Saturday, June 7, 2014

Heavy Duty

Kristen setting the AWAC & SeaFET
(pH sensor) in place. 
The immense spatial nature of internal waves, stretching thousands of feet across different density layers below the ocean's surface, leads to their important role in the mixing of ocean waters. Here at Dongsha in the South China Sea, observing the water column as it flows from the ocean, over the reef, and into the lagoon, requires a baseline measurement of temperature and currents offshore of the reef. A few days ago we successfully installed ‘E1’, our dense 16 meter mooring that holds 7 temperature loggers spaced evenly between a temperature and pressure sensor at the top, and a MicroCAT (temperature + pressure + oxygen sensor) at the bottom, in the deep offshore section of the reef. Each temperature logger is 2 m apart, allowing us to observe the thermal stratification of the water column before it enters the lagoon. 

4 large buckets filled with concrete helped
weigh down the 'E1' mooring. 
We were also fortunate enough to have Tom and Kristen scuba down a platform that holds the AWAC, an acoustic surface tracking instrument that profiles currents and wave direction, and a pH meter to a depth of ~20 m. We already installed a similar platform in the shallower lagoonal side of the reef, which contains an ADCP (acoustic Doppler current profiler) and another MicroCAT. This hard work marks a significant portion of our efforts to characterize flow across the reef, and will make for some interesting data!

-Aryan Safaie
Graduate Student
Coastal Dynamics Lab, UCI


  1. fabulous! keep up the good work

  2. Hey Aryan Nice post! Can you spell out "AWAC" for us? What's the difference between AWAC and ADCP?

  3. Hi!
    ADCP: Acoustic Doppler Current Profiler: uses the Doppler effect (change in frequency of a wave an observer hears as the source moves) to get a 3-d scattered ping of currents; the vector components of each beam can be combined to give the full magnitude and direction of currents. AWAC: Acoustic Waves and Current profiler: similar to the ADCP, but can also send an acoustic surface tracking pulse straight up to the surface, whereby the time lag between the transmission and reflection gives info on the surface elevation.
    Hope that clears things up a bit.

  4. Hi Aryan Safaie, wish you the best for the mission. Your work is in the frontier of internal solitons research. Hope to see in the future a great paper.