1 / 14

Robert Rogers and Sundararaman Gopalakrishnan NOAA/AOML Hurricane Research Division

The impact of horizontal resolution on the structure and intensity of Hurricane Dennis in HWRF TM simulations. Robert Rogers and Sundararaman Gopalakrishnan NOAA/AOML Hurricane Research Division Miami, FL 33149. Motivation. 45% reduction in 15 yr. 17% reduction in 15 yr.

shelly
Download Presentation

Robert Rogers and Sundararaman Gopalakrishnan NOAA/AOML Hurricane Research Division

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. The impact of horizontal resolution on the structure and intensity of Hurricane Dennis in HWRFTM simulations Robert Rogers and Sundararaman Gopalakrishnan NOAA/AOML Hurricane Research Division Miami, FL 33149

  2. Motivation 45% reduction in 15 yr 17% reduction in 15 yr • Improvements in intensity forecasts have lagged improvements in track forecasts Annually-averaged NHC 48-h forecast errors from 1990 to 2005 Track Intensity • Numerical model guidance can be key contributor to intensity forecasts, but it faces challenges • resolution • initial TC vortex • physical parameterizations

  3. Motivation Courtesy NRL Monterey • Rapid intensification (RI) – defined as 30-kt increase of peak winds in a 24-h time period convective bursts • Enhanced IR valid 0315 UTC October 17 2005 • 30-kt Tropical Depression 24 • RI began 14 h later, becoming Hurricane Wilma • Multiscale process • environment – O(1000 km) – troughs, anticyclones • vortex – O(1-100 km) – VRWs, eyewall, rainbands • convection – O(1 km) – convective cores, VHTs • turbulence – O(10-100 m) – PBL, detrainment • microscale – O(1 mm) – hydrometeor production, latent heat

  4. Questions to consider • To get improved predictions of RI, how important is it to adequately represent (resolve) the features mentioned above? • Is it sufficient to parameterize them? • Are lower-resolution ensemble approaches preferable?

  5. Approach • simulate with HWRFTM a case of observed RI • Hurricane Dennis (2005) • period of RI beginning at 18 UTC July 6 • run two cases • operational grid length of 27:9 km • higher-resolution run at 9:3 km • two-way interactive movable mesh • GFDL initial conditions, GFS forecast boundary conditions, GFDL/GFS physics • no ocean coupling, no GSI • no convective parameterization on 3 km grid • models initialized at 00 UTC July 6

  6. 7/9 7/8 7/7 7/6 RI period 7/5 Dennis Observed Track and Intensity Track Intensity

  7. Results 27-h animation of 850 hPa model-derived reflectivity TM TM 27-9 km run 9-3 km run

  8. 9-3 km 27-9 km Best track 7/7 7/7 7/7 7/6 Results Intensity Track

  9. Results TM TM dBZ dBZ NOAA P-3 radar 0045-0144 UTC 7 July 27-9 km run 9-3 km run kt

  10. Results dBZ dBZ kt kt 27-9 km run 9-3 km run TM TM Reflectivity and MSLP TM TM Winds

  11. Results dBZ dBZ X 10-4 s-1 X 10-4 s-1 27-9 km run 9-3 km run TM TM Reflectivity and MSLP TM TM Vorticity

  12. Summary • 9-3 km run better able to produce vortex structures • distribution of convection • wind distribution and structure • vorticity • not sure about convective structure yet • Despite this better representation of vortex structure, intensity forecast not significantly improved • track problems • vortex initialization • physical parameterizations • still insufficient resolution

  13. Future work • evaluate differences in convective structures between two runs • vertical motion, hydrometeor, reflectivity profiles and distributions • expand tests to more Dennis forecast cycles, more cases • perform direct and statistical comparisons of vortex and convective structures with observations • ensemble runs at 9 km vs. deterministic runs at 3 km • initial condition variations • physics diversity • try runs at 1 km

  14. Time-height mean profiles of 1.67-km MM5 simulation of Dennis level of peak upward motion stratiform convective vertical motion bursts bursts vorticity bursts bursts

More Related