Climate variability and change in Mediterranean-type climates

Seager, Richard, Osborn, Timothy ORCID: https://orcid.org/0000-0001-8425-6799, Kushnir, Yochanan, Simpson, Isla, Nakamura, Jennifer and Liu, Haibo (2019) Climate variability and change in Mediterranean-type climates. Journal of Climate, 32 (10). 2887–2915. ISSN 0894-8755

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Abstract

Mediterranean-type climates are defined by temperate, wet winters and hot or warm dry summers and exist at the western edges of five continents in locations determined by the geography of winter storm tracks and summer subtropical anticyclones. The climatology, variability and long term changes in winter precipitation in Mediterranean-type climates, and the mechanisms for model-projected near-term future change, are analyzed. Despite commonalities in terms of location in the context of planetary scale dynamics, the causes of variability are distinct across the regions. Internal atmospheric variability is the dominant source of winter precipitation variability in all Mediterranean-type climate regions, but only in the Mediterranean is this clearly related to annular mode variability. Ocean forcing of variability is a notable influence only for California and Chile. As a consequence, potential predictability of winter precipitation variability in the regions is low. In all regions, the trend in winter precipitation since 1901 is similar to that which arises as a response to changes in external forcing in the models participating in the Coupled Model Intercomparison Project Five. All Mediterranean-type climate regions, except in North America, have dried and the models project further drying over coming decades. In the northern hemisphere, dynamical processes are responsible: development of a winter ridge over the Mediterranean that suppresses precipitation and of a trough west of the North American west coast that shifts the Pacific stormtrack equatorward. In the southern hemisphere, mixed dynamic-thermodynamic changes are important that place a minimum in vertically integrated water vapor change at the coast and enhance zonal dry advection into Mediterranean-type climate regions inland.

Item Type: Article
Uncontrolled Keywords: sdg 13 - climate action ,/dk/atira/pure/sustainabledevelopmentgoals/climate_action
Faculty \ School: Faculty of Science > School of Environmental Sciences
University of East Anglia Research Groups/Centres > Theme - ClimateUEA
UEA Research Groups: Faculty of Science > Research Groups > Climatic Research Unit
Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences
Faculty of Social Sciences > Research Centres > Water Security Research Centre
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Depositing User: LivePure Connector
Date Deposited: 01 Mar 2019 13:30
Last Modified: 14 Jun 2023 13:40
URI: https://ueaeprints.uea.ac.uk/id/eprint/70067
DOI: 10.1175/JCLI-D-18-0472.1

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