Onboard the nasa terra satellite is the moderate resolution imaging spectroradiometer (modis) sensor. the terra satellite orbits the earth approximately 700 km above the surface and modis measures the radiance at a number of different wavelengths. the resolution at the earth’s surface of the modis sensor at earth-emitted radiation wavelengths (i. e., thermal infrared wavelengths) is 1km2.
consider a situation in which modis flies directly above a 1km2 region of the earth’s surface for which there are no clouds in the atmosphere above. across the modis measurement wavelength interval ∆λ centered on the wavelength λ assume that only water vapor has a nonzero (significant) absorption cross section σwva,λ. also assume that scattering of any sort is negligible at the wavelength λ.
for this particular scene the pressure varies with height and is given by