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Message: Fix to hot/dry RUC - Veg frac bug

Posted by Stan Benjamin on 8 Jun 99, 9:48 MT, in response to ALERT: RUC veg fraction erroneously set to zero, posted by Stan Benjamin on 28 May 99, 12:19 MT

The fix for the vegetation fraction error will probably be made tomorrow (Wed 9 June) for the 1200 UTC run. At the same time, new soil moisture and temperature fields from an FSL parallel run (without the bug) will be introduced into the RUC, replacing the current excessively dry conditions.

If you look at the "40km MAPS para" fields, you can see the behavior that we expect from the RUC after the fix is made. Last Thursday, this parallel cycle was restarted with a soil moisture field slightly drier than that used in the control 40km MAPS runs. The results have been good in verification against METARs, strong improvement in temp/dewpoint biases compared to the RUC, and modest improvement compared to the control 40km MAPS. (The control 40km MAPS soil fields will also be replaced with the parallel run fields later today.)

Overall, there will be a large reduction in warm/dry bias in the RUC at 2100-0900 UTC with the bug fix and soil moisture restart. Because the new soil moisture will be larger than the current RUC values, there will be a slight cool bias at 1200-1800 UTC, but the afternoon and nighttime improvement will be very noticeable. Verification of 24-h precipitation also shows improvement from the parallel MAPS runs.

Another message will be sent to verify when the change is actually made.

Stan Benjamin


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