PRR Manual

[ Index | Overview |Core Cruises | Process Cruises | Projects | People | Cruise Dates | Equipment | Methods Manual | Data Tracking | Data Products ]

PRR

Deployment

The profiling refelctance radiometer (PRR) is be deployed off the stern while the TSRB is collecting data. The unit consists of a deck unit, laptop computer, surface unit, and under-water unit. The deck unit and laptop computer will require 110 volt AC power for operation. The surface unit will need to be mounted were it will not be affected by the ship’s shadow. The under-water unit is a free falling instrument secured to the ship via a 200 meter conducting umbilical. The instrument is drifted out approximately 20 meters from the ship while the ship slowly steams forward. Once data acquisition begins the instrument is allowed to free-fall while the operator manually pays out the umbilical. The PRR profiles to no more than 100 meters. Deployment and recover takes approximately 15 minutes. Deployment and operation can be achieved by two people.

Data Processing

Data from the PRR is processed using standard BBOP scripts. Files are converted from raw binary files to *.lcd files.

Make a file that contains a list of the PRR files without extensions. Name this file `cruise’.list.

The software will ask for the correct calibration date and serial number for the underwater unit. The current calibration date for PRR underwater unit 9628 is 030599. If the default setting do not match this, press Y and enter the correct values.

The software will then ask for the correct calibration date and serial number for the surface unit. The current calibration date for PRR surface unit 9629 is 030599. If the default setting do not match this, press Y and enter the correct values.

The software will then ask: For each instrument, enter tag # and calibration file name:

Enter the first tag number as 0. This tag represents the first instrument, which corresponds to the PRR underwater unit Ed channels.

Next enter the appropriate calibration file and path. The calibration file will have the form `serial#_tag#_calibdate’.

/home/data65/pb/CALIB_FILES/`calib_file’.cfl

Enter the next tag number as 1. This tag represents the second instrument, which corresponds to the PRR underwater unit Lu channels.

Enter the next tag number as 2. This tag represents the third instrument, which corresponds to the PRR surface unit.

The software will next ask a series of question about station location and environmental conditions for each file. This information can be found on the cast sheets.

Once this information is input, the files are stripped using bbopstrip and Matlab is started.

Figure 1 is a plot of dark voltage versus record number. Figure 2 is a plot of Ed versus depth.

Click on Figure1 and select an appropriate dark voltage value. Once you have clicked on the figure press Enter. If an appropriate dark value cannot be selected press Enter.

Once dark values for each file have been selected the software will prompt: Enter file containing offset values: For PRR underwater unit 9628 enter: off_9628

The software will next prompt: Enter file containing scale values: For PRR underwater unit 9628 enter: scale_9628.

Matlab will then calculated new offset values. The files will then be recalibrated using the new offset values.

Once all files have been recalibrated, next pick the upcast/downcast portion of each cast. Each file will automatically be loaded into MatLab.

Once the upcast/dpwncast portions have been selected, the files will automatically be run through a suite of BBOP functions.