The PACE Mission: An Ultralite Solar Occultation Instrument for Simultaneous Infrared and Visible Measurements of Gases, Aerosols, Temperature, and Thin Cirrus

We have developed a concept for simultaneous solar occultation remote sensing of gases, aerosols, and thin cirrus in response to NASA's Announcement of Opportunity for Earth System Science Pathfinder (ESSP) Missions. The focus of our experiment is on the upper troposphere and lower stratosphere with the goal of filling critical gaps in the current climate research program. Specifically, the Particles, Atmosphere, and Climate Experiment (PACE) will * Measure temperature, aerosols, ozone, water vapor, and thin cirrus clouds to diagnose the response of climate to human-induced forcings and their interactions. * Extend the Atmospheric Trace Molecule Spectroscopy (ATMOS) database by providing measurements of key gases with increased precision and tropospheric coverage. * Extend the Stratospheric Aerosol and Gas Experiment (SAGE) database by providing aerosol and thin cirrus measurements with a new ability to measure horizontal inhomogeneity coupled with the ability to penetrate broken clouds.