1. Future for APS and related

2. APS-2 Reflight Report

3. What is the current state of the art and the uncertainties associated with estimates of aerosol radiative forcings based on existing satellite data and models? What are or will be the critical science questions concerning aerosol effects on the Earth system currently and extending to ~2020? What are the limitations of our current and confirmed space-borne aerosol observational capabilities to address these questions? Can an APS-2 sensor (a near-carbon copy of the Glory APS) add significantly to the aerosol retrieval capability of current satellite instruments and those expected to be launched before 2015? What are the gaps in our knowledge of aerosols that APS-2 would fill? What is the key aerosol and cloud information expected to be provided by APS-2 observations that can be used by process models and climate models to improve projections of changes in the Earth system? Can formation-flying enhance the ability of APS-2 to address these questions? What is the likely impact of postponement of an advanced aerosol polarimetry mission for ~10 years?

4. APS-2 Reflight Report

5. Rich Ice Pure dust Dusty mix Marine Polluted marine Urban Fresh smoke Smoke Phil Urban-Industrial Biomass-Burning Mineral Dust Asian Urban MISR Five aerosol air mass "Mixing Groups" and thirteen sub- groups Models Sulfate Nitrate Ammonium Ammonia Dust Sea salt Black carbon Organic carbon Aerosol water

6. APS-2 Reflight Report

12. 9 channels  250 angles  3 Stokes parameters = 6750 units of data Number of units of data  > 200 Number of unknowns

13. APS-2 Reflight Report

18. APS-2 is uniquely designed to achieve the following critical science objectives with policy relevance: ● provide long-term global and regional monitoring of essential aerosol properties in clear-sky conditions as well as above and between clouds; ● provide detailed aerosol information needed for improvement and validation of process and climate models; ● provide long-term global and regional monitoring of essential cloud properties; ● provide long-term global and regional monitoring of stratospheric aerosols caused by major volcanic eruptions; ● provide refined aerosol and cloud representations for use in various remote-sensing retrievals, thereby allowing improvements in aerosol and cloud assessments by other operational satellite instruments.

19. APS-2 Reflight Report Extensive pre-flight tests of the Glory APS have demonstrated a remarkable robustness of its design. The actual performance of the Glory APS was found to be fully consistent with original technical specifications and in many cases exceeded them considerably. This provides a strong argument in favor of rebuilding and reflying a near- carbon copy of the Glory APS.