In rst files, the dimension "two" or "three" stands for what

[Kun]

Just now I was watching my rst files, while I found there is a dimension called "two" or three, for example
double zeta(ocean_time, three, eta_rho, xi_rho) ;
zeta:long_name = "free-surface" ;
zeta:units = "meter" ;
zeta:time = "ocean_time" ;
zeta:coordinates = "lon_rho lat_rho ocean_time" ;
zeta:field = "free-surface, scalar, series" ;
zeta:_FillValue = 1.e+37 ;
I got the information through "ncdump" , so what's the dimension three stand for? actually the value of "three" equals 3.

[kate]

You have asked for the PERFECT_RESTART option, which saves more than one time level of various fields. "three" stands for 3 which is how many time levels of zeta are needed for a perfect restart.

[Kun]

You have asked for the PERFECT_RESTART option, which saves more than one time level of various fields. "three" stands for 3 which is how many time levels of zeta are needed for a perfect restart.

thanks for your kind help, Kate. So the 3 means three time levels which are very close in time level? maybe only one timestep between each record in these three?

[kate]

Yes, something like that.

Don't forget that PERFECT_RESTART depends on an even number of steps between restart records so that the indices match up.