Mauricio Oliveira - April 24

Large Sensitivity of Supercell Morphology, Cold Pool Intensity, and Tornadogenesis to Single- and Multimoment Microphysics   Mauricio I. Oliveira VIDEO AVAILABLE  OF THE SEMINAR ON GOOGLE DRIVE LINK: https://drive.google.com/open?id=1HBfNsgQj6VoyCQY8KbWCH4IGraNhQiZm ABSTRACT High-resolution numerical simulations of tornadic storms can exhibit extreme sensitivity to microphysics parameterizations. A simple change from a single to

Start

April 24, 2020 - 3:00 pm

End

April 24, 2020 - 4:00 pm

Large Sensitivity of Supercell Morphology, Cold Pool Intensity, and Tornadogenesis to Single- and Multimoment Microphysics

 

Mauricio I. Oliveira

VIDEO AVAILABLE  OF THE SEMINAR ON GOOGLE DRIVE LINK:

https://drive.google.com/open?id=1HBfNsgQj6VoyCQY8KbWCH4IGraNhQiZm

ABSTRACT

High-resolution numerical simulations of tornadic storms can exhibit extreme sensitivity to microphysics parameterizations. A simple change from a single to a multimoment scheme can drastically affect the tornadogenetic potential of storms or even change the parent convective mode. In this study, two idealized supercell simulations are performed in order to investigate how changes in storm morphology and cold pool affect tornadogenesis in a single-moment (SM) and a double-moment (DM) schemes. Results show remarkably different supercell structure among experiments, which range from high- to low-precipitation morphologies, depending on whether the BMP used is SM or DM, respectively. It is found that the storm in the SM experiment produces excessively cold outflow and is unable to sustain stronger vortices, although the baroclinic production of horizontal vorticity is far larger than in the DM scheme. The low-precipitation supercell produces a persistent tornado-like vortex even in the absence of significant baroclinity, suggesting that prevalence of warmer outflow overwhelms the effects of baroclinic vorticity generation in this case. A budget analysis of the microphysical processes that lead to latent cooling in downdrafts regions reveal large differences between the rates of hydrometeor melting and evaporation in the two experiments. Specifically, latent cooling in the SM scheme is found to be three times larger than in the DM scheme. These results indicate that more studies on the sensitivity of tornadic supercells that include a larger variety of MM schemes are warranted.