Climatic Change

, Volume 115, Issue 2, pp 291–309 | Cite as

Future heat vulnerability in California, Part I: projecting future weather types and heat events

  • Scott C. Sheridan
  • Cameron C. Lee
  • Michael J. Allen
  • Laurence S. Kalkstein


Excessive heat significantly impacts the health of Californians during irregular but intense heat events. Through the 21st century, a significant increase in impact is likely, as the state experiences a changing climate as well as an aging population. To assess this impact, future heat-related mortality estimates were derived for nine metropolitan areas in the state for the remainder of the century. Here in Part I, changes in oppressive weather days and consecutive-day events are projected for future years by a synoptic climatological method. First, historical surface weather types are related to circulation patterns at 500mb and 700mb, and temperature patterns at 850mb. GCM output is then utilized to classify future circulation patterns via discriminant function analysis, and multinomial logistic regression is used to derive future surface weather type at each of six stations in California. Five different climate model-scenarios are examined. Results show a significant increase in heat events over the 21st century, with oppressive weather types potentially more than doubling in frequency, and with heat events of 2 weeks or longer becoming up to ten times more common at coastal locations.



We would like to express our gratitude to the California Air Resources Board for their financial support of this research, especially Deborah Drechsler, our project manager. We also would like to acknowledge Katharine Hayhoe and Jeff Van Dorn for their provision of most of the raw NNR and GCM data. We thank the editors and three anonymous reviewers who helped make our manuscript stronger.


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Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Scott C. Sheridan
    • 1
  • Cameron C. Lee
    • 1
  • Michael J. Allen
    • 1
  • Laurence S. Kalkstein
    • 2
  1. 1.Department of GeographyKent State UniversityKentUSA
  2. 2.Department of Geography and Regional StudiesUniversity of MiamiCoral GablesUSA

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