CT drifters
CT drifters recorded conductivity (C) and temperature (T) in addition to position (± 3 m) and time.
All CT drifters were programmed to record data at 3-minute intervals.
Additionally, all CT drifters were deployed in a surface configuration.
The buoy itself spanned the top 1.25 m of the water and CT data was recorded at 1.25 m depth.
Processing of the data included linearly interpolating all data onto a 3-minutely time vector.
The data were snipped, meaning only data collected while in water are provided.
Raw CT data is given in addition to calibrated CT data (in case calibrations change).
Calibrations were performed and provided by Tom Wilson at Brightwaters Corp.
The calibrated CT data were used to calculate salinity and density, which are also included.
Finally, east and north velocity components, also provided, were calculated by central-differencing
of position data.
Note: BCO-DMO has compiled the separate files into one, single dataset. The original file names can be found in the "Drifter_Data_File" column of the dataset.
File naming:
CT drifter files are named according to:
Drifter PTT ID_MonthDay_Cruise.txt
For example, a file named 22362_A19_R3W.txt contains drifter data recorded by
drifter #22362 starting on August 19th, of the 3rd RISE cruise aboard the R/V Wecoma.
Cruises were:
R1W - July 2004
R2W - May/June 2005
R3W - August 2005
R4W - May/June 2006
Data are in the following units:
Lon - Decimal degrees
Lat - Decimal degrees
Date/Time - Pacific Daylight Time (PDT)
Temperature - Celsius (°C)
Conductivity - (mS cm-1)
Salinity - (psu)
Density - (kg m-3)
Velocity components - (m s-1)