An Analytical Model of Heating Errors in Marine Air Temperatures from Ships

Abstract

Marine air temperature reports from ships can contain significant biases due to the solar heating of the instruments and their surroundings. However, there have been very few attempts to derive corrections. The biases can reverse the sign of the measured air–sea temperature differences and cause significant errors in the sea surface latent and sensible heat flux estimates. In this paper a new correction for the radiative heating errors is presented. The correction is based on the analytical solution of the heat budget for an idealized ship, using empirical coefficients to represent the physical parameters. For the first time heat storage is included in the correction model. The heating errors are estimated for the Ocean Weather Ship Cumulus and the coefficients determined. When the correction is applied to the Cumulus data the average estimated error is reduced from 0.32° to 0.04°C and the diurnal cycle in the error is removed. The rms error is reduced by 30%. The correction technique, although not the coefficients derived here that are specific to the Cumulus, can be applied to air temperature data from any type of ship, or to data from groups of ships such as the Voluntary Observing Ships.