"December 2008." Includes bibliographical references.

Introduction -- Reanalysis -- Attribution -- Connections between reanalysis and attribution -- Reanalysis applications and uses -- Reanalysis of historical climate data for key atmospheric features -- Climate reanalysis and its role within a comprehensive climate observing system -- Role of reanalysis in understanding climate processes and evaluating climate models -- Using current reanalyses to identify and understand major seasonal-to-decadal climate variations -- Climate trends in surface temperature and precipitation derived from reanalyses versus from independent data -- Steps needed to improve climate reanalysis -- Attributation of the causes of climate variations and trends over North America during the modern reanalysis period -- Key findings -- Introduction -- Climate attribution and scientific methods used for establishing attribution -- Present understanding of North American annual temperature and precipitation climate trends from 1951 to 2006 -- Present understanding of United States seasonal and regional differences in temperature and precipitation trends from 1951 to 2006 -- Nature and cause of apparent rapid climate shifts from 1951 to 2006 -- Understanding of the causes for North American high-impact drought events for 1951 to 2006 -- Recommendations -- Need for a systematic approach to climate analysis and reanalysis -- Recommendations for improving future climate analyses and reanalyses -- Need for improved climate attribution -- Recommendations for improving climate attribution capabilities.