Meteorological Conditions Associated with Lightning Ignited Fires and Long-Continuing-Current Lightning in Arizona, New Mexico and Florida

Abstract

Lightning is the main precursor of wildfires in Arizona, New Mexico, and Florida during the fire season. Forecasting the occurrence of Lightning-Ignited Wildfires (LIW) is an essential tool to reduce their impacts on the environment and society. Long-Continuing-Current (LCC) lightning is proposed to be the main precursor of LIW. The long-lasting continuing current phase of LCC lightning is that which is more likely to ignite vegetation. We investigated the meteorological conditions and vegetation type associated with LIW and LCC lightning flashes in Arizona, New Mexico, and Florida. We analyzed LIW between 2009 and 2013 and LCC lightning between 1998 and 2014 and combined lightning and meteorological data from a reanalysis data set. According to our results, LIW tend to occur during dry thunderstorms with a high surface temperature and a high temperature gradient between the 700 hPa and the 450 hPa vertical levels for high-based clouds. In turn, we obtained a high lightning-ignition efficiency in coniferous forests, such as the ponderosa pine in Arizona and New Mexico and the slash pine in Florida. We found that the meteorological conditions that favor fire ignition and spread are more significant in Florida than in Arizona and New Mexico, while the meteorological conditions that favor the occurrence of LIW in Arizona and New Mexico are closely related with the meteorological conditions that favor high lightning activity. In turn, our results indicate high atmospheric instability during the occurrence of LIW. Our findings suggest that LCC (>18 ms) lightning tends to occur in thunderstorms with high relative humidity and ice content in the clouds, and with low temperature in the entire troposphere. Additionally, a weak updraft in the lower troposphere and a strong one in the upper troposphere favor the occurrence of LCC (>18 ms) lightning. We found that the meteorological conditions that favor the occurrence of LCC (>18 ms) lightning are not necessarily the preferential meteorological conditions for LIW.

Lightning‐Ignited Wildfires in the Western United States: Ignition Precipitation and Associated Environmental Conditions

“…Although the NIFC database provides latitude‐longitude coordinates for each fire's discovery location, these may not represent the precise ignition location (Fusco, Finn, Abatzoglou, et al., 2019; Pérez‐Invernón et al., 2022). Similarly, fire discovery dates are provided but they differ from ignition dates for holdover fires.…”

Variation of lightning-ignited wildfire patterns under climate change

“…The accumulated rainfall, the vapor pressure deficit, the relative humidity and the temperature at 2 m altitude influence the fuel availability and the survival and arrival of fires [8][9][10][11][12][13][14][15] . Thus, we calculate the annually averaged variation of these meteorological variables and the total and LCC lightning in each grid cell under climate change scenarios over the globe (Figure S4).…”

“…The data of the simulationsgenerated in this study have been deposited in the Zenodo repository [https://doi.org/10.5281/zenodo.6627112 (last access 04-01-2023)]. The processed LCC lightning flashes reported by GLM between 15…”

“…[5][6][7] ] indicate that continuing electrical currents in lightning flowing for more than some tens of milli-seconds (so called Long-Continuing-Currents, LCC) are likely to produce fires. The evolution and spreading of fires are determined by fuel availability and meteorological conditions, such as air temperature, precipitation rate, and wind strength [8][9][10][11][12][13][14][15] .…”

Optical observations of thunderstorms from the International Space Station: recent results and perspectives

“…Some recent publications based on ISS-LIS measurements discuss the cross-correlation of ground-based lightning detection systems to estimate the detection efficiencies of measurement techniques such as the LINET 3D system 39 and a lightning detection network in China 40 . Other papers study the quantification of NO X based on lightning and TROPOMI measurements 41 , parametrization of NO X -production in continuing currents 42 , and meteorological conditions for lightning-ignited fires 43 .…”