Coronavirus Information for the UC San Diego Community

Our leaders are working closely with federal and state officials to ensure your ongoing safety at the university. Stay up to date with the latest developments. Learn more.

Precipitation in a warming world: Assessing projected hydro-climate changes in California and other Mediterranean climate regions

TitlePrecipitation in a warming world: Assessing projected hydro-climate changes in California and other Mediterranean climate regions
Publication TypeJournal Article
Year of Publication2017
AuthorsPolade S.D, Gershunov A, Cayan DR, Dettinger MD, Pierce DW
JournalScientific Reports
Date Published2017/09
Type of ArticleArticle
ISBN Number2045-2322
Accession NumberWOS:000409561800036
Keywordsatmospheric rivers; CMIP5; ensemble; floods; frequency; models; resolution; variability; winter precipitation

In most Mediterranean climate (MedClim) regions around the world, global climate models (GCMs) consistently project drier futures. In California, however, projections of changes in annual precipitation are inconsistent. Analysis of daily precipitation in 30 GCMs reveals patterns in projected hydrometeorology over each of the five MedClm regions globally and helps disentangle their causes. MedClim regions, except California, are expected to dry via decreased frequency of winter precipitation. Frequencies of extreme precipitation, however, are projected to increase over the two MedClim regions of the Northern Hemisphere where projected warming is strongest. The increase in heavy and extreme precipitation is particularly robust over California, where it is only partially offset by projected decreases in low-medium intensity precipitation. Over the Mediterranean Basin, however, losses from decreasing frequency of low-medium-intensity precipitation are projected to dominate gains from intensifying projected extreme precipitation. MedClim regions are projected to become more sub-tropical, i.e. made dryer via pole-ward expanding subtropical subsidence. California's more nuanced hydrological future reflects a precarious balance between the expanding subtropical high from the south and the south-eastward extending Aleutian low from the north-west. These dynamical mechanisms and thermodynamic moistening of the warming atmosphere result in increased horizontal water vapor transport, bolstering extreme precipitation events.

Short TitleSci Rep
Student Publication: