Observations and models of thermal emission from natural and man made objects

Abstract

This thesis is concerned with the investigation of the measurement of radiometric temperatures of various terrestrial surfaces, and the implementation and validation of a number of mathematical models to represent and predict the thermal behaviour of such surfaces under various conditions. Data can be acquired for radiation in a number of wavebands. Three radiometer systems built in Durham have been upgraded to allow measurements to be made in the 2-5pm and 8-14 µm wavebands. The refurbishment of these systems is described. An empirical model has been developed in Durham to describe the thermal behaviour of surfaces in terms of meteorological parameters. An experiment was carried out to determine the validity of this model for dealing with thermally light surfaces such as textiles. The analysis of the results from this investigation is presented. Detection modelling involves the production of mathematical models to describe the behaviour of all components in a system, including the surface under observation, atmosphere and the detector. A number of published detection models are discussed, together with other models which describe the behaviour of one particular component, and which could be combined to produce a detection model for a particular purpose. One particular detector/atmosphere model, SenSAT-3, is the subject of a detailed evaluation, with a view to integrating it with the Durham General Purpose Model for surface temperature to produce a complete detection model. The final chapter summarizes the current status of the work, and indicates possible directions for the future, including the development of a detection model based on the characteristics of the radiation thermometers installed in the Durham-built radiometers.