ESC seminar No. 22

Adventures with the Solar Barometric Tide

Date
Wed., 13th July 2006 / 14:00-15:00
Place
Conference Room, 1F Earth Simulator Research building, YES
Speaker
Kevin P. Hamilton (International Pacific Research Center and Department of Meteorology, University of Hawaii at Manoa)
Language
English

Abstract

The diurnal cycle of radiation forces a large-scale wavelike response that propagates both zonally and vertically. The forcing and the response can both be conveniently resolved into diurnal (24-hour), semidiurnal (12-hour), terdiurnal (8-hour) etc. harmonics. These so-called atmospheric thermal tides are most easily observed at the ground by analysis of hourly barometric observations. The diurnal and semidiurnal surface barometric oscillations, denoted S1(p) and S2(p), respectively, have been determined at very large numbers of stations throughout the world.

The semidiurnal tide is effectively a global-scale inertia-gravity wave that is forced mainly by solar heating in the ozone layer. This talk will deal with two aspects of the semidiurnal tide, focusing on its surface expression as S2(p). First the simulation of the semidiurnal tide within comprehensive global atmospheric GCMs is reviewed, starting with the early work of Zwiers and Hamilton (1986) and Tokioka and Yagai (1987). I will then argue that, perhaps paradoxically given the global scale forcing of the tide, there are advantages to analyzing S2(p) in very-fine resolution GCMs. I will then show how fine-resolution AFES global model simulations together with observational analyses can be used to investigate the topographic effects on S2(p).

Contact

Wataru Ohfuchi
Earth Simulator Center
Tel: 045-778-5765
FAX: 045-778-5492
e-mail: ohfuchi