NCEP Modeling Synergy Meeting Highlights: December 31, 2007
This meeting was led by Michael Brennan and attended by Keith Brill, Mary Hart, Geoff DiMego, Ed Danaher, Bill Bua, Hendrik Tolman, and Ken Campana. Stephen Jascourt of UCAR/COMET and Rusty Billingsley of Southern Region HQ attended by remote teleconference.
No representative of NCO was present. A detailed list of all upcoming upgrades and implementations can be found here.
2. NOTES FROM EMC
2a. Global Climate and Weather Modeling Branch
Ken Campana reported on the following upcoming global branch implementations:
A new GFS upgrade will be discussed by the EMC implementation board on 10 January with code to be delivered to NCO shortly thereafter. This upgrade will involve changes to the GSI, a new quality control scheme, upgrades to the shortwave and longwave radiation physics and the enthalpy replacing virtual temperature as the thermodynamic state variable (due to the model extending beyond the mesosphere). Implementation is tentatively scheduled for 1 April.
This upgrade may impact downstream users of the native GFS “sigma” data, and these users may need to modify their software again. These users will be notified and an updated GFS "users’ manual" will be made available.
Another minor GFS upgrade is planned for the fall, largely to allow for the assimilation of new data types.
2b. Mesoscale Modeling Branch
Geoff DiMego reported on several issues related to MMB:
The change to the enthalpy formulation in the GFS
will impact the model output and has the potential to impact downstream users
of the GFS data, including the
Geoff has created a pair of tables highlighting
differences between the GFS and
Geoff also reported that although in many cases the performance of the NAM improves when the model is re-run with GFS initial conditions, is it not feasible to initialize the NAM with those data operationally due to time constraints (as too much satellite data arrives too late for the NAM to wait for the GFS analysis) and the domain configurations.
However, it is feasible to use an older global model state in the NDAS
cycle. This partial cycling is being
tested in which atmospheric fields at the beginning of the assimilation period
12 hours before the model cycle time will use a 6-hour global model forecast
from the GDAS valid 12 hours prior to the cycle time instead of a 3-h WRF-NMM
forecast valid 12 hours prior to the cycle time from the last NDAS cycle. For land surface states, full cycling will
continue to be used, due to problems initializing the NAM LSM from GFS
data. The assimilation will still follow
the usual NDAS procedure of running the NAM-GSI to assimilate data at 12, 9, 6,
3, and 0 hours before the cycle time and running the
The implementation of
2c. Global Ensemble Prediction System
A SREF upgrade scheduled for the 2nd Quarter of FY08 will include additional bias corrected output, but this output will not be delivered to the field immediately.
2e. Marine Modeling and Analysis Branch
Bandwidth issues are causing the delay of up to 20 minutes in the delivery of the high resolution wave model output.
Work is underway to sync the NCEP wave ensemble forecast system with that of FNMOC.
Issues with the location of the
Work to couple HWRF with HYCOM instead of the POM will continue, but this will not be operational for the start of the 2008 hurricane season. It is hoped that the HWRF coupled with HYCOM will be available in parallel for the hurricane season.
3. FEEDBACK FROM OPERATIONAL CENTERS/REGIONS
Stephen Jascourt passed along a question from the Reno WFO about a disparity in elevation between GFS forecast soundings from the 40-km AWIPS 212 grid and soundings from BUFR files. The entire sounding appears shifted to lower elevation in the BUFR sounding than on the 212 grid. Stephen will send an example of this problem to Ken Campana and Mark Iredell for further investigation.
4. The next Synergy Meeting will be held Monday, January 28 2008, at 12:00 pm EST in Room 209 at EMC, with remote conference capability.