bill lawrence – doh. “hydrologic model output statistics” current short term ensembles have...
TRANSCRIPT
Southern Region Tech Transfer
WGRFC Aug6-10, 2007
Bill Lawrence – DOH
ABRFC HMOS EXPERIENCES
“Hydrologic Model Output Statistics” Current short term ensembles have
proven unreliable, mainly because no hydrologic uncertainty included.
Mary Mullusky suggested using previous forecasts at XEFS workshop in 12/06
Includes both meteorological and hydrologic uncertainty.
Temporary gap-filler till better hydro uncertainty process developed
ABRFC HMOS EXPERIENCES
Basic premise is to compare historical forecasts with observed, then infer how a operational forecast might vary considering current observation and deterministic forecast.
Requires long archive of forecasts and observations.
Likely only usable at daily forecast points. ABRFC provided data (forecasts and
observed) for 12 points for 10 year period.
DJ Seo and Satish Regonda primary players.
HMOS Ensemble Processor
Reflect meteorological & hydrological uncertainties
Deterministic forecasts of precipitation, temperature
Deterministic forecasts of streamflow
Ensemble traces of streamflow
Weather forecasts
Correct bias, account for all uncertainties
Deterministic Preprocessor
Hydrologic Models
HMOS
State Updating/ Data
Assimilation
HMOS Results: Illinois River near Watts [WTTO2]
Red River near Arthur City, TX [ARCT2]
ObservationSingle value ensemble
mean forecast
Oper. Forecast
Ensem. mean
Number of ensembles 2000, Regime moves from low to high
12
34
56
7
8
9
Line numbers Percentiles1 – 0th (minimum), 2 – 1th, 3 – 5th, 4- 25th, 5 – 50th
6 – 75th, 7 – 95th, 8 – 99th, 9 – 100th (maximum)
ABRFC BACKUP UPDATE
Fully functional new system in place across Southern Region.Pros: Much faster and capable than previous system Allows for creation and distribution to web page of graphics. Allows for >90% functionality (No FOP, no ESRI, etc)
ABRFC BACKUP UPDATE
Cons: Region/NOAA required security patches/updates are killing the effectiveness of the system. Requires tremendous resources. Future of the system is very much up in the air with AWIPS2 Where does SR system fit in with “new” national project???
ABRFC RETRO P3
ABRFC started using P1 in Oct 1996Previous years/months were created using Stage 3
DMIP1 showed different biases pre/post Oct 1996
ABRFC wants consistent bias in gridded data sets
ABRFC also wants to leverage current knowledge of precipitation processing for early years; eliminate obvious bad data
Hope is to rerun bigger events (pre Oct 10\1996) using P3
ABRFC RETRO P3
Initial team meetings showed project to be complex and time consuming
Needed new software and data restoration
In early 2000s, ABRFC deleted all but 6 hourly PC and HG data from older archive db due to space limitations, wrote to tape
Need to restore hourly data into new archive db on ax
Restore data off old tapes Write shef encoding software Process thru shefdecoder – “clean entry”
ABRFC RETRO P3
James Paul has already written application to access ax and create gage files needed for RetroP3
Next step is to write software to create mosaic of old DPAs
Likely pick an event or two to test, using human qc and intelligence
If testing is successful, final step is human processing of any/all hours
Very labor intensive, but outcome worth it
ABRFC RETRO P3
James Paul has also written a PostP3 application…needs additional testing and coding
ABRFC eventually plans to develop a gridded version of local bias for WFOS
Latest hour Average of Last 6 hours Average of Last 24 hours
ABRFC RETRO P3
ABRFC RETRO P3
ABRFC RETRO P3
ABRFC Q2 EXPERIENCES
ABRFC has been collaborating with NSSL for several years now regarding Q2
Goal of Q2 is to create an automated QPE for the entire lower 48 every 5 minutes; main goal is to aid in the flash flood arena.
NSSL is thinking beyond the box, ie different z-r relationships for different areas depending on soundings, etc.
ABRFC is downloading xmrgs of data to compare to our QPEs
ABRFC Q2 EXPERIENCES
ABRFC will start sending “bad gage” list soon for automtic inclusion into analysis.
NSSL in no way intends to compete with RFC produced QPE
ABRFC’s initial impressions are that the QPE is very good, esp for an automated process; AP removal is excellent.
Web site : http://www.nmq.nssl.noaa.gov
ABRFC Q2 EXPERIENCES
Website is useful operationally, as one can “review” echos from “yesterday”.
Excellent archive of both qpe and radar echos.
Since this method will have real-time gages/biases input, along with varying ZRs, and will be updated every 5 minutes, it shows real promise as a precipitation source for the Flash Flood program.