1. Radar Refractivity: validation and application to forecasting
Crystalyne R. Pettet, Tammy M. Weckwerth, and James W. Wilson—NCAR/ATD
Frédéric Fabry and ShinJu Park—McGill University

2. Validation

3. Sfc comparisons
S-Pol N varies most strongly with moisture

4. High correlation between S-Pol N and station N
Sfc comparisons
High correlation between S-Pol N and station N

5. S-Pol N compares favorably with areas of relatively constant mobile N
Mobile mesonets
S-Pol N compares favorably with areas of relatively constant mobile N

6. S-Pol N gradients are smoothed
Mobile mesonets
S-Pol N gradients are smoothed

7. UWKA S-Pol N gradient smoothed over ~10 km
S-Pol N compares favorably with areas of relatively constant UWKA N

8. AERI—Atmospheric Emitted Radiance Interferometer

9. AERI
Transition between m from high to low r values

10. P-3
If CBL is well-mixed, N represents at least half the depth of the CBL.

11. AERI—diurnal and height differences
N bias is strongest at night and improves with mixing of CBL
Strongest relationship occurs at low levels

12. AERI—diurnal and height differences
Low levels—strong relationship from one hour after sunrise until 2 hours after sunset
Increasing height—strong relationship begins later in the morning and drops off by 2200 UTC

13. Soundings
Similar results to AERI—lowest m

14. SRL
Strong correspondence between SRL mixing ratio magnitude, surface station mixing ratio, and S-Pol N

15. Forecasting Utility

16. Boundary development

17. CI—10 June 2002

18. CI— 10 June 2002

19. CI—12-13 June 2002

20. CI— June 2002

21. Summary
Radar refractivity shows excellent correlation with refractivity calculated from other datasets
Vertical depth represented by radar refractivity is typically below m AGL, but may be dependent upon the extent of vertical mixing
Horizontal scale of refractivity varies, and appears to be as high as 2 km at times and lower than 4 km at other times

22. Summary
Radar refractivity shows great promise as a potential nowcasting and forecasting tool

23. For more information…
Contact me at to get a pdf of the manuscript that has been submitted to JAM that this talk is based on.