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AbstractThe region of the Middle East around the Red Sea (between 32° E and 44° E longitude and 12° N and 28° N latitude) is a currently undocumented hotspot for atmospheric gravity waves (AGWs). Satellite imagery shows evidence that this region is prone to relatively high occurrence of AGWs compared to other areas in the world, and reveals the spatial characteristics of these waves. The favorable conditions for wave propagation in this region are illustrated with three typical cases of AGWs propagating in the lower troposphere over the sea. Using weakly nonlinear long wave theory and the observed characteristic wavelengths we obtain phase speeds which are consistent with those observed and typical for AGWs, with the Korteweg-de Vries theory performing slightly better than Benjamin-Davis-Acrivos-Ono theory as far as phase speeds are concerned. ERS-SAR and Envisat-ASAR satellite data analysis between 1993 and 2008 reveals signatures consistent with horizontally propagating large-scale internal waves. These signatures cover the entire Red Sea and are more frequently observed between April and September, although they also occur during the rest of the year. The region's (seasonal) propagation conditions for AGWs, based upon average vertical atmospheric stratification profiles suggest that many of the signatures identified in the satellite images are atmospheric internal waves. © Author(s) 2011.
CitationMagalhaes JM, Araújo IB, da Silva JCB, Grimshaw RHJ, Davis K, et al. (2011) Atmospheric gravity waves in the Red Sea: a new hotspot. Nonlinear Processes in Geophysics 18: 71–79. Available: http://dx.doi.org/10.5194/npg-18-71-2011.
SponsorsThis research was conducted with support from KAUST (King Abdullah University for Science and Technology) in collaboration with the Woods Hole Oceanographic Institution, Biology Department. The views expressed in this manuscript are those of the authors and do not necessarily represent the official opinion of KAUST. Some support was also provided by a Treaty of Windsor Grant awarded by the British Council (Portugal). SAR image data was provided by ESA under contract AOPT-2423. One of us would like to thank the Portuguese Science and Technology Foundation (FCT) for a research grant (SFRH/BD/35898/2007).