Characteristics Of Thunderstorms Research Articles

The impact of aerosols as ice nucleating particle on microphysics and electrification in the cumulus model

Here, a heterogeneous ice nucleation parameterization associated with aerosol acting as ice nucleating particle (INP) was implanted into a two-dimensional numerical cumulus model. To explore the impact of INP on microphysical and electrical processes, a comparison was conducted with the original approach, which employs an empirical formula. Simulation results indicate that INP greatly impacted microphysical evolution in the heterogeneous ice nucleation process, reducing total liquid precipitation amounts and causing a slight precipitation delay, as well as increasing the diameter and mixing ratio of ice crystals and the expansion of the vertical distribution of ice crystals. This led to a notable change in electrification in thunderstorms. The increase of ice crystal diameter was the dominant contributor to the enhancement of electrification using the new parameterization. Additionally, unlike the structure of thunderclouds in a mature stage, which always retains a normal dipole structure adopting the empirical formula, a tripole structure developed a lower positive charge, and the polarity inversion with upper negative and lower positive charges occurred when the new parameterization was adopted. This predominately was the result of abundant ice crystals present below the reversal temperature. The electrification characteristics of thunderstorms may have a close connection with lightning activity. It has been found that charge structure changed significantly in the two cases, with the tripolar charge structure facilitating the production of inverted intra-cloud (IC) flashes and negative Cloud-to-ground (CG) flashes simulated by the new parameterization; additionally, clouds simulated using the empirical formula may be able to develop normal IC lightning and positive CG flashes. Therefore, it will be very meaningful to obtain greater insight into the characteristics of thunderstorms electrification in cumulus model with aerosols.

Polarimetric Radar Signatures in Various Lightning Activities During Seoul (Korea) Flood on August 8, 2022

On August 8 and 9, 2022, a record-breaking rain rate of 142 mm h−1, with an accumulated rainfall of more than 500 mm, was observed in the Seoul metropolitan area, Republic of Korea. This study focuses on analyzing the concentration of lightning in southern Seoul, which occurred solely on August 8. It is worth noting that the daily rainfall of August 8 was approximately twice that of August 9 (381 mm on August 8 vs. 198 mm on August 9). The RKSG (located in Yongin, 40 km south of Seoul) Weather Surveillance Radar-1988 Doppler was used to explore the characteristics of cloud microphysics associated with lightning activity. Four major heavy rain periods on August 8 were grouped into three categories of lightning rate (e.g., intense, moderate, and none), and their polarimetric signatures were compared. Significant differences in the vertical distribution of graupel were found within the temperature range of 0 °C and − 20 °C, as indicated by radar reflectivity (ZH) > 40 dBZ and differential reflectivity (ZDR) < 0.5 dB. Although graupel was detected in all three categories at the relatively warm temperatures of 0 °C to − 10 °C, its presence extended into colder regions exclusively in the intense category. This observation preceded the appearance of lightning by approximately 6 min. At heights with temperature ≤ − 20 °C, a high concentration of vertically aligned ice crystals was observed in lightning-prone regions, leading to a decrease in differential phase (ΦDP). In summary, this study provides valuable insights into the microphysical characteristics of thunderstorms and their relationship to lightning activity in the Seoul metropolitan area.

Role of Topography in Triggering Elevated Thunderstorms Associated With Winter Cold Fronts Over the Eastern Yunnan‐Guizhou Plateau

AbstractUsing observations and reanalysis data, the circulation characteristics of elevated thunderstorms behind winter cold fronts (ETCFs) over the eastern Yunnan‐Guizhou Plateau are summarized, and a new triggering mechanism in the cold season related to topography is proposed. ETCFs always occur on the ridge and eastern side of the Dalou Mountain and are triggered at night. Pattern classifications using obliquely rotated T‐mode principal component analysis show that low‐level large‐scale circulation patterns have the following two characteristics: a southwestern airflow at 850 hPa, changing from southwest wind to east wind; and a northeast airflow at 900 hPa, changing from northeast wind to east wind. ETCFs occur in the area of this low easterly wind. A case study of 21 January 2020, shows that it is the intersection of the topography and cold front that provides unique geographical and circulation conditions for triggering elevated thunderstorms. Lateral friction along the mountains causes horizontal wind shear to flow parallel to them, forming positive and negative vortices above and below the front, respectively. This pair of vortices is strengthened by inertial oscillation at night, producing a stronger easterly wind. In the combined effects of frontal lift and topographical lift of the easterly flow, the elevated convection is triggered in the convergence zone above the front. These results provide a new insight into how topography helps to trigger convection in the cold season.

Electrical Characteristics of Thunderstorms Under Different Weather Conditions in the Kashmir Valley, India

Electrical Characteristics of Thunderstorms Under Different Weather Conditions in the Kashmir Valley, India

Impact of sea-breeze circulation on the characteristics of convective thunderstorms over southeast India

Impact of sea-breeze circulation on the characteristics of convective thunderstorms over southeast India

The Characteristics of Thunderstorms and Their Lightning Activity on the Qinghai-Tibetan Plateau

This paper discusses the temporal and spatial distribution characteristics of cloud-to-ground (CG) lightning activity over the Qinghai-Tibetan Plateau (QTP) from 2009 to 2018 and their dependence on meteorological factors. It is found that (1) the number of CG flashes fluctuates, reaches a maximum in 2014, and then gradually decreases. The main active period of CG lightning is from June to September each year, after which it decreases rapidly. CG lightning is mainly distributed in the valley areas at around 4800 m above sea level at Lhasa, Nagqu, and Chamdo, and there are differences in the characteristics of CG activity in these three areas. The peak of daily CG lightning occurs at 1000 UTC, and the lowest value is at 0400 UTC. The distribution of CG lightning in all seasons has obvious differences in peak time and the proportion of positive CG (+CG) lightning, with the ratio of +CG lightning to total CG lightning flashes in spring and autumn exceeding 50%. (2) The ratio of +CG lightning to total CG lightning flashes over the QTP is influenced by a combination of thermodynamic and microphysical factors. Over the QTP, greater vertical wind shear leads to the movement of upper positive charges and promotes the occurrence of +CG lightning. Also, the higher total column liquid water content implies higher cloud water content in the warm-cloud region, and the higher cloud-base height implies a thicker warm-cloud region, which is not conducive to the occurrence of +CG lightning. (3) During high-value years (in this study, 2010, 2012, 2014, and 2016), the midlatitude (30°N–60°N) high pressure is strong and the plateau is situated at the intersection of the East Asian and South Asian monsoons and the cold air from the northwest, which strengthens the water vapor convergence and increases the frequency of thunderstorms. When the plateau is under the control of the southerly monsoon from June to September every year, its atmosphere is full of water vapor and lightning activity is accordingly high, with the proportion of +CG lightning being about 10%. Meanwhile, in the remaining months, when controlled by the westerly wind belt, the plateau’s water vapor condition is poor, the level of lightning activity weakens, and the proportion of +CG lightning gradually increases to more than 50%.

Characteristics of two different types of thunderstorms in summer over the Nagqu area in China

To investigate further the characteristics of thunderstorms on the Qinghai–Tibet plateau, a plateau vortex (PV) thunderstorm and a local thermoconvective (TC) thunderstorm over the Nagqu area are analyzed using cloud-radar, microwave-radiometer, and raindrop-spectrometer data, and their macrophysical and microphysical evolution characteristics are discussed in terms of thermodynamic processes, microphysical processes, and lightning activities. The results show the following. 1) The cloud layer was deeper in the PV thunderstorm, but the TC thunderstorm had a stronger short-time updraft with a radial velocity exceeding 10 m/s, and the warming from the strong updraft action and latent heat release from the hydromorphic phase change was about twice that of the PV thunderstorm. 2) The water vapor density increased significantly when the thunderstorm cloud passed, and the liquid water content in the middle and lower layers exceeded 4 g/m3. The maximum ice water content in the TC thunderstorm was twice bigger than that in the PV thunderstorm. The trends of raindrop number concentration and rain intensity of the PV thunderstorm were similar, and the average particle size of raindrops was smaller than that of the TC thunderstorm. 3) Both types of thunderstorms accounted for more than 90% of negative cloud-to-ground (CG) lightning, and the regions with black-body temperature (TBB) less than −40 °C and a larger TBB gradient were more favorable for the occurrence of CG lightning. 4) Thermodynamic fields bring water vapor and lift for microphysical processes, and microphysical changes release latent heat to enhance the dynamic effects, which together promote the development of lightning activities. The peak radial velocity and ice-phase particle concentration were more than 10 min ahead of the active peak of the CG lightning. This study reveals the macrophysical and microphysical evolution characteristics of different types of thunderstorms and provides a certain scientific basis for disaster prevention and mitigation regarding thunderstorms over the Nagqu area.

A statistical analysis of the distribution of convective windstorms and their radar characteristics in Hubei Province, China. Part 2

A statistical analysis of the distribution of convective windstorms and their radar characteristics in Hubei Province, China. Part 2

Characterising the dynamic movement of thunderstorms using very low- and low-frequency (VLF/LF) total lightning data over the Pearl River Delta region

Abstract. This paper reveals the dynamic movement characteristics of thunderstorms using total lightning data obtained from very low- and low-frequency (VLF/LF) location measurements. Eight thunderstorms, which were evenly distributed in the morning, midday, afternoon and evening, are selected to compare the different kinematic features over the Pearl River Delta (PRD) region in the south of China from 17 to 23 May 2014. The connected-neighbourhood labelling method is used to identify lightning clusters and obtain the centroids. Significant characterisation parameters are put forward as metrics to reveal the kinematic features of thunderstorms, including the duration time, valid area (VA), movement velocity, movement direction and farthest distance in longitude and latitude during the life cycle of the storm. A common trend is that the storms initiate in the west of the PRD region, moving to the east and disappearing after the thunderstorm travels around 106.5 km in longitude. There are two kinds of distributions to depict the property of the valid area, which are one-peak distribution with the maximum in the mature stage and two-peak distribution with a relatively smaller peak in the early time of the storm. The velocity does not show the same trend as the variation in VA which shows a steady increase or decrease during the lifetime of thunderstorms. The biggest VA and highest velocity are 891 km2 occurring on the evening of 17 May and 204.8 km h−1 occurring on the morning of 20 May. The 19 May evening storm was the weakest, with the maximum VA and velocity being 253 km2 and 115.3 km h−1, respectively. The motion of eight storms shows a distinct pattern as the spread of direction distributes tightly in the range of 0–180∘. The movement characteristics of thunderstorms and the associated parameters may help to improve the nowcasting and forecasting system of thunderstorms in the warm season.

Characteristics of Thunderstorms during the Monsoon and Post-monsoon Seasons in India

Characteristics of Thunderstorms during the Monsoon and Post-monsoon Seasons in India

ON THE POSSIBILITY OF USING MAPS OF METEOROLOGICAL EVENTS FROM RESEARCH CENTRE «PLANET» FOR STUDYING AND PREDICTING THUNDERSTORMS ON THE URAL TERRITORY

The diagnosis and prediction of convective events are a difficult and challenging process. One of the most promising methods used for such tasks are hydrodynamic modelling and remote sensing. The aim of this research is to make a comparative analysis of meteorological events maps and data from observational network to find the possibility of using the maps from research center «Planet» for studying and predicting thunderstorms on the territory of the Ural. The spatiotemporal features of thunderstorms were identified. The repeatability and success of detection of this event were also determined, depending on the barium field, synoptic situation and specific characteristics of thunderstorms. During the study it was found that about 20 % of thunderstorms observed by weather stations were not predicted on weather maps; the high probability prediction was better than the medium and low probability forecasts of thunderstorms; spatial and temporal shifts were common in the prediction of thunderstorms. For a more detailed and objective analysis, it is recommended to work with a larger sample and use data from other sources like meteorological radiolocators, stormscopes, and others.

Turbulence Characteristics of Thunderstorms Before the First Flash in Comparison to Non‐Thunderstorms

AbstractThis study evaluates how clouds evolve into thunderstorms in terms of the turbulence characteristics producing the first flash. Observations of 57 (39) isolated thunderstorm (non‐thunderstorm) cells during 2016/2017 in Southern China are provided by an S‐band polarimetric radar and three independent lightning location systems. The vertical turbulence characteristics of clouds associated with thunderstorms are obviously different from non‐thunderstorms. For thunderstorms, the maximum of the eddy dissipation rate (mean value in each height layer) in the entire height is 0.19 m2 s−3, which occurs at the first flash stage, and the achievable height of turbulence exceeds the −30°C layer. For non‐thunderstorms, however, the maximum is 0.12 m2 s−3, and the achievable turbulence height hardly exceeds the −10°C layer. Additionally, the turbulence intensities of the locations where the initial discharge pulse events of the first flashes occur are weak. These turbulence characteristics are useful for lightning nowcasting.

Physical and Dynamical Characteristics of Thunderstorms Over Bangladesh Based on Radar, Satellite, Upper-Air Observations, and WRF Model Simulations

Physical and Dynamical Characteristics of Thunderstorms Over Bangladesh Based on Radar, Satellite, Upper-Air Observations, and WRF Model Simulations

A Study of Enhancing the Prediction Techniques of Lightning Over Bangladesh Based on the Lightning Potential Index and Electric Field

The thunderstorm is a typical extreme weather event that has become one of the most alarming disasters in Bangladesh because of its more frequent occurrences and devastations in recent years. The purpose of this study is to investigate the physical and dynamical characteristics of thunderstorms using Weather Research and Forecasting (WRF) model. Three domains of 9-km, 3-km, and 1-km grid size have been used for the simulation of two events over Dhaka (25-April-2018) and Khulna (11-May-2018). The simulated results are then compared with the Bangladesh Meteorological Department (BMD) and University of Wyoming observed data. Lightning Potential Index (LPI) has been calculated by using different hydrometeors and vertical wind. For the calculation of electric field of thunder-cloud, we have considered an algorithm where ice and graupel are the main charge carriers. Convective Available Potential Energy (CAPE) and Total Total Index (TTI) are found over 1500 J/kg and 48°C respectively ten hours prior to the event. Vertical wind has been found around 4 m/s before the event. Ice and graupel mixing ratios are found at very high concentrations at cloud center. Maximum value of LPI is found 0.163 J/kg in Dhaka and 0.8 J/kg in Khulna. The electric field is found to be 70 kV/m at a vertical height of 8 km in Dhaka and -125 kV/m at a vertical height of 7 km in Khulna. All the parameters are recognized to be favorable for the occurrence of thunderstorms and lightning which indicates that the techniques used in this study may be useful to predict future thunderstorm events in Bangladesh.

Characterisation of thunderstorms that caused lightning-ignited wildfires

This work studies the characteristics of thunderstorms that cause lightning-caused wildfires in Catalonia, north-east Iberian Peninsula, using lightning and weather radar data. Although thunderstorms produce ~57 000 cloud-to-ground (CG) flashes yearly in Catalonia, only 1 in 1000 end up as a flaming wildfire. Characterisation of thunderstorms that ignite wildland fires can help fire weather forecasters identify regions of increased ignition potential. Lightning data and radar products like maximum reflectivity, echo tops heights and equivalent liquid content were obtained over a 7-year period. Characteristics of thunderstorms that ignite wildfires are examined including storm motion, duration, morphology and intensity. It was found that most probable ignition candidates are lightning associated with cellular thunderstorms and non-linear systems. Radar reflectivity values for lightning that ignites wildfires were found to be below average, these morphological types favouring the occurrence of lightning outside regions of high reflectivity, where precipitation reaching the ground is low or non-existent. Thunderstorms that ignite wildfires are typically of low intensity, with a CG flash rate below average. Most ignitions occur during the maturity phase when the CG flash rate is the highest. A better scientific understanding of the thunderstorms that cause lightning wildfires will help improve early firefighting response.

Infrasound characteristics of nontornadic and tornadic thunderstorms using high-resolution simulations

There has been increased interest in improving severe weather detection by supplementing NOAA's WSR-88D radar network with an infrasound observation network, which may be able to detect distinct sub-audible signatures from tornadic thunderstorms. While there is evidence that tornadic thunderstorms exhibit observable infrasound signals, what is not well-understood is whether these infrasound signals are unique to tornadic storms compared to nontornadic storms or whether there is any useful signal prior to tornadogenesis (which would be most relevant to NWS forecasters). In this presentation, we will present the results of high-resolution simulations of severe thunderstorms, specifically tailored to represent acoustic wave propagation with frequencies of 0.1 to 1 Hz. The spectral analysis of pressure perturbations generated by a nontornadic and tornadic supercell thunderstorm will be compared against each other. Two additional sensitivity tests that employ different microphysics schemes (i.e., the representation of precipitation within the storm) will be discussed, since prior work has indicated that the melting of precipitation is a dominant contributor to infrasound generation in thunderstorms. So far, preliminary results suggest that there are no discernible differences in infrasound observed in the vicinity of tornadic versus nontornadic supercell thunderstorms prior to tornadogenesis.

Calculation of Damage to Buildings and Structures by Lightning According to the Thunderstorms’ Visual and Instrumental Observations

The materials and construction of buildings and structures used should be linked to the number of lightning strikes per year. Lightning protection of buildings and structures should be based on the parameters of thunderstorms in the territory of the project design. Thunderstorm is one of the most dangerous meteorological phenomena. Both ground objects and aircrafts are affected by thunderstorm activity: airplanes and rockets. The main objective of this work is a comparative assessment of the buildings and structures impact by lightning, depending on the methodology for determining the thunderstorms duration in hours for the territories in the North Caucasus. The analysis on the basis of data from the thunderstorm direction finding net (TDFN) of the FSI “VGI” and data from weather stations has been performed. To solve this problem, a study on the relationship between the number of days with a thunderstorm and the duration of thunderstorms in hours for the territories in the North Caucasus has been performed on the FSI “VGI” (TDFN) data basis. In order to determine the above-mentioned statistical characteristics of thunderstorms and their variations in the North Caucasus, for the first time in Russia, the LS 8000 lightning recorder manufactured by “Vaisala” Finland was used.

Radar characteristics of summer thunderstorms in the Kanto Plain of Japan with and without cloud-to-ground lightning

The elucidation of characteristics of cumulonimbus clouds that cause lightning is important for predicting thunderstorm development. These characteristics, with and without lightning, were observed during a day (in 2010) of severe thunderstorms and lightning in Japan and statistically analyzed using radar observations with cell tracking. Observed cells were categorized into a cell including cloud-to-ground lightning (CG) and intra-cloud lightning (CGIC), a cell containing only intra-cloud lightning (IC), and a cell without lightning (NoL). These cells were compared to the average and temporal evolution of radar observations. Out of the 265 cells generated, 103 were CGIC cells, 30 were IC cells, and 132 were NoL cells. Significant differences were detected between the averaged values of lifetime, size, echo top, vertically integrated liquid (VIL), maximum radar reflectivity, and radar reflectivity of each cell category, when the − 10 °C isotherm height was considered. The temporal evolution of CGIC cell characteristics revealed changes in radar reflectivity at 0 °C and − 10 °C that were synchronized with lightning activity. The VIL value was elevated only for CGIC cells and had the tendency to decrease with time as lightning activity. CGIC cells produced the highest echo top and maintained their height during their lifetime. To predict CG within 20 min using 35 dBZ radar reflectivity at − 30 °C as the criterion, a critical success index (CSI) of 0.82 and false alarm rate (FAR) of 0.64 were found to have the best prediction scores.

The influence of symmetric and non-symmetric charge configurations on the possibility of sprite inception: Numerical experiments with a 3D electrostatic model

We present a simple, efficient, and flexible three-dimensional electrostatic model for calculating the magnitude and direction of the electric field from the ground to the base of the ionosphere for a given thunderstorm charge configuration, with the aim of evaluating the possibility for sprite inception. The model is based on a method-of-images solution to Poisson's equation, assuming near vacuum conditions and with perfectly conducting upper and lower boundaries. A dipole electrical structure within each thundercloud is assumed, with a screening (shielding) charge above the cloud. The charge centers (main positive, main negative, and screening charge) are modeled with average structural characteristics of summer and winter thunderstorms. To simulate a positive or negative cloud-to-ground lightning discharge, the main positive or main negative charge center, respectively, is removed from the domain. The computed electric potential at each grid point is converted to the electric field and is compared against the value of the conventional breakdown field to obtain an indication of the possibility of electrical breakdown and hence the possibility of sprite inception. This simple model is particularly useful for performing a sensitivity study with respect to variation in thunderstorm cell charge configuration, with no assumption of symmetry in the horizontal or vertical directions. Implications of the presence of neighboring clouds at different relative stages of development on the possibility of sprite inception and on the displacement of sprites from the location of the parent thunderstorm are also examined, as well as clouds with inverted dipole charge configuration.

A preliminary study on pre-monsoon summer thunderstorms using ground-based total lightning data over Gangetic West Bengal

This paper presents the preliminary results of observation of total lightning characteristics of pre-monsoon thunderstorms of 2018 over Gangetic West Bengal around Kolkata. Mainly, the analysis results of total lightning associated with pre-monsoon moderate and severe thunderstorm events, locally known as Kalbaishakhi or Nor’wester, are presented. The total lightning data include both in-cloud and cloud-to-ground lightning flashes and are obtained from the Earth Networks Total Lightning Network. Most of the events were multi-cellular in nature as inferred from lightning data. The total lightning count over an area of 10 km radius around the wind sensors, increased rapidly about $$\sim $$ 10–40 min before the onset of high wind on the surface. Primarily, total lightning count $$\ge 30$$ per minute was found to be associated with the Nor’westers which produced maximum surface wind speed above 50 km/h.