i 3n
ROBERT R. l.Oh(;
evpcrinient i\nd observation will be decisive. We have already stittcd that
experimental observutions of 5 ) : itre inconclusive although it is fair to point
oul that Croft's observations (Croft, 19%) support Eq. (2). The iitnlosphcric observations. of course. directly support Eq. (22).
The present theory is easily extended to obtain other mean quantities, for
example mp x z - '", and we have already seen that this is closer to observed
behavior than the similarity theory. The present theory also yields (5 7. z - 3
where S is the "dissipation function" for buoyancy fluctuations and this
agrees exactly with Townsend's observations.
5. COh'C'1,I:SIONS
The surface layer of the atmosphere transmits heat, momentum, and
moisture to the free atmosphere and it is obviously of practical importance
to understand it thoroughly. In addition. it is a portion of the atmosphere
which can he most conveniently examined and measured and then
compared with the predictions of theories. The most popular theory involves
an approach suggested by the highly successful theory of homogeneous flow
over a surface and leads to simple predictions based on dimensional
analysis. The above discussion questions the plausibility and the rigor of the
similarity arguments and points out a number of disagreements between
laboratory itnd atmospheric observations.
The paper concludes with a development of a new theory which differs
fundamentally from the similarity theory in assuming. essentially, that the
temperature difference between the heated lower surfitce and the fluid at
intinite heights IS a more fundaniental quantity than the heat flux. The
present theory has a number of predictions that agree exactly with observations or are in better agreement than the similarity theories. hut more and
hetter observations are clearly needed.
Businper. J. A,. Wyngullard. J D.. Izumi, Y.. and Bradley. E. F. (1971). Flux-protile relationships
Croft. J. b. (19%). 'The convective regime and tumprature ctistrihution ahovc ii hori/ontiil
kardorfl. J. W.. and Willis. G . E. (1967). Incertigation of iiirhulcnt, Ihcrmtl ainveciictn
it1 the iltmosphcric surrilcc layer. .I. A f m J , v . Sci. 28. 181.
heated surfwe. Qitcrri. 1. Roy. .HCVZO,O/. So'.. 114. 418.
hctwecn hotizontal plates. J . Fluid Mrck 28. 675.
ROBERT R. l.Oh(;
evpcrinient i\nd observation will be decisive. We have already stittcd that
experimental observutions of 5 ) : itre inconclusive although it is fair to point
oul that Croft's observations (Croft, 19%) support Eq. (2). The iitnlosphcric observations. of course. directly support Eq. (22).
The present theory is easily extended to obtain other mean quantities, for
example mp x z - '", and we have already seen that this is closer to observed
behavior than the similarity theory. The present theory also yields (5 7. z - 3
where S is the "dissipation function" for buoyancy fluctuations and this
agrees exactly with Townsend's observations.
5. COh'C'1,I:SIONS
The surface layer of the atmosphere transmits heat, momentum, and
moisture to the free atmosphere and it is obviously of practical importance
to understand it thoroughly. In addition. it is a portion of the atmosphere
which can he most conveniently examined and measured and then
compared with the predictions of theories. The most popular theory involves
an approach suggested by the highly successful theory of homogeneous flow
over a surface and leads to simple predictions based on dimensional
analysis. The above discussion questions the plausibility and the rigor of the
similarity arguments and points out a number of disagreements between
laboratory itnd atmospheric observations.
The paper concludes with a development of a new theory which differs
fundamentally from the similarity theory in assuming. essentially, that the
temperature difference between the heated lower surfitce and the fluid at
intinite heights IS a more fundaniental quantity than the heat flux. The
present theory has a number of predictions that agree exactly with observations or are in better agreement than the similarity theories. hut more and
hetter observations are clearly needed.
Businper. J. A,. Wyngullard. J D.. Izumi, Y.. and Bradley. E. F. (1971). Flux-protile relationships
Croft. J. b. (19%). 'The convective regime and tumprature ctistrihution ahovc ii hori/ontiil
kardorfl. J. W.. and Willis. G . E. (1967). Incertigation of iiirhulcnt, Ihcrmtl ainveciictn
it1 the iltmosphcric surrilcc layer. .I. A f m J , v . Sci. 28. 181.
heated surfwe. Qitcrri. 1. Roy. .HCVZO,O/. So'.. 114. 418.
hctwecn hotizontal plates. J . Fluid Mrck 28. 675.