Overview of Science Results from the Solar Occultation For Ice Experiment (SOFIE)

The Solar Occultation For Ice Experiment (SOFIE) has operated on NASA's Aeronomy of Ice in the Mesosphere (AIM) from April 2007 to present. SOFIE monitors the reduction in solar intensity as rays pass through the atmosphere on tangent paths during sunset or sunrise as viewed from orbit. The vertically resolved ( 1.8 km) measurements offer high sensitivity due to the bright solar source, a long path length ( 300 km), and a very precise electro-optical system. Observations at 16 wavelengths (l from 0.292 to 5.316 mm) are used to retrieve vertical profiles of temperature, polar mesospheric clouds (PMC), meteoric smoke, and the abundance of five gaseous species (O3, H2O, CO2, CH4, and NO). An overview is given of various achievements in mesospheric science based on SOFIE measurements. These include detailed characterizations of the ice particles in PMCs, revealing their phase, shape, temperature, and size. SOFIE also provided the first systematic observations of meteoric smoke in the middle atmosphere, discovered a seasonal layer of meteoric smoke mixed with sulfate, and revealed that PMC particles contain a small amount of meteor smoke.