Evaluation of several WRF/NMM-CMAQ vertical coupling configurations

1. Evaluation of several WRF/NMM-CMAQ vertical coupling configurations Pius Lee, Jeff McQueen, Marina Tsildulko, Geoff DiMego Sarah Lu and Bert Katz NOAA/NCEP Environmental Modeling Center Rohit Mathur, Hsin-Mu Lin, Daiwen Kang, Tanya Otte, Jon Pleim, George Pouliot, David Wong, Jeff Young, and Ken Schere U.S. EPA/ORD/ASMD and NOAA/OAR/ARL

2. PT η1= 0; η2= 0 Pressure domain PDT+PT η1= 1; η2= 0 Sigma domain η1= 1; η2= 1 ground HYBRID WRF/NMM Hybrid Coordinate Upper-levels Pressure Lower-levels σ-p Lin et al, Poster Session 3.1

3. WRF/NMM h’s limited to 0-1 Jacobian across the -p interface Lin et al, Poster Session 3.1

4. Remarks on the hybrid layer cases • (22L) 22 layers: Choose model layers aligned close to those used in the current National Air Quality Forecast System (AQFS). 14 lowest layers spanned ~ 2 km • *(29L) 29 layers: Finer resolution than (a) in lowest 500m; top of PBL; and near tropopause. • (40L) 40 layers: As fine as the met model for lowest 3.5 km. *29L result rather similar to that of 22L

5. Hybrid (a) 22L, (b) 29L, and (c) 40L

6. O3 episode (h max) Aug 3rd, 2006

7. 22L-40L 40L reduced low bias for regions near Bakersfield 40L reduced high bias for regions near mid Long Island

8. Spatial verification for 22L

9. Spatial verification for 40L

10. Spatial verification for 40L Cross section on Mid Long Island, NY Cross section on Central Valley, CA

11. Bakersfield 1 pm Local O3 S N W E PBL and Kz descriptions with less interoplation error S E N W

12. Bakersfield 1 am local O3 N W S E Resolves inversion better, retains more residual O3 S W E N

13. Bakersfield 1 pm Local NOy S N W E Industrial plume from south. S N W E

14. Bakersfield 1 am local NOy N E S W Lower diffusivity Resulted in relatively un-dispersed plume heading eastward S N W E

15. Bakersfield 1 pm Local Formaldehyde S N W E A more concentrated plume of VOC and biogenic product coming from Southwest E S N W

16. Bakersfield 1 am local Formaldehyde S N E W Better description of residual and surface layers S N W E

17. Bakersfield 1 pm Local CO N W E S S N W E

18. Bakersfield 1 am local CO N S W E Better description of inversion, increased surface level concentrations S N W E

19. Mid Long Island 4 pm local time O3 N W S E Decrease high bias for New York City Increased high bias for an offshore point to the south of Long Island S N W E

20. Mid Long Island 4 am local time O3 W E S N Stronger inversion resulted in higher concentration in residual layer S N W E

21. Mid Long Island 4 pm local time NOy N W E S Better description of PBL also better description of sea breeze return flow S N E W

22. NOy Mid Long Island 4 am local time S N W E Species such as PAN will contribute to elevated surface O3 upon sunrise S N W E

23. Mid Long Island 4 pm local time Formaldehyde S N W E Reduction of high bias near New York City for VOC and biogenic photochemical products S N E W

24. Formaldehyde Mid Long Island 4 am local time S W N E Maintains a less dispersed plume of sea breeze return flow S N W E

25. Summary • Three resolutions of a lower-levels σ-p terrain following and upper-levels pressure hybrid vertical co-ordinate systems have been tested: (a) 22L, (b) 29L, and ( c) 40L • 40L is superior in two challenging localities: • (1) Central Valley, CA: • Perennial inversion; and • Subsidence due to orographic and channel flows • (2) Long Island, NY: • Surrounding complex terrain and land-sea breezes • Future work: Derivation of an Optimal vertical structure • σ

26. 22L-29L

27. 29L-40L

28. Spatial verification for 29L

29. Definition based on a scatter plot b a d c

30. Definitions of measures

31. Categorical Statistics over 8/2-4, 2006

32. Mid Long Island 4 pm local time Surface SOx N E S W S N W E

33. Mid Long Island 4 am local time Surface SOx N E S W S N W E

34. Mid Long Island 4 pm local time Surface CO S N W E S W E N