ACE

1. ACE Aerosol, Cloud, & Ecosystem Mission Cloud Science Traceability Matrix David Starr, NASA Goddard Space Flight Center ACE Study Lead Scientist Cloud Team Lead: Jay Mace, University of Utah Cloud Team: Steve Platnick/GSFC, Roger Marchand/U.Wash., Graeme Stephens/JPL, Deb Vane/JPL, Simone Tanelli/JPL, Ann Fridlind/GSFC, Eric Jensen/Ames, Dave Winker/LaRC, Steve Ackerman/U.Wisc., et al….

2. Decadal Survey ACE Mission • Only Decadal Survey Mission in Tier 1 or Tier 2 that is focused on Aerosols and Clouds, and their interactions, including effects on precipitation • Climate prediction • Forcing to surface ecosystems (carbon cycle) and cryosphere • Intergovernmental Panel on Climate Change (IPCC, 2007) identified the largest uncertainty in our understanding of physical climate as that due to aerosols and clouds.

3. Everything else… Clouds • Cloud-related feedback processes dominate these uncertainties. • IPCC AR4: Cloud Feedbacks are a major source of climate change uncertainty - both to warming and global precipitation changes. From Dufresne and Bony (2008)

4. ACE Mission C, N, S, Fe, Halogens, organics ACE is the successor to a core complement of A-Train sensors and science that has been, and is today, highly productive. ACE represents a substantial step forward, beyond the A-Train and EarthCare, in remote sensing capability, for Aerosols, Clouds and Ocean Ecosystems, enabling critical science progress, especially with regard to physical processes. ACE is highly synergistic Atmospheric correction for ocean ecosystem characterization Interactions of aerosols and ocean ecosystems Interactions of aerosols and clouds, including precipitation

5. ACE Cloud Science Questions Advance our ability to observe and predict changes to the Earth’s hydrological cycle and energy balance in response to climate forcings, especially those changes associated with the effects of aerosol on clouds and precipitation.

6. Everything else… Clouds • Cloud-related feedback processes dominate these uncertainties. • IPCC AR4: Cloud Feedbacks are a major source of climate change uncertainty - both to warming and global precipitation changes. From Dufresne and Bony (2008)

8. Deep Convection - Microphysics B.3 What are the essential cloud radiative feedbacks on tropical convection and how are these feedbacks influenced by ice microphysics?

9. Cirrus • Deep Convection – Microphysics • Boundary Layer Clouds (cu & stcu) • Midlatitude Frontal Clouds • Polar Clouds

10. Evolution of our Measurement Strategy Past (passive): Characterize the integral properties Present (A-Train): Characterize gross features of microphysical profiles Future (ACE): Characterize the processes that drive changes to particles in the column

11. The problem is severely under-constrained with existing data. To resolve process, we need independent measurements that constrain simultaneously multiple particle modes. Future (ACE): Characterize the processes that drive changes to particles in the column

12. ACE Clouds Instrument Requirements/Goals

14. ACE Instruments • Lidar for aerosol/cloud heights, aerosol properties, & ocean particle load (TRL 3-4) • Two options: multi-beam system or high spectral resolution lidar (HSRL) • HSRL driven by science requirement to distinguish aerosol types/composition • Multi-beam system driven by desire for greater area coverage/sampling • Dual-frequency cloud radar for cloud properties and precipitation (TRL 4-6) • W-band (94 GHz) with Doppler to ±0.4 m s-1 • Ka-band (35 GHz) with Doppler to ± 1 m s-1 • Strongly recommended goal: Ka-band scanning over narrow swath (~25-50 km) • Polarimeter: Multi-angle, multi-spectral, swath for imaging aerosol and clouds (4-6) • Ocean ecosystem spectrometer (OES): multi-spectral uv-vis, wide-swath(5) • IR multi-channel imager for cloud temperatures and heights (TRL 6) • High-frequency microwave swath radiometer for cloud ice water path & De (TRL 6) • Low-frequency microwave swath radiometer: cloud liquid water path & precipitation(8)

15. September21, 2010 NASA GRIP – A-Train Underflight ~ 13.5N58.5W APR-2 13.4 GHz Reflectivity Factor Cirrus Light Stratiform Embedded Convection APR-2 35.6 GHz Reflectivity Factor APR-2 Mean Doppler Velocity Isolated Convection (Dust-Processing) CloudSat 94 GHz Reflectivity Factor Cirrus Dust - SAL CALIPSO 532 nm Total backscatter Dust - SAL MODIS 11 mm channel

17. ACE Cloud STM • Rationale for Wide Swath Cloud Observations • • Capability already necessary for narrow swath cloud science • • Enables robust science on transient large-scale geophysical events • • Enables synergy between process (narrow swath) and systems studies • • Aerosol-Cloud science synergy commensurate with aerosol observations • • Matches Expected Model Requirements (coverage & resolution) • => Supports Global Data Assimilation requirements, • & associated pathway for global model improvement • • Data Continuity • PACE: 0.66, 0.87, 0.94, 1.24, 1.6, 1.38/1.88, 2.25, and 3.7 µm bands. • No IR (window or CO2 channels)

18. The cycling of water between aerosols, clouds, and precipitation is and will continue to be the primary source of uncertainty in climate change prediction The past and present measurement data sets are not adequate to address questions of process. ACE is conceived to address the questions of microphysical processes that will dominate climate change science in the early 2020’s. Measurement concept reduces to two basic active instruments (dual frequency Doppler radar and lidar) combined with aerosol polarimeter to provide the baseline set of measurements.

19. ACE Aerosol-Cloud Science • Conclusion: To advance our ability to observe & predict changes to the Earth’s hydrological cycle and energy balance to climate forcings, especially those changes associated with the effects of aerosol on clouds and precipitation, it is imperative that we acquire global, cloud-resolving, coincident measurements of cloud microphysical profiles in the context of their aerosol environment. • To achieve the required accuracy and fidelity of cloud microphysics profile observations, we require passive and active, cloud-penetrating, remote sensing measurements, such as radar and lidar for optically thinner clouds, at multiple frequencies (and Doppler), responding to different moments of the particle size distribution. • Coincident measurements of integrated quantities, such as cloud liquid and ice water paths will greatly enhance the accuracy of cloud profile retrievals by providing integral constraints of sufficient accuracy.

20. ACE Cloud STM Summary ACE is the Climate Prediction Mission ! ACE is the next step required to understand the role of aerosol-cloud-precipitation processes in the hydrologic and energy cycles, and global climate change, and offers the potential for very significant advances. ACE 2010 Study Report available: http://dsm.gsfc.nasa.gov/ace/documents.html

21. ACE Cloud STM Backup Slides

22. ACE Mission • Algorithm Development – New & evolved sensors • Big step forward from what we have in space !! • • Ocean Ecosystem Sensor – many more channels, new geometry • • Polarimeter – moderately high-resolution, wide-swath, UV-SWIR data, • building on and beyond predecessor missions • • HSRL – major step forward (3b+2a+2d) from CALIOP (2b+1d) • • Radar – W (CloudSat) + Ka (GPM) together, with Doppler (EarthCare) • • Submillimeter – new channels and new geometry (versus MLS) • Each has new products !!! • AND !!!! Multi-sensor products (recent A-Train developments) => clouds

23. ACE Concepts

24. Near-term Future of Multisensor Remote Sensing of Aerosols and Clouds from Space • EOS A-Train platforms, including CloudSat and CALIPSO, are all past prime mission and their nominal design life. • Due to low solar cycle 23 minimum, the EOS platforms will likely not be de-orbited until 2018 (or beyond). • MODIS on Aqua should still be operating in 2014 (85%). • CALIPSO and CloudSat should last to 2014 as well • CloudSat dictated by spacecraft battery and high power amplifier. • CALIPSO dictated by laser lifetime. • GCOM-W1 launch in 2011 (AMSR-2) => into A-Train • NPP launch in October 2011 (VIIRS, CrIS, ATMS, OMPS) • NPP & JPSS not planned to formation fly with other platforms. • EarthCare launch in 2013 (ATLID, CPR, MSI, BBR) • EarthCare not planned to formation fly with other platforms. • EarthCare orbit is ~400 km and no wide-swath sensors.