Polarity and energetics of inner core lightning in three intense North Atlantic hurricanes
نویسندگان
چکیده
[1] We use the World Wide Lightning Location Network (WWLLN), low‐frequency magnetic fields measured at Duke University, and storm intensity data (winds and central pressure) to examine the polarity and energetics of lightning within 100 km of the centers (inner core regions) of North Atlantic hurricanes Emily, Katrina, and Rita (2005). WWLLN provides the lightning locations. Polarities, peak currents, and vertical impulse charge moment changes are derived from the Duke magnetic field measurements. In agreement with past studies, we find episodic inner core lightning outbreaks prior to and during most changes in storm intensity. A new result of our analysis indicates an increase in the relative number of positive cloud‐to‐ground lightning in the inner core prior to and during periods of storm weakening, which is potentially important for hurricane intensity change forecasting. Additionally, we find that the majority of inner core lightning located by WWLLN had peak currents that surpassed the threshold needed to produce optical emissions (elves) and drive electron density perturbations in the lower ionosphere (80–105 km). Since these high peak current lightning occurred in short‐duration outbreaks, they had an accumulated effect on the ionospheric electron density, as shown by recent modeling studies. Our results suggest that the inner core lightning in intense hurricanes might be significant drivers of perturbations in the lower ionosphere during these inner core lightning outbreaks.
منابع مشابه
Convective Structure of Hurricanes as Revealed by Lightning Locations
Cloud-to-ground lightning flash locations were examined for nine Atlantic basin hurricanes using data from the National Lightning Detection Network. A common radial distribution in ground flash density was evident: a weak maximum in the eyewall region, a clear minimum 80–100 km outside the eyewall, and a strong maximum in the vicinity of outer rainbands (210–290-km radius). These results are co...
متن کاملImpacts of the Lower Stratosphere on the Development of Intense Tropical Cyclones
This study examines potential impacts of the lower stratosphere on the development and the inner-core structure of intense tropical cyclones (TCs). By initializing the Hurricane Weather Research and Forecasting (HWRF) model with different monthly averaged sounding profiles in the Northwestern Pacific and the North Atlantic basins, it is shown that the lower stratosphere layer (LSL) can impose a...
متن کاملReflectivity, Ice Scattering, and Lightning Characteristics of Hurricane Eyewalls and Rainbands. Part I: Quantitative Description
Covering December 1997 through December 1998, 261 overpasses of 45 hurricanes by the Tropical Rainfall Measuring Mission (TRMM) satellite are used to document the observed radar reflectivity values, passive microwave ice scattering magnitudes, and total lightning (cloud to ground plus in cloud). These parameters are interpreted as describing convective vigor or intensity, with greater reflectiv...
متن کاملThe intertropical convergence zone modulates intense hurricane strikes on the western North Atlantic margin.
Most Atlantic hurricanes form in the Main Development Region between 9°N to 20°N along the northern edge of the Intertropical Convergence Zone (ITCZ). Previous research has suggested that meridional shifts in the ITCZ position on geologic timescales can modulate hurricane activity, but continuous and long-term storm records are needed from multiple sites to assess this hypothesis. Here we prese...
متن کاملLetter to the Editor Intense oceanic lightning
The electrodynamic properties of intense oceanic lightning discharges are compared to intense continental lightning discharges. Particularly intense negative lightning discharges with absolute charge moments > 2 kC·km occur more often over the oceans than over the continents during April 1998. Intense continental lightning discharges, with negative and positive polarity, and intense positive oc...
متن کامل