60-43 Vertical Alignment of Ice Crystals as an Indicator of Storm Cloud Electrification: Insights from Polarimetric Radar Signatures

Session: 2YC and 4YCU Geoscience Student Research Poster Showcase

Presenting Author:

Authors:

Abstract:

Polarimetric radar signatures resulting from the electrostatic alignment of ice crystals offer promising yet underutilized opportunities to quantify cloud electrification in atmospheric science. Building on conceptual models of ice alignment in electric fields—alongside recent advances in high-temporal-resolution radar detection—this study investigates the potential of using polarimetric radar variables, specifically specific differential phase (KDP) and co-polar correlation coefficient (CC), as indirect indicators of storm electrification. KDP reflects the rate of change in phase shift between horizontally and vertically polarized radar waves, while CC indicates the similarity between those two polarized returns.

To support this approach, we offer an illustrative framework for how ice crystals can align under electric fields, an area where physical modeling remains limited. We also present distinct KDP and CC signatures from an S-band WSR-88D radar, observed both before and after lightning events.

Radar analyses were conducted using Gibson Ridge Analyst (GR2Analyst) software to cross-reference archived NEXRAD Level II data from a pulse-type convective storm observed by the KSJT radar near San Angelo, TX (January 26, 2024), with time-synchronized lightning discharge records from the West Texas Lightning Mapping Array (WTLMA). We observed a significant accumulation of negative KDP values accompanied by decreasing CC values prior to lightning discharge—indicative of increased particle diversity and electrostatic alignment of ice crystals. Following the lightning events, KDP and CC rapidly returned to typical baseline values.

The correlation observed between negative KDP and reduced CC signatures preceding lightning events supports their potential use as reliable precursors in lightning prediction. Incorporating these polarimetric features into forecasting models could lead to earlier and more accurate lightning warnings—enhancing public safety, protecting critical infrastructure, and reducing costly disruptions. This has far-reaching implications for lightning-prone communities, aviation operations, space launch systems, and power grid reliability. The importance of such applications will only grow as radar technology evolves, particularly with the expected deployment of Polarimetric Phased Array Radar, which offers higher temporal resolution and broader coverage. Future modeling efforts using polarimetric radar will also help identify the specific ice crystal aggregates responsible for these polarimetric signatures.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-9639

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