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Literature Review:

Literature Review:. Stolz , D. C. , S. A. Rutledge , and J. R. Pierce (2015), Simultaneous influences of thermodynamics and aerosols on deep convection and lightning in the tropics, J. Geophys . Res. Atmos. , 120, doi:10.1002/2014JD023033. Kyle Hilburn AT740 April 16, 2019. Overview.

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Literature Review:

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  1. Literature Review: Stolz, D. C., S. A. Rutledge, and J. R. Pierce (2015), Simultaneous influences of thermodynamics and aerosols on deep convection and lightning in the tropics, J. Geophys. Res. Atmos., 120, doi:10.1002/2014JD023033. Kyle Hilburn AT740 April 16, 2019

  2. Overview • Subject: • Thermodynamics • Aerosols • Deep Convection • Lightning • Tropics • Datasets: • TRMM CF (PR + LIS) • 2004-2011 • Version 7 • GEOS-Chem-TOMAS • GFED3 biomass burning inventory • GEOS-Chem transport • TOMAS aerosol microphysics module • ERAi • Thermodynamic environment • Inflow swath to CFs • Main conclusions: • Higher CCN and NCAPE lead to stronger convection • WCD modules relationship • Inverse: greater TLD and H30 with shallower WCD High Flash Density 10,000 WCD 4.5-5 km 1,000 N40 (cm-3) 100 WCD 2-3.5 km 10 0.2 0.3 0.0 0.1 NCAPE (J kg-1 m-1) My cartoon summary of the paper, based on Figure 3 High Flash Density > 0.005 fl min-1 km-2 High FD area shifts right and gets smaller with increasing WCD Median WCD is 4.2 km

  3. Thermodynamic Hypothesis • Variability in lightning and convective intensity over continental and oceanic regions of tropics can be explained by differences in thermodynamic instability • Rutledge et al. 1992; Williams et al. 1992, 2002; Williams and Stanfill 2002; Williams and Sátori 2004 • Tropical land surfaces respond strongly to solar radiation; more energetic parcels ascend through deep BL and have less dilution via entrainment • Would expect more robust mixed phase microphysics and NIC over land

  4. Aerosol Hypothesis • Number of CCN significantly influences microphysical properties and vertical development • Rosenfeld and Lensky 1998; Rosenfeld 1999; Rosenfeld et al. 2008; … and many more • Aerosol-induced convective invigoration • High CCN environment hinders collision-coalescence warm rain process • Less offloading of condensate • More cloud water transported to mixed phase region • Latent heat release provides increased buoyancy and greater charge separation

  5. Warm Cloud Depth Hypothesis • WCD: distance between LCL and FL • WCD determines duration of ascent through warm phase region and time for collision-coalescence to operate • Deeper WCD: cloud liquid lost before reaching mixed phase region • Shallow WCD: more cloud liquid reaches mixed phase region • Very shallow WCD (outside tropics): time for aerosols to impact collision-coalescence too short to see sensitivity to aerosols

  6. ocean land Spatial Patterns Cloud Features Lightning Producing CFs Many LPCFs but low FD over Amazon ”Green Ocean” All cloud features - looks like precip map S. Hem. FD hotspots for southern S. Am. and Africa, Australia with few LPCFs - high flash rate storms Good correlation between H30 and FD …. Price and Rind not looking so bad! H30 FD NCAPE about same for ocean/land Aerosol CAPE Strong mean spatial correlation between N40 and FD Aerosol High WCD over Amazon, central Africa; lower over southern S. Am. and Africa, SE US, and Australia WCD

  7. Lightning/Height vs NCAPE, N40, and WCD • Results for lightning (left) and H30 (above) similar • Highest TLD for N40 > 1000 cm-3 and NCAPE > 0.15 J kg-1 m-1 • High FD retreats to highest NCAPE and N40 at deep WCD

  8. Land vs Ocean • Same WCD effect over land and ocean • Greater FD (left) and H30 (above) over land than ocean

  9. Partial Sensitivities • TLD has greater variability with N40 than NCAPE (except over oceans) • Slope with NCAPE roughly constant, but variable for N40 • Steepest slope for shallow WCD • Slope negative for low NCAPE, deep WCD, and high N40

  10. Shallow vs Deep Differences • Difference for shallow minus deep • Differences mostly > 0 • Maximum increases for higher NCAPE and higher N40

  11. Lightning/Reflectivity versus Aerosol • FD increases with H30 (below) • FD greater for greater N40 • Sensitivity decreases with decreasing N40 • VPRR vs CAPE, WCD, N40 (right) • Increase in reflectivity at given altitude for larger N40 • Largest change in VPRR for shallower WCD

  12. Summary and Conclusions • Highest flash rates (and highest 30 dBZ echo heights) associated with combination of high NCAPE, high N40, and shallower WCD • Reflectivity in mixed phase region 5.0-5.6 dB greater in polluted environment • Merged hypothesis for simultaneous roles of thermodynamics and aerosols influencing deep convection in tropics • Modulated by warm cloud depth

  13. Backup slides

  14. Land/Ocean Cloud/Lightning Histograms N40 different land/ocean, but NCAPE and WCD about the same

  15. Tables

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