Proceedings of the Symposium on Global and Environmental Monitoring: Proceedings of the Symposium on Global and Environmental Monitoring

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Persistent identifier:: 856665355

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts ; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856665355

Language:: English

Document type:: Multivolume work

Volume

Persistent identifier:: 856669164

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Scope:: XIV, 912 Seiten

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856669164

Illustration:: Illustrationen, Diagramme, Karten

Signature of the source:: ZS 312(28,7,1)

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: International Society for Photogrammetry and Remote Sensing, Commission of Photographic and Remote Sensing Data

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: [TA-1 OPENING PLENARY SESSION]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: GLOBAL AND ENVIRONMENTAL MONITORING: TECHNOLOGICAL CONSIDERATIONS. by John S. MacDonald, MacDonald Dettwiler, Richmond, B.C., Canada

Document type:: Multivolume work

Structure type:: Chapter

Measurements which are geocoded in this way are then entered into a Measurement Database, where they are integrated with information from other sources. Such a database can be thought of as a generic description of a region of the planetary system in space and time. Its contents describe that region. The final step in the information delivery system is to extract information from the database in support of resource and environmental management decisions. This is shown in Figure 2 by the many "Information Extraction & Decision Support" elements at the bottom of the delivery system. This final step in the process is very application dependent. The same physical measurements have different meanings and are interpreted in different contexts depending on the discipline of application. For example, the infrared reflectance profile over a forest has a different meaning and significance to a forester than it does to an exploration geologist. Thus we see that information drawn from the database is treated and interpreted differently by different application disciplines. Technological Considerations Sensors The process of acquiring information begins with the sensing instrument in the spacecraft. The function of these instruments is to acquire the basic measurements which the system requires. They can be divided into two broad categories: passive and active . Passive sensors rely on the sun to provide the illumination energy which is reflected off the surface or the atmosphere and measured by the instrument. Active sensors provide their own illumination energy. Tables 1a and 1 b show a list of the major categories of sensing instruments together with a brief description of the characteristics and typical applications of each instrument. PASSIVE SENSORS Measure reflected solar energy and/or energy emitted by earth SENSOR CHARACTERISTICS and TYPICAL APPLICATIONS Spectroradiometer A class of instruments which measure the radiant flux entering the instrument in a number of very narrow spectral bands. Many types of these instruments exist, using a variety of different techniques for achieving the desired spectral measurement characteristics. -- Substance identification. Multispectral Scanner An imaging radiometer which makes spectrally rather course measurements (typically 80 - 100 nanometer spectral resolution) in the form of a number of separate "images" at different wavelengths. Thus for each point on the image a crude "spectrum" is obtained. - Identification of broad classes of surface material and general indication of condition. Imaging Spectrometer A similar instrument to the multispectral scanner, except that its spectral resolution is much finer (typically 10 nanometers or less), which allows it to acquire detailed spectral responses from each point on the surface. -- Identification of specific surface materials and condition. Atmospheric Sounder Imaging Instruments which operate in a number of very narrow wavelength bands in the infrared and microwave areas of the spectrum where the atmosphere is known to absorb radiation. Operation in this way enables measurement of radiance from different levels in the atmosphere. -- Temp., pressure, and H2O profiles, Total ozone content. Imaging Microwave Radiometer An imaging instrument which measures and maps microwave energy radiated (emitted) from the earth in a number of spectral bands. -- Surface temp., moisture, precip. Atmospheric temp, and H2O vapour profiles. Limb Sounder A spectral radiometer which is directed at the limb of the planet, thus measuring the characteristics of the atmosphere at various heights above the surface. - Atmospheric profiles of H2O vapor, O3, CH4, CO2, HNO3, etc Table 1a Passive Sensing Instruments

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