Title
Modelling a tropical-like cyclone in the Mediterranean Sea under present and warmer climate
Date Issued
08 January 2021
Access level
open access
Resource Type
journal article
Author(s)
Koseki S.
Mooney P.A.
Angel Gaertner M.
De La Vara A.
Jesus Gonzalez-Aleman J.
Universidad de Alcalá
Publisher(s)
Copernicus GmbH
Abstract
This study focuses on a single Mediterranean hurricane (hereafter medicane), to investigate its response to global warming during the middle of the 21st century and assesses the effects of a warmer ocean and a warmer atmosphere on its development. Our investigation uses the state-of-The-Art regional climate model WRF to produce the six-member, multi-physics ensembles. Results show that our model setup simulates a realistic cyclone track and the transition from an initial disturbance to a tropical-like cyclone with a deep warm core. However, the simulated transition occurs earlier than for the observed medicane. The response of the medicane to future climate change is investigated with a pseudo global warming (PGW) approach. This is the first application of the PGW framework to medicanes. The PGW approach adds a climate change delta (defined as difference between future and present climate) to WRF s boundary conditions which is obtained for all prognostic variables using the mean change in an ensemble of CMIP5 simulations. A PGW simulation where the climate change delta is added to all prognostic variables (PGWALL) shows that most of the medicane characteristics moderately intensify, e.g. surface wind speed, uptake of water vapour, and precipitation. However, the minimum sea level pressure (SLP) is almost identical to that under present climate conditions. Two additional PGW simulations were undertaken; One simulation adds the projected change in sea surface and skin temperature only (PGWSST) while the second simulation adds the PGW changes to only atmospheric variables (PGWATMS); i.e. we use present-day sea surface temperatures. These simulations show opposing responses of the medicane. In PGWSST, the medicane is more intense than PGWALL as indicated by lower SLP values, the stronger surface wind, and the more intense evaporation and precipitation. In contrast, the medicane in PGWATMS still transitions into a tropical-like cyclone with a deep warm core, but the PGWATMS medicane weakens considerably (SLP, surface wind, and rainfall decrease). This difference can be explained by an increase in water vapour driven by the warmer ocean surface (favourable for cumulus convection). The warmer and drier atmosphere in PGWATMS tends to inhibit condensation (unfavourable for cumulus convection). The warmer ocean and warmer atmosphere have counteracting effects which leads to only a modest enhancement of the medicane by global warming. The novel approach in this study provides new insights into the different roles of warming of the ocean and atmosphere in medicane development.
Start page
53
End page
71
Volume
21
Issue
1
Language
English
OCDE Knowledge area
Meteorología y ciencias atmosféricas Investigación climática
Scopus EID
2-s2.0-85099092541
Source
Natural Hazards and Earth System Sciences
ISSN of the container
15618633
Sponsor(s)
Financial support. This study has been supported by IB-Acknowledgements. We would like to express our grateful appreciation to Emmanouil Flaounas and the one anonymous reviewer for their very constructive and helpful comments and suggestions so that our manuscript was improved substantially. This study has been carried out under the IBERTROPIC project (grant agreement no. CGL2017-89583-R), funded by the Spanish Ministry of Science, Innovation and Universities, the Spanish State Research Agency, and the European Regional Development Fund. Shunya Koseki is supported by Giner de los Ríos 2018/2019 and 2019/2020, which is a scholarship grant by la Universidad de Alcalá. Juan Jesus González Alemán has been funded through grants BES_2014-067905 and FJC2018-035821-I by the Spanish State Research Agency. The computational resources come from the Norwegian High-Performance Computing Program (NS9039K).
Sources of information: Directorio de Producción Científica Scopus