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Applications of Lightning Data to Tropical Cyclone Intensity Forecasting

Applications of Lightning Data to Tropical Cyclone Intensity Forecasting. Mark DeMaria NOAA/NESDIS/StAR, Fort Collins, CO Robert T. DeMaria CIRA/CSU, Fort Collins, CO. Lightning in the Eye of Hurricane Felix (2007). Picture courtesy of Richard Henning, from the Air Force Reserve C-130.

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Applications of Lightning Data to Tropical Cyclone Intensity Forecasting

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  1. Applications of Lightning Data to Tropical Cyclone Intensity Forecasting Mark DeMaria NOAA/NESDIS/StAR, Fort Collins, CO Robert T. DeMaria CIRA/CSU, Fort Collins, CO

  2. Lightning in the Eye of Hurricane Felix (2007) Picture courtesy of Richard Henning, from the Air Force Reserve C-130

  3. Outline • The GOES-R Geostationary Lightning Mapper • Lightning data available for tropical cyclone studies • Summary of previous TC lightning studies • Analysis of large TC data sample from the WWLLN • Lightning and TC genesis

  4. Geostationary Lightning Mapper (GLM) on GOES-R • GOES-R will include a geostationary lightning mapper (GLM) • Will provide nearly continuous total lightning counts over most of the GOES-E and GOES-W field of view • Higher detection rates over tropical oceans than ground-based networks • Much better temporal resolution than polar satellite data

  5. Annual Lightning Density Over GOES Coverage Area* Reference: *From OTD/LIS instruments, slide provided by Steve Goodman

  6. Lightning Data for Hurricane Studies • Satellite • Lightning Imaging Sensor (LIS) on TRMM • Provides total lightning to ~35oN • Low time resolution • Optical Transient Detector (OTD) • Provides total lightning to ~80oN • Low time resolution • Ground based • National Lightning Detection Network (NLDN) • Near continuous cloud to ground counts and polarity • Restricted to within ~500 km of U.S. • Long-range Lightning Detection Network (LLDN) • Additional stations extend NLDN coverage into Caribbean • World Wide Lightning Locator Network (WWLLN) • Sparse network with nearly global coverage, but low detection frequency

  7. Lightning Structure of Tropical Cyclones • Bi-modal radial structure • Max in eye-wall and rainbands, with min between • Eyewall lightning much more transient • Inner core lightning sometimes associated with intensification, but sometimes with eyewall replacement and weakening • Asymmetric structure related to environmental wind shear • Increase in lightning might be precursor to tropical cyclone genesis

  8. Radial Lightning Structure Reference: Convective Structure of Hurricanes as Revealed by Lightning Locations, Molinari et al 1999, MWR

  9. Lightning Time Evolution Reference: Convective Structure of Hurricanes as Revealed by Lightning Locations, Molinari et al 1999, MWR

  10. Rita and Katrina Inner Core Lightning Hurricane Rita Hurricane Katrina Fig. 3 Fig. 12 Reference: The Morphology of Eyewall Lightning Outbreaks in Two Category 5 Hurricanes, Squires and Businger 2008, MWR

  11. Vertical Shear and Lightning Structure Reference: The Effects of Vertical Wind Shear on the Distribution of Convection in Tropical Cyclones, Corbosiero and Molinari 2002, MWR

  12. Analysis of Large Data Sample • WWLLN provides nearly global lightning data • Low detection rate • Use only reprocessed data with new UW algorithm • 2005-2007 • Calibrated by making annual lightning density match that from the TRMM annual climatology • Adjustment factors: 2005 = 38, 2006 = 24, 2007 = 23 • Composite lightning over 6 hour intervals in storm-relative coordinates • Calculate lightning density on cylindrical grid • r = 100 km,  = 45o • Sample includes all Atlantic TCs with center over water for following 24 hr • 790 cases from 48 storms • Combine with SHIPS intensity model database • Includes SST, shear, etc

  13. LIS/OTD and WWLLN ComparisonAnnual Mean Lightning Density LIS/OTD Scaled 2007 WWLLN

  14. Lightning Density for Hurricane Felix 01 Sept. 2007 12 UTC – 03 Sept. 2007 21 UTC

  15. Mean Azimuthal Structure

  16. 0-100 km Lightning Density790 Atlantic Cases 2005-2007

  17. Top 10 Cases 0-100 km Lightning Density • Noel (3 cases), Starting extra-tropical transition • Maria (1 case), Starting rapid intensification • Philippe (3 cases), dissipating due to shear • Irene (1 case), initial formation • Ingrid (1 case), dissipating due to shear • Ernesto (1 case), weakening due to shear • All of top 10 were TS intensity (35 to 60 kt) • Only 3 of 10 intensified in the following 24 hr

  18. Correlation of Lightning Density and 24, 36, 48 hr Intensity Change

  19. Correlation of Vertical Shear and Lightning Density

  20. Vertical Shear vs. 0-300 km Lightning Density Low shear regime High shear regime

  21. Use of Lightning for Intensity Forecasting • Determine vertical shear • For high shear regime • May be indicator of extra-tropical transition (high latitude) or dissipation (low-latitude) • For low shear regime • Use multiple correlation that includes shear and lightning density • Shear variable accounts for negative relationship • High shear > increased lighting > less intensification • Isolates positive relationship between lightning and intensification

  22. Partial Correlation Coefficients for Prediction of 48 Intensity Change with Lightning Density and Shear

  23. Discrimination of Rapid Intensification Cases • RI defined by max wind increase of 25 kt or more in next 24 hr • Kaplan and DeMaria (2003) definition • ~90th percentile • One of NHC’s primary forecast problems • Stratify sample into RI and non-RI cases • Total sample • Low-shear regime cases

  24. Lightning Density for RI and non-RI Cases Total Sample Low-Shear Cases

  25. Lightning and TC Genesis Reference: East African Lightning as a Precursor of Atlantic Hurricane Activity, Price et al 2007, Geophysical Research Letters

  26. 4 3 2 1 Lightning Regions for WWLLN TC Genesis Study Main Development Region

  27. 2004 Lightning Density and TC Genesis Time Series

  28. Summary • GOES-R will include the GLM • WWLLN data provides large data sample for TC lightning studies • Max lightning density near the storm center • Weak positive correlation with intensity change • Vertical shear/lightning relationship is nonlinear • Positive correlation in low shear regime • Negative correlation in high shear regime • Lightning correlation with intensity change enhanced in low shear regime • Max correlation at 200-300 km radius • Lightning density is discriminator of rapid intensity change, especially in the low shear regime

  29. Future Work • Add 2008 and east Pacific to data sample • Examine lightning asymmetry • Develop version of operational SHIPS intensity model and related RI index with lightning input • Possible tests in GOES-R satellite proving ground • Extend work to TC genesis

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