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Dynamical analysis of sea breeze hodograph rotation in Sardinia

University of British Columbia

This study investigates the diurnal evolution of sea-breeze rotation over an island in the mid- latitudes. Earlier research on sea-breezes in Sardinia shows that the onshore winds around various coasts of the island exhibit both the theoretically predicted clockwise rotation as well as seemingly anomalous anti-clockwise rotation. A non-hydrostatic fully compressible numerical model (WRF) is used to simulate wind fields on and around the island on previously-studied sea-breeze days and is shown to accurately capture the circulation on all coasts. Diurnal rotation of wind is examined and patterns of clockwise and anti-clockwise rotation are identified. A dynamical analysis is per- formed by extracting individual forcing terms from the horizontal momentum equations. Analysis of several regions around the island shows that the direction of rotation is a result of a complex interaction between near-surface and synoptic pressure gradient, Coriolis and advection forcings. An idealized simulation is performed over an artificial island with dramatically simplified topog- raphy, yet similar dimensions and latitude to Sardinia. Dynamical analysis of the idealized runs reveals a rather different pattern of hodograph rotation to the real Sardinia, yet similar underlying dynamics. The research provides new insights into the dynamics underlying sea-breeze hodograph rotation, especially in coastal zones with complex topography and/or coastline.

Text

2014-02-25

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/46069

Atmospheric Science

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/