Surface Currents from HF Radar in the Beaufort Sea

A Presentation to the Alaska Marine Science Symposium

January 25, 2006Dave Musgrave, Hank Statscewich, Rachel Potter

(UAF) Pete Lilleboe, Belinda Lipa (CODAR Ocean Sensors)

Sponsored by Minerals Management Service and NOAA through

National Ocean Partnership Program

Thanks to British Petroleum Alaska and

Alaska Clean Seas

Beaufort Sea 101: Under open water conditions:Winds from east, westward currentsWinds from west, eastward currents

Under mixed ice/open water conditions: How well does HF radar work for surface currents?Can HF radar be used to detect ice floes?

New technology: switchable frequencies (12 and 25 Mhz)

Study the temporal and spatial variability of surface currents during ice-free and mixed ice/open water conditions using HF radar

HF radar in the Beaufort Sea

Install WEST

Install ENDI

Retrofit with Dual Frequency Rx Antennas

Trouble-shoot

APMs with Bruce

Repeat APMs, Remove 12 MHz Tx “Trap”

Retrofit with Repaired 12 MHZ Tx “Trap”

SITEVISITS:

WEST Operational = 79%

ENDIOperational = 91%

Beaufort Sea HF Radar Project Data Recovery Rate: Solid Dashes represent when radial files are made, gaps occur when the system was down.

12 MHz 25 MHz 12 MHz12 MHz

Sent switch.pl code

12 MHztesting25 12 25 12 MHz

25 12 25

24 MHz 12 MHz

CODAR:Mean U = - 17 cm/sMean V = 3 cm/sSTD = 23.3 cm/s

Wind:Mean U = - 654 cm/sMean V = 184 cm/sSTD = 682 cm/s

At a 2 hour lag Wind and CurrentsCorrelation Amplitude = 0.8Rotation Angle = 18 degrees CW (from wind to current)

Conclusions• Easterly Winds give Westward Currents

– (most of the time)– current field not uniform

• Occasional on-offshore transport

• Sea ice detection? need SAR

THANK YOU