Evolution of the total lightning activity in a leading-line and trailing stratiform mesoscale convective system over Beijing

Abstract Previous studies have demonstrated that rapid increases in total lightning activity (intracloud + cloud-to-ground) are often observed tens of minutes in advance of the occurrence of severe weather at the ground. These rapid increases in lightning activity have been termed “lightning jumps.” Herein, the authors document a positive correlation between lightning jumps and the manifestation of severe weather in thunderstorms occurring across the Tennessee Valley and Washington D.C. A total of 107 thunderstorms from the Tennessee Valley; Washington, D.C.; Dallas, Texas; and Houston, Texas, were examined in this study. Of the 107 thunderstorms, 69 thunderstorms fall into the category of nonsevere and 38 into the category of severe. From the dataset of 69 isolated nonsevere thunderstorms, an average, peak, 1-min flash rate of 10 flashes per minute was determined. A variety of severe thunderstorm types were examined for this study, including a mesoscale convective system, mesoscale convective vortex, tornadic outer rainbands of tropical remnants, supercells, and pulse severe thunderstorms. Of the 107 thunderstorms, 85 thunderstorms (47 nonsevere, 38 severe) were from the Tennessee Valley and Washington, D.C., and these 85 thunderstorms tested six lightning jump algorithm configurations (Gatlin, Gatlin 45, 2σ, 3σ, Threshold 10, and Threshold 8). Performance metrics for each algorithm were then calculated, yielding encouraging results from the limited sample of 85 thunderstorms. The 2σ lightning jump algorithm had a high probability of detection (POD; 87%), a modest false-alarm rate (FAR; 33%), and a solid Heidke skill score (0.75). These statistics exceed current NWS warning statistics with this dataset; however, this algorithm needs further testing because there is a large difference in sample sizes. A second and more simplistic lightning jump algorithm named the Threshold 8 lightning jump algorithm also shows promise, with a POD of 81% and a FAR of 41%. Average lead times to severe weather occurrence for these two algorithms were 23 min. The overall goal of this study is to advance the development of an operationally applicable jump algorithm that can be used with either total lightning observations made from the ground, or in the near future from space using the Geostationary Operational Environmental Satellite Series R (GOES-R) Geostationary Lightning Mapper.

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Assimilation of GOES-R Geostationary Lightning Mapper Flash Extent Density Data in GSI EnKF for the Analysis and Short-Term Forecast of a Mesoscale Convective System

Monthly Weather Review ◽

10.1175/mwr-d-19-0192.1 ◽

2020 ◽

Vol 148 (5) ◽

pp. 2111-2133 ◽

Cited By ~ 1

Author(s):

Rong Kong ◽

Ming Xue ◽

Alexandre O. Fierro ◽

Youngsun Jung ◽

Chengsi Liu ◽

...

Keyword(s):

Mesoscale Convective System ◽

Convective System ◽

Lightning Flash ◽

Moist Convection ◽

State Variables ◽

Short Term ◽

Pixel Resolution ◽

Cross Covariance ◽

Mesoscale Convective ◽

Total Lightning

Abstract The recently launched Geostationary Operational Environmental Satellite “R-series” (GOES-R) satellites carry the Geostationary Lightning Mapper (GLM) that measures from space the total lightning rate in convective storms at high spatial and temporal frequencies. This study assimilates, for the first time, real GLM total lightning data in an ensemble Kalman filter (EnKF) framework. The lightning flash extent density (FED) products at 10-km pixel resolution are assimilated. The capabilities to assimilate GLM FED data are first implemented into the GSI-based EnKF data assimilation (DA) system and tested with a mesoscale convective system (MCS). FED observation operators based on graupel mass or graupel volume are used. The operators are first tuned through sensitivity experiments to determine an optimal multiplying factor to the operator, before being used in FED DA experiments FEDM and FEDV that use the graupel-mass or graupel-volume-based operator, respectively. Their results are compared to a control experiment (CTRL) that does not assimilate any FED data. Overall, both DA experiments outperform CTRL in terms of the analyses and short-term forecasts of FED and composite/3D reflectivity. The assimilation of FED is primarily effective in regions of deep moist convection, which helps improve short-term forecasts of convective threats, including heavy precipitation and lightning. Direct adjustments to graupel mass via observation operator as well as adjustments to other model state variables through flow-dependent ensemble cross covariance within EnKF are shown to work together to generate model-consistent analyses and overall improved forecasts.

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SAETTA: high-resolution 3-D mapping of the total lightning activity in the Mediterranean Basin over Corsica, with a focus on a mesoscale convective system event

Atmospheric Measurement Techniques ◽

10.5194/amt-12-5765-2019 ◽

2019 ◽

Vol 12 (11) ◽

pp. 5765-5790 ◽

Cited By ~ 4

Author(s):

Sylvain Coquillat ◽

Eric Defer ◽

Pierre de Guibert ◽

Dominique Lambert ◽

Jean-Pierre Pinty ◽

...

Keyword(s):

High Altitude ◽

Mediterranean Basin ◽

Hot Spot ◽

Mesoscale Convective System ◽

Lightning Activity ◽

Convective System ◽

Stratiform Region ◽

Mesoscale Convective ◽

The Mediterranean ◽

The Mediterranean Basin

Abstract. Deployed on the mountainous island of Corsica for thunderstorm monitoring purposes in the Mediterranean Basin, SAETTA is a network of 12 LMA (Lightning Mapping Array, designed by New Mexico Tech, USA) stations that allows the 3-D mapping of very high-frequency (VHF) radiation emitted by cloud discharges in the 60–66 MHz band. It works at high temporal (∼40 ns in each 80 µs time window) and spatial (tens of meters at best) resolution within a range of about 350 km. Originally deployed in May 2014, SAETTA was commissioned during the summer and autumn seasons and has now been permanently operational since April 2016 until at least the end of 2020. We first evaluate the performances of SAETTA through the radial, azimuthal, and altitude errors of VHF source localization with the theoretical model of Thomas et al. (2004). We also compute on a 240 km × 240 km domain the minimum altitude at which a VHF source can be detected by at least six stations by taking into account the masking effect of the relief. We then report the 3-year observations on the same domain in terms of number of lightning days per square kilometer (i.e., total number of days during which lightning has been detected in a given 1 km square pixel) and in terms of lightning days integrated across the domain. The lightning activity is first maximum in June because of daytime convection driven by solar energy input, but concentrates on a specific hot spot in July just above the intersection of the three main valleys. This hot spot is probably due to the low-level convergence of moist air fluxes from sea breezes channeled by the three valleys. Lightning activity increases again in September due to numerous small thunderstorms above the sea and to some high-precipitation events. Finally we report lightning observations of unusual high-altitude discharges associated with the mesoscale convective system of 8 June 2015. Most of them are small discharges on top of an intense convective core during convective surges. They are considered in the flash classification of Thomas et al. (2003) to be small–isolated and short–isolated flashes. The other high-altitude discharges, much less numerous, are long-range flashes that develop through the stratiform region and suddenly undergo upward propagations towards an uppermost thin layer of charge. This latter observation is apparently consistent with the recent conceptual model of Dye and Bansemer (2019) that explains such an upper-level layer of charge in the stratiform region by the development of a non-riming ice collisional charging in a mesoscale updraft.

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Evaluation of Different Storm Parameters as the Proxies for Gridded Total Lightning Flash Rates: A Convection-Allowing Model Study

Atmosphere ◽

10.3390/atmos12010095 ◽

2021 ◽

Vol 12 (1) ◽

pp. 95

Author(s):

Xinyao Qian ◽

Haoliang Wang

Keyword(s):

Data Assimilation ◽

Mesoscale Convective System ◽

Radar Data ◽

Skill Score ◽

Convective System ◽

Test Case ◽

Lightning Flash ◽

Simulation Accuracy ◽

Mesoscale Convective ◽

Total Lightning

Lightning simulation is important for a variety of applications, including lightning forecast, atmospheric chemical simulation, and lightning data assimilation. In this study, the potential of five storm parameters (graupel volume, precipitation ice mass, radar echo volume, maximum updraft, and updraft volume) to be used as the proxy for the diagnosis of gridded total lightning flash rates has been investigated in a convection-allowing model. A mesoscale convective system occurred in the Guangdong province of China was selected as the test case. Radar data assimilation was used to improve the simulation accuracy of the convective clouds, hence providing strong instantaneous correlations between observed and simulated storm signatures. The areal coverage and magnitude of the simulated lightning flash rates were evaluated by comparing to those of the total lightning observations. Subjective and the Fractions Skill Score (FSS) evaluations suggest that all the five proxies tested in this study are useful to indicate general tendencies for the occurrence, region, and time of lightning at convection-allowing scale (FSS statistics for the threshold of 1 flash per 9 km2 per hour were around 0.7 for each scheme). The FSS values were decreasing as the lightning flash rate thresholds used for FSS computation increased for all the lightning diagnostic schemes with different proxies. For thresholds from 1 to 3 and 16 to 20 flashes per 9 km2 per hour, the graupel contents related schemes achieved higher FSS values compared to the other three schemes. For thresholds from 5 to 15 flashes per 9 km2 per hour, the updraft volume related scheme yielded the largest FSS. When the thresholds of lightning flash rates were greater than 13 flashes per 9 km2 per hour, the FSS values were below 0.5 for all the lightning diagnostic schemes with different proxies.

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Lightning activity related to satellite and radar observations of a mesoscale convective system over Texas on 7–8 April 2002

Atmospheric Research ◽

10.1016/j.atmosres.2004.11.020 ◽

2005 ◽

Vol 76 (1-4) ◽

pp. 127-166 ◽

Cited By ~ 36

Author(s):

Nikolai Dotzek ◽

Robert M. Rabin ◽

Lawrence D. Carey ◽

Donald R. MacGorman ◽

Tracy L. McCormick ◽

...

Keyword(s):

Mesoscale Convective System ◽

Lightning Activity ◽

Convective System ◽

Radar Observations ◽

Mesoscale Convective

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Evolution of the total lightning structure in a leading-line, trailing-stratiform mesoscale convective system over Houston, Texas

Journal of Geophysical Research Atmospheres ◽

10.1029/2007jd008445 ◽

2008 ◽

Vol 113 (D8) ◽

Cited By ~ 42

Author(s):

Brandon L. Ely ◽

Richard E. Orville ◽

Lawrence D. Carey ◽

Charles L. Hodapp

Keyword(s):

Mesoscale Convective System ◽

Convective System ◽

Mesoscale Convective ◽

Total Lightning

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Application of total-lightning data assimilation in a mesoscale convective system based on the WRF model

Atmospheric Research ◽

10.1016/j.atmosres.2014.04.012 ◽

2014 ◽

Vol 145-146 ◽

pp. 255-266 ◽

Cited By ~ 28

Author(s):

Xiushu Qie ◽

Runpeng Zhu ◽

Tie Yuan ◽

Xueke Wu ◽

Wanli Li ◽

...

Keyword(s):

Data Assimilation ◽

Wrf Model ◽

Mesoscale Convective System ◽

Convective System ◽

Mesoscale Convective ◽

Total Lightning

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Ensemble Probabilistic Prediction of a Mesoscale Convective System and Associated Polarimetric Radar Variables Using Single-Moment and Double-Moment Microphysics Schemes and EnKF Radar Data Assimilation

Monthly Weather Review ◽

10.1175/mwr-d-16-0162.1 ◽

2017 ◽

Vol 145 (6) ◽

pp. 2257-2279 ◽

Cited By ~ 12

Author(s):

Bryan J. Putnam ◽

Ming Xue ◽

Youngsun Jung ◽

Nathan A. Snook ◽

Guifu Zhang

Keyword(s):

Mesoscale Convective System ◽

Radar Data ◽

Convective Precipitation ◽

Convective System ◽

Ensemble Forecasts ◽

Verification Methods ◽

Probabilistic Forecasts ◽

Mesoscale Convective ◽

Single Moment ◽

Double Moment

Abstract Ensemble-based probabilistic forecasts are performed for a mesoscale convective system (MCS) that occurred over Oklahoma on 8–9 May 2007, initialized from ensemble Kalman filter analyses using multinetwork radar data and different microphysics schemes. Two experiments are conducted, using either a single-moment or double-moment microphysics scheme during the 1-h-long assimilation period and in subsequent 3-h ensemble forecasts. Qualitative and quantitative verifications are performed on the ensemble forecasts, including probabilistic skill scores. The predicted dual-polarization (dual-pol) radar variables and their probabilistic forecasts are also evaluated against available dual-pol radar observations, and discussed in relation to predicted microphysical states and structures. Evaluation of predicted reflectivity (Z) fields shows that the double-moment ensemble predicts the precipitation coverage of the leading convective line and stratiform precipitation regions of the MCS with higher probabilities throughout the forecast period compared to the single-moment ensemble. In terms of the simulated differential reflectivity (ZDR) and specific differential phase (KDP) fields, the double-moment ensemble compares more realistically to the observations and better distinguishes the stratiform and convective precipitation regions. The ZDR from individual ensemble members indicates better raindrop size sorting along the leading convective line in the double-moment ensemble. Various commonly used ensemble forecast verification methods are examined for the prediction of dual-pol variables. The results demonstrate the challenges associated with verifying predicted dual-pol fields that can vary significantly in value over small distances. Several microphysics biases are noted with the help of simulated dual-pol variables, such as substantial overprediction of KDP values in the single-moment ensemble.

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