Using Climate Divisions to Analyze Variations and Trends in Alaska Temperature and Precipitation

作者：Bieniek Peter A^*; Walsh John E; Thoman Richard L; Bhatt Uma S

来源：Journal of Climate, 2014, 27(8): 2800-2818.

DOI：10.1175/JCLI-D-13-00342.1

• Multidecadal variability
• Climate change
• Climate variability
• Arctic
• Trends
• Pacific decadal oscillation

By extending the record of Alaskan divisional temperature and precipitation back in time, regional variations and trends of temperature and precipitation over 1920-2012 are documented. The use of the divisional framework highlights the greater spatial coherence of temperature variations relative to precipitation variations. %26lt;br%26gt;The divisional time series of temperature are characterized by large interannual variability superimposed upon low-frequency variability, as well as by an underlying trend. Low-frequency variability corresponding to the Pacific decadal oscillation (PDO) includes Alaska%26apos;s generally warm period of the 1920s and 1930s, a cold period from the late 1940s through the mid-1970s, a warm period from the late 1970s through the early 2000s, and a cooler period in the most recent decade. An exception to the cooling of the past decade is the North Slope climate division, which has continued to warm. There has been a gradual upward trend of Alaskan temperatures relative to the PDO since 1920, resulting in a statewide average warming of about 1 degrees C. %26lt;br%26gt;In contrast to temperature, variations of precipitation are less consistent across climate divisions and have much less multidecadal character. Thirty-year trends of both variables are highly sensitive to the choice of the subperiod within the overall 93-yr period. The trends also vary seasonally, with winter and spring contributing the most to the annual trends.

• 出版日期2014-4