Status of Preparation of Manuscript for DWL BAMS Article Discussion at Lidar Working Group Meeting Miami February 8 - 9, 2011 Dr. Wayman Baker 1

The three-dimensional global wind field is the most important remaining measurement needed to assess the flow dynamics of the atmosphere. Wind information in tropical and Arctic/Antarctic areas, as well as in the stratosphere, is particularly deficient. Furthermore, only a small fraction of the global atmosphere is sampled in terms of wind profiles. Three dimensional atmospheric analyses are not sufficiently well constrained due to the deficit in wind information. This limits our ability to optimally specify initial conditions for numerical weather prediction (NWP) models and limits our understanding of several key climate change issues. Because of its extensive wind-measurement heritage (since 1968) and especially the rapid technology advances in the last several years, Doppler lidar has now reached a level of maturity required for a space-based wind mission. This paper reviews the expected impact of global Doppler lidar wind measurements on NWP and climate research, the concepts for wind measurement by Doppler lidar, and the recent advances in Doppler Wind Lidar (DWL) technology that will set the stage for space-based deployment. The planned Atmospheric Dynamics Mission (ADM)/Aeolus from the European Space Agency, expected to be launched in late 2013, will be the Lidar-Measured Wind Profiles – The Missing Link in the Global Observing System –– Abstract 2

3 first DWL in space. ADM/Aeolus is a demonstration mission; possible follow-on mission concepts for a U.S. space-based DWL are outlined in this paper. Forecast impact experiments with actual airborne DWL measurements collected over the North Atlantic in 2003 and assimilated into the European Centre for Medium-Range Weather Forecasts operational model are a further indication of the value of lidar-measured wind as has been suggested by Observing System Simulation Experiments (OSSEs) conducted over the past 25 years. In addition, a first case study with DWL data collected over the Western Pacific in 2008 also shows a large impact on tropical cyclone track and intensity forecasts. Similarly, global wind measurements obtained with a space-based DWL will advance the understanding of several important climate change issues, including those whose understanding is critically dependent on the accurate estimate of heat transport, such as the recent rapid decrease in the Arctic sea ice extent, or whether there is variability in the atmospheric general circulation on decadal timescales. Lidar-Measured Wind Profiles – The Missing Link in the Global Observing System –– Abstract (Cont.)

1.Introduction – Wayman, Jim Yoe, Lars Peter, and Erland Kallen - Draft completed 2. Impact of Global Wind Profiles on Weather Forecasting and Climate Research - OSSEs - Lars Peter, Bob Atlas, Zhaoxia Pu, and Michiko Masutani - Draft partially completed; still need GWOS OSSE results; include WISSCR OSSE results - Airborne DWL forecast impact experiments over the North Atlantic – Martin Weissmann and Carla Cardinali - Draft completed - Airborne DWL forecast impact experiments over the western Pacific – Zhaoxia Pu and Dave Emmitt - Draft completed - Preparing to assimilate ADM observations – Will McCarty and Lars Peter - Draft completed - Climate change studies – Erland Kallen and Amy Clement - Draft completed - Chemical transport – Brad Pierce and Ralph Ferrare - Draft completed; Mike will work with Brad to shorten text - Aerosol profiling – Brad Pierce and Ralph Ferrare - Draft completed; Mike will work with Brad to focus the section on how a wind lidar will make predictions of intercontinental pollution transport better Outline 4

3.Space-Based Wind Lidar Measurement Concepts - Excellent input received on coherent technology (Michael) and fundamental principles (Jim Ryan); Mike will modify text to focus the section on: scanning vs. non-scanning issues, the effects of cloud and aerosol distributions, and pros and cons of direct and coherent Hybrid DWL mission concepts (i.e., GWOS, NWOS, WISSCR) – Dave Emmitt, Steve Mango, and Ken Miller - drafted completed; Add WISSCR concept and findings from IDL/MDL study; Input still needed on: - The European Space Agency’s Atmospheric Dynamics Mission (ADM) – Lars Peter and Mike Hardesty - Direct detection (including UNH, briefly mention ADM again, GSFC, and private industry, including autocovariance) – Bruce Gentry, Jim Ryan, and Sara Tucker 4.Hybrid DWL Technology - Direct detection component (UNH, GSFC ADM, and private industry, including autocovariance) – Bruce Gentry, Jim Ryan, and Sara Tucker - Coherent detection component (LaRC, private industry) – Mike Hardesty and Michael Kavaya 5. Concluding Remarks – Wayman Baker and Jim Yoe Outline (Cont.) 5