Mike Gregg  
   Principal Investigator  

   Matthew Alford  
   Co-Principal Investigator  

   Ren-Chieh Lien  
   Co-Principal Investigator  

   Glenn Carter
   Principal Investigator  
   Univ. of Hawaii, Manoa  

   Dave Winkel

   Danielle Wain
   Postdoctoral Researcher  
   Univ. of Washington  

   Rob Hall
   Postdoctoral Researcher  
   Univ. of Hawaii, Manoa  

   OCE 07501420  
   OCE 0751226  


Between 14 and 22 February 2009 Matthew Alford set moorings in the canyon from the R/V Wecoma (see map, right). Instruments and bottom depths were:
  • MP1: McLane Profiler, 489 m
  • LR1: 75 kHz Long Ranger ADCP, 584 m
  • LR2: 75 kHz Long Ranger ADCP, 579 m
  • MP2: McLane Profiler, 370 m
  • LR3: 75 kHz Long Ranger ADCP, 420 m
  • MP3: McLane Profiler, 288 m
  • LR4: 75 kHz Long Ranger ADCP, 307 m
  • WH1: 300 kHz Workhorse Sentinel ADCP, 153 m

On 13 April, WH1 was recovered and reset at the head of Ascension Canyon.

McLane profilers measured profiles of vector velocity, turbidity, temperature and salinity every 30 minutes with 2-m vertical resolution.

Between 4 and 27 April the full group took Wecoma back to the canyon for intensive measurements with SWIMS3 (pictured below), a depth cycling towed body, and Advanced Microstructure Profilers (AMPs). For contrast with Monterey, a day of SWIMS3 and AMP observations were planned for nearby Ascension, a short, narrow canyon, but heavy swell limited neap observations to 14 microstructure profiles.

SWIMS3 measured dual pumped Sea-Bird temperature and conductivity, dissolved oxygen, optical backscatter intensity, and fluorescence with a filter sensitive to chlorophyll. In addition, it carried upward and downward 300-kHz Workhorse Sentinel ADCPs.

SWIMS3 runs were made principally across the canyon, starting seaward of the Gooseneck Meander, and continuing landward around the next bend. Most sections were sampled with repeated runs, extending over 25 hours to obtain averages over a cycle of the M2 semi-diurnal tide.

Lines run across and along the canyon with SWIMS3 and AMP. Most lines were repeated throughout a daily tidal cycle, typically for at least ten times. Large red circles mark positions of McLane Profilers, and small circles show where ADCPs were moored. The Gooseneck is the large bend between 53.5 and 55.5 minutes. The moorings were removed before making runs crossing the circles.

Times of SWIMS3 (S) and AMP (A) groups relative to barotropic tidal currents. Groups are defined as successive runs along the same waypoints.