Interannual and interdecadal variability in United States surface-air temperatures

• Main Authors: Michael D. Dettinger, Michael Ghil, Christian L. Keppenne
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1910
• Subjects: Pacific; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.482.7409; http://tenaya.ucsd.edu/~dettinge/hcn_temps95.pdf

Abstract. Monthly mean surface-air temperatures at 870 sites in the contiguous United States were analyzed for interannual nd interdecadal v riability over the time interval 1910-87. The tempera-tures were analyzed spatially by empirical-orthogonal-function analysis and temporally by singular-spectrum analysis (SSA). The dominant modes of spatio-temporal variability are trends and non-periodic variations with time scales longer than 15 years, decadal-scale oscillations with periods of roughly 7 and 10 years, and interannual oscillations of 2.2 and 3.3 years. Together, these modes contribute about 18 % of the slower-than-annual United States temperature variance. Two leading components roughly capture the m an hemispheric temperature trend and represent a long-term warming, largest in the southwest, accompanied by cooling of the domain's outheastern quadrant. The extremes of the 2.2-year interannual oscillation characterize temperature differences b tw en the Northeastern and Southwestern States, whereas the 3.3-year cycle is p esent mostly in the West-ern States. The 7- to 10-year oscillations are rauch less regular and persistent than the interannual oscillations and characterize temperature differences b tw en the western and interior sectors of the United States. These continental- orregionat-scale temperature variations may be related to climatic variations with similar periodicities, either global r centered in other regions; such variations include quasi-biennial oscillations over the tropical Pacific or North Atlantic and quasi-triennial oscillations of North Pacific sea-surface temperatures. 1.