Slide 1

Chapter 6: mesoscale gravity waves This ppt summarizes the slides in the textbook. The theory is covered in class. Note: this ppt does not include section 6.6 Bores. Slide 2 Iowa gravity wave time lapse movie mpeg You Tube Slide 3 Slide 4 Slide 5 Slide 6 UK Ireland cold front Slide 7 5/24/2002, 21:07 UTC IHOP Slide 8 Aral Sea Slide 9 Australia Slide 10 Slide 11 Fig. 6.1: isochrones of a mesoscale gravity wave crest during a major East Coast snowstorm. The wave was detected in the pressure trace. The wind barbs indicate the vector surface wind shift upon wave passage. x Greensboro (GSO) Slide 12 dry adiabat ( =46C) moist adiabat ( w =16C) w values (C) Fig. 6.9: the mesoscale gravity wave event may have been triggered by elevated convection, or gravity wave adjustment. The stable low-level layer may have allowed wave ducting towards the NE. Slide 13 Fig. 6.11: synoptic setting of gravity wave activity (p~ a few mb) Slide 14 Fig. 6.2: SLP analysis in a Midwest snowstorm. dotted lines: wave crests, dashed lines: troughs Slide 15 Fig. 6.10: schematic of a linear plane mesoscale gravity wave propagating to the right (U o =0) Slide 16 see youtube video Slide 17 Fig. 6.6: polarization relations between , p, u, and w in a westward tilting internal gravity wave blue = cold, red = warm Slide 18 Critical level: level where wave energy is absorbed cgcg c Fig. 6.7 Fig. 6.8 Slide 19 geostrophic adjustment: principle Rossby radius of deformation: see COMET module the balancing act of geostrophic adjustmentthe balancing act of geostrophic adjustment see YouTube video: geostrophic adjustment: inertio-gravity waves and the Coriolis force Slide 20 Will a feature last or dissipate? Estimate its L R Slide 21 6.6 undular bores and solitary waves: separate slide show