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Journal Article: BibTeX citation key:  Fink2010b
Fink, A. H., Schrage, J. M. & Kotthaus, S. (2010) On the potential causes of the non-stationary correlations between West African precipitation and Atlantic hurricane activity. IN Journal of Climate, 23. 5437–5456.
Added by: Andreas Fink 2010-08-19 15:33:39    Last Edited by: Fanny Lefebvre 2010-11-29 16:50:25
Categories: Atmospheric processes, Environment and Climate Monitoring, General
Keywords: Climate, Interannual variability, Rainfall
Creators: Fink, Kotthaus, Schrage
Collection: Journal of Climate

Peer reviewed
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For years, various indices of seasonal West African precipitation have served as useful predictors of the overall tropical cyclone activity in the Atlantic Ocean. Since the mid-1990s, the correlation unexpectedly deteriorated. In the present study, statistical techniques are developed to describe the nonstationary nature of the correlations between annual measures of Atlantic tropical cyclone activity and three selected West African precipitation indices (namely, western Sahelian precipitation in June–September, central Sahelian precipitation in June–September, and Guinean coastal precipitation in the preceding year’s August–November period). The correlations between these parameters are found to vary over the period from 1921 to 2007 on a range of time scales. Additionally, considerable year-to-year variability in the strength of these correlations is documented by selecting subsamples of years with respect to various meteorological factors. Broadly, in years when the environment in the main development region is generally favorable for enhanced tropical cyclogenesis (e.g., when sea surface temperatures are high, when there is relatively little wind shear through the depth of the troposphere, or when the relative vorticity in the midtroposphere is anomalously high), the correlations between indices of West African monsoon precipitation and Atlantic tropical cyclone activity are considerably weaker than in years when the overall conditions in the region are less conducive. Other moreremote climate parameters, such as the phase of the Southern Oscillation, are less effective at modulating the nature of these interactions.
Added by: Andreas Fink    Last Edited by: Fanny Lefebvre