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Journal Article: BibTeX citation key:  Schrage2007a
Schrage, J. M. & Fink, A. H. (2007) Use of a Rain Gage Network to Infer the Influence of Environmental Factors on the Propagation of Quasi-Linear Convective Systems in West Africa. IN Weather and Forecasting, 22. 1016–1030.
Added by: Andreas Fink 2010-08-19 14:15:58    Last Edited by: Fanny Lefebvre 2010-10-27 18:53:17
Categories: Atmospheric processes
Keywords: Dynamics, Observation system, Rainfall, Soudanian zone
Creators: Fink, Schrage
Collection: Weather and Forecasting

Peer reviewed
Number of views:  866
Popularity index:  45.82%
Maturity index:  published

The West African squall line is a key quasi-linear storm system that brings much of the precipitation observed in the data-poor Sudanian climate zone. Squall lines propagate at a wide range of speeds and headings, but the lack of operational radar stations in the region makes quantifying the propagation of the squall lines difficult. A new method of estimating the propagation rate and heading for squall lines is proposed. Based on measurements of the time of onset of precipitation (OOP) at a network of rain gauge stations, an estimate of the propagation characteristics of the squall line can be inferred. By combining estimates of propagation rate with upper-air observations gathered at a nearby radiosonde station, the impact of various environmental factors on the propagation characteristics of West African squall lines is inferred. Results suggest that the propagation speed for West African squall lines is related to the conditions at midtropospheric levels, where dry air and an enhanced easterly flow favor faster propagation. Northerly anomalies at these levels are also associated with faster propagation. When applied to West African squall lines, the correlations between these environmental factors and the speed of propagation are significantly higher than those of methods developed for mesoscale convective systems in other parts of the world.
Added by: Andreas Fink    Last Edited by: Fanny Lefebvre