1 / 25

Airborne Radar Observations of Atlantic Tropical Cyclones

Airborne Radar Observations of Atlantic Tropical Cyclones. Jennifer DeHart 09.21.11. Motivation. Andrew: $26.5 billion in damage Katrina: 1200 deaths, $108 billion in damage. Adam Willemssen. National Hurricane Center. Forecast error. National Hurricane Center.

beau-hull
Download Presentation

Airborne Radar Observations of Atlantic Tropical Cyclones

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. Airborne Radar Observations of Atlantic Tropical Cyclones Jennifer DeHart 09.21.11

  2. Motivation Andrew: $26.5 billion in damage Katrina: 1200 deaths, $108 billion in damage Adam Willemssen National Hurricane Center

  3. Forecast error National Hurricane Center

  4. Basic Axisymmetric Eyewall Structure Willoughby 1998

  5. Eyewall Asymmetries • Potential Causes • Gradient of f • Storm Track • Environmental Moisture Distribution • Vertical Shear Black et al., 2002 Braun et al., 2006 Chen et al., 2006

  6. UL DL UR DR Black et al., 2002 modified by Houze 2009

  7. Quantifying Vertical Structure • Deanna Hence studied satellite data from TRMM • Snapshots of radar reflectivity • 10+ years of data • Contoured by Frequency Altitude Diagrams (CFADs)

  8. Height (km) Reflectivity (dBZ) Hence and Houze 2011

  9. Hence and Houze 2011

  10. Statistics to Dynamics • Can we relate vertical structure of reflectivity to dynamics? • Aircraft Observations • 3-D reflectivity, thermodynamics, winds

  11. GRIP • August 15th – September 30th, 2010 • Aircraft: DC-8, Global Hawk, WB-57 • Data collected: Radar, dropsondes • APR-2: Ka and Ku band

  12. RAINEX • September – August 2005 • Hurricanes sampled • Katrina, Ophelia, Rita • P3 Tail and ELDORA Radars • X band

  13. Hurricane Katrina – 8.28.05 • Data from 17-23Z • Rapidly Intensified to Category 5 by 12Z • Peak Intensity of 150 kt at 18Z • Weakened, made landfall as Category 3 at 11Z on 8.29.05 • Shear shifted from SE toESE with constant speedof 4 m/s. National Hurricane Center

  14. Shear

  15. Conclusions So Far: Katrina’s Structure vs. TRMM • Consistent with statistics • Eyewall echoes stronger and taller downshear • Low-level DL echoes have more variability than DR • Upshear quadrants dominated by weak echoes at high altitudes • Differences related to intensity/shear • Modal distributions upshear on high end

  16. Future Plans • Extend shear analysis to other fields • Thermodynamics, vertical wind shear • Dropsondes • 3D Wind • Doppler analysis of radar data • Subdivide storm into eyewalls, concentric eyewalls, rainbands • Focus on Katrina (2005), Rita (2005) and Earl (2010)

  17. GRIP Flight Plan

  18. Doppler Analysis NOAA HRD

  19. Future Plans • Extend shear analysis to other fields • Subdivide storm into eyewalls, concentric eyewalls, rainbands • Focus on Katrina (2005), Rita (2005) and Earl (2010) • All major storms

  20. Thank you! • Dr. Houze • Stacy Brodzik • Housemates/Grads10+Kirsten • Mesoscale Group Felipe

  21. References • Black, M. L., J. F. Gamache, F. D. Marks, C. E. Samsury, and H. E. Willoughby, 2002: Eastern Pacific Hurricanes Jimenaof 1991 and Olivia of 1994: The effect of vertical shear on structure and intensity. Mon. Wea. Rev., 130, 2291–2312. • Braun, S. A., M. T. Montgomery, and Z. Pu, 2006: High-resolution simulation of Hurricane Bonnie (1998). Part I: The organization of eyewallvertical motion. J. Atmos. Sci., 63, 19–42. • Chen, S. Y. S., J. A. Knaff, and F. D. Marks, 2006: Effects of vertical wind shear and storm motion on tropical cyclone rainfall asymmetries deduced from TRMM. Mon. Wea. Rev., 134, 3190–3208. • Corbosiero, K. L., and J. Molinari, 2002: The effects of vertical wind shear on the distribution of convection in tropical cyclones. Mon. Wea. Rev., 130, 2110–2123. • Houze R. A., 2010: Clouds in tropical cyclones. Mon. Wea. Rev., 138, 293–344.

  22. Effects of Shear • Azimuthal distribution of vertical motion, lightning, reflectivity and rainfall • Asymmetries maximized downshear • Inner core: left of shear • Outer bands: right of shear • Vortex tilted Braun et al., 2006 Chen et al., 2006 Corbosiero and Molinari 2002 Corbosiero and Molinari 2003

  23. Mesovortices • Occur along inner edge of eyewall reflectivity • Instability of axisymmetric annulus of vorticity Braun et al., 2006

  24. Braun et al., 2006

More Related