966 .

[15]  E. Rasmusson,et al.  Meteorological Aspects of the El Ni�o/Southern Oscillation , 1983, Science.

[16]  Graeme L. Stephens,et al.  On the relationship between water vapor over the oceans and sea surface temperature , 1990 .

[17]  G. Young,et al.  Influence of precipitating convection on the surface energy budget observed during a tropical ocean global atmosphere pilot cruise in the tropical western Pacific Ocean , 1992 .

[18]  K. Liou.  Influence of Cirrus Clouds on Weather and Climate Processes: A Global Perspective , 1986 .

[19]  J. Bjerknes.  ATMOSPHERIC TELECONNECTIONS FROM THE EQUATORIAL PACIFIC1 , 1969 .

[20]  I. Held,et al.  Modeling Tropical Convergence Based on the Moist Static Energy Budget , 1987 .

[21]  R. Newell,et al.  Climate and the Ocean , 1979 .

[22]  R. Lindzen,et al.  On the role of sea surface temperature gradients in forcing low-level winds and convergence in the tropics , 1987 .

[23]  E. Schneider.  Axially symmetric steady-state models of the basic state for instability and climate studies , 1977 .

[24]  C. Ropelewski,et al.  Analysis of the Convectively Modified GATE Boundary Layer Using in situand Acoustic Sounder Data , 1979 .

[25]  A. Gruber,et al.  The Status of the NOAA Outgoing Longwave Radiation Data Set , 1984 .

[26]  Albert Arking,et al.  The radiative effects of clouds and their impact on climate , 1991 .

[27]  Lorraine A. Remer,et al.  Cloud optical thickness feedbacks in the CO2 climate problem , 1984 .

[28]  R. Lindzen.  Some Coolness Concerning Global Warming , 1990 .

[29]  Richard H. Johnson.  Large-Scale Effects of Deep Convection on the GATE Tropical Boundary Layer , 1981 .

[30]  Suhung Shen,et al.  On the Dynamics of Intraseasonal Oscillations and ENSO , 1988 .

[31]  W. Rossow,et al.  ISCCP Cloud Data Products , 1991 .

[32]  Ka-Ming Lau,et al.  Intraseasonal and Interannual Variations of Tropical Convection: A Possible Link between the 40–50 Day Oscillation and ENSO? , 1988 .

[33]  P. R. Julian,et al.  Description of Global-Scale Circulation Cells in the Tropics with a 40–50 Day Period , 1972 .

[34]  W. Liu,et al.  Cirrus-cloud thermostat for tropical sea surface temperatures tested using satellite data , 1992, Nature.

[35]  Chidong Zhang.  Large-Scale Variability of Atmospheric Deep Convection in Relation to Sea Surface Temperature in the Tropics , 1993 .

[36]  J. Wallace.  Effect of deep convection on the regulation of tropical sea surface temperature , 1992, Nature.

[37]  Syukuro Manabe,et al.  Thermal Equilibrium of the Atmosphere with a Given Distribution of Relative Humidity , 1967 .

[38]  John M. Wallace,et al.  Spectral studies of tropospheric wave disturbances in the tropical western Pacific , 1971 .

[39]  T. Barnett,et al.  Sea Surface Temperature, Surface Wind Divergence, and Convection over Tropical Oceans , 1987, Science.

[40]  D. Hartmann,et al.  Interannual Variations of Outgoing IR Associated with Tropical Circulation Changes During 1974–78 , 1982 .

[41]  Phillip A. Arkin,et al.  Large-scale interannual variability of monthly outgoing longwave radiation anomalies over the global tropics , 1992 .

[42]  W. Liu.  Statistical relation between monthly mean precipitable water and surface-level humidity over global oceans , 1986 .

[43]  Veerabhadran Ramanathan,et al.  Climate modeling through radiative‐convective models , 1978 .

[44]  J. Horel,et al.  Convection along the Coast of Northern Peru during 1983: Spatial and Temporal Variation of Clouds and Rainfall , 1986 .

[45]  C. Bohren,et al.  An introduction to atmospheric radiation , 1981 .

[46]  A. Betts,et al.  Climatic Equilibrium of the Atmospheric Convective Boundary Layer over a Tropical Ocean , 1989 .

[47]  V. Ramanathan,et al.  Thermodynamic regulation of ocean warming by cirrus clouds deduced from observations of the 1987 El Niño , 1991, Nature.

[48]  P. Webster.  Response of the Tropical Atmosphere to Local, Steady Forcing , 1972 .

[49]  Roger Lukas,et al.  The mixed layer of the western equatorial Pacific Ocean , 1991 .

[50]  R. Payne,et al.  Albedo of the Sea Surface , 1972 .

[51]  T. I. Gray,et al.  LONG-TERM VARIATIONS IN EQUATORIAL CIRCULATION AND RAINFALL , 1969 .