Dear Napoleon Thanks for your email. I'm sorry, I don't understand these, because some of them have two directions, some only one, yet all have the same unit s-2.
If P is the geopotential (J kg-1 = m2 s-2), the acceleration due to gravity g=dP/dz (m s-2). This could have eastward, northward and upward derivatives dg/dx=d2P/dxdz, dg/dy=d2P/dydz, dg/dz=d2P/dz2. By northward upward derivative, for instance, do you mean d2g/dydz=d3P/dydz2? Or perhaps by Tij you mean d2P/dx_i dx_j in my notation? In that case the northward upward derivative is d2P/dydz=dg/dy, which is the northward derivative of the acceleration due to gravity. Txz Tyz Tzz are then the three derivatives of g, and Txx Tyy Txy are Iward_Jward_derivative_of_geopotential. To be consistent we could name all six of them in this second form, as second derivatives of geopotential. Best wishes Jonathan ----- Forwarded message from Napoleon Cornejo <[email protected]> ----- > Date: Tue, 20 Jan 2015 17:23:20 +0100 > From: Napoleon Cornejo <[email protected]> > To: Jonathan Gregory <[email protected]> > CC: [email protected] > Subject: Re: [CF-metadata] Standard Names for: Ocean Kinetic Energy and > Relative Vorticity > > Hi Jonathan, > > Since these quantities will be calculated in Local North Oriented Frame > (LNOF), I would like to submit these names for the gradients: > > northward_derivative_of_acceleration_due_to_gravity (Txx) > westward_derivative_of_acceleration_due_to_gravity (Tyy) > upward_derivative_of_acceleration_due_to_gravity (Tzz) > northward_upward_derivative_of_acceleration_due_to_gravity (Txz) > northward_westward_derivative_of_acceleration_due_to_gravity (Txy) > westward_upward_derivative_of_acceleration_due_to_gravity (Tyz) > > Let me know if these seem appropriate. All with unit: s-2. > > Regards, > > On Wed, 2014-12-17 at 13:34 +0000, Jonathan Gregory wrote: > > > Dear Napoleon > > > > > Is it the convention to include the direction in the name? We will be > > > calculating the gradient in more then one axis (Txy, Txz, etc, for a > > > total of 6 quantities). > > > > Yes, it is the convention. There are not many tensor quantities named but it > > is not unpredented e.g. downward_eastward_momentum_flux_in_air. As you see, > > both sign and direction are indicated. > > > > Best wishes > > > > Jonathan > > _______________________________________________ > > CF-metadata mailing list > > [email protected] > > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > > > -- > N.E. Cornejo, Msc. > Engineering, Space & Science > http://www.stcorp.nl > s[&]t > > ----- End forwarded message ----- _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
