chapter 6: mesoscale gravity waves
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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.
UK
Ireland
cold front
5/24/2002, 21:07 UTC – IHOP
Aral Sea
Australia
Australia
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)
dry adiabat (q=46°C)
moist adiabat (qw=16°C)
qw 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.
Fig. 6.11: synoptic setting of gravity wave activity (p’~ a few mb)
Fig. 6.2: SLP analysis in a Midwest snowstorm. dotted lines: wave crests, dashed lines: troughs
Fig. 6.10: schematic of a linear plane mesoscale gravity wave propagating to the right (Uo=0)
see youtube video
Fig. 6.6: polarization relations between q’, p’, u’, and w’ in a westward tilting internal gravity wave
blue = cold, red = warm
Critical level: level where wave energy is absorbed
cg
c
Fig. 6.7Fig. 6.8
geostrophic adjustment: principle
Rossby radius of deformation:
see COMET module “the balancing act of geostrophic adjustment”
see YouTube video:geostrophic adjustment: inertio-gravity waves and the Coriolis force
𝐿𝑅=𝑐𝑔𝑟𝑎𝑣𝑖𝑡𝑦 𝑤𝑎𝑣𝑒
𝑓 ≅ 𝑁𝐻𝜋√ 𝑓 𝜁
Will a feature last or dissipate? Estimate its LR
6.6 undular bores and solitary waves:separate slide show
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