• RSK


  • latitudelatitude in decimal degrees north.
  • longitude : longitude in decimal degrees east.
  • seawaterLibrary: specify which library to use, should be either 'TEOS-10' or 'seawater', default is TEOS-10.


  • RSK

The function derives potential density anomaly using the TEOS-10 GSW toolbox ( or seawater library. The result is added to the RSK data structure, and the channel list is updated. The workflow of the function is as below:

  1. Calculate absolute salinity (SA)
    1. When latitude and longitude data are available (either from optional input or station data in, the function will call SA = gsw_SA_from_SP(salinity,seapressure,lon,lat)
    2. When latitude and longitude data are absent, the function will call SA = gsw_SR_from_SP(salinity) assuming that reference salinity equals absolute salinity approximately.
  2. Calculate conservative temperature CT = gsw_CT_from_t(absolute salinity,temperature,seapressure)
  3. Calculate potential density anomaly sigma0 = gsw_sigma0(absolute salinity,conservative temperature)



When geographic information is both available from optional inputs and the structure, the optional inputs will override. The input latitude/longitude must be either a single value or a vector of the same length of