Kinematic analysis of the large-scale mean state during phases I, II and III of GATE

✍ Scribed by Dayton G. Vincent

• Book ID: 104575372
• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 1023 KB
• Volume: 107
• Category: Article
• ISSN: 0035-9009
• DOI: 10.1002/qj.49710745410

✦ Synopsis

Abstract

An analysis is presented of the large‐scale mean state kinematic properties of the wind field based on observed rawinsonde data taken over western Africa and the eastern Atlantic during Phases I, II, and III of GATE. Variables presented are wind direction and speed, zonal wind component, temporal standard deviation of the zonal wind component, vertical p‐velocity and relative vorticity. Wind direction and speed and temporal standard deviation of zonal wind were subjectively analysed at the surface, 850mb, 700mb, 500mb, 400mb, 300mb, 250mb, 200mb, 150mb and 100mb. Grid point data were extracted from analyzed charts at increments of 2° latitude and longitude and used to compute vertical motion and vorticity. Resultant analyses are examined to determine kinematic properties common to all three phases of GATE, trends in these properties from one phase to the next, and differences between properties over western Africa (land) and the eastern Atlantic (water). Features of the mean state are compared with results obtained by other investigators for such phenomena as large‐scale westward propagating wave disturbances, low‐level cyclonic vortices, satellite‐derived precipitation and cloud clusters associated with squall lines.