Mechanisms of squall formation in the Moscow region on May 29, 2017 - - PowerPoint PPT Presentation

Mechanisms of squall formation in the Moscow region on May 29, 2017

Kuksova N.E., Toropov P.A.

Purpose: study of the mechanism of squally wind amplification in Moscow on May 29, 2017 Tasks:

• analysis of storm conditions based on station and

remote observational data, as well as reanalysis data.

• assessment of the event reproduction based on

numerical experiments using the WRF-ARW mesoscale non-hydrostatic model.

• formulation of a hypothesis about the physical

mechanisms of the phenomenon.

Materials and methods

АМК Vaisala MAWS-301 Satellite METEOSAT-10 DMRL-С SODAR«MODOS» MTP-5 plofier

Severe meteorological events

https://www.essl.org/cms/convective-windstorms-in-2017- episode-1-29-may/ (Report on climate features in the territory of the Russian Federation for 2016. Roshydromet, 2017)

100 200 300 400 500 600 700

Number of severe events

Fron

• ntal analysis at sea level

el pres essure

12 UTC

T=25° C T=15° C

Character eristics obser erved ed by the e meteor eorolog

• gical obser

ervator

• ry of MSU

995 997 999 1001 1003 1005 1007 1009 1011 1013 1015 5 10 15 20 25 30 Pressure, e, hPa Air temper erature, °С Wind speed ed, m/s Time

Causes es of extrem eme wind gusts

Low level jet Strong dynamic instability

Reanalysis Critical value Wind shear 0.0027 1/s > 0.0013 1/s

Low level jet

25 m/s

Mesoscale nonhydrostatic model el WRF-ARW

3 domains Grid spacing: 10, 5, 1 km Initial and boundary conditions: reanalysis ERA-Interim 0.75 °

Observation (SODAR «MODOS») Modeling

Wind speed

м/с

Con

• nclusion
• ns:
• 1. The event occurred as a result of:
• lowering the low level jet due to intense dynamic

instability of the atmosphere

• downward flow on the active cold atmospheric front
• 2. As a result of mesoscale modeling, it was revealed

that the model reproduced well the space-time structure of this phenomenon, with the exception of the temperature effect

Thanks for your attention!