The
thermohaline response of the ocean to a short (10 h) but intense (95 mm)
nighttime rainfall event was observed during a transit through the ITCZ.
Two CTD profiles and shipboard measurements of air–sea fluxes were consistent
with the assumption that rain temperature equals the wet-bulb temperature,
within measurement errors. Although the net freshwater input and the net
heat loss inferred from the T–S characteristics of the surface layer were 
30%
smaller than those obtained by integrating the measured air–sea fluxes, owing
to different spatial sampling, inherent limitations of rain measurement from
ship, and contamination by internal waves, the two independent estimates
of the net heat deficit agreed remarkably well, within 2.4%, when expressed
per unit mass of rain (72kj kg
1).
The heat flux due to the temperature of the rain accounted for about 40%
of the net heat flux during rain, and therefore cannot be neglected.