Woodcock, Deardorff, GrossmanSoaring gulls, the convective boundary layer and its similarity hypothesis

David FitzjarraldAtmospheric Sciences Research CenterUniversity at Albany, SUNYAlbany, New York, US of A

dfitzjarrald@albany.edu

April 17, 2014

Miller’s air-sea interaction class.

2006

Woodcock, 1940

Laboratory Bénard convection

Woodcock’s idealizations….

“Langmuir lines”—know to seaweed-watching Woodcock

We did not learn about the structure of the convective boundary layer only after computer simulations were available!

Habits of convection in laboratory flows

Whitehead, 1978

Woodcock, 1940

T(ocean) – T(air)

U (m

/s) Not soaring

Linear soaring

Circular soaring

How the herring gulls soared

Woodcock, 1942

T(ocean) – T(air)

U (m

/s)

Priestley (1957)

Woodcock, 1975

T(ocean) – T(air)

Digression about similarity hypotheses in boundary layer meteorology

•the atmospheric convective boundary layer--w*:

Ultimately, the thermals "know" more about acapping inversion lid than they do about the distance to the surface.

Then the situation issomewhat like convection between two plates. So we perform the similarity analysis using as our fundamental observables zi, (g/Θr)H.

What you get is a convective velocity w*. This is known asthe mixed layer similarity hypothesis

Wyman-Woodcock expedition to the Caribbean, 1946

Willis and Deardorff, 1974Convection chamber--water

Heat flux

zi

Grossman, 1982

LES simulations of the CBL, Schmidt & Schumann, 1989

Deardorff, 1982.

T(ocean) – T(air)

Modeling—the first ‘large-eddy’ published simulation….

5. Professional Affiliations, Honors or Awards 1971 - Editorial Award, American Meteorological Society 1972 - Publications Award, National Center for Atmospheric Research 1973 - Elected a Fellow of the American Meteorological Society 1974 - Second Half-Century Award American Meteorological Society 1978 - Rossby Research Medal, American Meteorological Society. 1986 - Was elected a Fellow of the American Association for the Advancement of Science

James Deardorff, we are finally get to where he already was in 1970…..

JD lost interest in meteorology…

Roll circulations in the ABL.

Spectra

Cartoon from Roland Stull

Benard convection.

Station B

2 - 5 km

Hazards of taking measurements in the Rolls

Station A

1-km

RABrown 2004

U

V Mean Flow Hodograph

Z/ 1

2

3

The Mean Wind

The OLE winds

Hodographfrom center zone

Hodographfrom convergent zone

Morrison et al. 2005

Liu et al, 2006

Morrison et al. 2005

Morrison et al. 2005

Weckworth et al 1999

Dopper radar investigations of rolls.

Weckworth (1999)

Florida, Weckworth et al. 1999

‘Weckworth (1997(