[ Read Responses | Return to the Index ]

[ Previous | Next in Thread | Next ]

Message: upcoming RUC2 changes

Posted by Stan Benjamin on 29 Sep 98, 13:15 MT

Within the next 2 weeks, a set of upgrades will be made to the RUC2. Here is a summary of those changes:

Y2K fixes

Analysis changes

- smaller horizontal error correlation near sfc for T/Td, slightly less dependence on stability => improved sfc T/Td/wind fit in mtns

- fix to use of cloud drift winds => will have much more effect (over water only)

Model changes

- fixes to evaporation physics -reduction of cool bias in daytime

- fixes to radiation - more cooling at night, more heating in daytime -- A big improvement in the RUC2 diurnal cycle. This fix was removal of the application of the water vapor mixing ratio from the model top level (~60 mb) up to 0 mb. This extra water vapor was acting a bit like a cloud at the top of the model, and damping both longwave and shortwave temperature changes beneath.

- addition of frozen soil physics - improved sfc temp in fall and spring, improved sfc runoff

Diagnostic fixes

- CAPE/CIN - mix lowest 30-40 mb instead of only 20-25 mb - less jumpiness from analysis to 1h fcst

- tropopause level fix

GRIB table fixes

A new post will be made when these changes actually get in.


The FSL RAP/HRRR/RUC Information Forum is maintained with a variant of WebBBS .