Ocean Tpray and the Thermodynamics of Tropical Cyclones

Serious gaps in knowledge about ocean spray at wind speeds over 40m/s remain difficult to fill by observation or experiment; yet refined study of the thermodynamics of Tropical Cyclones (including typhoons and hurricanes) requires assessment of the hypothesis that 'spray cooling' at extreme wind speeds may act to reduce (i) the initial temperature of saturated air rising in the eyewall and so also (ii) the input of mechanical energy into the airflow as a whole. Such progressive reductions at higher speeds could, for example, make any possible influence of future global warming on Tropical Cyclone intensification largely self-limiting. In order to help in extrapolation of knowledge on ocean spray to extreme wind speeds, a probabilistic analysis is introduced which allows for the effects of gusts, gravity and evaporation on droplet distributions, yet in other respects is as simple as possible. Preliminary indications from this simplified analysis appear to confirm the potential importance of spray cooling.