> How can I use ferret to calculate a particular depth? > The depth is the shallowest when temperature decreases by 0.5 from > the surface (the 1st layer). If variable TEMP is your temperature time series: let mld5a = temp[k=1] - 0.5 ! temperature at base of ML let mld5b = temp - mld5a ! equals 0 at base of ML let mld5 = mld5b[z=@loc:0] ! MLD (depth where mld5b=0) Billy K