Welcome to the new DiscussCESM forum!
We are still working on the website migration, so you may experience downtime during this process.

Existing users, please reset your password before logging in here: https://xenforo.cgd.ucar.edu/cesm/index.php?lost-password/

Will land surface changes (eg. LAI) affect air temperature under offline meteorology

Dear all,

May I ask will land surface changes (eg. LAI) affect air temperature and ozone concentration under offline meteorology?

I ask this because recently I found that air temperature (as an output of offline meteorology simulation) actually changes with LAI changes, which is contradictory to my previous thought that air temperature is read in from the database at every time step (so won't be changed by land surface changes) under offline meteorology.

Any suggestions will be appreciated. Thanks in advance!



Keith Oleson
CSEG and Liaisons
Staff member
The air temperature that is read in by the data atmosphere model when running offline (TBOT in the history files) is the air temperature at the atmospheric forcing height, which is typically above the vegetation canopy. There is also an air temperature at "2-m" height (2-m above the sink for sensible and latent heat at z0 - roughness length + d - displacement height) (TSA in the history files.) TSA can change in response to changes in fluxes caused by changes in the surface (e.g., LAI). In offline mode, the changes in TSA are somewhat constrained by the prescribed TBOT however.