There are 3 types of files that you will need, file names and contents are as follows:
station.loc: station number,date, time, latitude, longitude, and depth.
(nb. W and S are negative)
station##.ctd: pressure(dbars),temperature(ITS-90), salinity(PSS-78),
oxygen(umol/kg), #obs and quality. The data have been
sorted into 2dbar bins. The temperature will need to be
converted to IPTS-68 before using any UNESCO routine
(physical properties of seawater...phyprop).
t68=t90*1.0024
sta##.lad: depth(meters),u(cm/s),v(cm/s). The ladcp data are averaged
into 10 meter bins.
Geopotential anomaly can be calculated using the phyprop toolbox
which is on the web in the course directory. You will need to use the m-file
sw_gpan. If this toolbox is in your Matlab Path, type help [file]
to get information about the file [sw_gpan]. For pairs of stations, geostrophic
velocity requires that the distance between stations be calculated. The geostrophic
velocity is normal to line joining the two station pairs. You will need to use this
when comparing geostrophic velocity to the measured east and north velcity components.
I suggest you use the m-file [sw_dist] (also in phyprop toolbox).
You can also use the routine sw_gvel (in phyprop) to calculate geostrophic
velocity directly, but you are responbsible for understanding how it is done
(and for the correct answer!).
Note that the CTD files are different lengths as both the start and final
pressures can vary from station to station. Finally, be aware that the geostrophic
velocity is in m/s vs. pressure but the LADCP velocities are in cm/s and depth.
Pressure can be converted to depth using a standard ocean density following
Saunders. This m-file is in the phyprop directory and is called sw_dpth(pres,lat).
Matlab routine sw_pres(depth,lat) converts depth to pressure.