November 20, 2008 Meeting Summary
Vijay Tallapragada presented an update on the status of HWRF T&E for the
2009 implementation. He mentioned that the runs for H047 (New GFS/GSI)
are concluding. Morris Bender ran the GFDL using the new GFS/GSI at 00z
and 12z cycles for most of the available storms. He saw similar results
to what was observed with the HWRF, namely that the new GFS/GSI doesn't
produce significant differences in track and intensity values. H044
(gravity wave drag) runs for Kiko and Henriette in the East Pacific have
been completed. H044 showed no real improvement but no degradation for
track statistics and slight degradation from about 12-24 hours for
intensity. Some new experiments will be run using Fay, Gustav, Hanna,
and Ike from 2008. One set of experiments will feature HWRF runs without
the GSI to asses the impact of the GSI on the HWRF, and the other set
will use ECM analysis and boundary conditions to asses the influence of
initial boundary conditions on the HWRF. Preliminary results showing the
HWRF minus the GSI for Fay show strong positive bias in intensity and a
westward track bias.
Hyun-Sook Kim presented a status report on the NAOMIex benchmark cases
and preliminary results. Mean values of forecasted intensity for Katrina
and Rita show a larger negative bias for NAOMIex than H41A. Mean values
of track forecasts show similar values for both NAOMIex and H41A.
Compared to observations, HWRF-HYCOM exhibits much cooler SSTs than
HWRF-POM. This could be due to HYCOM's sensitivity to the wind field and
POM's production of a more "rigid" ocean than HYCOM. Hyun-Sook suggested
a diagnostic group form to further investigate these cooler SSTs. Such a
group would be comprised of Hyun-Sook, Carlos, and Bob Tuleya.
Yihua Wu gave a presentation on initial soil moisture and
hurricane-related inland flooding forecasts. His work used an EMC
routing scheme to compute the concentration time for runoff reaching the
outlet of a grid box and the transport of water in the channel system.
His experiment featured two types of experiments: the WET runs used
initial soil moisture from GFS for the US while the DRY runs used a
combination of GFS and NAM soil moisture for initial soil moisture.
Looking at results for the case of Hurricane Katrina, the WET and DRY
runs showed some of the largest differences for 12-hr subsurface runoff
and 12-hr total runoff. Yihua mentioned that forecasted runoff and
streamflow are very sensitive to initial soil moisture, and streamflow
forecasted from the predicted runoff using the NAM soil moisture as the
initial field is more realistic.