Determination of Stratospheric Temperature and Height Gradients From Nimbus 3 Radiation Data

Abstract

To improve the specification of stratospheric, horizontal, temperature and geopotential height fields needed for high-flying aircraft, we derived a technique to estimate data between satellite tracks using interpolated infrared interferometer spectrometer 15-µm radiation data from Nimbus 3. The interpolation is based on the observed gradients of the medium resolution infrared 15-µm radiances between subsatellite tracks. The technique was verified with radiosonde data taken within 6 hr of the satellite data. The sample varied from 1,126 pairs at low levels to 383 pairs at 10 mb using Northern Hemisphere data for June 15-July 18, 1969. The data were separated into five latitude bands. The root-mean-square (rms) temperature differences were generally from 2° to 5°C for all levels above 300 mb. From 500 to 300 mb, differences vary from 4° to 9°C except at high latitudes, where the differences were near 3°C. The rms differences between radiosonde heights and those calculated hydrostatically from the surface were from 30 to 280 m, increasing from the surface to 10 mb. Integration starting at 100 mb reduced the rms difference in the stratosphere to 20?120 m between 70 and 10 mb. Comparison with operational maps at 50 and 10 mb indicates that the techniques developed here produce analyses that are in general agreement with those from radiosonde data. In addition, these techniques provide details over areas of sparse data not shown by conventional techniques.