Wayman Baker (NOAA/NWS) brought the 23rd meeting of the Working Group on Space-Based Lidar Winds to order. The purpose of the meeting was to advance lidar technology toward achieving a space wind measurement capability. Wayman discussed an Integrated Program Office (IPO) Announcement of Opportunity (AO) seeking candidate instruments for inclusion on future NPOESS missions, including NPOESS C-2 with a 2011 launch. Discussion and studies are underway to determine how to respond with a proposal for a Doppler Wind Lidar (DWL) instrument. Any proposed DWL instrument will be constrained by limited resources on the spacecraft.

Action Items from the last meeting (see http://space.hsv.usra.edu/LWG/Jun04/ActionItems.jun04.html) were discussed, as follows.

1. A benchmark statistical description of the sub-grid scale velocity field is needed. - R. Brown, R. Frehlich, D. Emmitt, R. Foster. This activity is in progress. The product could be a paper or a website section. Status: Open.
2. Prepare a proposal to support a targeted observations field experiment with a wind lidar on a G4 aircraft. - M. Hardesty, Z. Toth, E. Kalnay. The G4 proposal was turned down. Status: Closed.
3. Prepare a whitepaper comparing a lidar and other wind sensors. - M. Kavaya, P. Flamant, I. Guch. The subcommittee offered these points.
   • There are now dozens of papers comparing Doppler lidar winds to anemometers, rawinsondes, radar wind profilers, and sodar wind profilers.
   • A majority of the comparisons provide a coplot but do no numerical analysis to the wind velocity difference, nor compare the difference to model predictions. Hence, the majority of papers only provide a qualitative confirmation that the Doppler lidar is working.
   • A few papers have recently shown excellent agreement, and provide a numerical analysis of the error. However, they do not yet analyze the theoretical vs experimental error.
   • The different measurement volumes and measurement time intervals of the different wind sensors probably prevent a conclusive analysis of how close the Doppler lidar performed compared to theory.
   • What is needed is to compare multiple Doppler lidars that are matched as closely as possible to each other in measurement volume, time interval, position, and direction; and then to compare the experimental performance to theory. This should be done for various atmospheric states.
   • There is no need to prepare a white paper describing the past publications.
   It was pointed out that validation of space-based lidar remains a challenge, and that we need to know more about atmospheric variability and how different instruments measure them. The point was made that DWL measurements are more satisfactory than other instruments for wind. Status: Closed.
4. Develop a proposal for deployment of a wind lidar on commercial aircraft. - R. Fleming, R. Atlas, D. Emmitt, M. Hardesty. Status: Open.
5. A co-plot of the CTI CAMEX backscatter data and the recent GTWS 2 micron backscatter profiles is needed. - P. Gatt, D. Emmitt. E. Kalnay. Dave Emmitt stated that the website has 2 micron GTWS backscatter profiles and showed a chart for enhanced and background profiles used for Observing System Simulation Experiments (OSSEs) and simulations. Data for 2 microns is modeled based on GLOBE measurements at other wavelengths. Measured and modeled profiles compare well. Backscatter observations are very broad. Status: Closed.
6. Why are global wind profiles necessary? E. Kalnay. Status: Open.
7. Reconvene an Executive Steering Committee to advise NASA/NOAA on actions required to implement the wind lidar roadmap. - I. Guch, D. Tratt. Ingrid and Dave are planning a joint NOAA/NASA review of requirements in Spring 2005. Status: Open.
8. The Lidar Working Group should use the Lidar Technology Roadmap to track progress and provide updates to Ken Miller. Ken Miller is to make a report card to track progress against the Roadmap. Status: Open.
9. The science requirements should be posted on the website. - J. Yoe. Status: Closed.
10. The use of GLAS data to improve the height assignment of GOES winds should be pursued. - J. Reagan. Although GLAS has had performance problems, data is logged and available. See Ingrid Guch for contacts to GOES to access data. Status: Open.
11. Explore potential collaboration with DoD on advances in telescope technology - S. Alejandro, I. Guch. Status: Open.
12. Explore funding possibilities and the path forward for design studies for the Hybrid DWL concept - D. Tratt, I. Guch. NASA is funding studies with Dave Emmitt. Status: Open.
13. Coordinate and scale to space, using observations from existing lidar systems, to verify space-based instrument specifications - M. Hardesty, D. Emmitt, B. Gentry, M. Kavaya, P.Gatt, I. Dors. Government reference designs need revisited. This activity is in progress. Status: Open.
14. Need to introduce the updated requirements for the tropospheric winds to the JARG, specifically those vetted through the GTWS process - I. Guch. Ingrid is working with Major Krasner, AF Space Command to update requirements. Ingrid is working on a process to update the IORD, and hopes to have updated wind requirements by the next Working Group meeting. Status: Open.
15. How to approach NASA HQ on the importance of tropospheric winds needs to be discussed, including how the measurements could be valuable in gaining a better understanding of the atmosphere of Mars - D. Tratt, R. Atlas, B. Gentry, D. Emmitt, W. Baker. Dave Tratt, the NASA contact for winds, is moving back to JPL. Action: send a memo to NASA to find out who will be responsible for winds after Dave goes back to JPL. Bruce Gentry stated that a Mars Roadmap item is to determine wind profiles for landings. Status: Open.
16. Need to prepare articles for the refereed literature updating the many advances in lidar technology, OSSEs, ground-based and airborne measurements, etc. since the BAMS 1995 article was published. - R. Atlas, D. Emmitt, J. Ryan, J. Yoe (J. Yoe to chair discussion of possible BAMS II article).
17. Invite someone from the FAA to attend the next Lidar Working Group meeting - W. Baker. Status: Closed
18. The technology readiness levels (TRLs) of the various subsystems need to be identified in the context of the technology roadmap. - U. Singh. DWL TRLs are ambiguous metrics so care and external review are needed. Status: Open.
19. Prepare a textbook on the basics of wind lidar, the advances in the past decade, and the potential benefits. D. Bowdle et al. A manuscript is in progress. Status: Closed.

Presentations

Stephan Rahm presented "ALADIN Airborne Demonstrator and Planned Campaigns." The Atmospheric Laser Doppler Instrument (ALADIN) is part of the ESA ADM sensor suite. It is a direct detection, single line of sight lidar with fringe-imaging detection for analyzing aerosol and cloud backscatter and a double-edge receiver for analyzing molecular backscatter. It is scheduled for launch in the Fall of 2007. It is designed to measure wind from 0 to 20 km altitude with better than 2 m/s accuracy. Stephan showed wind measurement coverage on a world map, showing wind accuracies and areas of no information. Priorities for numerical weather prediction are wind profiles at all levels, temperature, precipitation, soil moisture, surface pressure, and snow equivalent water content. He showed a mission requirements chart. The laser is being made by an Italian company. A backup laser in a breadboard package is being used for measurements. He presented wind measurement accuracy requirements, geometry of measurement samples, and some instrument parameters. The ALADIN instrument mass is 446 kg. It uses 866 watts and has a 1.5 m telescope. He discussed the receiver designs. Campaigns are needed to test the instrument, verify laboratory characterizations, and assess errors. Airborne demonstration is needed, since there are major differences between ground and airborne/satellite systems. Ground demonstrations are planned in September 2005 and airborne demonstrations are planned in 2006 using prototypes of the space instrument. These demonstrations will provide data for signal processing analysis as well as increased confidence in the instrument.

Rod Frehlich presented "The Importance of Atmospheric Variability for Data Requirements, Data Assimilation, Forecast Errors, OSSEs and Verification," coauthored with R. Sharman. The Global Aircraft Sampling Program (GASP) has collected extensive wind turbulence data along aircraft flight paths. Rod showed turbulence plots from an National Center for Atmospheric Research (NCAR) research aircraft flying at 5 km for longitudinal, transverse, and vertical winds and temperature. The plots illustrated the nature of small scale turbulence. Rawinsonde observations provide a poor representation of winds because of small scale turbulence. Satellites provide a better representation because they average over footprints on the order of 50 km by 100 km. Spatial spectral plots of turbulence have been shown to fit a k^-5/3 law, where k is the wave number in radians per meter. This provides a robust statistical description in the troposphere. This power-law was used as truth to quantify the under-representation of small-scale turbulence in mesoscale and numerical weather prediction models. Structure functions were used as an alternative spatial statistic to permit local estimates of turbulence. Structure functions and spectra from model output are filtered and corrections derived from in situ data can produce local estimates of turbulence. Structure function plots from National Center for Environmental Prediction (NCEP) Rapid Update Cycle (RUC20) and United Kingdom Meteorological Office (UKMO 0.5ƒ) global models showed substantial under-representation of the small scales, as compared to in situ data from GASP measurements. Observation error includes instrument error and observation sampling error. The sampling pattern and turbulence determine the sampling error. In high turbulence regions, turbulence dominates the total observation error for rawinsonde measurements. Optimal data assimilation is possible if you can estimate the local turbulence. Rod described adaptive data assimilation using local estimates of the total observation error covariance (instrument error and sampling error) for optimal weights of the data as well as a calculation of the analysis error. Plots showed reduction of analysis error with adaptive assimilation for the 0.5ƒ Global Model, especially in the low turbulence regions defined by the median level of turbulence from the GASP climatology. Implications for OSSEs and NWP were discussed. Synthetic data for OSSEs should include realistic sampling error from the local turbulence and optimal assimilation using local estimates of turbulence to correctly predict the future capabilities of space-based systems. Rod proposed future work to determine global climatology of turbulence and universal scaling of small scale turbulence, to calculate total observation error for different instrument types (profilers, aircraft data, future data from long lidar tracks), to optimize the numerics of models, to improve adaptive data assimilation techniques that include the large variations in observation error, to enhance OSSEs, and to include realistic observation error in initial perturbations for ensemble forecasts. In discussion, Rod observed that we may not be making the best use of high quality data in low turbulence regions and future space-based lidar data may require less instrument error to be competitive.

Dave Emmitt presented "Preliminary Results of GLAS Data Based Study of CFLOS Statistics," coauthored with S. Greco. The Geoscience Laser Altimeter System (GLAS) is an orbiting instrument measuring ice-sheet topography and temporal changes, cloud and atmospheric properties, and topography. GLAS is carried on the Ice, Cloud and land Elevation Satellite (ICESat), launched in January 2003. Dave discussed preliminary GLAS findings pertinent to DWL design. GLAS data included wavelengths, beam geometry, and sampling pattern. Useful for DWL design were cloud-free line of sight (CFLOS) data, backscatter distribution, and cloud motion vector (CMV) height assignment and wind vector adjustment. CFLOS statistical studies are funded by ESTO to compare GLAS data with Lidar In-space Technology Experiment (LITE) backscatter data, gather statistics on numbers of shots getting to different levels, and correlate CFLOS with vertical wind shear. GLAS backscatter data at 0.532 microns can be modeled to estimate backscatter profiles for 2.05 microns. Backscatter profiles developed and used for Global Tropospheric Winds Sounder (GTWS) studies continue to be substantiated by field data. Two unresolved questions were presented related to global distribution and usefulness of the enhanced aerosol mode. Dave discussed how DWL data would improve the utility of CMV data. Moderate-resolution Imaging Spectroradiometer (MODIS) cloud observations were compared with GLAS cloud observations, finding 75% agreement. Agreement was poorer at night and over snow and ice. GLAS provided unique statistics on multilayer clouds. Based on a small data sample, GLAS sees about 70% global cloud coverage.

Yucheng Song presented "Recent Forecast Impact Results from WSR and ATREC", coauthored with L. Holland, Z. Toth, S. Majumdar. The Atlantic-THORPEX Regional Campaign (A-TReC) is a field campaign to measure ability to reduce weather forecast errors over Europe and the eastern U.S. by targeting extra observations over oceanic storm-tracks and other sensitive areas. THORPEX is an international research program to improve weather forecast accuracy. The A-TReC data were gathered from 15 October to 17 December 2003 using a variety of observing platforms and adaptive observing strategies. The evaluation compared analysis and forecast cycles and verified forecasts over the pre-selected areas of interest. Yucheng reported results for surface pressure, temperature, vector wind, and humidity. Overall 83% of forecasts improved, 13% were neutral, and 4% degraded. The Winter Storm Reconnaissance (WSR) activity took place 21 January through 17 March 2004. Dropwindsonde observations were adaptively deployed over the northeast Pacific based on Ensemble Transform Kalman Filter (ETKF) calculations. Data were collected before significant winter weather events in areas expected to have the most influence on forecasts. Forecasts improved in 60-80% of past targeted cases since January 2001. Yucheng showed graphs of the geographic influence of WSR dropwindsonde observations on NCEP GFS forecasts and showed overall results for surface pressure, temperature, vector wind, and humidity. Overall, 69% of cases improved and 31% degraded. Improvements in the ETKF calculations and coding are planned for WSR 2005. Future WSR work includes examining the effects in precipitation forecasts, improved targeting method, increased resolution and ensemble membership in WSR06, using ensembles for WSR05, and evaluation of results.

Dave Bowdle presented "Structure, Dynamics, and Microphysics of Organized Aerosol Backscatter Features in the Marine Boundary Layer, Observed by TODWL and Optical Particle Counters," coauthored with D. Emmitt, S. Wood. This work is investigating data processing related to space-based DWLs. It was sponsored jointly by ONR and the NPOESS IPO. Areas covered include calibration/validation procedures for DWLs and basic research on lower tropospheric winds and aerosols in the marine and continental boundary layers. Objectives include characterizing backscatter-velocity covariance, relating observed covariance to atmospheric processes, determining the particle size fraction that dominates backscatter magnitude and variance, and relating measured and modeled aerosol backscatter. The study found consistency and regularity in statistics for turbulence velocity and SNR, suggesting that they can be used parametrically in modeling. Dave described the Twin Otter DWL (TODWL) aircraft platform, instruments, flight schedules, locations, plans, and data bases used for boundary layer wind measurements. Data were shown for the February 20, 2003 flight. Results were shown for line of sight (LOS) velocity and SNR (Hovmuller charts and plots vs. altitude), and turbulent fields from the Forward Scattering Spectrometer Probe (FSSP). Turbulent field plots showed broad variation and bias in LOS velocity and SNR vs. altitude. Asymmetry bias was judged to result from uneven distribution of aerosols in the atmosphere, resulting in more measurements from regions of higher aerosol concentration. Findings included:

• Velocity and SNR have well defined turbulent probability distributions
• Backscatter-velocity correlations would bias shot-integrated velocity measurements from a down-looking DWL
• 10 to 20 micron diameter particles dominate the average backscatter at 2 microns wavelength and 30 m. altitude over Monterey Bay.

Dave Emmitt presented "Mars Related Opportunities for DWL Applications," coauthored by G. Koch, M. Kavaya, and U. Singh. This paper addressed what is known about winds and aerosols on Mars and the Mars Lidar Simulation Model (MLSM). Primary sources of Mars atmospheric observations were the Mariner 9 orbiter, Viking orbiters and landers, Mars Global Surveyor, and Mars Orbital Laser Altimeter (MOLA). MOLA lidar parameters were presented. Two major issues in Mars weather are how dust is lofted and what initiates the global dust storms that dominate inter-annual variability. LaRC has funded addition of a Mars atmosphere to the Doppler Lidar Simulation Model (DLSM) to create MLSM, and new code for performing trade studies of lidars in Mars orbit. The team is working with Ames and Princeton to acquire a Mars Nature Run (Mars General Circulation Model, or MGCM) and working with Bob Atlas to conduct a Mars DWL OSSE. Several characteristics of the Mars atmosphere were presented, addressing lower atmospheric backscatter coefficient, dust, dust storms, CO₂, optical depth profile at 9 microns, photographs of a global Martian dust storm, surface photographs, dust devils and dust devil tracks. Dust storms and dust devils have major effects on the Martian atmosphere.

Michael Kavaya presented "Status of the Laser Risk Reduction Program at LaRC," coauthored with U. Singh. The Laser Risk Reduction Program (LRRP) is centered on R&D and knowledge. Although it addresses technology areas that are important to a DWL mission, LRRP does not directly address earth sciences missions. LRRP was jointly funded by Earth Science Enterprise and Aerospace Technology Enterprise. Since the beginning of the Exploration Initiative and attendant NASA reorganizations, LRRP is centered on exploration. The Exploration Systems Mission Directorate (ESMD) accepted an ESTO/LaRC/GSFC proposal to continue LRRP. Total funding will decrease in FY05 and end in FY07. There is still a long way to go to develop the technology for wind measurement from space. LaRC components of LRRP include

• 2 micron pulsed transmitter laser development,
• Pump laser diode arrays development, characterization, and qualification,
• Wavelength conversion from 1 micron to UV,
• Detector and receiver advancement for direct and coherent detection at 2 microns, and
• Laser physics and new materials.

LaRC LRRP accomplishments were presented, including:

• More efficient laser material,
• Over 1 J pulse energy at 2 microns,
• Fully conductively cooled 2 micron laser head,
• Diode laser character and lifetime facilities,
• Innovative UV generation architectures,
• 2 micron detector characterization facility,
• High responsivity detector, and
• First integrated receiver breadboard for 2 micron coherent lidar.

Activities in each component of LaRC LRRP were reviewed for FY05-07. The LRRP activity is continuing and producing significant advances, but is not the only thing that needs doing for DWL. NASA does not have a person with a budget to oversee all aspects of accomplishing the measurement of winds from space. Developments for Mars exploration may help to advance technology needed for measuring winds on Earth.

Stephan Rahm presented "IWAKE Airborne Wake Vortex Detection." IWAKE is a European project to develop an aircraft on-board warning system for wake-vortex and other hazards. It will use a 2 µm scanning LIDAR. The three-year program ends in April 2005. DLR is responsible for the (CTI) lidar and long range data unit. Other development activities are addressing 2 micron lasers. A photograph of a Cessna Citation aircraft illustrated the instrumentation bubble and scan geometry of the test system. Stephan showed the scan pattern and photographs of the lidar, cooling system, and data rack. He described the installation in the aircraft. Wake vortex and long range wind flights were conducted in June near Toulouse France. Spatial plots of wind measurements with wake vortices were shown. IWAKE demonstrated axial detectability of wake vortices. To detect clear air turbulence, it is necessary to look directly along the flight track. There is no clear air turbulence correlation from one altitude to another at 100 m difference. Ground and airborne Airbus A380 (twin-deck, four-aisle) airliner wake vortex measurements are planned by DLR this year.

Dave Emmitt presented "Status of NCEP and GSFC OSSEs with DWLs," coauthored with Steve Lord and Bob Atlas. The presentation covered NCEP work and GSFC work. GSFC work included Hurricane OSSEs, new Nature Run, The Observing System Research and Predictability Experiment (THORPEX), and CMV with laser height assignment. NCEP OSSE characteristics were presented for a winter time nature run (February 5 to March 7, 1993). The OSSE simulated and assimilated level 1B radiance, a different method than using interpolated temperature. LOS wind, not u and v components were used for DWL. DWL impact assessment was made through bracketing experiments with four DWL cases:

1. full tropospheric LOS soundings, clouds permitting,
2. mid and upper tropospheric winds only down to levels of significant cloud coverage,
3. wind observations from clouds and the PBL, and
4. non-scanning DWL that provides full tropospheric LOS soundings, clouds permitting, along a single line that parallels the ground track.

Highlights of the NCEP OSSE results were discussed. Scanning significantly increases DWL impact and is required to produce additional skill over existing data in the Northern Hemisphere. Non-scanning DWL may produce significant impacts in the Northern Hemisphere with radiance data. DWL impact in a synoptic event was shown, along with a number of impact findings and analysis graphics. The role of the Joint Center for Satellite Data Assimilation (JCSDA) was discussed. A new Nature Run is needed, and the search for a new Nature Run was discussed. ECMWF will make a higher resolution Nature Run. The role of OSSES in THORPEX was discussed. OSSEs support a quantitative basis for evaluation of new or improved methods, help design adaptive targeting experiments, accelerate preparedness of operational centers to use new observations, and provide a laboratory for international collaboration. GSFC OSSEs have recently focused on high impact weather forecasts and events (e.g., hurricane tracks). Results from a hurricane track prediction were presented. THORPEX OSSE testbed activities were discussed. NOAA is funding establishment of an OSSE framework for THORPEX mission planning. GSFC has plans for a new nature runs generated with the finite volume General Circulation Model (fvGCM). fvGCM was developed to be NASAís next generation modeling system. It is being developed into a full Earth System Model (ESM) for weather and climate. Partners include NASA/JPL, ARC, MSFC, NOAA/GFDL, NCAR, DOE/LLNL, and universities. fvGCM has increased resolution (0.25°) for improved representation in the tropics. THORPEX testbed plans were presented. Status and plans for developing the 0.25° fvGCM were discussed.

Bob Brown presented "WindSat, the New Competition." WindSat is a satellite-based multifrequency polarimetric microwave radiometer developed for the Navy and the NPOESS IPO. It is a demonstration program to evaluate the capability of polarimetric microwave radiometry to measure the ocean surface wind vector from space. The sensor provides risk reduction for the Conical Microwave Imager Sounder (CMIS), which will provide wind vector data operationally starting in 2010. WindSat is the primary payload on the Air Force Coriolis satellite, launched in January 2003. The radiometer is a passive microwave radar receiver that measures radiation from the oceanís surface in terms of brightness temperature. It operates on the same principal as the scatterometer, but the signal is weaker and the instrument is less expensive. Wind roughens the surface and increases brightness temperature. Surface wind vectors are inferred from this reflectance. Spatial resolution is 25 km. It also measures sea surface temperature, soil moisture, rain rate, ice and snow characteristics, and water vapor. Ocean Observer provides operational data for the Navy and NOAA, science data for NASA and NOAA, and sensor proof of concept for NASA. It provides an operational transition for the CMIS instrument for NASA and NOAA. Primary contributions to Environmental Data Records (EDRs) by different sensors were shown. Several CMIS EDRs are also provided by WindSat. WindSat calibration/validation with sea level pressure retrievals was discussed. Two questions addressed were how well WindSat performs and can surface level pressure (SLP) fields help improve model function and ambiguity selection. Surface pressure plots reflected good agreement between ECMWF analysis and QuikScat analysis. Wind estimate comparisons between WindSat and QuikScat were mixed. A lot of wind vector information is available in WindSat data, and surface pressure can be used to assess and improve WindSat wind data. SLP fields demonstrate that the WindSat model often produces poor wind speed distribution and wind directions are noisy. Work is being done to use buoy/analysis pressures to identify and correct deficiencies in model function, and to continue development of SLP ambiguity selection procedures. Combining SLP with water vapor, clouds, and SST will greatly improve storms and fronts research and analysis.

Michael Kavaya presented "Wind Observations with the VALIDAR Doppler Lidar" coauthored with G. Koch, J. Beyon, and B. Barnes. VALidation Lidar (VALIDAR) is a testbed for advanced high-energy lasers and optical components for future airborne and spaceborne Doppler lidars. It supports validation for future airborne and spaceborne measurements and to test advanced receiver and processing components. The coherent lidar specifications are:

• Laser material: Ho:Tm:LuLiF
• Pulse energy = 95 mJ
• Pulse width = 180 ns
• Pulse repetition rate = 5 Hz
• Spectrum = single frequency
• Wavelength = 2053.5 nm
• Telescope aperture = 6 inches
• Detector: InGaAs heterodyne
• Digitization rate up to 2 Gs/s at 8 bits (500 Ms/s typical)
• Beam scanning: hemispherical coverage

The lidar design was discussed, followed by examples of vertical wind measurement with clouds, downdrafts, and a thunderstorm. Horizontal wind measurements were discussed, and measurements of a nocturnal jet and cirrus in the jet stream were shown. Future work includes incorporating higher energy lasers, improving receiver efficiency, implementing advanced signal processing, and developing a flight-hardened version.

Stephan Rahm presented "Targeted Observations with a Doppler Lidar during THORPEX." Targeted observations were acquired using aircraft flights from Keflavick, Iceland 14-26 November 2003. Dropsondes measured horizontal wind, temperature, pressure, and humidity. A 2 micron Doppler lidar measured horizontal and vertical wind profiles. Eight missions were flown, with 28.5 h of flight time, 20 h of wind Lidar data, and 49 sondes dropped. Photographs and drawings showed the lidar hardware in the laboratory and showed the airborne configuration of instrumentation as well as the interior of the aircraft. Graphics from November 22, 24 showed ECMWF analysis, lidar wind profiles, flight tracks, comparison of lidar wind profiles with dropsondes, clouds at the Greenland jet, and comparison of measured lidar wind vs. ECMWF model winds. Preliminary assimilation of the lidar data into the ECMWF model shows a positive impact at 500 hPa forecast. Complete assimilation is planned for February 2005. The website address is http://www.pa.op.dlr.de/na-trec/

Geary Schwemmer presented "Improvements in UV HOE Performance for Scanning." Geary described the Holographic Optical Element (HOE) and Shared Aperture Diffractive Optical Elements (SHADOE). In the HOE telescope, a holographic film is attached to a transparent optical element. The hologram points the telescope off axis, and scanning is implemented by rotating the HOE. In SHADOE, several holograms are multiplexed onto the transparent optical element and scanning is achieved without rotating the optical element. A roadmap for spaceborne SHADOE capability showed steps to be followed and projected the attainment of TRL level 5 in 2009 for SHADOE for a hybrid DWL. Supported efforts include UV optical testing, Doppler Lidar HOE demonstration, SHADOE design concepts, radiation testing, and wavefront error correction. Geary described current test results on HOE and on a SHADOE implementation with five HOE elements. He showed photographs of the UV HOE with beam steering assembly and of test setups. He described alternative receiver designs.

Michael Dehring presented "BalloonWinds and GroundWinds: A Status Update." The discussion covered status of the GroundWinds Hawaii and New Hampshire instruments and the Hawaii validation campaign. The BalloonWinds flight schedule and goals, program status, engineering hardware build and design progress, and a current best estimate of performance were presented. The GroundWinds New Hampshire instrument is being used operationally and in testing BalloonWinds control software. The Hawaii instrument is undergoing minor repairs and will be fully operational in mid February. A validation campaign is scheduled for April, in which simultaneous measurements will be compared among GWHI, radiosonde, H₂O Raman LIDAR (Barnes), aerosol CLIDAR (Barnes), and O₃ Raman LIDAR (JPL). Aerosol backscatter coefficient, H₂O vapor, and temperature profiles will be inter-compared. BalloonWinds will demonstrate a photon recycled fringe imaging DWL operating from 30 km altitude under a variety of atmospheric conditions. A three-flight schedule, March through September 2006, was discussed. Responsibilities of the BalloonWinds team members were discussed, including NOAA, University of New Hampshire, Michigan Aerospace Corporation, Fibertek, and Raytheon. Balloon flight timelines and overviews were discussed. The design has switched from a flash-pumped laser to a diode pumped laser. Design and status of main subsystems were reviewed and horizontal wind error predictions were described.

Floyd Hovis presented "Laser Transmitter for BalloonWinds Program, " coauthored with Jinxue Wang and Michael Dehring. The objective is to develop a robust, single frequency 355 nm laser for airborne and space-based direct detection DWLs. The laser will be solid-state, diode pumped, robust, vibration tolerant, and space-qualifiable. Lasers will be demonstrated in ground-based and airborne field systems and the designs will be iterated to achieve space capability. Floyd described the BalloonWinds laser transmitter development approach, performance goals, design, status, and future development work.

Dave Emmitt presented "Status of Twin Otter DWL (TODWL) and Ground-based Wind Observing Lidar Facility (GWOLF)" coauthored with S. Greco and C. OíHandley. The presentation covered new results and plans for future work. A smaller lidar package was installed on the Twin Otter aircraft. TODWL missions studied rolls and Organized Large Eddies (OLEs) on flights at different levels in the vicinity of Monterey, CA. A paper is being prepared on findings. Low level jets of 12 to 15 m/s] were observed at 150 m altitude. In FY05/06, work is planned for the Army Research Office (SBIR) to use TODWL for adaptive targeting demonstrations. The GWOLF is a ground-based version of TODWL. The TODWL scanner was sent to CTI for integration and testing. The scanner will be installed on a trailer for mobile use. Formerly GWOLF shared a scanner with TODWL. Work at Langley Research Center includes studies of variability of cloud returns and hard target work. FY05/06 plans include a rooftop GWOLF scanner, VALIDAR comparisons, and GLOW comparisons. Work will be done to populate the climatology of backscatter for use in predicting backscatter from a lidar in space.

Major Richard Krasner presented "Air Force Commandís Environmental Monitoring Requirements and Planning Process." The DoD Integrated Operational Requirements Document (IORD) objective requirements for tropospheric winds were discussed. IORD objective requirements are more demanding than GTWS threshold requirements for wind speed range and accuracy, latency, and refresh rate. The IORD does not include threshold requirements. The Air Force Space Command (AFSPC) will work with NOAA to review these requirements. Near-real time analysis of global tropospheric winds is needed to aid operational decision cycles and for input to numerical weather prediction models. Examples of missions impacted by improved numerical weather prediction included: space launch, flight planning/aviation operations, dispersion forecasts for NBC releases, weapons delivery/strike planning, airdrop, reconnaissance, aerial refueling, artillery, and battle space awareness. Knowledge of the jet stream is very important to saving money in aviation. The mission and vision of AFSPC were described. Air Force planning, requirements, and acquisition processes were discussed. AFSPC partnerships were discussed. These include work with Air Force Weather to define Army and Air Force space-based environmental sensing requirements and weather support for operations, and work with NOAA to operate Defense Meteorological Satellite Program satellites, acquire NPOESS, and provide space environmental sensing capabilities to support AFSPC operations.

Michael Kavaya presented "Components of the Space-Based Lidar Winds Roadmap" coauthored by F. Amzajerdian, G. Koch, J. Yu, and U. Singh. Roadmaps help advance a mission by eliminating unnecessary steps, shrinking time line before launch, matching tasks to the best implementing groups, communicating needs to funding sources, and ensuring that pieces of a mission fit together smoothly. A sample roadmap was presented showing steps toward an operational hybrid DWL mission. Tasks included work on 2-micron coherent DWL and 1-micron direct detection DWL leading to hybrid airborne, unmanned aerial vehicle (UAV), and Earth System Science Partnership (ESSP) operations as steps to an NPOESS operational mission. The figure identified steps that have received past funding, current LRRP funding, IIP proposal tasks, and numerous tasks not yet funded. LRRP-supported work in conductive cooling is to be completed in FY07. Proposed compact packaging, aircraft operations, hybrid aircraft operations, autonomous operations, UAV operations, space qualification, lifetime and pre-launch validation, ESSP class mission, atmosphere characterization, and hybrid scanner tasks were discussed. Michael asked if the working group should pick and advocate a specific roadmap, and whether we can perform more tasks in parallel to save calendar time. Michael also discussed a committee meeting he attended on Earth Science and Applications from Space. The charter of the committee is to prepare unified recommendations for Earth Science for the next 30 years.

Dave Emmitt presented "Status of IPO Airborne DWL Testbed" coauthored with M. Hardesty, M. Kavaya, and B. Gentry. The Doppler Lidar Technology Accelerator (DLTA) and the Multi-agency Airborne Lidar Testbed (MALT) were discussed. DLTA is a multi-Center partnership (GSFC, LaRC, MSFC, JPL, Utah State/SDL and Simpson Weather Associates) to advance technology readiness of key DWL components. These technologies will be tested as a hybrid system flying on the NASA DC-8. The direct detection lidar will be tested on the NASA ER-2. A roadmap chart showed DLTA activity in FY03 through FY06 to demonstrate the hybrid instrument and to advance enabling technologies to TRL 6 or higher. IPO is supporting work on a DWL airborne testbed and calibration/validation instruments. This activity will put DWLs on a high altitude platform along with the NPOESS Atmospheric Sounding Testbed (NAST) to study synergisms between passive temperature and moisture sounders and DWLs. IPO has funded planning for a project. The Proteus has been considered as the target platform. Proteus will accommodate a 7200 lb payload and 19 to 30 kw of power. However, there is only one Proteus aircraft, and its availability is unknown. Proposals have been prepared. The objective of MALT is to develop an airborne active/passive sounder instrument package suitable for autonomous operations on manned and unmanned platforms. The objectives of MALT were presented. Proteus specifications and adaptations for DWL were discussed. DWL data quality profiles were presented for coherent, direct detection, and hybrid lidars.

Steve Mango presented the "Status of NPOESS." Steve discussed wind lidar as an NPOESS Preplanned Product Improvement and commented on the NPOESS schedule. He suggested consideration of where wind lidar fits in the Earth Observation Summit, Integrated Global Observing Strategy (IGOS) and Global Earth Observation System of Systems (GEOSS). IGOS international partners seek a strategy and framework for the common interests of existing space-based and in-situ observation systems. GEOSS now involves 61 countries in a ten year plan to advance the understanding of Earth. He reviewed areas of societal benefits from wind data and discussed the role of NPOESS. There are 55 NPOESS/NPP data products and 14 NPOESS sensors. The U.S. and Europe together will have the basis for major advances in a system of systems. He discussed the NPOESS AO to provide access to space. NPOESS will provide space for payloads to help fulfill unaccommodated Environmental Data Requirements (EDRs). The announcement addresses C1 and C2 satellites with 2009 and 2011 launch dates. Landsat will go on NPOESS, built by NASA for C1 and C4.

Bruce Gentry presented "Status of DWL at GSFC." Bruce discussed the Goddard Lidar Observatory for Winds (GLOW) data from the International H20 Project (IHOP) 2002, new technology, and GLAS data products. Comparison of GLOW data (from IHOP) with other sensors is continuing. There are 230 h of wind speed and direction observations. GLOW and sonde comparisons show effects of different sampling techniques, since GLOW profile measurements are nearly instantaneous while sondes take nearly an hour to reach altitude and the sondes drift far downstream. Limiting data to time coincident pairs reduced observed differences. Lidar data saw more structure than was apparent in sonde data. Scatter plots of sonde vs. lidar data showed good agreement on mean winds with a standard deviation of 4 m/s. Surprisingly, averaging the lidar data did not reduce scatter very much. Bruce suggested that the observed differences are approaching the spatial differences in wind turbulence at 4 m/s. Steve Mango suggested an experiment using a line of sondes to get them in position to coincide with lidar in space and time. GSFC work on the key technology roadmap addressed lasers, optical filters, photon detectors, telescopes and scanners. Advances are mostly through the Small Business Innovation Research (SBIR) program. An advanced receiver will reduce volume by more than 90%, improve mechanical robustness, and improve performance. Polarization increased edge signals by two times. Work is being done on high altitude direct detection scanning. Scanning demonstrations are imminent using HOE and SHADOE. GLAS is still operating (at reduced capacity) and has produced a lot of good data, e.g., compared to LITE, which produced ten days of data.

Dave Emmitt presented "DWL Options for An NPOESS P^3I Mission" coauthored with the Mission Definition Team. The Mission Definition Team is preparing a DWL mission proposal to respond to the NPOESS AO. The IPO released an AO offering available satellite space on a competitive basis for instruments that address unmet EDRs. The DWL mission objectives are to provide useful wind data from space, meet other NPOESS EDRs and/or enhance the usability of data derived from other instruments, and demonstrate a capability that could transition to an operational status with appropriate advances. The proposed wind observations will have synergism with CRIS, CMIS, Coastal Winds, GOES CMV, atmospheric chemistry, and CO₂. NPOESS would provide the launch, platform resources, and data links. Support is needed to develop and integrate the instrument. One concept uses adaptive targeting with reduced lidar duty cycle to comply with available satellite power budget. Adaptive targeting addresses high impact weather situations such as hurricanes, air quality episodes, etc. In this concept a coherent detection sub-system will operate on a 100% duty cycle and a direct detection subsystem on a 10-15% duty cycle. DWL parameters and data quality profiles were presented.

Subcommittee Discussions

A government-only meeting was held to discuss a DWL response to the IPO AO.

Subcommittee Reports and Recommendations

New action items were reviewed and completed.

Updating of the DoD IORD wind data requirements was discussed. Major Richard Krasner (USAF) and Ingrid Guch (NOAA) are co-chairs of the NPOESS Joint Agency Requirements Group (JARG) and will follow up.

The NPOESS AO for a P3I mission on NPOESS satellites was discussed. It was released during the week of this Working Group meeting. A government Request for Information was discussed to identify industry capabilities that might support instrument development and integration. Funding alternatives for instrument development and integration were discussed.

The Space Test Program was discussed as an alternative mission and Ingrid Guch agreed to contact STP.

There was a discussion of power limitations on NPOESS spacecraft and minimum power estimates to operate DWLs. John Reagan described new capacitor technology (ultra-capacitor) announcements that could augment batteries on an adaptive targeting mission.

Presentation of Short Subjects

Dave Bowdle presented "Updated Prospectus for a CHEM/CLOUD Experiment Using Multiple Lidars in Huntsville, AL," coauthored with D. Emmitt, M. Newchurch, R. McNider, M. Botts. K. Knupp, W. Petersen, A. Bidzar, K. Fuller, S. Johnson. The goal of CHEM/CLOUD is to improve modeling of vertical transport and chemical processes associated with non-precipitating or shallow precipitating cumulus clouds. It focuses on the humid continental boundary layer over the southeastern U.S. The approach includes coordinated remote sensing of clouds, winds, aerosols, and trace gases; identification and parameterization of correlated satellite observables; and Large Eddy Simulation modeling and mesoscale modeling of meteorology and chemistry. Science questions address convective roots of non-precipitating clouds, interaction with land surface effects, cloud-driven circulation, entrainment of trace materials, exchange processes, and the search for useful satellite-observable signatures. Dave discussed current instrumentation needs and status. The Huntsville Regional Atmospheric Profiling Center for Discovery (RAPCD) is built and operational, with collaborations developing. It is co-located with the National Weather Service office. Instrument deployment will use the facilities of RAPCD.

Review of Action Items; Next Meeting

Action items were reviewed.

The Summer 2005 meeting will be at Welches, OR (near Mt. Wood) June 28-July 1, 2005.

The Winter 2006 meeting will be in Key West, FL.

Adjourn

The meeting was adjourned.

The minutes were prepared by Kenneth Miller.