Oceanographers and meteorologists have always had a mutual interest in the interactions of ocean and atmosphere at the Earth's surface. There are frictional forces at work where the air and water interface. The drag effect this has on atmospheric circulation was addressed by American geophysicist William Ferrel during the mid-1800s. The parallel effect that friction has on ocean currents was taken into consideration by Swedish oceanographer Vagn Walfrid Ekman in the 1920s. For obvious reasons, seafarers have also had an interest in weather and surface water conditions. For this reason, H. P. Douglas developed a standard sea scale by which ocean roughness could be reported. It differentiated waves generated by local and distant wind conditions.

A true appreciation for the impact that ocean temperatures have on weather conditions began to develop in the late 19th century with reports from Peruvian sailors. In 1891 sailors at the...