Estimation of the Equivalent Depth of the Pekeris Mode Using Reanalysis Data

Abstract

Inspired by two recent studies on the Pekeris mode, one of which first detected the Pekeris mode in satellite data after the eruption of the Hunga Tonga-Hunga Ha'apai (HTHH) volcano in January 2022, and the other of which obtained the theoretical equivalent depth of the Pekeris mode under the vertical temperature profile of the US Standard Atmosphere, the present manuscript calculates the theoretical equivalent depths of the Pekeris and Lamb modes under the realistic vertical temperature profile of the atmosphere after the eruption of the HTHH and longer period averages using global reanalysis data. The obtained equivalent depths depend to some extent on the location and range of the horizontal mean used to determine the vertical temperature profile, as well as the time and length of the temporal mean, but the equivalent depth of the Lamb mode is about 10.1 km, and that of the Pekeris mode is about 6.5 km. The reason why the equivalent depth of the Pekeris mode differs from the values obtained in the two recent studies mentioned above is also discussed.