What is the difference between 'reference height' and 'surface'?

[xlong@ncsu_edu]

In the output file,

There is a TREFHT Reference height temperature"
and a TS, Surface temperature (radiative)

What is the difference between them?

Is the reference height the same as surface?
Thank you

 

[brianpm]

TREFHT is a "2 m temperature" or "near-surface air temperature." It is calculated by interpolation between the surface temperature and the lowest model level temperature.

 

[brianpm]

TREFHT is a "2 m temperature" or "near-surface air temperature." It is calculated by interpolation between the surface temperature and the lowest model level temperature.

 

[micah_wilhelm@env_ethz_ch]

Hi Brian,Are you sure the reference height is 2m? I was confused to see that ZBOT is listed at the atmospheric reference height in CLM's history fields, while in CAM's it's listed as the lowest model level. Either way, when I look at the output of ZBOT it's on the order of 30-60m and not constant in space.

I think many of these variable long names in each of CESM's models need clarification and standardization to avoid confusion :/

 

[micah_wilhelm@env_ethz_ch]

Hi Brian,Are you sure the reference height is 2m? I was confused to see that ZBOT is listed at the atmospheric reference height in CLM's history fields, while in CAM's it's listed as the lowest model level. Either way, when I look at the output of ZBOT it's on the order of 30-60m and not constant in space.

I think many of these variable long names in each of CESM's models need clarification and standardization to avoid confusion :/

 

[hannay]

In CAM: ZBOT is the height of the lowest level model. This is not the same height as the reference height for TREFHT.TREFHT is computed in the coupler in: shr_flux_mod.F90 at the height:real(R8),parameter :: ztref =  2.0_R8 ! reference height for air T (m)

 

[hannay]

In CAM: ZBOT is the height of the lowest level model. This is not the same height as the reference height for TREFHT.TREFHT is computed in the coupler in: shr_flux_mod.F90 at the height:real(R8),parameter :: ztref =  2.0_R8 ! reference height for air T (m)