Interannual to interdecadal surface temperature variability of Florida

Patterns of interannual to interdecadal temperature variability in Florida will be presented, with discussion of possible links to and correlations with the Pacific Decadal Oscillation (PDO), the North Atlantic Oscillation (NAO), El Nino/Southern Oscillation (ENSO), and the North Atlantic Subtropical Anticyclone. Change of large-scale circulation explains the observed temperature changes. These circulation patterns are examined with the Hadley Center's North Atlantic Ocean basin sea level pressure (SLP) dataset, which was used to create the North Atlantic Subtropical Anticyclone Index (NASAI). This new index was used in conjunction with established climate indices for PDO, NAO, and ENSO and the United States Historical Climatology Network (USHCN) monthly mean temperatures over Florida to investigate links to temperature patterns for the period 1927-1997.

Through statistical and visual analyses some influence on Florida's temperatures is found to come from the NAO and ENSO. There is no influence found in the PDO. Empirical Orthogonal Function (EOF) analysis shows the dominant SLP patterns of the North Atlantic Ocean basin. The most energetic or leading mode of the EOF analysis accounts for 30.59% of the variance. The NASAI is defined as this mode's Principle Component (PC) time series, given the associated spatial pattern's primary action center in the vicinity of the subtropical high. Through Canonical Correlation Analysis (CCA) a statistical relationship is identified between Florida's surface temperatures and the North Atlantic Subtropical Anticyclone. The first mode of the CCA for the winter (DJF) season has temperatures ranging from 0.9 to 1.5°C above normal for all 20 stations. This mode also has a coefficient of determination (r²) value of .68. The first mode for the spring (MAM) also has temperatures above normal. They range from 0.3 to 0.6°C with an r² value of .78.