There are some pictures from the meeting after the minutes.
Wayman Baker brought the 26th meeting of the Working Group on Space-Based Lidar Winds (LWG) to order with introductory remarks. Wayman recognized several attendees who had attended early meetings of the Lidar Working Group or the LAWS Science Team, including Ramesh Kakar from NASA Headquarters, John Petheram from Lockheed Martin Space Systems, and Tim Miller from NASA Marshall Space Flight Center (MSFC). The purpose of the meeting was to review advances in atmospheric science and lidar technology toward a capability to measure the global wind field from space. Since 1994, the LWG has met twice a year to bring together potential Doppler Wind Lidar (DWL) data users, including international representatives, and lidar technologists to enhance the exchange of information, review the latest technology developments, and build a consensus for space missions. Excellent progress continues in technology, instrument architecture, mission concepts, benefit studies, field demonstrations, and other areas. Interagency support for a hybrid demonstration is building. A recent NASA Earth-Sun System Technology Office (ESTO) study assigned high priority to lidar winds, and the U.S. Integrated Earth Observing System Strategic Plan lists “wind profiles at all levels” as the highest priority measurement. Following the European Space Agency’s (ESA’s) Atmospheric Dynamics Mission (ADM) launch, scheduled for late 2008, we hope to see a US space demonstration of a hybrid bi-perspective DWL. Feasibility has improved since the Global Tropospheric Wind Sounder (GTWS) studies in 2001, with advances in laser power and efficiency, the hybrid instrument concept, and adaptive targeting studies. The National Polar-Orbiting Environmental Satellite System (NPOESS) Pre-Planned Product Improvement (P3I) program and the Air Force Space Test Program (STP) are candidates to support spacecraft integration and launch for a hybrid DWL demonstration.
Debra Hallmark discussed some logistics for the meeting.
Wayman reviewed action items and status from previous meetings.
Minutes, action items and presentations from this and previous meetings are posted on the LWG website, http://space.hsv.usra.edu/LWG/Index.html.
Ramesh Kakar presented “NASA’s Interest in Wind Lidar.” Ramesh is the Weather Focus Lead for the NASA Science Mission Directorate. He reviewed fundamental science questions in Earth Science research. They included:
He discussed major components of the Earth system, including Sun-Earth Connection, Climate, Earth Surface and Interior, Weather, Water and Energy Cycle, Atmospheric Composition, and Carbon Cycle and Ecosystems. Ramesh summarized the science questions from the Earth Science Research Strategy related to variability, forcing, response, consequence, and prediction. He also discussed how weather forecast skill can be improved by new space-based observations, assimilation, and modeling. In recent years, several areas have been funded. GEO missions with infrared and microwave sounding for severe weather forecasts were projected for future funding. Global tropospheric winds were projected for forecast improvement. Weather and severe storm forecasting improvements expected by 2015 include:
Ramesh discussed enabling elements for temperature and moisture (AIRS/AMSU and AMSR-E now, lidar sounders needed for future), precipitation, wind (4 Instrument Incubator Program (IIP) proposals selected for technology development and discussion with NASA, NOAA and DOD for joint satellite demo), modeling (Short-term Prediction Research and Transition Center (SPORT) and Joint Center for Satellite Data Assimilation (JCSDA)), and field experiments (contributing significantly to hurricane research). He reviewed the NASA historical role in DWL, beginning with aircraft measurements in the early eighties, LAWS, GLOBE, Observing System Simulation Experiments (OSSEs), MACAWS flights, ESTO Laser Risk Reduction Program (LRRP), and the 4 IIP projects that are underway today. Wind Lidar is the highest priority mission concept in the Weather Focus Area, and was independently assigned a high priority by the ESTO Laser/Lidar Working Group. He pointed out the need for NOAA to develop strong interest and support for a mission. Ramesh is also getting support on the DWL priority from other focus areas (not just weather but also climate composition, etc.). Ramesh showed a recommended winds roadmap with three steps, each using a combined 0.355 and 2-micron instrument (hybrid instrument): (1) aircraft platform with space-like geometry and scanning, (2) NPOESS 833 km space demo, and (3) NASA 400 km three year mission.
Steve Mango presented “Update on the Status of NPOESS.” NPOESS is still undergoing management review and restructuring resulting from projected cost overruns. Winds remain a high priority. The NPOESS Preparatory Project (NPP) is going forward with an planned launch in 2009. NPOESS requirements are solidified and re-validated in the restructuring process. The NPOESS schedule is delayed and its capability reduced. The parent agencies need to consider their priorities and how to make the program work. Important aspects of international cooperation are still there. The sensor suites have changed. Space and cost to integrate are preserved for a possible government-provided instrument. Wind lidar integration cost is not there, but the integrated program could support some integration costs. Restructuring highlights include: reduction from three orbits to two, reduction from six satellites to four, and a reduction in the number of sensors. Weather forecasting ability is preserved in the restructuring. The decision criteria for restructuring include continuity (Defense Meteorological Satellite Program (DMSP), Earth Observing System (EOS), ...), lower risk, growth potential, and affordability. Some sensors will not be manifested, but support for the integration costs is possible if the instrument is provided. The NPOESS/NPP operations center is also still available.
Michael Kavaya presented “IIP Update: A Packaged Coherent Doppler Wind Lidar Transceiver”, coauthored with G. Koch, Y. Yu, B. Trieu, F. Amzajerdian, U. Singh, and M. Petros. Michael discussed a Doppler Aerosol WiNd Lidar (DAWN) being developed under the IIP at the NASA Langley Research Center (LaRC). He identified key personnel at NASA, STC, and SAIC. The primary motivation for the project is measurement of wind profiles for weather and climate, with secondary motivations including CO2 profiles, Mars atmospheric density and wind profiles, Earth aerosol profiles, and Mars dust profiles. The project will produce a state-of-the-art 2-micron coherent DWL breadboard and make atmospheric wind measurements to validate the packaged technology. This will advance the coherent part of the hybrid DWL. Michael showed the IIP and global tropospheric wind profiles roadmap, indicating funding status of each step. Many vital steps, including aircraft operations, are not yet funded. He discussed Technology Readiness Level (TRL) advancement through the IIP packaging and future aircraft validation, lifetime demonstration, and space qualification tests. The IIP activity is six months into a 36-month schedule. Key milestones, schedule, and packaged transceiver requirements were discussed. Oscillator, amplifier, seed laser, transceiver, and test bed features, photographs, and drawings were shown. The VAlidation LIDAR (VALIDAR) testbed at LaRC was discussed.
Dave Emmitt presented “OSSE Plans Related to a Hybrid Mission and ADM Follow-on Missions.” Dave discussed an overview of OSSE efforts. NASA formed a Software Integration and Visualization Office (SIVO) at GSFC, one of whose responsibilities is to carry out OSSEs in support of instrument development initiatives. The Hemispheric Observing system Research and Predictability Experiment (THORPEX) program is funding an OSSE testbed, and the National Centers for Environmental Prediction (NCEP) is establishing a core OSSE system for general use, closely aligned with JCSDA. The core capability will reduce cost and effort before OSSE runs. Available nature runs are sufficient for the near future. Dave discussed the extensive role of OSSEs in THORPEX. OSSEs help quantify potential improvement for new instruments, data assimilation systems, and forecast models. He described the THORPEX OSSE Testbed and plans. Recent NCEP and GSFC experience was discussed. They are shifting focus to high impact weather forecasts and events, including precipitation, hurricane track, jet stream strength and location, air traffic routing, and utility load management. Adaptive Targeting OSSEs (in connection with the hybrid DWL) are in progress at NCEP and hurricane lifecycle OSSEs at GSFC. DWL simulation activities include hybrid DWL performance assessments and Adaptive Targeting strategy evaluations. ADM follow-on concepts will be addressed. Hybrid DWL specifications to meet demonstration and threshold requirements were discussed, with performance profiles for an 833 km demo mission and a 400 km demo and for a mission meeting threshold requirements. Dave discussed ADM simulations as an opportunity to calibrate our Doppler Lidar Simulation Model (DLSM) simulation models, validate OSSE predictions, and provide input to US mission planning. He described several ADM follow-on options. NASA and NOAA are establishing a core level of support for the OSSE testbed, and JCSDA is working to coordinate OSSE activities.
Sara Tucker presented “Spectral Broadening of Coherent Doppler Lidar Returns as Characterized by Ship-Based Wind Measurements”, coauthored with M. Hardesty, W. Brewer, and M. Post. NOAA Earth System Research Laboratory (ESRL) activities with ship-based lidar include investigating wind structure and other properties of the marine boundary, evaluating impacts on WindSat observations (to date, no overlapping WindSat data is available), assessing potential performance issues of a space based DWL, and examining the potential use of DWLs deployed on ground and ship-based platforms along side instruments such as weather radars, wind profilers, radiometers, etc., for calibration and validation of a satellite-based DWL. Sara described the 2-micron 2 mJ High Resolution Doppler Lidar (HRDL). It has maximum range of 3 to 8 km and range resolution of 30 m with full hemispheric scan capability. She described the Mini-MOPA lidar with wavelength of 9- to 11-microns, 1 to 2 mJ pulse energy, maximum range of 18 km, 45 to 300 m range resolution, and hemispheric scan. five ship-based experiments were conducted in 2004 through 2006: ASAP 2004, New England Air Quality Study (NEAQS) 2004, Rain in Cumulus over Oceans (RICO) 2004-2005, ASAP 2005-Emma, and Texas Air Quality Study (TexAQS) 2006. HRDL was used for NEAQS 2004 and TexAQS 2006. MOPA was used for the other experiments. Sara described the experiments and findings. She described models for return signal bandwidth spreading. Data will be reprocessed using space-based parameters (e.g., long range gates), experiment-based velocity turbulence profiles will be created for models, velocity variance constant (Cv2), and turbulent kinetic energy (TKE), and limited effectiveness of longer averaging will be studied. The next data acquisition step will be a TexAQS study in the Gulf of Mexico. These measurements will be used to characterize the Bay/Gulf region for use in space-based lidar predictions. Investigation procedures were discussed.
Tim Miller presented “Effects of Wind Uncertainties on Knowledge of Tropical Upper Tropospheric Humidity Fields,” coauthored with J. Pittman and P. Robertson. Tim discussed water vapor concentrations in the tropics, which range four orders of magnitude from the surface to the tropopause and stratosphere. Quantitative knowledge is essential. Mechanisms for water transport from troposphere to stratosphere are not well understood. Measurements in the upper troposphere are sparse and not always dependable. Major assimilation systems mostly use model data above 300 mb, and these may not compare well with satellite data. Rather than having a tropopause acting virtually as a material surface (as for the mid-latitudes), the tropics have a transition layer between the troposphere (where convection is active) and the stratosphere (where radiation is dominant). Tim described a Tropical Tropopause Layer (TTL) dehydration process. Aircraft measurements in the eastern equatorial Pacific indicate mostly sub-saturated TTL, suggesting dehydration did not occur locally. Backward trajectory studies were used to investigate where and when dehydration occurred. Tim described backward trajectory calculations and showed plots of winds at 70 mb and 100 mb and example trajectories. Results were not inconsistent with the cold trap theory of Holton et al, although with some bias. Details were highly dependent on wind data set and/or trajectory model. These studies need consistent, dependable, and validated global wind analyses.
Dave Emmitt presented “Geoscience Laser Altimeter System (GLAS) Cloud Statistics and Implications for a Hybrid DWL Mission,” coauthored with S. Greco. The main points covered were integration times, fraction of times that multiple cloud layers are detected, correlation of clouds with targets, and attenuation by cirrus. The integration time study addressed distribution of sequences of fractions of shots down to various levels of the atmosphere as a function of the distance between shots. Summary cloud penetration statistics were presented for the following cases: Cloud and Ground return, Cloud and No Ground, No Cloud and Ground, No Cloud and No Ground. The statistics were computed for six different horizontal resolution cases from low to full. Statistics were presented for number of cloud layers, from 0 to 10 layers. Curves were shown for six altitude levels showing percent of shot segments passed through versus percent of occurrence for high resolution. Cirrus transmission statistics for a 24 hour DWL simulation were plotted. Proposed future analysis of GLAS data included correlation of clouds with Adaptive Targeting target areas, use of DWL cloud returns to calibrate Cloud Motion Vectors (CMVs), statistics on surface returns from oceans, and use of GLAS coverage statistics to adjust OSSE simulations of space-based lidars.
Michael Dehring presented “Tropospheric Wind Lidar Technology Experiment (TWiLITE) Aircraft Etalon Qualification,” coauthored with S. Lindemann, B. Gentry. The briefing covered project description, goals, etalon specifications and design, vibration power spectrum inputs, tests, and test results. The tunable Fabry-Perot etalon will be capable of operation on a B-57 aircraft for the GSFC IIP TWiLiTE program. Tunable Fabry-Perot etalons are not typically flown on aircraft. The project will verify that the etalon will survive takeoff and landing and operate during flight profile. The etalon must maintain stability to <=0.1 to 0.2 m/s for operational testing. Michael showed specifications, drawings and photographs of the etalon approach. The design ruggedizes a space qualified etalon design for stability in an aircraft vibration environment. Finite Element Analysis (FEA) methods were used. Vibration isolators were added to the receiver. Input power spectrum plots were shown for x, y, and z axes of the WB-57, and a plot of vibrational power transmitted to the etalon. Illustrations of the etalon FEA were discussed. Space and aircraft designs were compared and photographs provided. Vibration profiles were compared for various launch vehicles and the WB-57. The vibration test setup and parameters were described. Test results were encouraging and provide important risk reduction. Measured etalon instability was ~1-2 m/s at 1 s sampling time for the worst case operational environment. Data reduction and analysis of the experimental conditions are still underway. Rope isolators are being augmented to absorb low frequency power. Operation during vibration is not a concern for a space mission.
Dave Emmitt presented “Planning for Airborne DWL Participation in Pacific-Asia Regional Campaign (PARC),” coauthored with M. Hardesty.THORPEX is aWorld Meteorological Organization (WMO) research programseekingto improve the accuracy of high-impact, 1-14 day weather forecasts. PARC will be a collaboration of North American and Asian THORPEX regional efforts. PARC will have a dual emphasis on the shorter-range dynamics and forecast problems of one region and the resulting medium range dynamics and forecast problems of a downstream region. PARC is scheduled for 2008 and one objective is to assess the value of DWL data in forecasting. The areas to be observed are large and a long distance off-shore, so the aircraft platform capability is important. Potential DWLs for use in PARC include Twin Otter DWL (TODWL), TODWL augmented with a direct detection DWL, Ground-based Wind Observing Lidar Facility (GWOLF), an ESRL DWL, and a NASA IIP instrument. Candidate aircraft include the Twin Otter, NOAA P3, NOAA G4, AF C130, NASA 737, WB57, Proteus, DC8 (has nadir and up-look ports), and the ER2 (high altitude capability). The Twin Otter may not have sufficient speed, altitude, and range capability for this mission. There was a discussion of the benefits of designing a pod to minimize aircraft modification. Mike Hardesty said the DC8 would be particularly good for a hybrid DWL because of the space availability and multiple nadir ports. Ramesh Kakar suggested looking closely at the ER2. Ramesh also suggested that NSF support for PARC is needed. He said that the French may fly a lidar in a Cape Verde project.
Robert Brown presented “What Simple-Minded Surface Winds Can Do for Forecasting Weather.” Bob expressed continuing concern with use of outdated models for the Planetary Boundary Layer (PBL) and recommended discontinuing the Ekman solution and K-theory in PBL modeling. The nonlinear solutions for the PBL are more difficult, but more complete and correct. Bob discussed the hazards of taking wind measurements in the rolls. Faster and more complex models can’t necessarily improve performance in the PBL if the models themselves are inadequate. Bob discussed the nonlinear solution applied to satellite surface winds to yield accurate surface pressure fields. Bob showed graphic data indicating that NCEP analysis, used as the first guess in real time forecasts, is improved with the QuikScat surface pressure analyses. Using surface wind as a lower boundary condition on a PBL model provides considerable information. Surface backscatter data and the PBL model are mutually beneficial. Satellite data have proven that the nonlinear PBL solution with Organized Large Eddy (OLE) winds is frequently observed.
Michael Kavaya presented “Status of Laser/Lidar Working Group Requirements,” coauthored with B. Gentry. The NASA ESTO Laser/Lidar Working Group charter was to “develop a strategy for targeted technology development and risk mitigation efforts at NASA by leveraging technological advancement made by other government agencies, industry and academia, and move NASA into the next logical era of laser remote sensing by enabling critical Earth Science measurements from space.” This requirements work was conducted in the NASA ESTO Atmospheric Dynamics Science Requirements Subgroup. A draft copy of the final report is available at http://esto.nasa.gov/lwg/lwg.htm. Michael presented the latest requirements tables for DWL winds from space, including requirements for a Demo mission, a Threshold mission, and an Objective mission. The recommended roadmap for atmospheric winds includes airborne demonstrations of combined (hybrid) direct and coherent lidars with space-like geometry and scanning, followed by an NPOESS demonstration mission in an 833 km orbit, followed by a three-year threshold mission at 400 km orbit. The definition process, investment priority analysis, and technology roadmap were discussed. Michael discussed laser remote sensing techniques and applications, and identified measurements that are primarily achieved by laser remote sensing. Prioritization criteria included scientific impact, societal benefit, measurement scenario uniqueness, technology development criticality, technology utility, measurement timeline, and risk reduction. Tropospheric winds priority ranked highly in the assessment.
Dave Emmitt presented “New Sampling Perspectives for TODWL,” coauthored with C. O’Handley. Dave discussed point scans versus Velocity Azimuth Display (VAD) scans. Point scans acquire multi-perspective line of sight wind measurements in a confined sample volume, whereas VAD scans sample along a pattern around the flight track with a continuous conical scanner on a moving platform. VAD scans can produce vector wind profiles, but they have different statistical sampling properties from those produced with point scans. Plots of VAD and point scan wind speed profiles and vertical motion plots were shown. DARPA funded flights were managed out of LaRC, with interest in vertical motions ahead of Unmanned Aerial Vehicles (UAVs). This project will review previous TODWL flights for cases with vertical wind components above 500 m altitude and will design flights for Fall 06. An Army Research Office (ARO) Small Business Innovative Research (SBIR) Phase II project will begin this summer. The Airborne Doppler Lidar Analyses and Adaptive Targeting System (ADLAATS) will be used. It is an SWA concept for onboard execution of 3D flow models along with DWL. TODWL will be used to develop and refine techniques. Flights are scheduled for late 2007. An Office of Naval Research (ONR) SBIR Phase I activity will develop an onboard system for integrating DWL with radar, in situ instruments and model data into a single mission focus display. This will include redesigning the DWL physical layout in the Twin Otter aircraft. The National Environmental Satellite, Data, and Information Service (NESDIS) funded TODWL/GWOLF activities including flights to investigate synergisms between DWL and WindSat, QuikScat, and CMV over coastal waters in California. This activity will conduct ground and airborne observations to evaluate space-based performance models.
Tim Miller presented “Update on Development of an Integrated Remote-Sensing Testbed for Tropospheric Air Quality and Winds,” coauthored by M. Newchurch, S. Christopher, D. Bowdle, K. Knupp, W. Petersen, M. Botts, S. Johnson, R. Williams, and D. Emmitt. Tim described activities including hosting an Army Workshop, installing a Doppler lidar scanner, integrating lidar winds with radar winds, initiating NOAA Air Quality research, and integrating Huntsville assets. A Workshop on Soldier-Scale Atmospheric Testbed was held in Huntsville in March 06, sponsored by the ARO and hosted by the University of Alabama in Huntsville (UAH). Attendance included UAH, NASA/MSFC, Army, and Air Force personnel. Issues included improved characterization of the atmospheric boundary layer, comparison of model results with observations, high spatial and temporal resolution, and data collection requirements. A Doppler Lidar scanner is scheduled to be installed in summer 06. A 2-micron DWL will be integrated with two radars (C-band and X-band) for wind observations. The project will emphasize clear-air wind analyses in the boundary layer. The NOAA Air Quality Research Initiative objective is to study and predict the impact of air pollution on climate, health, and other environmental applications and develop improved transferable air quality models for the Huntsville-Madison-Decatur transportation corridor. The project will integrate a wide variety of resources, sponsors, and collaborators, with anticipated start date in summer 06.
Michiko Masutani presented “OSSEs at NCEP and JCSDA.” Several coauthors were named from NOAA, JCSDA, and SWA. The presentation addressed a new high resolution nature run, OSSEs with uniform data, and lidar adaptive experiments. Good new nature runs are needed that can be used by many OSSEs. Preparation of the nature run is expensive. Using the same nature run for multiple OSSEs enables comparison of results. The European Centre for Medium-range Weather Forecasts (ECMWF) has prepared a new nature run based on recommendations by JCSDA, NCEP, GMAO, GLA, SIVO, SWA, NESDIS, and ESRL. Michiko described a new low resolution nature run and a high resolution nature run, development status, and contacts for access. She discussed the impact of high resolution data. Michiko also discussed the impact of adding DWL data and increasing model resolution from T62 to T170. The results with a scanning DWL were superior to other alternatives. She presented comparative results for combinations of observations and resolutions. Targeted DWL experiments addressed two lidar types: DWL-Upper and DWL-Lower. DWL-Upper provides mid and upper tropospheric winds only down to the levels of significant cloud coverage, operating at 10% to 20% duty cycle. DWL-Lower provides wind observations from clouds and the Planetary Boundary Layer (PBL). It was found that target selection for DWL-Upper has a strong impact on performance with best performance at 100% duty cycle.
Jinxue Wang presented “NPOESS Doppler Winds LIDAR Accommodation Study,” coauthored with M. Kavaya, J. Bell, and K. Kane. The primary objective of this study was to answer feasibility questions and formulate the baseline mission concept for a DWL demonstration through the NPOESS P3I process. The tasks addressed (1) timeline assuming NPOESS C2 and beyond, (2) available mass budget on the spacecraft for a nominal hybrid DWL, (3) available volume budget, (4) available power budget, (5) thermal management and heat removal options, (6) spacecraft vibration environment, (7) vibration and jitter introduced by the scanner, (8) nominal instrument footprint on the spacecraft, (9) available field-of-view, (10) fields-of-view of other instruments and potential conflicts, (11) five pointing requirements, and (12) estimate instrument integration cost. Jinxue presented a timeline and suggested the timeline for a mission on spacecraft C2 after the Nunn-McCurdy review and restructuring looked promising. Steve Mango pointed out that the schedule did not show time for contracts work and acquisition. The rescheduled C3 spacecraft is too far out in time for immediate consideration. Jinxue showed the planned sensor payload for NPOESS platforms C1 through C6, and for 4 rescheduled platforms. The rescheduled C2 is less crowded, with more mass and power budget potentially available after CMIS removal. Steve pointed out that an alternative to CMIS (microwave sounder) may be on C3. Jinxue discussed the required documents for NPOESS instruments and their due dates, beginning with an Instrument Description Document due 53 months before launch. Timelines were discussed for a demonstration mission on NPOESS C3 and C4 (before rescheduling). The study concluded that NPOESS C3 (launched in 2013) and C4 (2015) are feasible from a schedule point of view. To make C3, Phase A must start by mid 07. To make C4, Phase A must start no later than 2008. Mass, volume, and power budgets were discussed for C1 through C4. From volume, mass, and power budget point of view, C4 (rescheduled C2) is more desirable. The C3 resources budget may not accommodate the DWL package used in this study. The shared telescope aperture was assumed to have a 1.26 m aperture.Thermal management and heat removal options were discussed and a summary baseline thermal management system design was presented. The instrument is assumed to provide its own radiators. Spacecraft and scanner vibration analysis was presented. The scanner will require torque and momentum compensation, and a reaction wheel assembly approach was described. A CAD drawing of the DWL on NPOESS C4, and the instrument layout and footprint were discussed. DWL modules can be accommodated on the nadir deck of the C1/C4 (RC2) spacecraft.The available field of view satisfies DWL needs, and the instrument does not interfere with the field of view of any other instrument. The five DWL pointing requirements appear feasible, with the possible addition of two star trackers. A beam-steering mirror will be required to hold the line of sight within tolerance during the pulse round trip time. Instrument integration costs were estimated by a combination of analogy and parametric methods.
Michael Dehring presented “BalloonWinds Update,” coauthored with I. Dors. The purpose of BalloonWinds is to demonstrate direct detection DWL technologies from an altitude of 30 km. BalloonWinds will validate instrument performance and atmospheric models and address scalability to space. The flight timeline includes balloon ascent of less than two hours, up to ten hours of flight at 30 km, and parachute descent in less than one hour. Model validation objectives include the atmosphere model, the laser-telescope model, the optics-camera model, and the wind uncertainty model. Three flights are planned under varying day/night and clear/cloudy conditions. Objectives of each flight were discussed. The instrument is integrated to the gondola and post-integration tests are being performed. The ground station is complete and undergoing testing. The mass budget (2161 kg) and as-built (2542 kg) and power budget (1306 W) and as-built (933 W) were discussed. The thermal system was augmented for over 12 h of flight and temperature control loops are operational. Telemetry data, displays, and graphs were shown. The laser chamber is operational, with heaters added for ascent. Laser-telescope alignment routines are operational and being refined. The interferometer parameters and system measurement comparison (pre-ship and post-ship) were discussed. Mission simulated operations are scheduled for July at the University of New Hampshire (UNH). Environmental tests are scheduled for August at Kirtland AFB.
Floyd Hovis presented “Testing of the Space Winds Lidar Laser Transmitter Prototype,” coauthored with J. Wang. This activity is developing and testing a robust, single frequency 355 nm laser for airborne and space-based direct detection wind lidar systems. The laser is all solid-state and diode pumped, with robust packaging. It is tolerant of moderate vibration levels during operation, with a space-qualifiable design. The project will incorporate first generation laser transmitters into ground-based and airborne field systems to demonstrate and evaluate designs, including the Goddard Lidar Observatory for Winds (GLOW) and BalloonWinds. The design will be scaled to higher powers and pulse energies through the Raytheon-funded Space Winds Lidar Risk Reduction Laser Transmitter project and an Air Force SBIR. The SBIR is to develop a 500 mJ, 100 Hz 1064 nm pump source. Designs will be iterated for improved compatibility with a space-based mission, including lighter and smaller packaging and radiation hardened electronics. Floyd reviewed the status of related laser development programs for UNH, NASA LaRC, Raytheon, Air Force, Navy, and NASA GSFC. He described the transmitter technical approach. Of importance to the Adaptive Targeting concept, Floyd presented an analysis of power consumption for the laser transmitter, including several modes of operation. He said cycling the laser on and off is not a problem, although it takes a couple of minutes from standby to full power. Measured performance, including Off/On cycling, was presented. Transmitter status was summarized as follows: >900 mJ/pulse, single frequency 1064 nm pump laser, 50 Hz, good beam quality, 33% conversion to 355 nm, 300 mJ/pulse. Improvement to >45% conversion is still anticipated. Acceptance testing is planned in July and amplifier tests to demonstrate scaling to 100 Hz are planned in August with Air Force SBIR funding. Performance characterization and testing are planned in Q3 of 2006. Life testing and characterization are planned in Q4 2006 and beyond at Raytheon.
Floyd Hovis presented “Qualification and Integration of the Laser Transmitter for the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation satellite (CALIPSO) Aerosol Lidar Mission,” coauthored with G. Witt, E. Sullivan, K. Le, C. Weimer, and J. Applegate. Fibertek designed, built, and qualified the laser transmitter for CALIPSO. Ball Aerospace designed, produced, and integrated the payload, including the Rayleigh/Mie lidar for clouds and aerosols (CALIOP), wide field camera, and imaging infrared radiometer. Ball was also responsible for the payload flight software, science data delivery system, integration and test support, and on-orbit commissioning system. NASA LaRC provided the lidar requirements. A Risk Reduction Laser was built before the flight build to demonstrate the laser design approach and performance. The laser requirements were within the state-of-the-art. They included 100 to 125 mJ at 1065 nm and at 532 nm, with a pulse width between 15 and 50 ns, and 20 Hz pulse repetition frequency (prf). System level requirements were more challenging, including a lifetime of two billion shots, conductive cooling, power budgets, vibration environment, 100 microradian final divergence, and electromagnetic interference. Two laser boxes are included for redundancy, weighing 12 kg each. Wall plug efficiency is 4%. Floyd discussed how the lidar requirements determined the laser specifications, and the iterative development process for key components. He discussed laser transmitter reliability, laser stability, laser efficiency, polarization measurements, environmental qualification, and optics qualification. Drawings and photographs of the transmitter, laser electronics unit, and payload and spacecraft integration were discussed. CALIPSO was launched April 28, 2006 and first lidar data released June 9. Floyd showed CALIPSO lidar measurements of total attenuated backscatter at 532 nm from June 7.
Carl Weimer presented “CALIPSO Commissioning Status.” The CALIPSO satellite is operational on-orbit with all subsystems operating nominally. Design and performance information is available from Ball Aerospace to support wind lidar trades and development. Carl showed pictures of Total Attenuated Backscatter data from 532 nm lidar and radiance swath images from the wide field camera and imaging infrared radiometer. The on-orbit program structure includes Dr. David Winker of NASA LaRC is Principal Investigator, the Satellite Operation Command Center is operated by Centre National d’Etudes Spatiales (CNES) in Toulouse France, the Mission Operation Command Center is operated by LaRC. Ball Aerospace is a partner for Payload Operations. Hampton University is coordinating the calibration/validation campaign. The validation campaign includes sharing data between CALIPSO and ground and airborne systems, and LaRC is flying its airborne High Spectral Resolution Lidar for validation studies. The Alcatel Proteus spacecraft and Ball/NASA payload are fully operational. Views of the payload and lidar were presented. Total power for the spacecraft is 500 W, with 350 W for CALIPSO. The lidar transmitter includes two redundant Nd:YAG lasers, each capable of full mission life. Pulse power is 110 mJ at both 532 nm and 1063 nm @ 20 Hz. The lasers were delivered by Fibertek in 2002. A total of 80 million shots (4% of mission) were fired during integration and test and 27 million shots on-orbit as of June 23. They are conductively cooled. Thermal performance has been excellent, although a slight shift from their ground operating points indicates subtle thermal effects. The transmitter is o-ring sealed. Laser pulse energy is stable and receiver and detectors are working properly. Built in Test has verified sensitivity and timing response. Signal levels from Rayleigh are slightly higher than predicted by radiometric math models. A fixed etalon limits bandwidth and daytime background light. Data on etalon tuning was presented. Data processing and science data handling are functioning properly. An active boresight system corrects for shifts due to launch, thermal, humidity, and 1-g effects. Polarization measurements to distinguish water from ice clouds are being collected for calibration. A wedged quartz depolarizer can be inserted into beam to calibrate the two channels. Final polarization characterization will be reported in the future by Chris Hostetler of LaRC.
Carl Weimer presented “Observations of a Volcanic Plume from the Eruption of Soufriere Hills, Montserrat, on May 20.” A CALIPSO Total Attenuated Backscatter plot at 532 nm was shown along with maps of the plume coverage and the satellite track. The data was taken on June 7, 2006. The Soufriere volcano on Montserrat experienced a major eruption on May 20, 2006. The plume was estimated to reach 17 km, probably entering the lower stratosphere. The SO2 column was tracked by the Aura Ozone Monitoring Instrument (OMI) instrument for several weeks. On 6 and 8 June, OMI observed the SO2 plume over Indonesia. On June 7, during its first day of lidar operations, CALIPSO observed a thin scattering layer at an altitude of about 20 km. Because of the altitude and the correlation with the location of the SO2 plume this appears to be the aerosol component of the plume from Soufriere. The layer appears to be non-depolarizing and primarily composed of sulfuric acid droplets, rather than ash particles. Volcanic plumes such as this can be hazardous to air traffic if they cross air traffic lanes at the altitude where commercial aircraft fly. This example illustrates the ability of CALIPSO to detect and track these volcanic plumes. Also visible are thin tropical cirrus clouds (12-15 km), the tops of tropical storm systems (5-10 km) and aerosols in the planetary boundary layer (lowest few kilometers). The ability of CALIPSO to observe where aerosols occur and their altitude around the globe improves our assessments and forecasts of air quality. The lidar image was calibrated Level 1 data. There was a range bias at the time this data was acquired, so the ocean surface appears to be at an altitude of ~500 m.
The presentation“Coherent Lidar Measurements during the 2003 GroundWinds Intercomparison Campaign,” coauthored by S. Tucker, M. Hardesty, A. Brewer was rescheduled to the February 2007 meeting.
Dave Emmitt presented “NPOESS P3I & Follow-on Threshold Operational Mission.” This briefing included design performance plots created with the Doppler Lidar Simulation Model (DLSM). Dave provided tables of lidar parameters for the direct detection and coherent detection subsystems of the hybrid lidar for a demo mission and a threshold mission. The differences between the demo and threshold mission lidar parameters were integration time (12 s for the demo mission versus 6 s for the threshold mission) and prf for the coherent detection system (5 Hz for demo and 10 Hz for threshold). Performance profiles plotted RMS error (color coded) for percentage of target volumes viewed (x axis) versus height up to 19 km (y axis). Profiles were provided for an 833 km demo mission and a 400 km threshold mission, and for background aerosol and enhanced aerosol atmospheres. Performance profiles were provided for both 30 degree and 45 degree nadir angles for the 400 km threshold mission. A table of data requirements was shown for demo, threshold, and objective missions. The table indicated that requirements would be met or exceeded, with the exception of minimum wind measurement success rate of 50% for the demo mission. It is not yet determined whether that requirement would be met by this point design. A conceptual design study is planned, to be conducted by the Instrument Synthesis and Analysis Laboratory (ISAL) and Integrated Mission Design Center (IMDC) at GSFC. Dave identified three important questions to be addressed in the mission conceptual design: (1) what subsystems can be shared, (2) what is the standby power requirement for the direct detection subsystem, and (3) what are the scanner power requirements?
Ken Miller presented “Architecture Alternatives for the DWL Space Demonstration.” This presentation identified instrument architecture trades for discussion in this session. The space demonstration mission concept includes multiagency support, significant science products, and a hybrid biperspective DWL with adaptive targeting for the direct detection subsystem. The roadmap steps include a hybrid DWL ground demonstration, aircraft demonstration, and space demonstration (on NPOESS, Air Force Space Test Program (STP) or other opportunity). The space demonstration would be followed by an operational mission meeting threshold tropospheric wind requirements. Some data requirements are relaxed for the demonstration mission versus threshold data requirements. These changes reduce risk and time to mission and include relaxed resolution, maximum wind speed, latitude coverage, and product latency. Space demonstration phases include instrument development, spacecraft integration, launch, operations, and data simulation, processing, and assimilation. Top level alternatives addressed how to acquire and organize multiagency support for the different phases, and choice of platform and orbit. The question of how to share agency responsibilities and three alternative scenarios (NPOESS, STP, International) was discussed, considering traditional agency roles in each phase. ESA Atmospheric Dynamics Mission (ADM) follow-on and a Japanese International Space Station (ISS) demonstration were discussed as possible alternative platforms, and will be investigated by the Working Group. The NPOESS alternative reduces some costs by sharing a spacecraft with other instruments but imposes constraints on instrument power, mass, volume, instrument-induced vibration, and orbit (833 km). The STP alternative could have the advantages of larger power, mass, and volume budgets, a 400 km orbit, and reduced interoperability concerns. The lower orbit significantly reduces instrument technology challenges for a given level of performance. Implementation trades were discussed, including instrument power, mass, volume, orbit, telescope aperture, scanner, laser power and efficiency, pulse rate and integration time, optical and detector efficiencies, component sharing, and direct detection duty cycle. The telescope aperture was shown to have important impacts on instrument power, mass, and volume and it was shown that increased laser power and wallplug efficiency are vital to meeting NPOESS resource budget constraints. Orbit altitude effects on instrument aperture, power, mass, volume, momentum compensation, pulse round trip time were discussed. Today’s direct detection instrument design concepts were compared to the Global Tropospheric Winds Sounder reference design concept from 2001, showing major technology advances and risk reduction. Scanner power versus aperture size and alternative optics concepts were discussed.
Discussions Open discussions of architecture alternatives and related topics were held, followed by off-line discussions of proprietary and government-only topics.
Subcommittee discussions were held.
Action Items were prepared.
Wayman Baker presented action items for review and discussion.
The Working Group confirmed the selection of Miami for the Winter 07 meeting. The meeting will be held February 6 through 9.
The group selected Breckenridge Colorado for the Summer 07 meeting.
The meeting was adjourned.
These minutes were prepared by Kenneth Miller with assistance from Sara Tucker.
Glossary
A2D ALADIN Airborne Demonstrator
ADLAATS Airborne Doppler Lidar Analyses and Adaptive Targeting System
ADM ESA’s Atmospheric Dynamics Mission
AIRS Atmospheric Infrared Sounder
ALADIN Atmospheric Laser Doppler Instrument
AMSR-E Advanced Microwave Scanning Radiometer-EOS
AMSU Advanced Microwave Sounding Unit
ARO Army Research Office
ATReC Atlantic THORPEX Regional Campaign
BAMS Bulletin of the American Meteorological Society
CALIPSO Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation satellite
CAMEX Convection and Moisture Experiment
CCD Charge Coupled Device
CIRPAS Center for Inter-Disciplinary Remotely Piloted Aircraft Studies
CLIO Circle to Line Optic
CLRC Coherent Laser Radar Conference
Cv2 Velocity Variance Constant
DAWN Doppler Aerosol Wind Lidar
DOD Department of Defense
DLR German Aerospace Centre
DLSM Doppler Lidar Simulation Model
DMSP Defense Meteorological Satellite Program
DWL Doppler Wind Lidar
ECMWF European Centre for Medium-range Weather Forecasts
EOS Earth Observing System
ESA European Space Agency
ESRL NOAA Earth System Research Laboratory
ESSP Earth System Science Pathfinder (ESSP) program
ESTEC European Space Research and Technology Center
ESTO Earth-Sun System Technology Office
ETKF Ensemble Transform Kalman Filter
FEA Finite Element Analysis
GEO Geosynchronous Earth Orbit
GEOSS Global Earth Observation System of Systems
GLAS Geoscience Laser Altimeter System
GLOBE Global Backscatter Experiment
GLOW Goddard Lidar Observatory for Winds
GOES Geostationary Operational Environmental Satellite
GSFC Goddard Space Flight Center
GTWS Global Tropospheric Wind Sounder
GWHI GroundWinds Hawaii
GWNH GroundWinds New Hampshire
GWOLF Ground-based Wind Observing Lidar Facility
HLOS Horizontal Line of Sight
HOE Holographic Optical Element
HRDL High Resolution Doppler Lidar
IIP Instrument Incubator Program
ICESat Ice, Cloud, and land Elevation Satellite
IMDC GSFC Integrated Mission Design Center
IORD Integrated Operational Requirements Document
IPO Integrated Program Office that manages NPOESS
ISAL GSFC Instrument Synthesis and Analysis Lab
ISS International Space Station
JCSDA Joint Center for Satellite Data Assimilation
LaRC Langley Research Center
LAWS Laser Atmospheric Wind Sounder
LEO Low Earth Orbit
LETKF Local Ensemble Transform Kalman Filter
LRRP Laser Risk Reduction Program
LWG Working Group on Space-Based Lidar Winds, or Lidar Working Group
MACAWS Multi-Center Airborne Coherent Atmospheric Wind Sensor
MDT Mission Definition Team
MODIS Moderate-resolution Imaging Spectroradiometer
MOPA Master Oscillator Power Amplifier Lidar
MSFC Marshall Space Flight Center
NAS National Academy of Sciences
NASA National Aeronautics and Space Administration
NCEP National Centers for Environmental Prediction
NEAQS New England Air Quality Study
NESDIS National Environmental Satellite, Data, and Information Service
NIR Near infrared region of the electromagnetic spectrum
NPOESS National Polar-orbiting Observing Environmental Satellite System
NPP NPOESS Preparatory Project
NSF National Science Foundation
NWP Numerical Weather Prediction
OES Office of Earth Sciences
OLE Organized Large Eddy
OMI Ozone Monitoring Instrument
OSSE Observing System Simulation Experiment
PARC Pacific Asia Regional Campaign (THORPEX)
P3I Pre-Planned Product Improvement program (NPOESS)
PBL Planetary Boundary Layer
PIEW Prediction Improvement for Extreme Weather
Prf Pulse Repetition Frequency
RICO Rain In Cumulus Over Oceans
SAIC Science Applications International Corporation
SBIR Small Business Innovation Research
SNR Signal to Noise Ratio
SOSE Sensitivity Observing System Experiment
SPORT NASA Short-term Prediction Research and Transition Center
STC Science and Technology Corporation
STP Space Test Program
SWA Simpson Weather Associates
TexAQS Texas Air Quality Study
THORPEX The Hemispheric Observing system Research and Predictability Experiment
TKE Turbulent Kinetic Energy
TODWL Twin Otter DWL
TOVS TIROS Operational Vertical Sounder
TRL Technology Readiness Level
TTL Tropical Tropopause Layer
TWiLiTE Tropospheric Wind Lidar Technology Experiment
UAH University of Alabama in Huntsville
UAV Unmanned Aerial Vehicles
UNH University of New Hampshire
UV Ultraviolet
VALIDAR Validation Lidar Facility
WSR Winter Storm Reconnaissance Program
PowerPoint file containing pictures provided by Michiko Masutani.
pdf file containing pictures provided by Jim Hawley.
The photos below were provided by Debra Hallmark.
