Abstract
Recent oceanic data and measurements at Johnston Island were used to examine insolation over the tropical Pacific by comparison with empirical formulas which are reliable for mid-latitudes. In the eastern Pacific the observed insolation is in reasonable agreement with the formulas, but over the central and western parts of the ocean the observed values are systematically larger than the estimates. This is in agreement with earlier studies of Quinn and Burt who concluded that insolation over these areas was greater than estimates from formulas because of extensive cirrus cloudiness in the absence of other types. Finally, it is concluded that Budyko's climatological values are too low in the tropics, primarily because of systematic errors in the formulas that he used.
