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BNF Deep Convection

Kyra Britton (UAH)

Rebecca Weinstein (UVA)

Melissa Zavaleta (Florida Institute of Technology)

Angel Chui (UW)

Scott Giangrande (Brookhaven National Lab)

Max Grover (Argonne National Lab)

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ARM Summer School at Bankhead National Forest 2025

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Vertical Velocity in Deep Convection (bnf-deep-convection)

  • Science question(s): What are updraft velocities in a deep convective cell in different environments (and/or how does it relate to surface precipitation rates) as derived from precipitation radars?
  • Project Scope (what does success look like)? Analysis of convective case from 2 different locations for comparison.
    • Case studies running multi-Doppler analyses
    • Track deep convective updraft structures
      • Max updraft speed, updraft area, vertical structure of convective cell, cold pool evolution
  • Datasets:
    • CSAPR (+CHIVO or ARMOR) data from TRACER, SGP, CACTI, BNF?
      • Cases: March 15, March 31, May 20 2025
    • GOES Data - Look at storm top characteristics
      • Track using mesoscale domain sector
    • Would need a wind synthesis routine (SAMURAI, Py_dda, etc.)
  • Team Members: Brenda, Scott Giangrande(@ScottGiangrande), Max Grover (@mgrover1), Angel Chui (@abchui), Melissa Zavaleta (@melissazavaleta), Rebecca Weinstein (@becca260), Kyra Britton (@kgbritton)
  • Github Repository Link: bnf-deep-convection

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Case Study: April 1, 2023

(multicellular convection)

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  • April 1, 2023
  • Threshold of 3, 5, and 10 m/s
  • Running tobac with the maximum vertical velocity first
  • Found a 10 m/s cell close to the strongest updrafts

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  • Strong in the mid-height levels
  • Weakens over the 3 time stamps

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  • Cell was strong, tracked above the threshold for all 5 time stamps
  • Stronger vertical velocity in the upper levels
  • Gains strength in the mid-heights, weakens, then strengthens again

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Case Study: May 20, 2025

(the tornadic supercell)

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Radar Analysis

C-SAPR:

NEXRAD:

Reflectivity

Velocity (raw)

Velocity (corrected)

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Divergence analysis

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Brightness Temperature Analysis

  • Colder Brightness Temperature (BT) values allow us to locate the updraft

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Vertical Velocity Analysis

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Case Study: May 10, 2025

(multicellular convection)

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Cold Pool Analysis

Improve understanding of QLCS cell structure and associated dynamical processes by using radar data to visualize cold pools

GOES satellite imagery courtesy of John Rausch

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Quasi Vertical Profiles (QVP) and Columnar Vertical Profiles (CVPs)

Ryzhkov, A., P. Zhang, H. Reeves, M. Kumjian, T. Tschallener, S. Trömel, and C. Simmer, 2016: Quasi-Vertical Profiles—A New Way to Look at Polarimetric Radar Data. J. Atmos. Oceanic Technol., 33, 551–562, https://doi.org/10.1175/JTECH-D-15-0020.1.

A QVP or CVP is a method to average full or sectors of radar volumetric data to get a quasi time-height time-series to compare against profiling ARM instruments.

Figures courtesy of Scott Giangrande

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Quasi Vertical Profile (QVP)

Notebook/ode for plots courtesy of Mindy Deng

Contributors: Scott Collis, Scott Giangrande

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Cold Pool Passage and tie-ins with Team ACID

M1 site CVP Sector (210-230) @ 7 deg

Possible cold-pool passage on 10 May 2025

We sample the insects kicked up by the cold pool in ZDR reflecting the change in air mass at M1 prior to the precipitation.

SMPS plot courtesy of ACID team