ADV Cruise Log

30 Aug 2005
Switching my computer to GMT for the rest of the cruise
so I am in synch with the rest of the data and event logs.
GMT = AST + 3 hours (done)

Planning.
The only three parameters to change are sample rate, velocity range and probe orientation. All other settings are as follows. XYZ Coordinate system, can be convert to ENU later but one must interpolate the heading and tilt for higher data rates and acocunt for vibrations of the sled (i.e. filter or smooth the data). Burst sampling was used, which was adjusted to take up to 2 Mb of data to fill the recorder but not be sampling when the instrument was to be taken on deck. It was set to use advanced settings to make the sample volume 18.0 mm in length. The Geography was set to "Open Ocean". The Salinity will be set to 35 nominally but may be adjusted later. 

The Burst Interval was adjusted to take 

11 hours = 0.4583 days
12.5 Hours = 0.52083 days duration (set for this to let it make sure I have the memory.)
1 kt = 0.513 m s^{-1}.

They were seeing currents of 1 kt in the eddy so I have to
account for this in the setup.

ADV 01
  12:30 GMT (21:30 AST) Launch 20:00 AST 31 Aug 2005
  Settings. (Default Settings)
  Perpandicular
  8 Hz
  2.00 m/s

Burst Interval = 3000 
# Samp per burst = 4800
XYZ


 NOTES:
It was in the water when it started to take data but it was not at depth and being towed.
Atle said that it will stop recording when it runs out of memory so no worries about taking data on deck.
When it was recovered, there was a carosel sampler tube over the arms of the ADV. There may have been interference.


ADV02
  Start at 01:00 GMT (22:00 AST) 1 Sep 2005
  Perpandicular
  8 Hz
  2.00 m/s
  Burst Interval = 3000 sec (10 min)
  4800
  Everything the same but the probe was mounted further toward the front in undisturbed flow.
 
01 Sep 2005
 It appears that there is very little signal. Low SNR and low correlation. Seems that there are very few scatterers. I am going to try to maximize all internal averaging and signal techniques
 
ADV03 - try to maximize the signal.
Drop messenger 10:00 pm local (AST) 01:00 GMT 2 Sep 2005
1 Hz, 7 m/s velocity range, perpendicular, 18 mm sample volume.
 
  # Sample per burst = 4 samp/sec * 60 sec / min * 10 min = 2400 (4 Hz)

02 Sep 2005
Trouble communicating with the instrument when it came on board. The signal was still bad. Correlations were slightly better. One receiver was noticably better than the others. I fear damage?

All tows are at night. I am wondering if the phytoplankton migrate to avoid the zooplankton. I am wondering if the bloom failed as well, zooplankton eating up the phytoplankton.



02 Sep 2005
Deployed the ADV same as pervious day with 1 m/s velocity range.


03 Sep 2005
Suspect that the ADV head is vibrating with the sled frequencies and shaking the sensors. Could be explained by decorrelation but not low amplitude and SNR. I may try to isolate the ADV head more or try a cast on a line or without the sled. Later. For today, I will change the velocity range to 2 m/s at 1 Hz.


04 Sep 2005

Ok, Jim wants to see some data on his sled motion. The idea is to break out the sensor data and then do power spectra of the ensembles. I do not think that I need to do anything with pressure data.