1. November 1, 2013 Bart Brashers, ENVIRON Jared Heath Bowden, UNC 3SAQS WRF Modeling Recommendations

2. Week long simulations for beginning of January and July Tests included: –ECMWF vs. NAM Initial and Boundary Conditions –USGS vs. NLCD land-use datasets –PX vs. NOAH land-surface model –TOPO option –Reduced vertical levels Where We Left Off at the Last Meeting 2

3. Initial Conclusions from Last Meeting Our conclusions from model metrics (T,Q,WS,WD) –Keep NAM instead of ECMWF –NLCD with NOAH requires more development –TOPO option created larger negative wind speed bias –Do not reduce number of vertical levels, especially given the desire to model temperature inversions –PX LSM/ACM2 vs. NOAH/YSU – found that PX crashed for January; preliminary comparison for July indicated PX was also comparable to our BASE configuration 3

4. PX LSM/ACM2 would run with 27 levels, crash consistently with 37 levels –wrfhelp and Jon Pleim consulted –Coding error caused crash instead of graceful stop Nudging with MESONET data (part of MADIS) caused some runs to crash (segmentation fault) –Could not find bad observation –Did not improve WRF performance noticeably New “snow” data from Polar WRF turned out to be only over ice, not over land –Good for them, but not for us Where We Went: Several Blind Alleys 4

5. Do not use objectively analyzed fields (metoa files created by OBSGRID.EXE) for any domains –NAM already analyzed at 12km (c.f. 36 & 12km domains) –4km domain has no analysis nudging, so uses metoa file only for initial conditions, which should have no effect after spin-up –Using metoa files produced far to much precipitation in previous ENVIRON work near Four Corners Use OBS nudging every hour –Was set to every 3 hours –Retain nudging coef’s used in ENVIRON Four Corners WRF Revised “Base Case” 5

6. PRISM is gridded observational data Sophisticated interpolation techniques 4km resolution, monthly total precip PRISM data is interpolated to each WRF nested grid WRF output is simply summed PRISM Precipitation Comparison 6

7. WRF Base Case vs. PRISM, January 2011 WRFPRISM 7

8. WRF Base Case vs. PRISM, July 2011 WRFPRISM 8

9. WRF Base Case vs. PRISM, January 2011 WRFPRISM 9

10. WRF Base Case vs. PRISM, July 2011 WRFPRISM 10

11. Preliminary Conclusion Base Case precipitation performance is acceptable. Let’s look at the rest of the typical performance metrics (METSTAT). 11

12. Plots of model Bias vs. Error for each month Performance envelopes from survey of many MM5 and WRF runs Introduction to Soccerplots How many months score a goal? GOOOOAAALLL! ERROR BIAS 12

13. BASE EPA 13

14. BASE EPA 14

15. BASE EPA 15

16. BASE EPA 16

17. Preliminary Conclusion We’re doing about as well as EPA’s WRF modeling, which they use for CMAQ. But can we do better with stronger nudging? 17

18. New test case, following Kristi Gebhart/RoMANS II Analysis (3D) nudging the same as Base case OBS nudging on 4km domain stronger Nudge Winds and Temperature, but not Humidity Winds nudging coefficient = 1.2E-3 Temperature nudging coefficient = 6.0E-4 Radius of influence = 60km Do not nudge to ACARS, SatWind, or Profiler data Nudging Case 18

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21. Preliminary Conclusion Stronger nudging reduces model error. At least when you verify using the same data you used for nudging... 21

22. MADIS data contains many “data streams” –ACARSAircraftNo thanks –HDWSatellite windsNo thanks –MARITIMEShip reportsNot relevant for 4km –METARASOS, AWOS, more.Yes please! –RAOBRadiosondesNot relevant for SFC –SAOCanadian stationsNot relevant for 4km –MESONETSmaller stationInteresting… Could we nudge with METAR & RAOB, and verify against MESONET data? Verifying Against MESONET Data 22

23. 4 WRF Runs vs. 3 Verification Sets 23

24. 4 WRF Runs vs. 3 Verification Sets 24

25. 4 WRF Runs vs. 3 Verification Sets 25

26. 4 WRF Runs vs. 3 Verification Sets 26

27. Preliminary Conclusion Stronger nudging did not change model performance, when using independent verification data (MESONET). Precip? 27

28. Base Case vs. Nudging Case, July 2011 Base CaseNudging Case Inches 28

29. New Case: No Temperature Nudging Base CaseNo Temp Nudging 29

30. Preliminary Conclusion OBS nudging too strongly produces too much precipitation, without changing performance vs. independent data. 30

31. Taken from Base Case 37 Vertical Levels NOAH LSM YSU PBL RRTMG shortwave & longwave radiation Thompson Moist Physics KF Cumulus on 36 & 12km –kfeta_trigger = 2 –No shallow Cu (not tied to deep convection) Light OBS nudging of Winds, Temp, and Humidity ENVIRON/UNC WRF Recommendations 31

32. Thanks for listening! Questions? Discussion? Bart Brashers bbrashers@environcorp.com Jared Heath Bowden jhbowden@email.unc.edu jhbowden@email.unc.edu