Characteristics of Upward Lightning on the Beijing 325 m Meteorology Tower and Corresponding Thunderstorm Conditions

Abstract

Comprehensive observation on lightning striking the 325 m meteorology tower has been conducted in Beijing, China, during the summer season from 2012 to 2016. For the 20 tower flashes captured by high‐speed video camera, 19 (95%) cases were initiated from the tower (termed as upward lightning (UL)), with duration of 42–844 ms. Most ULs (84.2%, 16/19) were triggered by nearby lightning, of which positive cloud‐to‐ground flashes (+CGs) account for 87.5% (14/16). Analysis on the characteristics of the causal or triggering lightning flashes suggests that the approaching of negative leader process through in‐cloud horizontal channel is the vital condition for the initiation of upward leader. Generally, the UL initiation follows the nearby discharges, while for a special case in our data set, the nearby positive return stroke was found to occur after the establishment of an upward channel from the tower. It is worth noting that this +CG led to a significant enhancement of the tower‐initiating leader, with eight subsequent return strokes and two M component processes occurring to the tower thereafter. The radar echo of the corresponding thunderstorm indicates that the other‐triggered UL (OTUL) tended to occur at the dissipation stage of the thunderstorm with relatively low cloud top height and weak radar echo, while the self‐initiating UL (SIUL) was more likely to occur when the thunderstorm was in the mature stage and the tower was underneath the stratiform clouds behind the convective region. The meteorology condition for SIUL involved lower ambient temperature and higher wind speed, as compared to the OTUL.

Meteorological aspects of winter upward lightning from an instrumented tower in the Pyrenees

“…Our findings agree with previous studies (e.g. [24], [26], [27]), where upward lightning from towers were initiated in the stratiform region of a stormy system with low cloud top heights, low charge centres and overall low lightning frequency.…”

“…Evidence of lightning at the ENT leads us to think in an effective charge transfer from the active convection area to the neighbouring stratiform region (Fig.6), favouring the electric field enhancement above the tower and the efficient charge accumulation in the stratiform cloud, enough to support UL. According to Yuan et al [24] while the charge transferred from the active convection area may had facilitated the efficient charge accumulation in the stratiform cloud, the low cloud top height may also be vital for the initiation of the upwards. Micro Rain Radar profiles from 2018/01/06 22:00 UTC to 2018/01/07 00:00 UTC reflecitivity (top panel) and fall speed (bottom panel) MRR observations (Fig.…”

“…The -10ºC was at 3,500 m asl (fulfilling Shindo's condition), while the -20ºC was around 5,000 m asl, which is indicative of the height of the main negative charge region. Such low charge centre is vital for the initiation of upward leaders from high structures [24].…”

Evolution of an Upward Negative Lightning Flash Triggered by a Distant +CG From a 257‐m‐Tall Tower, Including Initiation of Subsequent Strokes

“…The triggering negative leaders in categories (2) and (3) were often observed to be horizontally extensive and travel through trailing stratiform regions of thunderclouds (e.g., Jiang et al, 2014;Qi et al, 2018;Warner, Saba, Rudge, et al, 2012;Yuan et al, 2017). The triggering negative leaders in categories (2) and (3) were often observed to be horizontally extensive and travel through trailing stratiform regions of thunderclouds (e.g., Jiang et al, 2014;Qi et al, 2018;Warner, Saba, Rudge, et al, 2012;Yuan et al, 2017).…”

Synchronized Two‐Station Optical and Electric Field Observations of Multiple Upward Lightning Flashes Triggered by a 310‐kA +CG Flash

“…Wu, B., Lyu, W., Qi, Q., Ma, Y., Chen, L., Zhang, Y., et al (2019). The existence of one or more tall objects in urban areas can be used for studying the processes of upward lightning flashes initiation and development (Lu et al, 2009;Mazur & Ruhnke, 2011;Smorgonskiy et al, 2015;Yuan et al, 2017;Zhu et al, 2016). Tall buildings in different areas of the city can modify the electrical environment over a large area and facilitate the occurrence of upward lightning flashes from multiple tall objects in response to the same +CG flash (Garolera et al, 2015;Miki et al, 2005;Saba et al, 2016;Warner, 2012).…”