16–19 May 2022
Utrecht
Europe/Amsterdam timezone

MCS longevity in the transition from land to sea

17 May 2022, 12:27
2m
Public Library (Utrecht)

Public Library

Utrecht

Neude 11, 3512 AE Utrecht, the Netherlands
Poster Mesoscale organization of shallow and deep cumulus convection Poster pitches

Speaker

Irene Livia Kruse (NBI)

Description

Mesoscale convective systems (MCSs) are organized clusters of thunderstorms spanning more than 100 km horizontally, persisting often for multiple hours. They are known to be the dominant source of rainfall in the tropics, and the longest-lived MCSs are shown to be largely responsible for tropical extreme precipitation [Roca and Fiolleau, 2020]. Globally, the most extreme storms tend to be located over land, and the most intense storms over oceans tend to be adjacent to land, where motion is favored from land to ocean, e.g. tropical West Africa and the adjacent Eastern Atlantic Ocean [Zipser et al., 2006]. The mechanisms behind the intensification or dissipation of MCSs advected from land to sea are not well established yet, and hurricanes in the Western Atlantic can often be traced back to MCSs originating off the African coast.

We here investigate the evolution of MCSs emerging from satellite data over tropical Africa and the Eastern Atlantic Ocean. We use a 5-year database of tracked MCSs from infrared satellite data, TOOCAN [Fioellau and Roca, 2013]. We focus on the Atlantic hurricane season (June-November) and on all MCSs that are formed over land and cross over to sea. We look for relationships between MCS longevity, the time of crossing, and the surface temperature. We compare the results to CRM simulations of deep convection over a land surface (oscillating surface temperatures) progressing to sea surface (constant surface temperatures).

Primary author

Co-authors

Jan Haerter (Niels Bohr Institute, Copenhagen University) Romain Fiévet (Niels Bohr Institute)

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