[CF-metadata] Vertical Coordinate Systems

From: Schmidli Juerg <schmidli>
Date: Tue, 22 Jul 2003 17:56:23 +0200

Dear All

I'm following the development of the CF-conventions
with great interest. At our institute we use different
hydrostatic and non-hydrostatic models with different
vertical coordinates. Currently I'm implementing a
subset of the CF-conventions for our visualization
software.

I propose the following modifications and extensions
to the vertical coordinate section (for details see
text below)

1. Additional vertical coordinate systems
- atmosphere_sleve_coordinate
- atmosphere_general_height_coordinate

2. Extension of the atmosphere hybrid height coordinate
for a time dependent surface height, as some models
have a time-dependent topopgraphy.

3. Consistent naming and consistent ordering of the
formula terms for the different vertical coordinates.

Thank you for considering my suggestions.

Juerg



Vertical Coordinate Systems
===========================

Atmosphere sigma coordinate
---------------------------

standard_name = "atmoshpere_sigma_coordinate"

Definition:
p(n,k,j,i) = (1-sigma)*ptop + sigma*psurf(n,j,i)

formuala_terms attribute:
formula_terms = "sigma:var1 ptop:var2 psurf:var3"


Atmosphere hybrid sigma pressure coordinate
-------------------------------------------

standard_name = "atmoshpere_hybrid_sigma_pressure_coordinate"

Definition:
p(n,k,j,i) = a(k)*ptop + b(k)*psurf(n,j,i)

formuala_terms attribute:
formula_terms = "a:var1 b:var2 ptop:var3 psurf:var4"

The hybrid sigma-pressure coordinate for level k is defined as b(k).


Atmosphere hybrid height coordinate
-----------------------------------

standard_name = "atmoshpere_hybrid_height_coordinate"

Definition:
z(n,k,j,i) = a(k)*ztop + b(k)*zsurf(n,j,i)

formuala_terms attribute:
formula_terms = "a:var1 b:var2 ztop:var3 zsurf:var4"

The hybrid height coordinate for level k is defined as a(k)*ztop.


Atmosphere smooth level vertical (SLEVE) coordinate
---------------------------------------------------

standard_name = "atmosphere_sleve_coordinate"

Definition:
z(n,k,j,i) = a(k)*ztop + b1(k)*zsurf1(n,j,i) + b2(k)*zsurf2(n,j,i)

formuala_terms attribute:
formula_terms = "a:var1 b1:var2 b2:var3 ztop:var4 zsurf1:var5
zsurf2:var6"

The hybrid height coordinate for level k is defined as a(k)*ztop.

Reference:
Schaer C, Leuenberger D, Fuhrer O, et al. 2002:
A new terrain-following vertical coordiante formulation for atmospheric
prediction models. Mon. Wea. Rev. 130, 2459-2480.


Atmosphere general height coordinate
------------------------------------

standard_name = "atmosphere_general_height_coordinate"

Definition:
z(n,k,j,i) = z(n,k,j,i)

formuala_terms attribute:
formula_terms = "z:var1"
Received on Tue Jul 22 2003 - 09:56:23 BST