Glacial-interglacial mean sea level pressure change due to sea level, ice sheet and atmospheric mass changes

The change in the global mean atmospheric pressure between glacial and interglacial periods is evaluated at sea level. This change originates in a modification of topography and in a possible variation in the atmospheric mass. In this calculation the atmosphere is at hydrostatic equilibrium, and the parameters describing the glacial period are varied in a plausible range. The result, with constant atmospheric mass, is a mean sea level pressure decrease of 9–15 hPa linked with the deglaciation. The corresponding pressure change at the reference level corresponding to the present day sea level does not exceed one hPa. When considering only the change in the atmospheric mass, an increase which does not exceed 2 hPa is found, linked with the deglaciation.