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Cooperative Institute for Meteorological Satellite Studies / University of Wisconsin-Madison
Tropical Cyclones
Deep Layer Mean (DLM) Analysis

Background: These wind analyses depict the environmental flow in various oceanic basins for selected tropospheric layer-means. Based on previous studies (listed below), the depth of this layer is correlated with the TC steering layer, and generally increases with increasing TC intensity (Fig. 1). These layer-mean steering fields are created by mass-weighting mandatory-level, high-resolution wind analyses derived locally at UW-CIMSS using a three-dimensional recursive filter technique. These analyses are strongly influenced by high-density, multispectral satellite-derived wind information. Data from NWP global models provide background field information for each analysis run.
 
Uses: This product has applications as a tool for approximating the current and short-term environmental steering flow for tropical cyclones of varying intensities in the Atlantic basin. By selecting the intensity range for a TC of interest, plots of the best-correlated layer-mean environmental steering flow can be displayed.

 
Reference:
•  Velden, C.S.: The relationship between tropical cyclone motion, intensity and the vertical extent of the environmental steering layer in the Atlantic basin. 20th Conf. Hurr. and Trop Meteor., San Antonio, TX, May, 1993.
 
And for further information:
•  Velden, C.S., and L.M. Leslie: The relationship between tropical cyclone intensity and the depth of the environmental steering layer in the Australian region. 19th Conf. Hurr. Trop. Meteor., Miami, Fl, May, 1991.
•  Velden, C.S., and L.M. Leslie, 1991: The basic relationship between tropical cyclone intensity and the depth of the environmental steering layer in the Australian region. Wea. and Forecasting 6, 244-253.

 
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