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On the relationship of in-cloud convective turbulence and total lightning

On the relationship of in-cloud convective turbulence and total lightning. Wiebke Deierling, John Williams, Sarah Al- Momar , Bob Sharman, Matthias Steiner and Cathy Kessinger. Our Purpose.

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On the relationship of in-cloud convective turbulence and total lightning

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  1. On the relationship of in-cloud convective turbulence and total lightning Wiebke Deierling, John Williams, Sarah Al-Momar, Bob Sharman, Matthias Steiner and Cathy Kessinger

  2. Our Purpose • Examine possible relationships between lightning occurrence and turbulence production for different storm types • Examine relationships over CONUS first because of good data coverage • Extend examination to oceanic storms in the near future • If successful, GLM on GOES-R may provide valuable information for underserved regions to help identify regions of convective turbulence

  3. Background – Updraft and Lightning Turbulence Reflectivity 5.5 km MSL • Evidence that updraft volume correlates with total lightning • (Wienset al. 2005, Deierling et al. 2008) • Large updraft volumes of higher updraft speeds are capable of producing more hydrometeors in the mixed ice phase region, promoting electrification Turbulence + + Turbulence + − − − Question: How does convective turbulence relate to total lightning?

  4. Data Sets Used Height [km LMA Detected Lightning Time [ms] • In-Cloud and Cloud-to-Ground Lightning: • Measured by Lightning Mapping Array (LMA) at New Mexico and Northern Colorado • Turbulence intensity: • NEXRAD Turbulence Detection Algorithm (NTDA) Eddy Dissipation Rate (EDR) • Radar reflectivity: • NTDA mosaic Height [km LMA Flash Extent North-South Distance [km] NTDA EDR NTDA Turbulence East-West Distance [km] Height [km PID NTDA Reflectivity

  5. Higher Turbulence and lightning • in upper levels of cloud. • Highest turbulence above highest • lightning VHF sources above • highest radar reflectivity. EDR – light-moderate-severe color scale EDR Growing Air Mass Storms at 21:55UTC LMA 3D lightning Radar Reflectivity

  6. EDR EDR – light-moderate-severe color scale Mature Air Mass Storms at 22:20UTC LMA 3D lightning Radar Reflectivity Radar Reflectivity

  7. Decaying Air Mass Stormsat 23:20UTC EDR EDR – light-moderate-severe color scale LMA 3D lightning Radar Reflectivity

  8. Horizontal LMA Flash Extent Radar reflectivity volume>35 dBZfor T<0C EDR Volumes for T<0C Blue: EDR>0.15Red: EDR>0.3 (multiplied by 5) LMA Flash Extent [fl/km2] Refl. Vol. [km3] EDR Volume [km3]

  9. Variations by Lifecycle Total Lightning vs. Z>35dBZ volume for T<0C Total Lightning vs. EDR>0.3 volume for T<0C r=0.75 r=0.87 Developing storm Mature storm EDR Volume of EDR>0.3 [km3] Refl. Vol. of Z>35dBZ [km3] Decaying storm LMA Flash Extent [fl/km2] LMA Flash Extent [fl/km2]

  10. Horizontal Cross-Section with Height • During growth period of storms, the turbulent regions tend to: • Have a larger area of MOD turbulence at higher levels within storms • Are horizontally aligned (not necessarily vertically aligned) with lightning regions EDR FL 150 EDR FL 330 Reflectivity 5.5 km MSL Extreme Extreme Severe Severe Moderate Moderate Light Light EDR values at different height levels and horizontal lightning extent contours (magenta).

  11. Best correlation for total EDR volumes for EDR values >0.16-0.22 • New Mexico air mass storms, total lightning correlates best to light-moderate turbulence at FL300-400 R=0.89 Total Ltg & EDR volume>0.2 of Air Mass Storms in New Mexico over 2 weeks EDR Volume of EDR>0.2 5 min Total Lightning

  12. Higher turbulence regions often • above highest VHF source • densities above highest radar • reflectivity NTDA Radar Reflectivity CO Severe Storms – Mature Stage LMA 3D lightning NTDA EDR

  13. Severe storm cells on 27 May 2013 • SPC reports of several tornadoes, 1 inch hail, and 60 knot winds NTDA Radar Reflectivity Severe Storms – CO LMA 3D lightning NTDA EDR

  14. Severe Storms – CO Time –Height histograms VHF sources 35 dBZ Refl. Flash Extent [fl/km2] Refl. Vol. > 35dBZ [km3] EDR>0.15 EDR>0.3 EDR>0.15 EDR>0.3 EDR Volume [km3] EDR>0.4 Time [UTC] Time [UTC]

  15. Summary & Outlook • Higher lightning frequencies relate to higher turbulence intensities • Most storms exhibited charge centers in between the maximum reflectivity cores and peak turbulence during a storms mature stage • Regions of higher EDR are horizontally collocated with higher flash extents for air mass storms • EDR and lightning relationship looks promising for air mass storms but more complicated for severe storms, needs more investigation • Look at more storm types, including oceanic storms • Compare with modeling studies

  16. Thank you!

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