Variation Of The Köppen C/D Climate Boundary In The Central United States During The 20Th Century
Climate change, Climate classification
The spatial and temporal variation of the C/D Köppen climate boundary in the central United States is examined for the period 1900 to 1999. Mean January temperature data from the U.S. Historical Climatology Network for 67 sites located between 37°N and 41.5°N latitude and 90°W and 100°W longitude are utilized. The variation of the boundary between the C and D climates (i.e.; 26.6°F isoline) is illustrated for the entire 100-year study period and four quarter-century periods, as well as for individual decades (1900s, 1910s.,, 1980s, 1990s). For the quarter-century climatic periods, the latter two (1950 to 1974, 1975 to 1999) had C/D boundaries farther south (implying "colder" winters) compared to the positions for the first two quarter-century periods. The most anomalous feature for the decadal maps is the distinct southerly location of the C/D boundary for the recent decade of the 1970s. Although the C/D boundaries for the decades of the 1980s and 1990s generally are located slightly north of the 100-year overall mean location (implying "warmer" than average winter conditions), several earlier decades (e.g., 1900s, 1920s, 1930s) had even more northerly positions. Therefore, this study does not provide evidence of a trend toward wintertime warming and a northerly migration of the C/D climate boundary within the central United States.
Original Publication Date
DOI of published version
Suckling, Philip W. and Mitchell, Martin D., "Variation Of The Köppen C/D Climate Boundary In The Central United States During The 20Th Century" (2000). Faculty Publications. 3681.