Effects of environmental conditions on inducing charge structures of thunderstorms over Eastern India
© Pawar et al.; licensee Springer. 2014
Received: 5 August 2013
Accepted: 6 March 2014
Published: 16 June 2014
It is well known that environmental conditions like convective instability, aerosol loading, and availability of moisture content affect the polarity of charge structures of thunderstorms. The electrical characteristics of thunderstorms observed during the pre-monsoon season of year 2009, over Eastern India were studied to identify the effects of different environmental conditions on charge structures of thunderstorms occurring over this region. Electric field and Maxwell current data suggest that at least one of these thunderstorms had an inverted charge structure. Doppler RADAR, radiosonde, and Moderate Resolution Imaging Spectroradiometer (MODIS) Aerosol Optical Depth (AOD) data have been used to compare the microphysical and dynamical characteristics of these thunderstorms. The thermo dynamical structure observed by radiosonde during the day on which an inverted polarity thunderstorm was observed showed very high CAPE in the mixed-phase region compared to other thunderstorm days. Furthermore, the AOD peaked 1 day before this thunderstorm. The back trajectories of winds also suggest that the aerosols might have been transported from a desert region on that day. It has been proposed that the large ice nuclei concentration can produce dominant positive charge in the lower portion of the mixed-phase region by maintaining ice saturation.
It has long since been known that some of the more severe thunderstorms can have different charge structures than generally observed in ordinary thunderstorms. From the observations of electric field changes produced by lightning during a severe thunderstorm, Vonnegut and Moore (1958) suggested that severe thunderstorms could have an inverted charge structure. In three storms that occurred during the Severe Thunderstorm Electrification and Precipitation Study (STEPS), Rust et al. (2005) have observed the positive and negative charge regions at altitudes where negative and positive charge would normally be found in ordinary thunderstorms. Lang et al. (2004) and Wiens et al. (2005) reported storms with consistent dominant upper level inverted dipole charge structure near the updraft (i.e., the upper negative charge region and the main positive charge region below it). There are many other reports of inverted polarity charge structure in severe thunderstorms which produce positive Cloud-to-Ground (CG) flashes comparable to negative CG flashes (e.g., MacGorman and Burgess 1994; Stolzenburg 1994; Carey and Rutledge 1998; Lang and Rutledge 2002; Carey et al. 2003). Over a region from the Kansas/Colorado border to Minnesota, Carey and Rutledge (2003) found that the properties of CG lightning flashes produced from severe storms during warm seasons (i.e., large hail or tornado producing) were different from those produced by non-severe storms. They found that the percentage of CG lightning flashes lowering positive charge to ground was up to three times higher in severe storms. The median positive peak current in severe storms was larger by about 25%. Furthermore, the median negative peak current in severe storms was very low (i.e., as low as 12 to 16 kA) and was noticeably less than in non-severe storms (i.e., by at least 10%).
Although earlier reports suggest most thunderstorms with inverted polarity charge structures were characterized by a high degree of severity, Qie et al. (2005) and Pawar and Kamra (2004 and 2009) have also reported some non-severe thunderstorms over the Tibetan Plateau and India, with a wide spread and strong positive charge in the lower portion of cloud. Majority of lightning activity arises from lower negative dipole of these thunderclouds. These thunderstorms can also be termed inverted polarity thunderstorms because for most of their lifetimes, lower negative dipole dominated the lightning activity of these storms.
Williams et al. (2005) hypothesized that the inverted polarity charge structure in thunderstorms is the result of superlative liquid water content in the mixed-phase region. Many observational studies support this idea (Krehbiel et al. 2000; Rust and MacGorman 2002; Lang et al. 2004). However, as emphasized by Williams et al. (2005), a strong updraft, an extraordinarily dry environment, or a high concentration of aerosols are necessary but not sufficient conditions for formation of inverted polarity thunderstorms. Many observations clearly show that thunderstorms fulfilling all the conditions above do not always form inverted polarity thunderstorms (MacGorman and Burgess 1994). Furthermore, the observations by Pawar and Kamra (2004, 2009) and Qie et al. (2005) show that some ordinary thunderstorms without strong updrafts can also have inverted polarity charge structures. All these observations clearly suggest that formation of inverted polarity is not fully understood.
In this paper, we report our observations of surface electric field and Maxwell current density made at Kharagpur (22.31°N, 87.31°E) in Eastern India, beneath three thunderstorms that occurred during the pre-monsoon season of 2009. Electric field and Maxwell current data suggest that at least one of these thunderstorms had an inverted polarity charge structure. Doppler RADAR, radiosonde, and Moderate Resolution Imaging Spectroradiometer (MODIS) Aerosol Optical Depth (AOD) data have been used to compare the microphysical and dynamical characteristics of these three thunderstorms. Possible causes that may be responsible for formation of an inverted dipole charge structure in one of these thunderstorms are also discussed.
As described in detail by Pawar and Kamra (2007), an electric field mill flushed with the ground level and a plate antenna are used for electric field and Maxwell current measurements, respectively. Measurements of both these parameters are made throughout the day at a sampling rate of 10 Hz. In our measurements, we consider the fair-weather electric field and the associated conduction current that brings positive charge to the ground, as negative polarity. In addition, we take the positive displacement current to be affected by a positive field change, lowering positive charge to the ground and vice-versa. For our analysis, AOD data is taken from MODIS, which acquires data in 36 high-resolution spectral bands between 0.415 and 14.235 μm. These data are obtained from a level-3 MODIS gridded atmosphere daily global joint product (MOD08_D3). We took the daily averaged AOD at 550 nm from MODIS-Terra Version 5. Those data for which cloud cover was greater than 20% were excluded from analysis while averaging.
Electric field changes induced by lightning discharges
Maxwell current density measurements
Electrical structure of the thunderstorm
Previous studies have revealed that in thunderstorms with non-inverted polarity charge structures (with midlevel negative and upper level positive charge regions), most of the electric field changes produced by lightning are of negative polarity, indicating removal of negative charge from overhead (Jacobson and Krider 1976; Livingston and Krider 1978; Mohanty and Pradeep Kumar 2004; Pawar and Kamra 2004). Our observations of electric field changes produced by lightning, of Maxwell current densities, and of recovery curves of the electric field during the thunderstorms of 6 May 2009 and 12 May 2009, indicate the removal of negative charge from overhead by lightning and buildup of negative charge after lightning. Therefore, it is clear from the electric field and Maxwell current density data for those 2 days that these thunderstorms had non-inverted polarity charge structures.
Possible causes of inverted polarity charge structure
Many laboratory and field experiments have clearly shown that inverted polarity in thunderstorms is the result of superlative liquid water content in the mixed-phase region (Williams et al. 2005). One or more of the following factors can account for superlative liquid water content in the mixed-phase region, i.e., strong instability, strong updraft, greater cloud base height, and high aerosol concentration. In our observation, as shown in Figure 2, CAPE was very high 3,124 J/kg on 11 May 2009. In addition, it should be noted here that the vertical distribution of CAPE was very peculiar on that day. As can be seen in Figure 2, most of the CAPE is concentrated in the 5- to 10-km altitude range. Even though the CAPE was very high (3,054 J/kg) on May 6, it was distributed over a larger region compared to May 11. The high CAPE and its vertical distribution clearly suggest that the updraft could be high in the mixed-phase region on May 11. As shown in Figure 8, the aerosol concentration was also very high on May 11 compared to the other days.
Our observations not only show high concentrations of aerosols but also that the degree of concentration of ice nuclei may be playing an important role in the formation of inverted polarity charge structures in thunderclouds. Our study site located in the IGB region is known for its very high aerosol concentrations owing to its unique topography. During the pre-monsoon or summer seasons, this region receives large amounts of natural dust aerosols, transported from neighboring desert regions (i.e., from the Thar Desert) (Dey et al. 2004; Pandithurai et al. 2008). These dust particles can act as ice nuclei. Our observations on 11 May 2009 are similar to the observations of Pawar and Kamra (2009), during which back trajectories were shown to be indicative of aerosol transport from desert regions on the day when an inverted polarity thunderstorm was observed. Small inverted polarity thunderstorms reported by Gopalakrishnan et al. (2010) in this region and by Pawar and Kamra (2002, 2004, and 2009) at Pune, India, support the idea that large ice nuclei concentrations can play an important role in the alteration of charge structures of thunderstorms with moderate or low instability. Many laboratory experiments (Baker et al. 1987; Williams et al. 1991; Caranti et al. 1991) suggest that dominant positive charge will appear on larger precipitation particles in the lower portion of the mixed-phase region if ice saturation is maintained.
The authors are aware that the aerosol and/or ice nuclei concentrations cannot influence the polarity of thunderstorms by themselves. More observations of such thunderstorms are required to confirm our proposal that increased optical depth leads to changes in ice nuclei, which in turn affect the charging mechanism. Although many severe thunderstorms occur over this area during pre- and post-monsoon seasons, occurrences of thunderstorms with inverted polarity are rare. We have made observations of thunderstorms over this region and over Pune, for three seasons and for about 2 decades, respectively. However, only three to four thunderstorms with inverted polarity have been observed over these regions. Gopalakrishnan et al. (2010) have already reported one such thunderstorm over this region. Occurrences of such inverted polarity thunderstorms over other parts of India are also few. Pawar and Kamra (2002, 2004, and 2009) have reported some of such thunderstorms over Pune. There are no other reports of such thunderstorms from any other part of India. This complicates the task of finding a robust statistical test to corroborate our claim. In the absence of such a test, our proposal is merely speculative. Nevertheless, observations of greater optical depth prior to the occurrence of a severe thunderstorm in the present case do lend support to our speculation.
Electric field and Maxwell current density measurements clearly illustrate that the 11 May 2009 thunderstorm had a strong and dominant positive charge region in the lower portion of cloud. Analysis of back trajectories (Figure 10) and satellite-derived AOD observations (Figure 8) lend support to our argument that the May 11 thundercloud formed in an environment with high ice nuclei concentration, i.e., high compared to other thunderstorms. Therefore, our studies suggest that a large ice nuclei concentration can produce dominant positive charge in the lower portion of the mixed-phase region by maintaining ice saturation.
The authors express their sincere gratitude to Dr. M Mandal of IIT, Kharagpur for providing the logistics necessary to conduct fieldwork, and are also grateful to the Department of Science and Technology, Government of India, for funding this study under the Severe Thunderstorm-Observation and Regional Modeling (STORM) program. A part of this work was carried out under the DST-RFBR Indo-Russian program (DST/INT/RFBR/P-158). The authors thank Dr. D. Pradhan of IMD, Kolkata for providing RADAR data, and are also grateful to the NOAA Air Research Laboratory (ARL) for providing the HYSPLIT transport and dispersion model and the READY website (http://www.arl.noaa.gov/ready.html). Finally, the authors thank the Department of Atmospheric Science, University of Wyoming, for allowing access to their data.
- Albrecht RI, Morales CA, Silva Dias MAF: Electrification of precipitation systems over the Amazon: physical processes of thunderstorm development. J Geophys Res 2011, 116: D08209. doi:10.1029/2011JD014756 doi:10.1029/2011JD014756Google Scholar
- Baker B, Baker MB, Jayaratne ER, Latham J, Saunders CPR: The influence of diffusional growth rates on the charge transfer accompanying rebounding collisions between ice crystals and soft hailstones. QJR Meteorol Soc 1987, 113: 1193–1215. doi:10.1256/smsqj.47806 doi:10.1256/ smsqj.47806 10.1002/qj.49711347807View ArticleGoogle Scholar
- Blakeslee RJ: The electric current densities beneath thunderstorms. Ph. D. dissertation, University of Arizona, TX, USA; 1984.Google Scholar
- Browning GL, Tzur I, Roble RG: A global time-dependent model of thunderstorm electricity I: mathematical properties of the physical and numerical models. J Atmos Sci 1987, 44: 2166–2177. 10.1175/1520-0469(1987)044<2166:AGTDMO>2.0.CO;2View ArticleGoogle Scholar
- Caranti GM, Avila EE, Re MA: Charge transfer during individual collisions in ice growing from vapor deposition. J Geophys Res 1991, 96: 15365–15375. 10.1029/90JD02691View ArticleGoogle Scholar
- Carey LD, Buffalo KM: Environmental control of cloud-to-ground lightning polarity in severe storms. Mon Weather Rev 2007, 135: 1327–1353. doi:10.1175/MWR3361 doi:10.1175/MWR3361 10.1175/MWR3361.1View ArticleGoogle Scholar
- Carey LD, Rutledge SA: Electrical and multiparameter radar observations of a severe hailstorm. J Geophys Res 1998, 103(13):979–14 000.Google Scholar
- Carey LD, Rutledge SA: Characteristics of cloud-to-ground lightning in severe and nonsevere storms over the central United States from 1989–1998. J Geophys Res 2003, 108: 4483. doi:10.1029/2002JD002951 doi:10.1029/2002JD002951View ArticleGoogle Scholar
- Carey LD, Rutledge SA, Petersen WA: The relationship between severe weather reports and cloud-to-ground lightning polarity in the contiguous United States from 1989 to 1998. Mon Weather Rev 2003, 131: 1211–1228. 10.1175/1520-0493(2003)131<1211:TRBSSR>2.0.CO;2View ArticleGoogle Scholar
- Deaver LE, Krider EP: Electric fields and current densities under small Florida thunderstorms. J Geophys Res 1991, 96: 22273–22281. 10.1029/91JD02264View ArticleGoogle Scholar
- Dey S, Tripathi SN, Singh RP, Holben BN: Influence of dust storms on the aerosol optical properties over the Indo-Gangetic basin. J Geophys Res 2004, 109: D20211. doi:10.1029/2004JD004924 doi:10.1029/2004JD004924View ArticleGoogle Scholar
- Gopalakrishnan V, Pawar SD, Murugavel P, Johare KP: Electrical characteristics of thunderstorms in the Eastern part of India. J Atmos Solar Terr Phys 2010, 73: 1876–1882. doi:10.1016/j.jastp.2011.04.022 doi:10.1016/j.jastp.2011.04.022View ArticleGoogle Scholar
- Jacobson EA, Krider EP: Electrostatic field changes produced by Florida lightning. J Atmos Sci 1976, 33: 103–117. 10.1175/1520-0469(1976)033<0103:EFCPBF>2.0.CO;2View ArticleGoogle Scholar
- Kamra AK, Pawar SD: Evolution of lightning in an isolated hailstorm of moderate size in the tropics. J Geophys Res 2007, 112: D20205. doi:10.1029/2006JD007820 doi:10.1029/2006JD007820View ArticleGoogle Scholar
- Krehbiel PR, Thomas RJ, Rison W, Hamlin T, Harlin J, Davis M: GPS-based mapping system reveals lightning inside storms. Eos Trans Amer Geophys Union 2000, 81: 21–25. 10.1029/00EO00014View ArticleGoogle Scholar
- Krider EP, Musser JA: Maxwell currents under thunderstorms. J Geophys Res 1982, 87: 11171–11176. 10.1029/JC087iC13p11171View ArticleGoogle Scholar
- Lang TJ, Rutledge SA: Relationships between convective storm kinematics, precipitation, and lightning. Mon Weather Rev 2002, 130: 2492–2506. 10.1175/1520-0493(2002)130<2492:RBCSKP>2.0.CO;2View ArticleGoogle Scholar
- Lang TJ, Miller LJ, Weisman M, Rutledge SA, Barker LJ III, Bringi VN, Chandrasekar V, Detwiler A, Doesken N, Helsdon J, Knight C, Krehbiel P, Lyons WA, MacGorman D, Rasmussen E, Rison W, Rust WD, Thomas R: The Severe Thunderstorm Electrification and Precipitation Study (STEPS). Bull Am Meteorol Soc 2004, 85: 1102–1125.View ArticleGoogle Scholar
- Livingston JM, Krider EP: Electric fields produced by Florida thunderstorms. J Geophys Res 1978, 83: 385–401. 10.1029/JC083iC01p00385View ArticleGoogle Scholar
- Lyons WA, Nelson TE, Williams ER, Cramer J, Turner T: Enhanced positive cloud-to-ground lightning in thunderstorms ingesting smoke. Science 1998, 282: 77–81.View ArticleGoogle Scholar
- MacGorman DR, Burgess DW: Positive cloud-to-ground lightning in tornadic storms and hailstorms. Mon Weather Rev 1994, 122: 1671–1697. 10.1175/1520-0493(1994)122<1671:PCTGLI>2.0.CO;2View ArticleGoogle Scholar
- Mohanty M, Pradeep Kumar P: Electric field measurements of overhead thunderstorms at a tropical station using network of plate antennas. Indian J Radiol & Space Phys 2004, 33: 310–315.Google Scholar
- Murray N, Orivlle R, Huffines G: Effect of pollution from Central American fires on cloud-to-ground lightning in May 1998. Geophys Res Lett 2000, 28: 2597–2600.Google Scholar
- Nisbet JS: Thundercloud current determination from measurements at Earth’s surface. J Geophys Res 1985, 90: 5840–5856. 10.1029/JD090iD03p05840View ArticleGoogle Scholar
- Pandithurai G, Dipu S, Dani KK, Tiwari S, Bisht DS, Devara PCS, Pinker RT: Aerosol radiative forcing during dust events over New Delhi, India. J Geophys Res 2008, 113: D13209. doi:10.1029/2008JD009804View ArticleGoogle Scholar
- Pawar SD, Kamra AK: Recovery curves of the surface electric field after lightning discharges occurring between the positive charge pocket and negative charge centre in a thundercloud. Geophys Res Lett 2002, 29: 2108–2111.View ArticleGoogle Scholar
- Pawar SD, Kamra AK: Evolution of lightning and the possible initiation/triggering of lightning discharges by the lower positive charge centre in an isolated thundercloud in Tropics. J Geophys Res 2004, 109: D02205. doi:10.1029.2003JD003735Google Scholar
- Pawar SD, Kamra AK: Maxwell current density characteristics below isolated thunderstorms in tropics. J Geophys Res 2009, 114: D04208. doi:10.1029/2008JD010348Google Scholar
- Qie X, Kong X, Zhang G, Zhang T, Yuan T, Zhou Y, Zhang Y, Wang H, Sun A: The possible charge structure of thunderstorm and lightning discharges in northeastern verge of Qinghai–Tibetan Plateau. Atmos Res 2005, 76: 231–246. 10.1016/j.atmosres.2004.11.034View ArticleGoogle Scholar
- Rengarajan R, Sarin MM, Sudheer AK: Carbonaceous and inorganic species in atmospheric aerosols during wintertime over urban and high-altitude sites in North India. J Geophys Res 2007, 112: D21307. doi:10.1029/2006JD008150View ArticleGoogle Scholar
- Rust WD, MacGorman DR: Possibly inverted-polarity electrical structures in thunderstorms during STEPS. Geophys Res Lett 2002, 29: 29. doi:10.1029/2001GL014303Google Scholar
- Rust WD, MacGorman DR, Arnold RT: Positive cloud-to-ground lightning flashes in severe storms. Geophys Res Lett 1981, 8: 791–794. 10.1029/GL008i007p00791View ArticleGoogle Scholar
- Rust WD, MacGorman DR, Bruning EC, Weiss SA, Krehbiel PR, Thomas RJ, Rison W, Hamlim T, Harlin J: Inverted polarity electrical structures in thunderstorms in the Severe Thunderstorm Electrification and Precipitation Study (STEPS). Atmos Res 2005, 76: 247–271. doi:10.1016/j.atmosres.2004.11.029 doi:10.1016/j.atmosres.2004.11.029 10.1016/j.atmosres.2004.11.029View ArticleGoogle Scholar
- Stolzenburg M: Observations of high ground flash densities of positive lightning in summertime thunderstorms. Mon Weather Rev 1994, 122: 1740–1750. 10.1175/1520-0493(1994)122<1740:OOHGFD>2.0.CO;2View ArticleGoogle Scholar
- Tiwari S, Srivastava AK, Bisht DS, Bano T, Singh S, Behura S, Srivastava Manoj K, Chate DM, Padmanabhamurty B: Black carbon and chemical characteristics of PM10 and PM2.5 at an urban site of North India. J Atmos Chem 2010, 62: 193–209. doi:10.1007/s10874–010–9148View ArticleGoogle Scholar
- Vonnegut B, Moore CB: Giant electrical storms. Atmos Res. In 2005: Thermodynamic conditions favorable to superlative thunderstorm updraft, mixed phase microphysics and lightning flash rate Edited by: Smith LG. 1958, 76: 288–306.Google Scholar
- Wiens KC, Rutledge SA, Tessendorf SA: The 29 June 2000 suppercell observed during STEPS. Part II: lightning and charge structure. J Atmos Sci 2005, 62: 4151–4177. 10.1175/JAS3615.1View ArticleGoogle Scholar
- Williams ER, Zhang R, Rydock J: Mixed-phase microphysics and cloud electrification. J Atmos Sci 1991, 48: 2195. 10.1175/1520-0469(1991)048<2195:MPMACE>2.0.CO;2View ArticleGoogle Scholar
- Williams E, Rosenfeld D, Madden N, Gerlach J, Gears N, Atkinson L, Dunnemann N, Frostrom G, Antonio M, Biazon B, Camargo R, Franca H, Gomes A, Lima M, Machado R, Manhaes S, Nachtigall L, Piva H, Quintiliano W, Machado L, Artaxo P, Roberts G, Renno N, Blakeslee R, Bailey J, Boccippio D, Betts A, Wolff D, Roy B, Halverson J, et al.: Contrasting convective regimes over the Amazon: implications for cloud electrification. J Geophys Res 2002, 107(D20):LBA 50–1-LBA 50–19. doi:10.1029/2001JD000380 doi:10.1029/2001JD000380Google Scholar
- Williams ER, Mustak V, Rosenfeld D, Goodman S, Boccippio D: Thermodynamic conditions favorable to superlative thunderstorm updraft, mixed phase microphysics and lightning flash rate. Atmos Res 2005, 76: 288–306. 10.1016/j.atmosres.2004.11.009View ArticleGoogle Scholar
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