Near-simultaneous Observations of Polar Mesospheric Clouds from the International Space Station and from Orbiting Optical Instruments

The orbit of the International Space Station (ISS) carried the spacecraft to latitudes high enough for observations of Polar Mesospheric Clouds (PMC). During the PMC southern-hemisphere season 2002-2003, a series of digital images and visual observations were taken over the Antarctic continent of PMC at the sunlit limb. Approximately twenty such observations, available through the ISS LAB window towards the summer pole, revealed the PMC as a distinct narrow scattering layer in the upper mesosphere, often many thousands of kilometers in horizontal expanse. The field of view from the ISS covered a sufficiently wide area of the polar region, that it was possible to co-locate measurements taken by instruments on board unmanned spacecraft in the near vicinity of the Space Station (but taken from a higher altitude). This provided an opportunity to combine accurate limb scans and nadir views of PMC with high-resolution information on the horizontal spatial structure. The SNOE and NOAA-16 and NOAA-17 SBUV/2 instruments obtained 15 orbits per day of PMC measurements at UV wavelengths. In addition, the SABER experiment on board the TIMED satellite obtained temperature profiles in the same vicinity. We will report on the first comparisons of these data, and describe the specific advantages of this unique combination of data.