Understanding the Relationships between Lightning, Cloud Microphysics, and Airborne Radar-Derived Storm Structure during Hurricane Karl (2010)

Abstract

This study explores relationships between lightning, cloud microphysics, and tropical cyclone (TC) storm structure in Hurricane Karl (16 September 2010) using data collected by the NASA DC-8 and Global Hawk (GH) aircraft during NASA's Genesis and Rapid Intensification Processes (GRIP) experiment. The research capitalizes on the unique opportunity provided by GRIP to synthesize multiple datasets from two aircraft and analyze the microphysical and kinematic properties of an electrified TC. Five coordinated flight legs through Karl by the DC-8 and GH are investigated, focusing on the inner-core region (within 50 km of the storm center) where the lightning was concentrated and the aircraft were well coordinated. GRIP datasets are used to compare properties of electrified and nonelectrified inner-core regions that are related to the noninductive charging mechanism, which is widely accepted to explain the observed electric fields within thunderstorms. Three common characteristics of Karl's electrified regions are identified: 1) strong updrafts of 10-20 m s 21 ,2) deep mixed-phase layers indicated by reflectivities .30 dBZ extending several kilometers above the freezing level, and 3) microphysical environments consisting of graupel, very small ice particles, and the inferred presence of supercooled water. These characteristics describe an environment favorable for in situ noninductive charging and, hence, TC electrification. The electrified regions in Karl's inner core are attributable to a microphysical environment that was conducive to electrification because of occasional, strong convective updrafts in the eyewall.

An Electrical and Polarimetric Analysis of the Overland Reintensification of Tropical Storm Erin (2007)

“…This CE is comparable to hot towers observed within the eyewalls of Hurricanes Dennis (2005; Guimond et al 2010), Rita (2005Fierro et al 2011), andKarl (2010;Reinhart et al 2014). 36 dBZ often reached 11 km, suggesting the presence of deep convective updrafts.…”

Simulation of Chemical Transport by Typhoon Mireille (1991)

“…The most intense simulated convection (Figure 3a) is in the eyewall (> 50 dBZ), while the eye region exhibits minimal reflectivity (< 5 dBZ). Furthermore, the strongest simulated updrafts in Mireille's eyewall exceed 10 m/s in d03 (not shown) which is consistent with previous TC studies (e.g., Allison et al, 2018;Reinhart et al, 2014).…”

The Role of Observed Environmental Conditions and Precipitation Evolution in the Rapid Intensification of Hurricane Earl (2010)

“…Electrification of convective cells requires much stronger updrafts than what is typically observed in tropical maritime convection (Zipser and Lutz 1994;Black and Hallett 1999;Reinhart et al 2014), so lightning can serve as a proxy for intense convective activity in tropical cyclones. Despite the low DE, WWLLN data accurately capture the mesoscale spatial structure of lightning within TCs (Abarca et al 2011), so WWLLN data can serve as a useful indication of the frequency and spatial distribution of intense convection in Earl.…”