A few summary slides

AOS C115/228 - Spring 2008

Thermals:buoyancy pressuredynamic pressure

decompositionof pdyn

< Textbook sea-breeze circulation

Rotunno’s analytic solutionIf f > (poleward of 30˚) equation is elliptic

• sea-breeze circulation spatially confined• circulation in phase with heating• circulation, onshore flow strongest at noon• circulation amplitude decreases poleward

If f < (equatorward of 30˚) equation is hyperbolic• sea-breeze circulation is extensive• circulation, heating out of phase• f = 0 onshore flow strongest at sunset• f = 0 circulation strongest at midnight [and noon]

If f = (30˚N) equation is singular• some friction or diffusion is needed• circulation max at sunset• onshore flow strongest at noon

f < (equatorward of 30˚) at three times

sunrise

noon (reverse sign for midnight)

[Circ magnitude

max]

sunset

Note coastline onshore flowmax at sunset

Circulation vs. time

Eq

30N

60N

90N

sunset

• Physically, why does circulation magnitude decr. with latitude?

• Why is circ. max become earlier?

• Why does DTDM results differ slightly from theory?

midnight

Hovmoller diagrams

What is missing?

Two slides from Asai (1970a) on thermal instability

Slides from Asai (1972)’s two cases.One of these local max was dubbed inflection-point

instability. How was that justified?

Weckwerth’s experimentsWhat did we learn from these?

Houze’s concept model

^ T-storm project life cycle concept ^ Newton’s (1963) concept;

what was wrong with it?

< Browning’s multicell concept

How were the features in this surface pressure trace explained?

How was the wake low explained?

What was the RKW argument, and what does its explanation imply?

^ Why do supercells seem to split?

< What environmental conditions favor supercells vs. multicell storms?

What was BRi?

What favors right-movers in US?

L

LHow were these pressure features explained? Which terms explained splitting, which explained forward motion, how was motion to the left or right of the mean winds explained?

Our first look at flow near obstacles examined the “simple” case of the hydraulic jump. We soon realized this was a special case in the theory of mountain-type waves.

What was the Scorer parameter and what role did it play in understanding these very different results?