The thermally emitted microwave spectrum of the terrestrial atmosphere, viewed from above, is calculated for frequencies in the vicinity of a Zeeman-split oxygen line. Previously omitted phase terms are included; their effect on brightness temperature can be as large as 1.5 K for linearly polarized measurements. For the purpose of using oxygen lines as a probe of the atmospheric temperature profile, circular polarization of the radiometer would yield better vertical resolution. A double-sideband radiometer measuring two lines would include a polarizer that reverses the handedness of polarization between the upper and lower sidebands. With channels covering frequencies from −4 to +4 MHz from the center of the 7+ or 9+ lines a satellite radiometer could measure the temperature profile for altitudes from 43 to 70 km.
If you can't find a tool you're looking for, please click the link at the top of the page to "Go to old article view". Alternatively, view our Knowledge Base articles for additional help. Your feedback is important to us, so please let us know if you have comments or ideas for improvement.