How are temperatures of soil layers handled?
[12/2/97] The annual cycle in the soil temperature decreases in amplitude with depth. The model assumes that the bottom layer has no time variations of temperature (not a bad assumption). The temperature of the bottom layer is set to the annual-mean surface temperature climatology so that the net heat flux from the bottom layer should approach zero. (Wesley Ebisuzaki, NCEP) • How useful are upper level specific humidity fields on sigma surfaces?[11/15/97] The higher levels in this stack do not contain sufficient precision for many applications. For levels above the 0.1682 sigma level, the fields may contain only constant zero values. • How does reanalysis handle snow cover?[11/14/97] The snow coverage was estimated from satellite imagery (once per week) and snow coverage was converted into a snow depth by assuming it is a simple function of the surface temperature. (Yes, it is unrealistic but we have no snow depth observations.) For the purposes of data assimilation, the snow depth is
