Micrometeorology

The book focusses on atmospheric processes, which directly affect human environments within the lowest 100–1000 meters of the atmosphere over regions of only a few kilometres in extent. The book is the translation into English of the third edition of the German book “Applied Meteorology – Micrometeorological Methods”. It presents, with selected examples, the basics of micrometeorology applied to disciplines such as biometeorology, agrometeorology, hydrometeorology, technical meteorology, environmental meteorology, and biogeosciences. The important issues discussed in this book are the transport processes and fluxes between the atmosphere and the underlying surface. Vegetated and heterogeneous surfaces are special subjects. The author covers the areas of theory, measurement techniques, experimental methods, and modelling all in ways that can be used independently in teaching, research, or practical applications.

James R. Holton

The Handbook of Micrometeorology is the most up-to-date reference for micrometeorological issues and methods related to the eddy covariance technique for estimating mass and energy exchange between the terrestrial biosphere and the atmosphere. It provides useful insight for interpreting estimates of mass and energy exchange and understanding the role of the terrestrial biosphere in global environmental change.

In the micrometeorological literature, reference is sometimes made to the 'Businger-Dyer Profiles' or the 'Dyer-Businger profiles/relations' without referring to the origin of these relations. For example, in the textbook on 'Atmospheric Turbulence' by Panofsky and Dutton (1984) on p. 134, reference is made to the 'Businger-Dyer formula'. To add to the mystery, these authors refer on p. 141 to the Businger-Dyer-Pandolfo empirical result (Businger, 1966; Pandolfo, 1966) that in unstable air • Z r (1) Ri=-== ... L So it seemed to me that it would be appropriate for this issue of Boundary-Layer Meteorology which is dedicated to Arch Dyer, to go back to 1965 and describe the circumstances that led to the above mentioned profiles as I remember them. 2. Aspendale, 1965 In the academic year 1965-1966 I found myself in Australia on a sabbatical leave. The first part of this leave was spent at the CSIRO Division of Meteorological Physics in Aspendale, Victoria. It was in many ways a good choice. The fall is exchanged for spring, SE Australia is a pleasant place to be in spring and summer, and the scientists in the division were hospitable and stimulating. Priestley, Swinbank, Dyer, Webb, McIlroy, Taylor, Clarke, Deacon and several others carried out an active research program.

Descriptive Micrometeorology compiles views and findings in micrometeorology, which is concerned with the surface boundary layer or thin slice of atmosphere extending from the ground up to a height of approximately 50 meters. This book describes the micrometeorology of soil, short vegetation, forest, water, ice, snow, and built-up urban surfaces. The properties and influence of the planetary boundary layer are not included. The topics discussed include the energy balance at the earth-atmosphere boundary, radiative flux divergence, factors influencing air temperatures, and Kolmogorov similarity theory. The Eddy correlation method for measuring evaporation, radiation balance of snow and ice surfaces, heat storage and horizontal advection in water, and changes in wind patterns are also covered. This publication is intended for meteorologists, but is also a good reference for chemists, engineers, geographers, botanists, hydrologists, health physicists, glaciologists, town planners, limnologists, oceanographers, air pollution control officers, foresters, and ecologists interested in the surface boundary layer.

How to interpret meteorological measurements made at a given level over a surface with regard to characteristic properties such as roughness, albedo, heat, moisture, carbon dioxide, and other gases is an old question which goes back to the very beginnings of modern micrometeorology. It is made even more challenging when it is unclear whether these measurements are only valid for this point/region and precisely describe the conditions there, or if they are also influenced by surrounding areas. After 50 years of field experiments, it has become both apparent and problematic that meteorological measurements are influenced from surfaces on the windward side. As such, extending these measurements for inhomogeneous experimental sites requires a quantitative understanding of these influences. When combined with atmospheric transport models similar to air pollution models, the ‘footprint’ concept – a fundamental approach introduced roughly 20 years ago – provides us with information on whether or not the condition of upwind site homogeneity is fulfilled. Since these first models, the development of more scientifically based versions, validation experiments and applications has advanced rapidly. The aim of this book is to provide an overview of these developments, to analyze present deficits, to describe applications and to advance this topic at the forefront of micrometeorological research.

Part of the excitement in boundary-layer meteorology is the challenge associated with turbulent flow - one of the unsolved problems in classical physics. An additional attraction of the filed is the rich diversity of topics and research methods that are collected under the umbrella-term of boundary-layer meteorology. The flavor of the challenges and the excitement associated with the study of the atmospheric boundary layer are captured in this textbook. Fundamental concepts and mathematics are presented prior to their use, physical interpretations of the terms in equations are given, sample data are shown, examples are solved, and exercises are included. The work should also be considered as a major reference and as a review of the literature, since it includes tables of parameterizatlons, procedures, filed experiments, useful constants, and graphs of various phenomena under a variety of conditions. It is assumed that the work will be used at the beginning graduate level for students with an undergraduate background in meteorology, but the author envisions, and has catered for, a heterogeneity in the background and experience of his readers.