Table Of ContentBuoyant Convection in Geophysical Flows
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Series C: Mathematical and Physical Sciences - Vol. 513
Buoyant Convection
I• n
Geophysical Flows
edited by
E. J. Plate
and
E. E. Fedorovich
University of Karlsruhe,
Germany
D. X. Viegas
University of COimbra,
Portugal
and
J. C. Wyngaard
Pennsylvania State University,
U.S.A.
SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.
Proceedings 01 the NATO Advanced Study Institute on
Buoyant Convection in Geophysical Flows
Plorzheim, Baden-WOrtlemberg, Germany
17-27 March 1997
A C.I.P. Catalogue record for this book is available from the Library of Congress.
ISBN 978-94-010-6125-4 ISBN 978-94-011-5058-3 (eBook)
DOI 10.1007/978-94-011-5058-3
Printed on acid-free paper
AII Rights Reserved
© 1998 Springer Science+Business Media Oordrecht
Originally published by Kluwer Academic Publishers in 1998
Softcover reprint of the hardcover 1s t edition 1995
No part of the material protected by this copyright notice may be reproduced or
utilized in any form or by any means, electronic or mechanical, includ ing photocopying,
record ing or by any information storage and retrieval system, without written
permission from the copyright owner.
TABLE OF CONTENTS
Preface ............................................................ vii
E. J. Plate
Convective boundary layer: a historical introduction ....................... 1
J. C. Wyngaard
Convection viewed from a turbulence perspective ........................ 23
J.C. R. Hunt
Eddy dynamics and kinematics of convective turbulenc~ ... . . . . . . . . . . . . . . .. 41
S. Zilitinkevich, A. Grachev, and J. C. R. Hunt
Surface frictional processes and non-local heat / mass transfer
in the shear-free convective boundary layer .............................. 83
R. B. Stull
Convective transport theory and the radix layer ......................... 115
G. S. Golitsyn
Convection in viscous and rotating fluids from the viewpoint
of the forced flow theory ........................................... 129
R. H. Kase
Modeling the oceanic mixed layer and effects of deep convection ........... 157
D. H. Lenschow
Observations of clear and cloud-capped convective boundary layers,
and techniques for probing them . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 185
C. Kiemle, G. Ehret, K. J. Davis, D. H. Lenschow, and S. P. Oncley
Airborne water vapor differential absorption lidar studies of the
convective boundary layer .......................................... 207
J. C. Wyngaard
Experiment, numerical modeling, numerical simulation, and their
roles in the study of convection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 239
R. B. Stull
Transilient turbulence theory: a non local description of convection .......... 253
E. Fedorovich
Bulk models of the atmospheric convective boundary layer ................ 265
vi
C.-H. Moeng
Pararneterizations of the convective boundary layer in atmospheric
models. . . . . . . ... . .. . . . . .. . . . . . ....... . . . . . ... . . . . . . . . . . . . . ... .. 291
R. N. Meroney
Wind tunnel simulation of convective boundary layer phenomena:
simulation criteria and operating ranges of laboratory facilities .............. 313
E. Fedorovich and R. Kaiser
Wind tunnel model study of turbulence regime in the atmospheric
convective boundary layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 327
F. T. M. Nieuwstadt
Review of diffusion processes in the convective boundary layer ............ 371
D. X. Viegas
Convective processes in forest ftres .................................. 401
C.-H. Moeng
Stratocumulus-topped atmospheric planetary boundary layer ............... 421
A. P. Siebesma
Shallow cumulus convection ........................................ 441
Index ............................................................. 487
PREFACE
Buoyant convection is of interest in many fields of geophysical fluid mechanics, in
particular in atmospheric and oceanic dynamics, where buoyancy-driven processes play
important roles on a variety of scales of motion.
Although the importance of buoyant convection has been recognised for many
decades, only recently have the tools become available for effective theoretical and
experimental analysis of convective flows. Starting in the 1960s with the pioneering
laboratory investigations of atmospheric convection by J. Deardorff, D. Lilly and
colleagues and the introduction of bulk models of convectively mixed layers by F. Ball
and D. Lilly, convective flows have become a testing ground for numerical models and
for sophisticated experimental techniques. The 1960s and 1970s saw a series of field
experiments carried out in different countries and aimed at better understanding of the
peculiar properties of geophysical convection. The famous Kansas experiment of 1968
allowed fundamental new insights into the nature of convective turbulence in the
atmospheric surface layer and has provided a unique data set for two generations of
boundary-layer meteorologists. In the 1970s, the first numerical experiments by
J. Deardorff on large-eddy simulation of the atmospheric boundary layer raised
theoretical studies of geophysical convection to a new level.
Today, buoyant convection in geophysical flows is an advanced and still-developing
area of research relevant to problems of the natural environment. During the last
decade, significant progress has been achieved through experimental studies, both in
nature and in the laboratory, and through large-eddy and direct numerical simulations.
Coherent structures have been found to playa key role in geophysical boundary layers
and in larger-scale atmospheric and hydrospheric circulations driven by buoyant
forcing. New aspects of the interaction between convective motions and rotation have
recently been discovered in nature and have been investigated numerically. Extensive
experimental data have been collected on the role of convection in cloud dynamics and
microphysics. New theoretical concepts and approaches have been outlined regarding
scaling and parameterizations of physical processes in buoyancy-driven geophysical
flows.
In several different countries technically advanced laboratory facilities have been
constructed for experimental studies of geophysical convection. Efforts to simulate the
atmospheric convective boundary layer in a wind tunnel have been made at the Institute
of Hydrology and Water Resources Planning (IHW), University of Karlsruhe. The
construction of their stratified wind tunnel, which was financed by the German Science
Foundation (DFG) and built by M. Rau, was finished in the early 1990s. The first
results from the tunnel display a plethora of fascinating flow phenomena closely
resembling regimes of turbulent convection in the atmospheric boundary layer.
While proceeding with the model studies of buoyant convection, the IHW group
established scientific contacts with other research teams over the world dealing with
geophysical convection studies. A natural result was the idea of bringing people from
these teams together in order to exchange their knowledge and deliver it to the
community of young researchers interested in buoyant convection studies. The
vii
viii
Advanced Study Institute (ASI) Programme of the NATO Science Committee was a
natural vehicle for implementing this idea.
From the beginning the concept of the ASI on Buoyant Convection in Geophysical
Flows was supported by a number of experts in the area of convection research and
modelling. About twenty of them agreed to contribute to the ASI as invited lecturers.
The Programme of the ASI "Buoyant Convection in Geophysical Flows" drafted in
1995-1996 by the editors of this volume (formerly - members of the ASI Organising
Committee) was approved and accepted for funding by the NATO Science Committee.
The response to our invitation to participate in the ASI was gratifying: we received
more than 150 applications from potential participants. Unfortunately, only about 80
could be accepted.
The ASI took place during the period from 17 to 27 March 1997 in Pforzheim, a
small town at the northern edge of Schwarzwald (Black Forest), Baden-Wiirttemberg,
Germany.
The programme of the Institute included buoyancy effects in different media:
atmosphere, hydrosphere, and the Earth's mantle; on a wide range of scales: from
small-scale phenomena in· unstably stratified and convectively mixed layers to deep
convection in the atmosphere and the ocean; by different methods of research: field
measurements, laboratory simulations, theoretical analysis, and numerical modelling,
and within diverse application areas: dispersion of pollutants, parameterization of
convection in applied geophysical models, and hazardous phenomena associated with
convection. Much of the ASI lecture programme was devoted to fundamentals of
convection as a physical phenomenon.
We believe that the present volume, which contains focused versions of the invited
lectures, will be a useful compendium on the subject for years to come. The volume
falls naturally into four parts.
The first part contains a collection of introductory lectures focusing on fundamental
and phenomenological aspects of geophysical convection, and presenting historical and
conceptual overviews of convection studies (chapters by E. J. Plate, J. C. Wyngaard,
J. C. R. Hunt, S. S. Zilitinkevich et aI., R. B. Stull, G. S. Golitsyn, R. H. Kiise,
D. H. Lenschow, and C. Kiemle et al.).
The second part of the volume comprises lecture material on convection modelling
and parameterization (chapters by J. C. Wyngaard, R. B. Stull, E. Fedorovich, and
C.-H. Moeng).
In the third part, the lectures of R. N. Meroney, and E. Fedorovich and R. Kaiser on
experimental studies of geophysical convection in the laboratory are presented.
Overview of applied aspects of convection studies and convective cloud dynamics is
given in the fourth part of the volume (chapters by F. T. M. Nieuwstadt, D. X. Viegas,
C.-H. Moeng, and A. P. Siebesma).
We hope that the ASI succeeded in filling the gap between fundamental studies of
convective geophysical flows and applied modelling of natural phenomena associated
with buoyant forcing. Lecturers of the ASI represented both scientific and engineering
communities. Their treatment of a variety of the buoyancy-driven natural processes
within a common methodological framework should foster links between the theoretical
and applied branches of convection research and modelling.
ix
We are grateful to all lecturers of the ASI for their contributions, especially to those
who gave their time to prepare their lecture material for publication in this volume.
Thanks are due also to the ASI students, whose active participation in lectures and
discussions made the ASI a creative and lively scientific meeting.
Our special thanks go to the Local Arrangement Committee members Susanne Rau and
Klaus Ammer for their vital help in organising the ASI and in attending to the needs of
lecturers and participants. We also extend our gratitude to the administration and
personnel of MARITIM Hotel "Goldene Pforte" in Pforzheim, who provided a very
comfortable venue for the ASI.
We gratefully acknowledge the financial support of the NATO Science Committee. The
grant issued by NATO covered the principal portion of the ASI organisation costs. We
are also thankful for donations to the ASI by the University of Karlsruhe,
Gemeinschaftskernkraftwerk Neckar GmbH, and Neckarwerke Elektrizitatsversorgugs
AG.
Finally we would like to thank Robert Kolotilo and Dmitrii Mironov for their assistance
in preparing the ASI book for publication.
Erich Plate, Evgeni Fedorovich, Domingos Viegas, and John Wyngaard
March 1998
CONVECTIVE BOUNDARY LAYER: A HISTORICAL INTRODUCTION
E. J. PLATE
Institute of Hydrology and Water Resources Planning
Karlsruhe University
Kaiserstrasse 12, 76128 Karlsruhe, Germany
Abstract
A review is given of early research and concepts on the convective boundary layer,
which set the stage for all subsequent developments that have been possible via
numerical calculations. The historical development proceeded first with inquiries into
the stationary turbulent boundary layer. Starting from concepts developed for
aeronautical applications of aerodynamics, early research on the atmospheric boundary
layer was concerned almost exclusively with stationary flows. Only in the sixties, was
the non-stationarity of the planetary boundary layer considered for the first time, with
results that left a number of questions open. The first approaches, which are
summarized in this paper, were only concerned with obtaining profiles of mean
velocity, mean shear, mean temperature, and mean heat flux, which were governed by
conservation equations of mass, momentum, and energy.
1. Introduction
As a lower boundary condition for atmospheric motions, the planetary boundary layer is
of major interest to meteorological modelling, in particular when one considers
processes which take place near the earth's surface, for example in agriculture, where
estimates for evaporation and transpiration are needed, or environmental processes,
such as emissions from chimneys and exhaust gases from automobiles. Recently, the
interest of city planners has also been directed toward such processes, and it is to be
expected that environmental issues in city planning will require models which also need
parameterizations of the lower part of the atmosphere. The wide interest in the latter
issues has been the reason for a previous NATO Advanced Study Institute, conducted
by the Institute of Hydrology and Water Resources Planning (Cermak et al. [7]).
In response to this interest, scientists all over the world have created a body of
knowledge that forms the subject of micrometeorology: the study of the processes in the
planetary boundary layer. They started the investigations by considering stationary
turbulent boundary layers, which were first considered between 1920 and 1930, notably
by G. Taylor, Th. von KarrlUm, and by L. Prandtl and his students, and used basic
concepts from the theory of turbulence, as developed by G. Taylor and A. Kolmogorov.
Their tool used to overcome the non-linearity of the dominant equations of fluid
mechanics was the idea of similarity. The dominant concept which evolved from these
EJ. Plate et al. (eds.), Buoyant COlWection in Geophysical Flows, 1-22.
© 1998 Kluwer Academic Publishers.
