2002 MM5 Model Evaluation 12 & 36 km Sensitivity Tests Chris Emery, Yiqin Jia, and Ralph Morris ENVIRON International Corporation Zion Wang UCR CE-CERT Western Regional Air Partnership (WRAP) Regional Modeling Center (RMC) National RPO Meeting May 25, 2004
Addition of 12-km WRAP Grid IC/BC’s extracted from 36-km MM5 fields 3-D FDDA fields extracted from 36-km MM5 fields Preliminary 5-day run starting 12Z July 1
Subdomains for 12-km Model Evaluation 1 = Pacific NW 2 = SW 3 = North 4 = Desert SW 5 = CenrapN 6 = CenrapS 7 = Great Lakes 8 = Ohio Valley 9 = SE 10 = NE 11 = MidAtlantic
2002 MM5 12 km Sensitivity Tests Tests with 12-km grid: Run 1 (initial simulation): Soil moisture nudging on Initial soil moisture from 36-km output 3-D FDDA from 36-km output (no 2-D surface FDDA) No Obs FDDA Run 2: Soil moisture nudging off Initial soil moisture from LANDUSE.TBL 3-D FDDA from 36-km output Observational FDDA from NCAR DS.472
2002 MM5 12 km Sensitivity Tests Run 3: Soil moisture nudging off Initial soil moisture from 36-km output 3-D FDDA from 36-km output Obs FDDA from NCAR DS.472 Run 4: Initial soil moisture from 36-km EDAS fields 3-D FDDA from 36-km EDAS fields
2002 MM5 12 km Sensitivity Tests Overall: No significant impact on wind speed/direction performance in any run Focus on temperature & humidity performance Run 2 (soil nudging off, default moisture, Obs FDDA): Best performance in Desert SW, but worst in other regions Run 3 (soil nudging off, Obs FDDA): Performance slightly improved in all 3 regions
2002 MM5 12 km Sensitivity Tests Run 4 (soil nudging off, EDAS moisture, EDAS + Obs FDDA): Similar to Run 3, but even better performance in Desert SW Removing soil moisture nudging has a positive impact on performance Using EDAS to provide initial soil moisture and analysis FDDA (instead of 36-km MM5 results) has a positive impact on performance Obs FDDA has negligible impact on performance
2002 MM5 36 km Sensitivity Tests Tests with 36-km grid: Run 0 (initial simulation): Soil moisture nudging on 3-D & 2-D nudging to EDAS enhanced with NWS observations Cumulus parameterization is KF LSM/PBL is P-X Run 1: Soil moisture nudging off
2002 MM5 36 km Sensitivity Tests Run 2: Soil moisture nudging off Cumulus parameterization changed to KF II (based on comparison to VISTAS results) Run 3: LSM/PBL changed to NOAH and modified-MRF (removal of “scaled virtual temperature excess” and “convective velocity” contribution in U* calculation)
2002 MM5 36 km Sensitivity Tests Overall: No significant impact on wind performance, generally sensitivity cases slightly reduce speed Focus on temperature & humidity performance Run 1 (soil nudging off): No significant impact in Desert SW Improved performance in SW Mixed performance in Pacific NW Run 2 (KF II): Similar results to Run 1 in SW and Pacific NW Good improvement in Desert SW
2002 MM5 36 km Sensitivity Tests Run 3 (NOAH + modified MRF): Best overall performance in Desert SW Worst performance in SW and Pacific NW Summary: Soil moisture nudging is generally a negative attribute KF II helps performance where most convection occurs Moving to a different LSM/PBL combo is not a universally good idea
New 36/12 Nested Sensitivity Test Run 5: 2-way nesting No soil moisture nudging KF II P-X LSM/PBL Wind performance similar to all other runs in all regions Similar temperature & humidity performance to other tests in SW and Pacific NW Best temperature & humidity performance of all runs in Desert SW
New 36/12 Nested Sensitivity Test Run 5 forms basis for revised 2002 36/12 WRAP simulations Identical physical configuration 1-way grid nesting (2-way set up but no feedback) Adds 2-D surface nudging on 12-km grid to EDAS enhanced with NWS observations