Set-up of Sydney Harbour by waves, wind and atmospheric pressure

Abstract

Nine years of hourly tide-gauge data from inside Sydney Harbour were detided and combined with wave- rider observations from outside, to test the effect of the waves on water level in the Harbour. Weather records were appended, to account for the confounding factors of wind and atmospheric pressure via a multiple regression analysis. The regression of water level on wave variance was found to be 2.88 cm m^-2, in satisfactory agreement with the theoretical value of 3/4H, where H is the average depth of the Harbour entrance. Wind set up the Harbour most efficiently (0.48 cm perm s^-1) when blowing toward 18º west of north. The regression of water level on atmospheric pressure was 0.74 cm mb^-1, definitely less than 1.01 cm mb^-1, the value of isostasy.