Atmospheric Tides Cause Semidiurnal Variation of Marine Air Temperature

Abstract Surface marine air temperature (MAT) is a fundamental variable in weather and climate applications. However, non‐aspirated MAT sensors, commonly used on ocean observing platforms due to power constraints, often experience radiative heating when the sun is low, producing secondary mid‐morning and mid‐afternoon peaks typically considered erroneous. This study challenges that assumption, showing these peaks can have a geophysical basis. Using a free‐running coupled model, we analyze the relationship between MAT and sea surface temperature (SST). Results indicate that MAT variation includes a significant component from the adiabatic response to pressure changes driven by the semi‐diurnal solar atmospheric tide. This component can cause secondary MAT maxima. Furthermore, it influences air‐sea heat fluxes. The findings emphasize the role of atmospheric tides in air‐sea interactions and caution against uniformly classifying secondary MAT peaks as errors.