On the relationship between tropical convection and sea surface temperature

Tropical observations show convective activity increasing sharply above sea surface temperatures (SSTs) of around 26 degreesC and then decreasing as t he SST exceeds 30 degreesC, with maximum observed SSTs of around 32 degrees C. Although some aspects of this relationship are reasonably well understoo d, as of yet no theory has explained the decrease in convective activity ab ove 30 degreesC. Here it is suggested that this aspect of the relationship could result from a organizational positive feedback, sometimes termed " se lf aggregation, '' whereby the occurrence of convection makes future convec tion more likely to occur in the same location. Using cloud- resolving simu lations, it is shown that the feedback between convection and the water vap or field is a good candidate for this role.