Moisture analysis of the A-scale phase means during GATE

✍ Scribed by Huo-Jin Huang; Dayton G. Vincent

• Book ID: 104575401
• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: English
• Weight: 436 KB
• Volume: 108
• Category: Article
• ISSN: 0035-9009
• DOI: 10.1002/qj.49710845610

✦ Synopsis

Abstract

A moisture analysis, based on GATE A‐scale phase means, is presented for western Africa (land) and the eastern Atlantic (water) area. Vertically‐integrated moisture budget terms are calculated for the whole area, as well as for land, water and A/B ship array areas. Precipitation minus evaporation (P̄−Ē) is solved as the residual. Upward vertical motion, associated with organised convective disturbances and westward‐propagating waves, causes the vertical advection term to dominate. Over land P̄−Ē decreases slightly from Phase I to Phase III, whereas over water it increases greatly during the same time span. When the evaporation rate of 3.8mmd^−1^ from the Phase III B‐scale results of Thompson et al. (1979) is applied to our A/B scale results, it yields a precipitation rate of 10.8mmd^−1^. This compares favourably with the remotely‐sensed estimates of 12.7mmd^−1^ for the B‐scale array obtained by radar and 14.0mmd^−1^ for the A/B ship array derived from satellite observations. Furthermore, P̄−Ē in the GATE area is found to be considerably greater than the global estimate for approximately the same latitude band.