The case of successive passage of two mesoscale convective systems (a mesoscale convective complex and a squall line) in the vicinity of Tomsk, which was observed on 26 June 2020 is analyzed. It is noted that the passage of the mesoscale convective complex corresponds to a sharp change in the structure of the vertical temperature profile and a high value of the vertical temperature gradient. The time interval that precedes the development of thunderclouds corresponds to the value of the vertical temperature gradient for the IMCES SB RAS territory – 2.18 °/100 m. Sudden changes in values from the positive vertical temperature gradient to the negative and vice versa correspond to the passage of the squall line. The data of the electric field potential gradient profile and the intensity of thunderstorm activity allow us to consider in more detail the dynamics of changes in the atmospheric boundary layer.
In this work, estimates of thunderstorm activity during the passage of mesoscale convective complexes (MCC) in the south of Western Siberia for 2016–2019 were obtained. When analyzing the trajectories of the MCC movement, it was revealed that it passes from the southwest to the northeast. The duration of the thunderstorm activity generated by the MCC is on average about 9 hours. At the same time, the duration of thunderstorm activity less than 4 hours was not noted. average area of a thunderstorm center ~ 5700 km2. The average distance covered by a thunderstorm is ~ 470 km. According to WWLLN, the number of lightning strikes is ~ 530.
The slow variations of electric field potential gradient were investigated during the passage of mesoscale convective complexes (MCC) over the city of Tomsk. Variations of potential gradient during the MCC are characterized by prolonged periods of negative disturbance related with the passage of the base of the cloud system, which has mainly a negative charge, according to 31 cases. The positive disturbance has a shorter duration and is linked to the anvil. Variations of electric field potential gradient under the effect of MCC have an average duration of 2 hours and an amplitude of 12 kV/m.
Estimations of the morphological and microphysical characteristics of mesoscale convective complexes (MCC) in the south of Western Siberia for 2010–2019 years received. It was noted that the MCC lengths along latitude and longitude are on average ~ 140 and 120 km, and typical ranges of their change (limited by the 25th and 75th percentiles) are 120÷160 km and 100÷130 km, respectively. The MCC upper boundary height is on average 12 km and generally changes in the range from 9 to 13 km. The MCC cloud particles effective radius is on average 27 microns and typical range of his change are 25÷29 microns. The integral water content of MCC clouds is on average 1,2 kg/m2 , and most often varies in the range from 0,8 to 2,1 kg/m2 .
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.