Hurricane tritium II: Air-sea exchange of water in Betsy 1965

The radial and vertical distribution of tritium (as HTO) in rain water and in water vapor was investigated in hurricane Betsy on four days, each day having different storm characteristics. On one day, 3 September, stratospheric subsidence was detected in the eye. The tritium concentration of underlying seawater was also measured. The molecular exchange of water at the air/sea interface was clearly exhibited on all four days, and the extent of exchange increased with increasing storm intensity. On 3 September the wall cloud vapor had a composition equivalent to 86% seawater vapor and 14% vapor from outside the storm envelope.

Together with the measured radial distribution of total wind velocity and reasonable assumptions of the effect of spray on rate of exchange, the tritium data were used to calculate possible distributions of relative inflow angle and of specific vapor inflow. A maximum in the inflow function around 120 km was obtained in one case, indicating subsidence between 200 km and 120 km. In the same area the distribution of tritium changes drastically from a vertical gradient to vertically well mixed and a horizontal gradient.