Hi,
there are three derivatives defined in ferret. If a variable depends on "z", say on the vertical coordinate, the derivative is
let drho_dz = rho[z=@ddb]
let drho_dz = rho[z=@ddc]
let drho_dz = rho[z=@ddf]
where @ddb, @ ddc and @ddf denote the backward, central and forward derivative.
You find examples and more details in the manual:
http://www.ferret.noaa.gov/Ferret/documentation/users-guide/variables-xpressions/XPRESSIONS#_VPINDEXENTRY_482
Best,
Martin
On 05/15/2018 07:13 PM, Nanda Kishore Reddy wrote:
there are three derivatives defined in ferret. If a variable depends on "z", say on the vertical coordinate, the derivative is
let drho_dz = rho[z=@ddb]
let drho_dz = rho[z=@ddc]
let drho_dz = rho[z=@ddf]
where @ddb, @ ddc and @ddf denote the backward, central and forward derivative.
You find examples and more details in the manual:
http://www.ferret.noaa.gov/Ferret/documentation/users-guide/variables-xpressions/XPRESSIONS#_VPINDEXENTRY_482
Best,
Martin
On 05/15/2018 07:13 PM, Nanda Kishore Reddy wrote:
Hi ferret users,
I am trying to calculate the brunt vaisala frequencyby using the pyferret. For this, I computed the density (ρ) with the help of temperature and salinity fields, but I am getting difficulties to calculate the dρ/dz. Is there any ferret function is available to calculate the density gradient (dρ/dz) in the ferret.
Regards
B. Nanda Kishore Reddy,
-- Dr. Martin Schmidt Leibniz-Institute for Baltic Sea Research Seestrasse 15 D18119 Rostock Germany