Wayman Baker (NOAA/NWS) brought to order the 22nd meeting of the Working Group on Space-Based Lidar Winds. He introduced the meeting theme "Wind - the Final Frontier" and a new mission graphic by Michael Kavaya. Wayman stated the meeting purpose: to advance lidar technology toward achieving a space wind measurement capability. After opening remarks, he led discussions of action items from the previous meeting.
Action item discussions:
1. A benchmark statistical description of the
sub-grid scale velocity field is needed. - R. Brown, R. Frehlich, D. Emmitt,
R. Foster. Bob Brown will discuss status in a later briefing.
2. Prepare a proposal to support a targeted observations field experiment with a wind lidar on a C130 or other aircraft. - M. Hardesty, Z. Toth, E. Kalnay. The aircraft will probably not be a C130. Mike Hardesty will discuss progress in a later briefing.
3. Prepare a whitepaper comparing a lidar and other wind sensors. - M. Kavaya, P. Flamant, I. Guch. Preparation is underway.
4. Develop a proposal for deployment of a wind lidar on commercial aircraft. - R. Fleming, R. Atlas, D. Emmitt, M. Hardesty. UCAR proposed this to the Department of Homeland Security, but it is not funded at this time.
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. This action item was completed and results will be posted on the Working Group website. E. Kalnay was added to the list of responders to the action item.
6. Is a space-based DWL the appropriate technology solution for global tropospheric wind profiles? - D. Emmitt, R. Atlas, J. Yoe. This action item is closed, and the answer is posted on the Working Group website.
7. How do we interpret multiple OSSE results? - J. Yoe, R. Atlas, D. Emmitt. This action item is closed, and the answer is posted on the WG website. Although the magnitude of the predicted impacts and the choice of impact metrics vary considerably, all of the recent OSSEs performed at NOAA and NASA using current global and regional forecasting models show significant positive impacts from plausible DWL concepts.
8. How do we ensure the NWP centers are ready to use wind profiles when they become available? - D. Emmitt, J. Yoe, W. Baker. This action item is closed, and the answer is posted on the WG website. OSSEs provide the needed background.
9. DWL FAQs should be sent to I. Guch for posting on the website. - All. Action Item is closed.
10. Reconvene an Executive Steering Committee to advise NASA/NOAA on actions required to implement the wind lidar roadmap. - I. Guch, D. Trapp, S. Alejandro. Dave Trapp and Steve Alejandro were added to this Action Item.
11. The Lidar Working Group should use the Lidar Technology Roadmap to track progress and provide updates to Ken Miller. - All
12. The science requirements should be posted on the website. - J. Yoe
13. The use of GLAS data to improve the height
assignment of GOES winds should be pursued. - J. Reagan. A report was not yet available.
Dave Tratt, Ingrid Guch, and Steve Alejandro presented "Possible Opportunities for FY07" as viewed by their respective organizations. Their comments are summarized below.
Dave Tratt discussed "The New NASA". He provided an update on recent changes in NASA organization and directions. Code S (Space Science) and Code Y (Earth Science) will be merged into a singe Science organization and a new position, Director for Advanced Planning, will be created effective August 1. (See also http://www.nasa.gov/home/hqnews/2004/jun/HQ_04205_Transformation.html). Dave discussed new roles for four mission directorates: Exploration Systems, Space Operations, Science, and Aeronautics Research. The Science Directorate will carry out scientific exploration of the Earth, Moon, Mars, and beyond, and apply lessons of Earth studies to exploration of the Solar System. He showed an organization chart of the new NASA structure (see NASA website). Dave stated that wind measurement is a critical capability needed both on Earth and on Mars. Emphasis on Earth Science may be reduced. He discussed some Aldrich Commission recommendations to NASA, including a recommendation that Centers follow an FFRDC model and that systems engineering emphasis be increased.
Ingrid Guch discussed preliminary thoughts on FY07 Planning at NOAA. By FY07, the NASA Laser Risk Reduction Program will be over and will have raised critical Technology Readiness Levels (TRLs). Results from down-looking direct detection lidars will be available from ADM, BalloonWinds, and other programs. Down-looking results are already available from coherent lidars. The funding situation may be flat or increasing for Defense, Homeland Security, and Space Exploration. Funding may be flat or decreasing for the rest of the R&D budget (source- AAAS analysis of president?s budget). This budget trend may not be ideal for NOAA or non-Mars NASA R&D. Ingrid presented a table showing technology items needed in FY07. The table addressed coherent, direct, and hybrid lidars and categories of Point Design, Reference Design, Laser, Detector, Telescope, Scanner, Momentum Compensation and Stability. The table generated extended discussions. Farzin Amzajerdian and Jinxue Wang stated that lasers capable of supporting the hybrid design should be attained in 2006. Dave Emmitt said point designs are pretty good for the instrument alternatives and that work is needed on system trades, shared optics, and spacecraft architecture. Bruce Gentry pointed out that a lot of work is being done in lighter Holographic Optical Element (HOE) scanning telescopes. Concern was expressed that more attention is needed on scanning techniques, momentum compensation, and stability. Steve Alejandro said the Air Force is emphasizing lightweight optics, although not meter-class optics, and this activity may help. The Air Force is supporting work on HOE, liquid crystal optical phased arrays, and scanner technology. Ingrid then addressed the future selection of a technology from among the three choices: hybrid, coherent, or direct detection. She raised the questions of who has the credibility to decide on a technology and how to best involve numerous agencies so that the selected approach will be funded. Participants in a selection activity could include the Lidar Working Group, Government, Industry, and Academia. She pointed out that an external review for the AIRS/Interferometer took two years to complete. She suggested the possibility that DOT, DHS, DOE, and EPA could support external peer reviews. Participation by Japan, ESA, and non-governmental organizations should be considered. This subject generated discussions. There was feeling that the Roadmap priorities working toward the hybrid instrument should be maintained, and it was pointed out that TRLs are much more promising for components of the hybrid instrument. It was also pointed out that more study is needed into the trades between data requirements and benefits to determine if some driving requirements could be relaxed. Wayman asked Ingrid and Dave Tratt if their organizations could fund design studies for the hybrid instrument. In discussing the topic "Few Partners vs. Many Partners", Ingrid suggested that an FY07 focus should be on gaining more partners, perhaps through economic cost-benefit studies for DOT, DHS, DOE, and EPA applications, as well as considering Japan, ESA, and NGOs. Although many agencies will benefit from global wind profiles, few have the budget to fund them. Ingrid discussed thoughts on how to get started into multi-agency funding.
Steve Alejandro discussed a draft initiative he submitted to the Air Force based on materials available to him. He cautioned that the initiative statement needs to be finalized. However, DWL is in the Air Force long-range program plan for improved weather prediction and tactical wind sensing. Wind profiles are needed for air drops, parachutes, guided munitions, troop movements in bad weather, and other applications. It was suggested that Steve consider the NASA/NOAA requirements and roadmap in preparing his final program plan.
Eugenia Kalnay presented "The New Local Ensemble Kalman Filter (LEKF): An Accurate and Efficient Optimal Method for Data Assimilation and Adaptive Observations", coauthored with the Chaos Group and students from the University of Maryland. An ensemble forecast starts from initial perturbations to the analysis, and these initial perturbations should reflect the analysis "errors of the day". The errors of the day are instabilities of the background flow. Strong instabilities tend to have simple shapes, which can reduce computational complexity. Initial perturbations should provide a good sample of the analysis errors, and should have a covariance that represents the analysis error covariance. New approaches to LEKF permit the analysis error covariance and the ideal perturbations to be determined simultaneously with less computational intensity than conventional Kalman filtering. LEKF is accurate and efficient computationally, being performed in local regions and in low dimensional space. It provides optimal analysis and ideal initial ensemble perturbations. Examples showed very low temperature errors. Wind errors were low, but very sensitive to the number of observation points, supporting the importance of wind observation coverage. LEKF simplifies adaptive observations by showing where important changes are occurring - the lidar instrument should simply dwell where the errors are large. The method may reduce observation resolution requirements for a given error requirement. Jan Paegle and Dave Emmitt pointed out that this technique could benefit the wind measurement instrument, allowing increased distance between observations and turning off the instrument where observations are not needed. Current work includes:
Future plans include:
The group aims to develop a system that will become operational at NCEP and be economical enough to be collocated with space instruments for adaptive observations.
Bob Atlas presented "The Impact of AIRS Data at NASA/GSFC and Implications for Lidar Winds". Bob presented impact study results with and without AIRS data, obtained with the Finite Volume Data Assimilation System (FVDAS), similar to earlier Observing System Simulation Experiments (OSSEs). The most favorable AIRS impact was observed in the southern hemisphere for partially cloudy data and in sea level pressure. A positive impact was observed for cyclone tracking. Addition of simulated lidar winds to AIRS data added further significant impact, indicating that the AIRS and lidar data types are complementary. QuikSCAT wind speed and direction data were also used in control forecasts. A study of the tradeoffs between sampling and accuracy showed it is useful to include data that contain up to 80% clouds.
Farzin Amzajerdian presented "Advancement of Lidar Technologies at NASA Langley", coauthored with Michael Kavaya, Upendra Singh et al. The work is funded primarily by the NASA Laser Risk Reduction Program (LRRP). The main focus is on high power lasers for space-based remote sensing, with a smaller investment in detectors, receivers, and other enhancing and enabling technologies. Deficiencies in lasers are targeted for development and risk mitigation. Flight lasers are still at the "build-to-order" research and development stage. Elements include 2-micron laser transmitter, high-power diode laser pump arrays, nonlinear optics, receiver technologies, and research in laser physics and advanced materials. The laser technology roadmap plans to accomplish a fully conductively-cooled laser head in 2004, conductively-cooled oscillator and amplifier in 2005, conductively-cooled laser in 2006, and a space-capable design in 2007. Laser head assemblies have progressed from fully water-cooled to fully conductively-cooled. A 2-micron high energy coherent wind lidar has been demonstrated and delivered to the Validar facility. An Ho:Tm:LuLF laser system with 1050 mJ Q-switched output has been demonstrated. It is the first time that a Q-switched 2-micron laser exceeded the 1 J power level, an order of magnitude beyond earlier energy capabilities. Laser diode arrays establish the instrument lifetime, and have been identified as a major risk area for a lidar in space. Issues include limited reliability and life, lack of statistical basis for performance and lifetime prediction, and limited commercial availability. Farzin discussed diode array packages, causes of failure, thermal effects, the Laser Diode Characterization/Lifetime Test Facility, and different types of diode arrays, including diamond and carbon composite. Commercial availability has improved somewhat. He discussed the integrated heterodyne photoreceiver, which reduces mass by approximately 20% and power by 35%. He described the Validar mobile validation lidar facility and recent upgrades to it, and showed samples of data acquired from Validar. Some work is being done on liquid crystal scanners, however, these will not have a near term role because of size, scan angle, and efficiency limitations. LRRP has provided funding for the past three years, and is planned to complete in FY07. NASA's mission realignment is expected to affect the LRRP. He discussed the new NASA structure, Earth Sciences application focus, and how LRRP fits into the Exploration focus.
Dave Emmitt presented "OSSEs for Realistic DWL Concepts", coauthored with Bob Atlas. Bracketing OSSEs were used to predict the difference between non-scanning wind observation systems (such as ADM) and scanning systems. Work is moving on to more realistic systems, by including cloud attenuation and other factors in models. OSSEs are led by Steve Lord at NOAA/NWS/NCEP and by Bob Atlas at NASA/GSFC/GLA. Multiple perspectives have proven to be important for weather forecasting. Full soundings produce the best results for weather prediction, with upper atmospheric soundings providing more information than lower atmospheric soundings. Little impact was found for single line-of-sight wind observation systems, and about 5% improvement in forecast skill was found for scanning with full tropospheric coverage. The control in the OSSEs used all conventional data types. Dave estimated that enhanced aerosols are convectively added to the normal background atmosphere over about 25% of the globe. Increased pollution increases the amount of enhanced aerosols. Future OSSEs will look at reduced spatial resolution.
Bob Brown presented "Dynamics of the PBL (and a Little Troposphere) State-of-the-Art". Bob pointed out that problems of measuring winds from space include lack of understanding of basic fluid dynamics in key places, measurements of surface "truth" are difficult, and sensors are expensive and subject to politics. He provided the basic equations for atmospheric flow and a summary of the nonlinear PBL model. Theory predicts Organized Large Eddies (OLE) for 80% of observed conditions. He showed a Skylab photograph of OLE and a sketch of nonlinear PBL flow containing OLE. Consequences of OLE include (1) non-homogeneous surface winds that must be taken into account in surface truth measurements; (2) widely varying wind profile across a 25 km satellite footprint, which may include ten OLEs (he noted that this is not the case for Synthetic Aperture Radar (SAR) resolution of 6 km or less); and (3) PBL contains advecting flow not amenable to diffusion modeling, so that numerical models cannot portray the correct physics of mean flow without an extreme increase in resolution. Sources of marine surface wind fields include surface measurements, models, and satellites. Satellite instruments include scatterometers, SAR, altimeter, WindSat (passive microwave polarimetry), and in the future will include lidar. Wind measurement from buoys is affected by high seas because of sheltering and height displacement. Bob described basic concepts for scatterometer wind measurement using backscatter-to-velocity curve fits. Bob discussed active radar (SAR), passive radar (radiometers), and lidar (LAWS and GLAS). He provided brief histories of instruments in space. Today there are no US SARs. SAR data are available from a private Canadian firm and from ESA Envisat. ESA, NASA, and NASDA plan future SAR missions. In his summary, Bob pointed out that (1) satellite global wind data is revolutionary in making weather and climate more predictable and correcting wind and flux errors in climatology, (2) the global winds program has peaked due to accidents and politics and the scatterometers and lidar futures are in limbo, and (3) money in the near future will be applied to Mars and the rest of the solar system so future studies will look at winds on other planets. Doppler winds are necessary because understanding of weather and climate and environment is proportional to understanding equations for fluid flow, where the basic parameter is wind flow. Other variables (pressure, temperature, density, and chemistry) are secondary. Doppler lidar is the only prospect for direct wind measurement.
Dave Bowdle gave an update on
"The Regional Atmospheric Profiling Center for Discovery (RAPCD) at the
National Space Science and Technology Center (NSSTC) in Huntsville, Alabama:
Update on Infrastructure, Instrumentation, and Science", coauthored with M.
Newchurch and K. Fuller. RAPCD opened in spring 2003. Several instruments and
meso-scale chemical transport models are operational, other instruments and
tools are in progress. RAPCD provides a unique research tool for scientists and
students. RAPCD is intended to support improved air quality forecasting,
including measurements of trace gases, aerosols, winds, vertical fluxes, and
clouds. Mismatches between measured and modeled tropospheric ozone are being
investigated. Dave discussed the Huntsville Ozonesonde Station and instruments,
including the Ozone Differential Absorption Lidar (DIAL). He discussed topics
in aerosols and forcing. A map of average annual extinction coefficients over
the United States showed Huntsville located in the region of highest
atmospheric aerosol concentration, showing that it is a good location for
atmospheric studies. Dave discussed
a scanning aerosol lidar, MSFC ground-based DWL, applied microparticle optics
and radiometry, and a Mobile Integrated Profiler System with radar and sodar
instruments. He showed results of direct insertion of satellite observed
insolation data into the MM5 model, which resulted in improved location and
impact of clouds in the MM5 output. Planned measurements include atmospheric
profiles of aerosols, gases, wind, and temperature; ground-based radiation; and
characteristics of atmospheric aerosols. Applications include satellite
validation, chemistry and aerosols, diurnal and long-term studies, and
combination with similar systems in the northeast and in the Rocky Mountains.
Dave Bowdle continued with a talk on "Potential Contribution of Multiple Doppler Wind Lidars to a Prospective CHEM/CLOUD Experiment in Huntsville, Alabama", coauthored with D. Emmitt and M. Newchurch. He discussed the overview of CHEM/CLOUD, the science basis, site selection, experiment, and program issues. 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 United States. 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 instrumentation needs and status. Instruments include wind sensors, trace constituent sensors, and satellite-based sensors. Multiple DWLs are desired. Modeling is performed on microscale and mesoscale. Instrument deployment will use the facilities of Regional Atmospheric Profiling Center for Discovery (RAPCD) and Mobile Integrated Profiler System (MIPS) and instruments will be networked. Dave is seeking multiagency sponsorship and interested researchers. A white paper is scheduled for summer 2004, an exploratory experiment in spring 2005, followed by an intensive experiment in spring 2007. Applications include air pollution assessments, ground-truth for satellite-based sensors, climate modeling, and tracer models for national security. This activity will provide an opportunity to demonstrate maturity of DWLs.
Jan Paegle presented "Regional Forecast Sensitivity to Regional Changes in the Initial State". Long wave components are more important sources of error than short wave components. The new results included higher resolution observations than previous studies and addressed the question of whether forecast errors are more sensitive to model errors or initial state errors. The paper explores initial state errors, how they affect forecasts over time, and how they propagate geographically. Local targeting of the initial state produces little local impact in mid-latitude winter cases after two-three days of prediction. It produces some downwind impact in mid latitude winter cases. Local targeting of the initial state produces substantial local forecast impact in precipitating summer cases of the subtropics and tropics (both in North and South America). A model with good skill in precipitation prediction is needed to obtain correct local impact in wet cases.
Mark Phillips reported on the "Amplification of Q-switched Pulses to 400 mJ at 2051 nm using a Conduction-Cooled Laser Pump Module", coauthored with P. Tucker. Coherent Technologies, Inc. completed a contract with the Japanese Communications Research Laboratory to demonstrate a coherent DWL laser amplifier prototype with a path to deployment on the International Space Station. The contract was for an initial risk reduction demonstration showing about 0.5 J at 10 Hz pulse repetition frequency in the first stage amplifier with 2% wall plug efficiency. Final performance requirements include 2 J, 10 Hz, and 300 to 400 nanosecond pulse width. Mark described performance specifications for the Japanese Experiment Module Coherent Doppler Lidar (JEM/CDL). The risk reduction demonstration included a first stage Q-switched Tm,Ho:YLF amplifier with up to 400 mJ output pulse. Two-pass amplification provided gain of ten times for 35 mJ and eight times for 50 mJ input energy. Optical-to-optical efficiency at 400 mJ was about 8%. This was the first demonstration of multiple hundred mJ output in an all conduction-cooled two micron laser pump module. Cooling was closed loop compatible with either passive heat-pipe or closed loop refrigeration. The rod and laser diodes were conduction cooled to exchangeable cold-plates. He provided photographs and descriptions of the conduction cooled laser head, layout of the amplifier and Q-switched laser resonator, and packaged hardware. Mark described two-pass amplifier performance for 35 mJ input pulse energy and 50 mJ input pulse energy, and amplifier characteristics at 400 mJ pulse energy.
Bruce Gentry presented "Design Considerations and Performance Simulations for the Molecular Channel of a High Altitude Doppler Lidar Testbed", coauthored with G. Schwemmer, M. McGill, J. Marzouk, S. Mathur, and T. Wilkerson. Doppler lidar flying on a high altitude aircraft is an important precursor to a space-borne instrument. It will provide a wind lidar testbed, support atmospheric studies, and support calibration and validation for a space-borne wind instrument. Bruce described a detailed design study for a molecular Doppler lidar test bed to fly on an ER-2 or Proteus aircraft and capable of scanning and observing the full atmosphere. The design leverages previous investments from IPO, ESTO, SBIR, and IR&D. The airborne testbed concept incorporates advanced lidar technologies in lasers, HOEs, and receivers and builds on experience gained fielding lidar systems such as GLOW, CPL, and HARLIE. Designs of mechanical, thermal, electrical, and data handling subsystems were studied. The design meets baseline science requirements, including step-stare scanning. Simulation parameters and results were shown for the instrument flying at 20 km altitude for two different lasers, a Fibertek laser and a LiteCycles laser. The double edge molecular receiver derives from Zephyr and GLOW heritage. An advanced photon counter, system block diagram, and mechanical package concept were described. Bruce's group invites further discussion of science requirements and research applications. An implementation proposal is in preparation.
Bruce Gentry reported on "HARLIE GLOW Union and UV Doppler Demonstration", coauthored with G. Schwemmer. The objectives were to test the ultraviolet (UV) HOE in lidar operation, verify laser beam steering and boresight alignment, and demonstrate HOE in Doppler measurements. Components included a Fibertek laser, HARLIE telescope/scanner, GLOW Doppler receiver, and GLOW data system. The HOE had a 1 m focal length, 45o diffraction angle, and 40 cm diameter. Efficiency was 62%. Schedule milestones include designs completion in May 2004, assembly and alignment complete August 2004, and measurements in September 2004.
Jim Yoe presented "CALIPSO Status Update" coauthored with D. Winker, and ?Possibilities for Exploiting CALIPSO Data? coauthored with D. Emmitt, C. Barnet, and R. Hoff. Cloud-Aerosol Lidar and Infrared Pathfinder Satellite (CALIPSO) is an Earth System Science Pathfinder satellite mission. Observations from CALIPSO will improve understanding of how aerosols and clouds affect climate processes and improve representation of aerosols and clouds in models. CALIPSO will have a three channel lidar instrument to measure aerosol and cloud layer heights, β and σ profiles, and cloud ice/water phase. An imaging IR radiometer and a wide-field camera will measure cloud emissivity and ice particle size. Jim reviewed instrument specifications. A lidar atmospheric test in December 2003 showed outstanding lidar performance with no problems. Jim showed cloud data taken in the tests, and comparisons with profiles from a collocated lidar. The payload integration to the platform, performance verification, electromagnetic compatibility test, and sine vibration test are completed. Satellite T/V is scheduled for August 2004. Launch is scheduled for 15 April 2005 with first lidar profiles 1 June 2005. The orbit is in the A-train constellation at 705 km, 98o inclination, and 1:30 PM equator crossing. Objectives beyond climate studies include application to design and operations of future DIAL and DWL instruments, analysis of Cloud Track Winds (CTWs), and application to radiometric sounders and numerical weather prediction. CALIPSO will provide new knowledge that is vital to a future DWL mission, including Cloud-Free Line of Sight (CFLOS) statistics, multiple cloud layers, global distribution of aerosols, and backscatter statistics. The CALIPSO mission should lower the risk and cost for future DWL missions.
Dave Bowdle discussed "Using TODWL and In Situ Particle Probes to Understand the Backscatter Signature of Marine, Boundary Layer Organized Structures", coauthored with D. Emmitt, S. Wood. This experiment was a joint research project supported by ONR and NPOESS IPO to investigate data processing issues in space-based wind lidar operations, develop calibration/validation procedures, and conduct basic research on lower tropospheric winds and aerosols in the marine and continental boundary layers. Three series of experiments were flown in the vicinity of Monterey, CA on the NPS CIRPAS Twin Otter aircraft. Instruments included optical particle counters, the Twin Otter Doppler Wind Lidar (TODWL) coherent detection lidar, and a TODWL scanner. A total of eight flights under varying conditions collected approximately 30 h of data. Dave discussed the measurements and the backscatter equation. He pointed out that numerous analytical assumptions may be avoided by measuring relative instead of absolute backscatter variability. He discussed analytical methods with regard to dropouts and anomalies, turbulent residuals, filtering, and correlation. He discussed results regarding sampling conditions, Hovmuller plots in radial velocity and SNR, and optical particle counters. Turbulent waves in aerosol, velocity on multiple scales, and aerosol-velocity correlations that will bias DWL LEO winds were observed. The bias will be a function of shot integration strategy. Analytical challenges included beam elevation offset, pitch and altitude fluctuations, measured vs. modeled absolute backscatter, and optical particle counter operation and count statistics. The TODWL database contains substantial information content that has not yet been explored. There was discussion of operations and analysis of TODWL and optical particle counters, and analysis of mean and turbulent conditions.
Ralph Foster gave a paper entitled "Using TODWL Data to Validate Marine Boundary Layer Models", coauthored with R. Brown, C. O'Handley, and D. Emmitt. PBL winds are organized on scales from meters to 100 km. Lidar data show significant structure and eddies. Therefore, this IPO-funded study compared TODWL observations of marine boundary layer wind data with theoretical models. Rolls, streaks, and other effects were studied for winds near the surface. The theoretical model for rolls is nonlinear. Ralph discussed model predictions for surface winds. Rolls have important implications for calibration and validation of space wind instruments, since surface sensors a short distance apart can observe very different winds. He also discussed findings on streaks. Future work will address how to average observations for use in calibration and validation, further comparison of theory with data, and incorporation of aircraft attitude perturbations into the analysis.
Dave Emmitt presented "Hybrid DWL Simulations for OSSEs", coauthored with S. Wood. Two types of simulations were performed for a hybrid DWL. One met all of the GTWS requirements, the other met all except for two resolution requirements: (1) 700 km spacing instead of 350 and (2) four scans instead of eight across track. The simulations provided estimates of key lidar parameters and provided observations for use in OSSEs. Next steps for the hybrid DWL include studying the use of individual scanners for the two lidars vs. a shared scanner, ISAL/IMDC rapid design teams to develop instrument and mission reference designs for the government, hybrid OSSEs, and analysis of how to work with clouds in point designs. A better understanding is needed for cloud properties and distributions. Dave observed that 50% of shots that hit clouds made it to the ground in LITE data. Mike Hardesty pointed out that scaling experimental results to a 400 km orbit altitude needs more attention, and that power requirements may be underestimated. Dave Bowdle pointed out that more experience is needed with the effects of downlooking on scaling.
Dave Emmitt continued with a paper entitled "Accuracy of Airborne Doppler Lidar Using Threading and Ground Returns", coauthored with C. O'Handley. New TODWL data with the 2-micron lidar were analyzed for Lidar Attitude Determination and Scanning Algorithm (LADSA) accuracy. LADSA fit is equivalent to a Velocity Azimuth Display (VAD) sine fit. The instrument was calibrated over land and then flown over water. Dave showed wind velocity profiles for several flights. RMS errors in wind velocity components were less than 10 cm/sec. In experiments using sector scans instead of 360o scans, different winds were measured for each sector. The threading technique uses correlation among proximate range gates to reduce error and extend range up to three to five range gates. Since SNR decreases with increasing range, the threading algorithm seeks to track the higher SNR readings from nearer range gates in statistically estimating the reading for a further range gate.
Steve Mango discussed the "Status of NPOESS". Steve presented an overview of current status and future plans for NPOESS and its many components. He discussed a number of special topics, including the new Global Earth Observation System of Systems (GEOSS) activity. The Earth Observation Summit has brought together more than 50 nations and is committed to developing a comprehensive, coordinated and sustained GEOSS System to collect and disseminate improved data, information, and models to stakeholders and decision makers. LANDSAT may be supported by NPOESS in the future. An NPOESS Wind Lidar can be considered as a Preplanned Product Improvement (P3I). Wind lidar requires validating the scaling of lidars to space and getting GTWS requirements into the NPOESS requirements. NPOESS wind requirements today are those provided by the earlier IORG study. These need updating through liaison between the Joint Agency Requirements Group (JARG), NASA, and NOAA. Steve suggested that the proof of concept is still inadequate for wind lidar and that a firmer foundation is needed. He discussed NPOESS availability (weight, power, and bandwidth) for a wind instrument and many aspects of wind lidar work that have been funded by IPO. He pointed out that a new partnership is needed among NASA, NOAA, DOD, and IPO. The IPO can't build the instrument. Therefore, a principal partner is needed.
Dave Emmitt updated the "Status of TODWL and GWOLF Activities and Plans for Future Airborne DWL", coauthored with B. Gentry, M. Hardesty, and M. Kavaya. TODWL is moving to a new system with newer CTI lasers. The size, mass and power are reduced. It will be installed on the aircraft in September 2004. GWOLF is the ground-based mobile version of TODWL. IPO is funding calibration/validation activities to determine the effect of comparing GWOLF observations with those of a space-based lidar having much less resolution and a different track through the atmosphere. Vertical velocities and their effects on Velocity Azimuth Display (VAD) accuracy were studied. Dave discussed the IPO airborne testbed. The objective is to mount an instrument on a high altitude aircraft such as the Proteus. He discussed a Multi-Agency Lidar Testbed (MALT). Plans for 2004 include OSSEs with more realism and a design for a Proteus DWL/NAST instrument package.
Mike Hardesty presented "Doppler Lidar Activities at Environmental Technology Laboratory (ETL)", coauthored with A. Brewer. Topics included fine structures of moisture transport measured during the International H2O Project (IHOP), lidar upgrades and deployments for current field experiments, and the NOAA G-IV Doppler lidar. Mike showed results from winds and water vapor measurements, lidar and dropsonde comparisons, fine scale transport curves, and moisture vs. height. He discussed current lidar activities, including New England Air Quality (NEAQ) activities on a ship and on a plane, and a Key West Air Sea Interaction study. Mike described upgrades to the high resolution lidar, Master Oscillator Power Amplification (MOPA) CO2 Doppler lidar, and NOAA G-IV aircraft instrumentation. The next generation of National Weather Service numerical prediction models is the Weather Research and Forecasting (WRF) system. WRF for hurricanes (HWRF) will be an advanced system to track intensity and rainfall. A preliminary instrumentation and modification plan was drafted to address HWRF data requirements. 3D winds are a critical requirement for HWRF. The G-IV will fly above 40,000 feet using a diode pumped solid state laser and direct detection fringe imaging Doppler techniques. It is expected to use an HOE for scanning. Testing the G-IV capability is scheduled for the 2006 winter storm season and initial deployment of the G-IV Doppler lidar is scheduled for the 2006 hurricane season. Work is continuing on IHOP analysis of observed transport vs. model estimates and vertical velocity fluctuations. Solid state Doppler lidar will be used in the tropical cumulus experiment on a NOAA ship and on the Twin Otter aircraft (2005), and in a Texas experiment (2006). Dual wavelength CO2 MOPA lidar will be used in DIAL experiments to measure hydrocarbons.
Jim Spinhirne presented "Global Distribution of Clouds and Aerosol in the Atmosphere from the EOS GLAS Lidar Mission". Jim discussed the Geoscience Laser Altimeter System (GLAS). GLAS is the primary science instrument on the Ice, Cloud, and land Elevation Satellite (ICESat). ICESat was launched in January 2003 and the first operations began in September 2003. A laser reliability problem promises to limit the mission. The GLAS lidar is a nadir-looking instrument to measure ice sheet elevations, changes in elevation through time, height profiles of clouds and aerosols, land elevations, vegetation cover, and sea ice thickness. GLAS combines a surface lidar with a dual wavelength cloud and aerosol lidar. GLAS data provides new knowledge of downlooking lidar and cloud distributions. The main noise observed is solar background. GLAS has lost two of its three lasers. The third is working with diminished performance. GLAS is eye-safe to an 8 cm telescope.
Bruce Gentry summarized "Lidar Research Progress". authored by S. Cornelson, J. Cutts, C. Earl, D. Huish, and T. Wilkerson. Bruce discussed HARLIE measurement campaign history, multiple cloud layers, comparison of HOE lidar wind results with other methods, Sonde wind variability, and development of an airborne lidar. Six joint lidar measurement campaigns were conducted since 1999 with the HARLIE holographic scan lidar. Other instruments in these campaigns included SkyCam for cloud visual imagery, AROL-2 profiler, and GLOW Doppler lidar. Comparisons were discussed for HARLIE wind data from multiple cloud layers as determined manually by an operator, the same HARLIE data interpreted automatically with a Hough transform method, and SkyCam visual data. Good agreement was found in speed and direction. For HARLIE, manual extraction of wind velocity had closer agreement than automatic extraction as compared with sonde velocity. Current work on the Hough transform algorithm includes improving noise removal and image pre-processing, and adding new features. Sonde precision studies over vertical regions led to the conclusion that sondes provide a reasonable standard for wind measurement. The rugged UVC-12 HOE Transceiver is being designed for airborne calibration/validation in the Proteus or ER-2 aircraft. The mechanical design concept was shown with displacement and stress graphics. The team is continuing comparisons of HOE lidar wind results with other methods. The team concluded that HOE lidar and cloud tracking are suitable for 24/7 operations and for calibration and validation of wind sensors. They are continuing development of new instruments for lidar winds.
Michael Dehring reported on the "Status of BalloonWinds", coauthored with J. Pavlich, C. Nardell, P. Hays, I. Dors, B. Moore, J. Ryan, D. Dykeman, J. Wang, and S. Silverman. BalloonWinds plans to simulate and validate the Direct Detection fringe imaging wind measurement concept from a downward looking high altitude platform. The fit and function are intended to be more similar to a space instrument than are the GroundWinds DWLs. The experiment will quantify the photometric efficiency of the fringe imaging system, verify wind measurement capability, and verify parametric lidar models. Michael made some comparisons of properties of balloon, space, and aircraft experiments. He indicated that thermal and environmental engineering for the interferometer, telescope, laser, and control electronics hardware were similar between balloon and space missions. Little vibration is encountered in a balloon mission, while a space mission encounters shake on launch and an aircraft encounters flight vibration. The balloon and space missions are similar in their need to address instrument stability in low pressure and low temperature, and in downlooking measurement through the entire troposphere. The BalloonWinds payload uses the basic GroundWinds HI and second generation GroundWinds NH interferometer designs. It is optically similar to a space instrument, and uses a 0.5 m telescope. Changes are being made in the laser, going from flash pumped to diode pumped. The laser is a Raytheon prototype. The detector uses a streaking CCD approach. Operation is autonomous and data processing is on-board. Thermal engineering for the high altitude balloon environment is addressed, but components will not be hardened for use in a vacuum. AFRL is providing the gondola, balloon, launch and operations, telemetry and instrumentation, as well as an environmental chamber for thermal and vacuum testing and a high bay test area. Three flights of eight hours duration are planned. Six hours of each flight are spent at 30 km altitude. Profiles will be collected from 0 to 30 km, with 0.25 to 1 km range bins, and wind error less than 3 m/s. Michael described interferometer improvements in etalon design, CLIO extender, and CCD camera redundancy. He described the redundant camera optical concept and expected and simulated spectra. He provided an overview of the instrument specifications. Stability of the telescope and interferometer alignment through ascent are important considerations. Specifications were presented for the receive telescope, receive transfer optics, etalons, component transmission efficiencies, interference filter, CCD, and laser. He discussed performance predictions (molecular channel horizontal wind errors at 30 km vs. altitude, integration time, and recycling efficiency, with and without an interference filter. Aerosol channel benefits are expected because of the narrower line width in that channel. Michael discussed the BalloonWinds schedule leading to first flight in 2005.
Jim Ryan presented a "GroundWinds Status Update". GroundWinds DWLs are in operation in New Hampshire and Hawaii. Jim described the GroundWinds NH direct detection Doppler lidar, operating at 532 nm, 3.5 watts, 10 Hz, 0.5 meter aperture, with molecular and aerosol channels, CCD detectors, and 0.7 to 18 km range. This lidar has been operating for some time. The aerosol channel is down because of CCD temperature sensor problems, with reinstallation planned in July. Mechanical and cooling problems were repaired on the molecular camera in June. Laser seeder and control computer failures were corrected. In Hawaii, the GroundWinds HI DWL will soon be operational after correcting problems. Daily operations are expected to resume in July. Power supply, etalon controller, and camera chiller failures were encountered. Upcoming campaigns include GroundWinds NH North East Air Quality Study (NEAQS) this summer and GroundWinds HI Validation Campaign in mid November. Data analysis activities include calculation of uncertainty estimates for each data product and running self-consistency tests to relate discrepancies to statistical, systematic, instrumental, and/or computational errors. Jim discussed fringe detection measurement theory in the atmosphere, including effects of density and temperature on fringe shape. He showed curves of measured photometric return from an atmosphere with no aerosols. He showed curves of backscatter coefficients from observations and from Rayleigh theory that suggest most computations assume lower backscatter coefficients than those actually observed.
Ingrid Guch presented "NOAA and Earth Observation Summit Activities Related to Observations and Requirements Planning". The Summit seeks to promote a comprehensive, coordinated, and sustained Earth observation system among governments and the international community to understand and address global environmental and economic challenges. The intergovernmental Group on Earth Observations (GEO) was launched and a framework document prepared to develop a 10-Year Implementation Plan for a GEO System of Systems (GEOSS). The GEOSS concept will build on existing systems. The plan is to be presented at Earth Observation Summit III in March 2005 (see http://earthobservation.org). A NOAA strategic planning team with representatives from across NOAA is considering inputs to develop requirements. Ingrid pointed out that wind measurement requirements are not receiving attention. It is important to develop stakeholder feedback to ensure inclusion in GEOSS requirements. The NOAA planning schedule includes a Strategic Plan and Guidance Memorandum in August 2004, and a Program Decision Memorandum in January 2005. Ingrid plans to brief NOAA executives to seek support for wind profiling. Ingrid also discussed the NPOESS Joint Agency Requirements Group (JARG), of which she is the Vice Chair.
Subcommittee Discussions were held following the last talk of the day.
On the need for support to advance global tropospheric winds acquisition
Dave Emmitt discussed the wind measurement community's need for advocates and the importance of other forums such as the WMO and GEOSS. He said we should address benefits to the aviation community, e.g., knowing where jet streams are, and invite FAA and industry representatives to the next meeting. He pointed out that the Army and Homeland Security have strong interests in winds. There was a discussion of whether more should be done with international and stakeholder meetings.
Bob Atlas said he does not see strong support at stakeholder meetings for extending weather forecasts. Traditionally, NASA buys science satellite capabilities and their utility creates support for NOAA to use new data. It was suggested that Dave Tratt, Bruce Gentry, Bob Atlas and others talk to the new Science Director and Associate Administrator at NASA to seek support. Dave Tratt agreed to take the lead. He pointed out that DOD support would be helpful.
Ingrid Guch is Vice Chair of JARG and can help get the GTWS requirements adopted by NPOESS.
Steve Mango asked what we can define as a US offering in wind measurement to GEOSS.
Bob Brown suggested more emphasis on benefits in areas other than forecasting, e.g., hurricanes.
Bob Atlas said there is a need for global high resolution models and wind measurement capabilities for Mars. He also suggested a joint NASA/NOAA article on OSSE results.
Steve Mango observed that the new NASA structure will lead to a change in programs, so we need to understand how to respond to the new structure. He also pointed out that academic courses were effective in advancing science applications in the past and suggested the Working Group should have courses integrating temperature, moisture, as well as motion in the atmosphere. Bob Atlas said that AMS has some courses of this type. Dave Emmitt said the National Institute of Aeronautics puts together courses on optical sensing and atmospheric science to be used by participating universities. Dave gives related seminars at UVA, Rod Frehlich teaches courses at Boulder. Dave Bowdle brought up the possibility of writing a book on basics of wind lidar. Steve Mango suggested putting proceedings of the WG into a textbook. Michael Dehring suggested articles on practical uses of wind measurements.
New Action Items
The next meeting will be held in Sedona Arizona, February 1-3, 2005. The Summer 2005 meeting will be in Mount Hood, Oregon, and the Winter 2006 meeting will be in Key West, Florida.
The meeting was adjourned.
Minutes were prepared by Kenneth Miller.