Vladimir V. Kozoderov

Remote Sensing of the Earth from Space: Atmospheric Correction

The practical use of space-borne information, its processing and interpretation needs atmospheric correction of aerospace images and spectra. With this book the authors offer a review of this young technique and present their results from 20 years work. The atmospheric modulation transfer function is elucidated from the first theoretical investigations to practical aspects of the atmospheric correction of space imagery. The problems are analysed by modelling the main important parameters, e.g. the atmospheric aerosol, radiative transfer in the Earths surface - atmosphere systems, interaction of short - and longways components of the radiation budget with the atmosphere and the Earths surface.

Remote sensing of the state of crops and soils

Abstract Various techniques as well as some general problems of agricultural remote sensing are discussed, with emphasis on the development of techniques to assess soil productivity (humus content) and the slate of crops (weediness, etc.). The techniques considered were tested in conditions of the southern part of the USSR European territory (the Ukraine, Moldavia). Applications of the technique have been exemplified.

A One-Dimensional Scalar Transfer Function of the Atmosphere

To reduce the spectrophotometric information obtained from the Earth’s survey from space, a theoretical determination of the transfer function for the brightness of the atmosphere-object-background system is important [31, 94, 273, 288]. Using the spatial inhomogeneity of spectrophotometered surfaces (backgrounds), parts of which are “cut out” by the space-born spectrophotometer’s slit during the survey from a space-borne platform, the system “object-background” can be divided conditionally into the following types (Fig. 4.1): (1) a horizontally homogeneous, infinitely extended surface (background); (2) a small (point) object against a horizontally-homogeneous, infinitely-extended background; (3) a set of randomly distributed small (point) objects against an extended background; (4) an interface between two horizontally homogeneous surfaces.

The Radiation-Environment Interaction

The practical use of the results of the Earth studies from space is largely determined by the possibility of solving two basic problems: developing automated systems to process and interpret video information (ASPIV) and establishing relationships between the parameters characterizing the environmental state and the outgoing radiation field. The development of special processors, the networking and use of computers in series, and the development of computer-processing mathematical-support help in solving the first problem. The solution of the second problem is connected with mathematical description of the environment and of its interaction with electromagnetic radiation.

Optical-Physical Models of Atmospheric Aerosol

The optical parameters of a cloud-free atmosphere as a scattering medium are, firstly, determined by the presence of an aerosol, by its stratification, size distribution, chemical composition and other characteristics. The contribution of an aerosol to the absorption of radiation by the atmosphere in the optical wavelength region 0.2 -13 µm is also considerable. Besides, at certain sun elevations aerosols affect radiation absorption by the surface. Aerosols are generally understood to be the finest suspended particles, referring to all liquid and solid particles in the troposphere, stratosphere and at higher altitudes, but not cloud particles and ice crystals. An analysis performed recently both in the USSR and in other countries [9, 24, 59, 60, 65, 91, 92, 99, 104, 112, 153, 154, 231, 269] reveals the importance of aerosol radiative effects. However, there is no theory on the formation of the global aerosol field yet which determines the complex problem of the parameterization of its effect on the radiation fields in the atmosphere-surface system.

Radiative Correction of the Space-Derived Images of the Earth Surface

Techniques for the transformation of air- and space-derived images based on the mathematical apparatus of statistical solutions are now widely used. On the one hand, these transformations are aimed at the removal of distortions from space-derived information about the state of natural objects, and on the other hand, they improve the quality of the multispectral survey from both aircraft and satellites. Very often, however, transformations of images brightnesses are based on pure mathematical formalism, which does not consider the principal laws of formation of the outgoing radiation field. Transformations based on preliminary modeling of the processes of interaction of electromagnetic emission with the atmosphere and Earth’s surface are a qualitatively different way of removing atmospheric radiative distortions [347]. Here, the principal energy balance relationships and the related functions of conversion of radiation into the data recorded remotely by sensors are included. This approach to the transformation of spectral brightnesses obtained from multispectral air- and space-based survey will be used next.

Observations of the Earth Radiation Budget from Space

In this chapter we consider the western experience in the application of spaceborne hydrometeorological systems to assess the components of radiation budget at the Earth’s surface level.

Theoretical Models of the Non-Polarized Optical Radiation in the Atmosphere-Surface System

In studies of the Earth from space, the spectrophotometry of natural formations, surface and above-water objects on the day-side of the Earth, seen from MS and POS, are of great interest [1, 25, 141, 143, 191].

Models of Interaction of the Shortwave and Longwave Components of the Radiation Budget with the Atmosphere and the Earth Surface

Chapter 2 dealt with the general theory of interaction between radiation and natural media represented as a random cloud of scatterers, a random continuum medium, and a rough surface. Extreme transitions have been shown from the general theory of interaction to the radiation transfer theory as a partial case of the general theory with certain supposition concerning the radiation wavelength, the size of scattering centers and the coherence functions. Proceeding from the theory of shortwave radiation transfer, Chapters 3 to 5 were dedicated to the theory of the transfer function of the atmosphere-object-background system, and Chapter 6 discussed the atmospheric correction of digital air- and space-derived video information.

The Effect of Horizontal Inhomogeneities of the Underlying Surface on the Scalar Transfer Function of the Atmospheric

By the definition given in [94], the transfer operator transforms the atmosphere-induced distortions into real brightnesses of objects and of backgrounds. The actual content of a transfer function is much more complicated, since the functions of the transformation of the brightness of an object, viewed at different angles and with different combinations of objects in a given scene, will be different. This is determined by the horizontal inhomogeneity of the atmosphere and Earth’s surface as well as by the different extent of non-orthotropicity of natural objects.