Brahan Project High Frequency Radar Ocean Measurements: Currents, Winds, Waves and Their Interactions

Belinda Lipa,Donald Barrick,Bruce Nyden,Maria Fernandes,Andres Alonso-Martirena,Maria Ferrer

doi:10.3390/rs61212094

Abstract

We describe radar measurements of waves, currents and winds made on the coast of northern Scotland during two 2013/14 winter storms, giving methods, results and interpretation. Wave parameters (height, period, direction and short-wave/wind direction) were derived and compared with measurements made by a neighboring buoy and local weather stations. Wind direction and current velocity maps were produced and the interactions of winds and currents discussed. Significant oscillations in wave parameters were observed, which appear to be due to forcing by tidal current velocity variations. The oscillations in waveheight are explained using hydrodynamic analysis and derived amplitudes are compared with radar measurements.

Highlights

A pair of long-range SeaSonde HF radars deployed on the Orkney and Shetland Islands observed the sea surface off the north coast of Scotland during the Brahan Project, a collaborative effort among several organizations [1] and named after the Brahan Seer, a predictor of the future who lived in the 17th century.Intense winter storms often pass through this area of the North Sea
We present examples of current velocity and wind direction maps selected to demonstrate changes occurring through the storm
The complete set of Brahan current velocity and wind direction maps for the first storm period may be viewed at http://youtu.be/3iVHNtSoHNg

Summary

Introduction

A pair of long-range SeaSonde HF radars deployed on the Orkney and Shetland Islands observed the sea surface off the north coast of Scotland during the Brahan Project, a collaborative effort among several organizations [1] and named after the Brahan Seer, a predictor of the future who lived in the 17th century. Intense winter storms often pass through this area of the North Sea. We present measurements made during two storms in the 2013/14 winter of wave parameters (height, period, direction), short-wave directions (which approximate wind directions), current velocity and wind direction maps. A new method is described to produce surface wind direction maps from a small broad-beam radar system. There was often a clear semi-diurnal periodicity in measured wave parameters with significant oscillations, which is explained using a local hydrodynamic model. Mean waveheight and wind directions were confirmed with a neighboring buoy and local weather stations

Objectives

Methods

Results

Discussion

Conclusion