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Multidecadal global and regional trends in 1000 mb and 500 mb cyclone frequencies
Author(s) -
Key Jeffrey R.,
Chan Alan C. K.
Publication year - 1999
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl900367
Subject(s) - climatology , cyclogenesis , northern hemisphere , tropical cyclogenesis , cyclone (programming language) , tropical cyclone , southern hemisphere , extratropical cyclone , environmental science , geology , field programmable gate array , computer science , computer hardware
Trends in seasonal and annual frequencies of 1000 mb and 500 mb closed low pressure centers, or “cyclones”, over the 40 year period 1958–1997 are determined for latitudinal zones and regions of cyclogenesis. Statistically significant trends are found throughout the northern hemisphere and in the southern hemisphere tropics, though the trends vary by season. Opposite trends were observed at the two levels in some regions. No significant differences in cyclone frequencies were found when El Niño and La Niña years were compared. Cyclone frequencies in North America and Europe are poorly correlated with the North Atlantic Oscillation.