Recorded presentation10B.3
Evidence of a late 20th century North Atlantic wet regime
Steven A. Mauget, USDA, Lubbock, Texas
An analysis here of intra- to multi-decadal variation in terrestrial precipitation time series during 1901-98 revealed indirect evidence of a significant North Atlantic wet regime in the final decades of the 20th century. By sampling annual precipitation rankings over 6-30 year moving time windows and converting those rankings to Mann-Whitney U statistics, significant concentrations of wet and dry years were identified relative to a null hypothesis that assumed stationary climate variability. This approach showed a highly significant incidence of wet years in a time series of spatially averaged North American precipitation during 1972-98, with 8 of the 10 wettest years of 1901-98 occurring during that 27-year period. A comparably significant incidence of late century wetness was also found over a northern European region, with 7 of the 10 wettest years occurring during 1978-98. Although wet and dry regimes were also found over other continental areas in the closing decades of the 20th century, these late century North American and northern European wet periods stood out as the most statistically significant found here during 1901-98. It is suggested that these recent wet periods are actually terrestrial evidence of a single and significant multi-decadal precipitation mode extending across the North Atlantic, and are possibly representative of a broader change in North Atlantic hydrology. Recorded presentation
Session 10B, Climate of the 20th Century (C20C) Part III
Wednesday, 23 January 2008, 10:30 AM-12:00 PM, 217-218
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