Radiative processes in the atmosphere: fundamentals

Marcia Akemi Yamasoe , Marcelo de Paula Corrêa

Solar radiation is a fundamental source of energy for the physical, chemical and biological processes that occur on both the Earth’s surface and the atmosphere. This book presents the fundamentals of radiative transference: terminology, definitions of physical quantities, physical laws involved, and their mathematical formulation.

 

The authors explain how the electromagnetic spectrum is usually divided into climatology studies; discuss the main processes that determine the variation of the solar radiation flux at the top of the atmosphere; present the instrumentation used to measure radiation and describe its physical principles of operation. The book also discusses the processes of interaction of radiation with matter, such as absorption, emission and spreading, and provides clarification on how the radiation balance in the atmosphere and the rates of radiative heating or cooling are estimated.

 

This work offers a careful and attentive look at solar and terrestrial radiation, its propagation and its interaction with matter and climate.

Original title
Processos radiativos na atmosfera
ISBN
978-85-7975-229-2
eISBN
978-85-7975-230-8
Pages
142
Year of publication
2016
Edition
1st

About the authors

Marcia Akemi Yamasoe

Marcia Akemi Yamasoe holds a bachelor’s degree (1991) and a master’s degree (1994) in Physics from the University of São Paulo and a PhD in Applied Physics from the same institution. She completed postdoctoral studies in 2000 at NASA's Goddard Space Flight Center in Greenbelt (USA) and in 2013 at Paul Sabatier University in Toulouse, France. She is currently an Associate Professor at the Institute of Astronomy, Geophysics and Atmospheric Sciences of University of São Paulo. She has experience in the area of Geosciences with emphasis in Physical Meteorology, dealing mainly with the following subjects: atmospheric aerosol, forest fires in the Amazon, remote sensing, aerosol forest fires’ optical properties and photosynthetically active radiation.

Marcelo de Paula Corrêa

Marcelo de Paula Corrêa is an Associate Professor and current coordinator of the Masters’ degree in Environment and Water Resources from Federal University of Itajubá. He graduated (1996) in Meteorology and holds a Master’s degree (1999) and a PhD (2003) in Sciences from the University of São Paulo. Between 2008 and 2009 he obtained a postdoctoral degree from Pierre and Marie Curie University (Paris VI) and in 2012 he was a Visiting Researcher in the Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS) in France. His main research area is Physical Meteorology, dealing mainly with the following topics: ultraviolet radiation and its interactions with the atmosphere (aerosols, clouds and ozone) and human health (skin cancer, vitamin D production, awareness and prevention).

Introduction

 

Radiometric quantities

Radiation and the electromagnetic spectrum

Solid angle

Flow, intensity, irradiance and radiance

Spectral densities

Absorbance, reflectance and transmittance

 

Black-body radiation

Kirchhoff’s law

Planck’s law

Wien’s law

Stefan–Boltzmann law

 

Solar radiation

The sun

Position of the solar disk above the horizon

Annual cycles

Solar irradiation (dose) at the top of the atmosphere

 

Irradiance measurement

Main quantities measured

Physical principles of radiation measurement

Calibration

Some applications

Conventional instruments

 

Absorption and spreading

Relevant atmospheric constituents

Molecular absorption

Spreading

The role of the clouds

 

Radiative transfer equation

Beer’s Law

Differential form of the radiative transfer equation in the absence of spreading – Schwarzschild equation

Differential form of the radiative transfer equation in the absence of absorption / emission

General equation of radiative transfer

Plane-parallel atmosphere approach

Propagation of solar radiation

Propagation of terrestrial radiation

 

Radiative balances

Radiative balance of the planet

Radiative heating / cooling rate

Surface energy balance

 

Bibliographical references

Preface

We are moving toward the end of the second decade of the twenty-first century. Forty years ago, there was an appreciable number of professionals working in Brazil in the measurement of solar and terrestrial radiation, concentrating more on aspects of total flows and energy balances of interest to Agrometeorology, Micrometeorology, Environmental Sciences and Engineering. Books in Portuguese addressing issues of solar and terrestrial radiation were not rare, but they were not numerous either. Classical and detailed texts on radiation propagation, in English, French and German, plus a few translations of Russian, were reading a smaller fraction of professionals.
Since then, the theme of propagation and radiation measurement has flooded the daily meteorological and environmental with increasing needs for conceptual detailing. The solar spectrum is no longer just a rainbow theme, but also subject to ultraviolet and health studies, environmental pollution and aerosol interacting with visible radiation absorbed by vegetation and affecting the formation and dynamics of clouds; in the infrared, the climate study includes analysis of emission/absorption bands by clouds and by minority gases. Satellite imagery has become a daily instrument of weather information, monitoring vegetation and pollution, and detecting fires. Modern atmospheric and cloud probes use spectral microwave properties. A professional in Atmospheric and Environmental Sciences can no longer evade this information and the conceptual tools for its interpretation.
A generation of physicists and meteorologists active in atmospheric sciences has been trained in the last 20 years, accumulating experience in the country and abroad and covering this sophisticated range of knowledge. It is natural and desirable that this know-how, or “savoir-faire” in the professional and academic activity, compose texts in the national language, with standards suitable for local needs. A promising sign of intellectual maturity.
The PhD and professors Yamasoe and Corrêa participate in this generation, and I seem to hear the echoes of a dear friend, vehement master and colleague at USP. The book they present is intended to serve as a basic text to new generations of university students and to introduce them to classical conceptual aspects with a modern look at solar and terrestrial radiation, their propagation and their interaction with matter and climate. An additional advantage is that it provides mathematical tools to start dealing with these topics, from a level that allows you to assimilate higher level readings. A warm congratulations on the idea and the achievement.

Juan Carlos Ceballos