1. Oct 20081 October 2008 An update provided by Thomas Nehrkorn Atmospheric & Environmental Research, Inc. 131 Hartwell Ave Lexington, Massachusetts 02421 www.aer.com High-resolution WRF runs for NACP

2. Atmospheric and Environmental Research, Inc. Introduction Provide overview of available WRF fields Generated at NASA Columbia supercomputer facility Funding provided by NASA and NOAA Provide overview of verification procedure and sample verification results Discuss future plans Oct 2008 2

3. Atmospheric and Environmental Research, Inc. Overview of Time periods and Domains 2004 and 2006: 5-domain setup: 40km, 10km, 3@2km resolution 2005: 2-domain setup: 40km and 10km 2007: 2-domain setup: 40km and 10km (extended further west) Oct 2008 3

4. Atmospheric and Environmental Research, Inc. WRF domains used for 2004 and 2006 40km: 207x192 10km: 349x357 (encloses d03-d05) 2km: 251x251 (Moody, WLEF, and Argyle) Oct 2008 4

5. Atmospheric and Environmental Research, Inc. WRF domains used for 2005 40km: 207x192 10km: 393x357 (extended W for OK/CO sites) Oct 2008 5

6. Atmospheric and Environmental Research, Inc. WRF domains used for 2007 40km: 207x192 10km: 521x357 (extended W to CA) Oct 2008 6

7. Atmospheric and Environmental Research, Inc. WRF runs setup Using WRF v2.2 Customized to provide: Time-averaged mass-coupled winds, convective fluxes NARR input used for I.C. and B.C. 30-hr Forecasts, initialized every 24 hr (00 UTC) Use hours 7-30 from each forecast (avoid spin-up) Outer domain uses analysis nudging to NARR Inner domains use 1-way nesting Hourly output Netcdf (WRF native format), all fields archived ARL (compressed, STILT-compatible) Oct 2008 7

8. Atmospheric and Environmental Research, Inc. WRF runs verification Winds: using WRF/STILT to colocate: WRF winds as determined from short-term trajectory computation Raob winds at selected pressure levels 925, 850, 700, 500, 400, 300 hPa PBL heights: Profilers: TEXAQS (2006) and ICARTT (2004) Raobs: derived from T,q,u,v using WRF/STILT to colocate: PBL heights computed by STILT from WRF T,q,u,v PBL heights computed by WRF Oct 2008 8

9. Atmospheric and Environmental Research, Inc. Raob winds results: effects of nudging For May-Aug 2004, compare: WRF v2.2 fields with nudging (case06, 40km) WRF v2.1.2 fields without nudging (case09, 40km) Fields generated during earlier work for Argyle tower simulations Result show effectiveness of nudging in limiting error growth Oct 2008 9

10. Atmospheric and Environmental Research, Inc. Raob winds results: outer / inner domains Results shown for June-July-August 2004: d01 and d02 compared against identical Raobs Oct 2008 10

11. Atmospheric and Environmental Research, Inc. Raob winds results: outer / inner domains Results shown for June-July-August 2004: d03-d05 have 1-3 Raobs inside domain Oct 2008 11

12. Atmospheric and Environmental Research, Inc. Raob winds results: outer / inner domains Wind errors generally larger in nested domains Nudging only through B.C. from outer domain Smaller scales get penalized by point statistics Error growth from 12-24 hours evident (viz. jja_d04 in previous slide), but not uniformly at all seasons/domains/levels Colocations have been performed for all domains, and all years: 2004 and 2006: subsampled forecasts (~1/3) 2005 and 2007: all forecasts Oct 2008 12

13. Atmospheric and Environmental Research, Inc. PBL height verification Ongoing. Preliminary results: WRF/STILT PBL heights tend to be overestimates Errors are comparable for d01, d02, and d03 Oct 2008 13

14. Atmospheric and Environmental Research, Inc. PBL height verification Sample time series of simulated/observed: Simulated values only shown for hours with obs Oct 2008 14

15. Atmospheric and Environmental Research, Inc. Future Plans Characterization of uncertainties Characterize transport uncertainties based on Raob wind-colocation error statistics Characterize PBL height bias and random errors Extend PBL height verification: Extend to ICARTT 2004 profiler data Cross-compare against Raob-derived PBL heights Extend WRF runs to additional time periods Use existing setup Oct 2008 15

16. Atmospheric and Environmental Research, Inc. Future Plans - continued Pending NSF project: Upgrade to WRF v3, explore different physics options, evaluate impact on WRF fields Outstanding issue: Handling of nested domains in STILT A single particle exiting inner-most domain causes switching to coarser domain for all particles We will evaluate the feasibility of importing relevant upgrades from HYSPLIT to STILT Oct 2008 16