Evaluation of infrared emission of clouds and ground as measured by weather satellites /

Of prime interest are the radiation data from that portion of the infrared spectrum known as the atmospheric water-vapor window, ranging from about 8 to 12 microns. Infrared signals received by weather satellites and aircraft depend, in clear air, on surface temperature, atmospheric interference and surface emissivity. For the latter, very different data in literature are found for clouds, water, rocks, etc. In this report correct emissivity data were sought in three ways: (1) Reflectivity of polished rock samples was tested in an infrared spectrograph for 5-16 microns wavelength. Using Kirchhoff's law this method yielded emissivities for near normal incidence. (2) Using an 8-13 microns sensitive radiometer and an aggregate, called emissivity box, the emissivity of many surfaces was measured directly. (3) A summer noon time flight of Tiros over the Mediterranean and the Sahara was evaluated.Research supported by the Terrestrial Sciences Laboratory, Air Force Cambridge Research Laboratories, Office of Aerospace Research, United States Air Force, L.G. Hanscom Field, Bedford, Massachusetts.Terrestrial Sciences Laboratory Project 7638.AD0617417 (from http://www.dtic.mil)."November 1965."Includes bibliographical references (pages 69-71).Of prime interest are the radiation data from that portion of the infrared spectrum known as the atmospheric water-vapor window, ranging from about 8 to 12 microns. Infrared signals received by weather satellites and aircraft depend, in clear air, on surface temperature, atmospheric interference and surface emissivity. For the latter, very different data in literature are found for clouds, water, rocks, etc. In this report correct emissivity data were sought in three ways: (1) Reflectivity of polished rock samples was tested in an infrared spectrograph for 5-16 microns wavelength. Using Kirchhoff's law this method yielded emissivities for near normal incidence. (2) Using an 8-13 microns sensitive radiometer and an aggregate, called emissivity box, the emissivity of many surfaces was measured directly. (3) A summer noon time flight of Tiros over the Mediterranean and the Sahara was evaluated.Mode of access: Internet