Michael Kavaya (NASA/LaRC) brought the meeting to order in the absence of W. Baker. (A severe snowstorm on the East Coast caused airport closures and kept a number of participants away from this meeting.) Review of the Action Items from the July 2003 meeting in North Conway, NH was suspended due to the multiple absentees. Michael chaired the meeting and re-ordered the agenda to accommodate speakers arriving later than planned.
Stephan Rahm (DLR) presented a summary of the Coherent 2 micron Doppler Lidar Measurements at the DLR in Germany. Highlights in 2002 included ground wake vortex measurements and 3-D wind components measured over the Mediterranean Sea, the Alps, and Sicily from the DLR Falcon aircraft. Validation using dropsondes showed some differences, probably as a result of separate sampling volumes. More campaigns are anticipated. Stephan indicated that a higher energy lidar is desired, if one can be found and outfitted.
Dave Emmitt (Simpson Weather Associates) gave an update on the Integrated Program Office (IPO) supported study for space-based wind calibration and validation. The IPO intends to have a role in DWL cal/val via pre-selection of sensors and pre/post launch operations. Contributing platforms might be the DLR Falcon (with DLR and NOAA/ETL sensors) or the Japanese 2 micron airborne system. Instrument performance models are being pursued via OSSEs (simulation experiments) and OSEs (real-data experiments, with current ground-based DWLs providing models for data characterization. An airborne hybrid DWL concept is being developed in hopes that it might provide pre-launch insight and post-launch truth for a space instrument.
Dave Emmitt then spoke on the use of airborne wind lidar to evaluate air/ocean exchanges at high wind speeds. The Twin Otter coherent DWL (TODWL) is to be used for these campaigns. Recent TODWL flights demonstrated vertical velocity accuracy of ±5 cm/s, using land surface returns. Significant correlations between backscatter and velocity were observed in and above the PBL. TODWL studies are also assessing water surface returns for cal/val on space-based DWL and scatterometer systems. In addition to the airborne DWL exercises, ground-based studies of DWL returns from a water slide are being used to assist in the data interpretation.
Gary Wilson (Ball Aerospace) ěpinch hitî for LaPole and Weimar and presented the status of ICESAT and CALIPSO, emphasizing flight qualification of subsystems and other aspects of risk reduction. Gary urged the working group to use CALIPSO as a ěpathfinderî for a global wind sounding mission.
Rex Fleming (UCAR) spoke about Strategic and Tactical Observing Systems for Homeland Security. He provided an update on the status of a proposal to use commercial aircraft as the platform for providing wind observations to mesoscale models to predict the trajectories of chemical, biological, or radioactive plumes for Home Security. Rex has calculated that aircraft DWL may provide wind profiles at a cost of $1.10 each, compared to $250 for those from radiosondes. He believes this may be a step toward a space-based DWL.
Jan Paegle (University of Utah) presented the results of ěObserving and Model Accuracy Requirements Inferred from Recent Global Predictability Experiments.î Jan has found that the performance of the Utah Model in improving forecasts (relative to NCEPís using anomaly correlation as a metric) has little dependence on resolution or observation period. For long-range forecasts (7-14 days), shortwave uncertainty in the initial conditions is more important than model differences.
Julia Paegle addressed the importance of South American Low Level Jets for moisture transport and analysis of that regionís hydrology. There is a consensus that space-based DWL would help detect and characterize the LLJs and aid in analysis of this type.
Michael Kavaya gave an update on the NASA Laser Risk Reduction Program. Two laser technologies are being advanced to support four techniques aimed at making six priority measurements. Winds are part of the picture, but by no means the sole ‚ or even primary ‚ driver.
Bob Atlas (NASA/GSFC) discussed the impact of space-based winds for improving numerical weather prediction toward the goals for 2010. He discussed the generation of a new high resolution, extended nature run (NR) containing realistic phenomena (for example two Atlantic hurricanes making landfall on the United States) and climatology, and the simulation of high accuracy wind profiles based on this NR. The simulated winds showed a significant impact via a variety of metrics.
Steve Weygandt (NOAA/FSL) added more motivation for making wind measurements by presenting results of regional DWL OSSEs conducted at FSL. The regional OSSEs show potential impact using a molecular DWL. Steve urged caution since the regional studies are very sensitive to DWL error specifications and still need more realistic cloud models.
Steve Weygandt briefly summarized the NOAA/ETL WINDLAB development in the absence of Mike Hardesty. WINDLAB is a MATLAB facility that models lidar, platform and atmospheric environment as a tool for the regional wind OSSEs.
Geary Schwemmer (NASA/GSFC) made a presentation entitled ěUltraviolet and Multiplexed HOEs: Current Performance and Future Prospects.î Geary described the development of a Shared Aperture Diffractive Optical Element (SHADOE), which uses no moving parts to produce up to 5 laser spots, all as small or smaller than earlier HOEs and with better optical efficiency. Damage at high power remains a challenge.
Ivan Dors (University of New Hampshire) presented an update on GroundWinds Science. Highlights included using GroundWinds New Hampshire (GWNH) during the 2002 New England Air Quality Campaign and turbulence studies with GroundWinds Hawaii (GWHI) above Mauna Loa. GroundWinds temperature retrievals are being produced experimentally, using deconvolution of the Brillouin scattering spectrum.
Carl Nardell (Michigan Aerospace Corporation) outlined status and plans of GroundWinds. GWNH and GWHI are essentially complete and operational, and focus has shifted to the development of BalloonWinds, intended to be a high altitude demonstration planned for 2005. New partners include Raytheon as well as the AFRL, which will provide the gondola and handle launch and related services. Recent progress includes reducing fringe-tilt errors; improving thermal stability in the interferometer; and combining aerosol and molecular returns on a single off-the-shelf CCD camera.
Geary Schwemmer substituted for Bruce Gentry and reported on HARGLO-2 winds intercomparisons. The use of HARLIE, GLOW, an all-sky camera, and rawinsondes at Wallops was reviewed. Data have been subjected to QC and analysis should be complete in two months. The data should help address question including the utility of sondes for DWL cal/val, the representativeness of scanning, and how to establish appropriate temporal and spatial parameters for cal/val.
Geary Schwemmer also presented Bruce Gentryís paper on recent GLOW field measurements, including IHOP in addition to the HARGLO-2 exercise. During IHOP, GLOW collected some 270 hours of data over 34 days. A host of other wind and moisture sensors were utilized during for IHOP. However, temporal and spatial variations require that great care be exercised when attempting to interpret comparisons or produce derived quantities. Coincident comparisons with LORAN sondes provided good agreement.
Tom Wilkerson (Utah State University) discussed the Detection and Measurement of Contrails to produce winds at cloud altitudes. An all-sky camera feeds frames to a block matching software, which calculates velocities based on successive images. The HARLIE laser is used to provide range/height.
Geary Schwemmer discussed the HARGLO-3 wind intercomparisons during IHOP. HARLIE collected a large volume of data during IHOP (less than 5 % blocked by clouds) and many correlative or ancillary data sources (GLOW, sondes, sodar, FM-CW radar, and the ETL DWL on the DLR Falcon aircraft) are available, too. Hybrid data products are being derived. A HARGLO-4 campaign is being designed to better relate airborne and ground-based wind measurements.
Geary Schwemmer presented Bruce Gentryís view on the prospects for an airborne technical demonstration of the molecular direct detection component of a Hybrid DWL. Ideally, such an instrument would serve not only as a demo, but as a cal/val platform, too. The concept calls for a system assembled from currently available components and featuring Doppler compensation for the platform as well as real-time data processing.
Dave Emmitt gave an update on the status of the Hybrid DWL study. He discussed the JPL evaluation and comparative cost analyses that are underway, plans for simulating data sets for adaptive targeting OSSEs, new ground-based demonstrations to refine direct and coherent detection performance limits, and the hope for an airborne demonstration as early as 2004. Data requirements are expected to remain fairly stable, so that trade studies for optimizing the two components can be undertaken with relative confidence. Discussions covered the possibility of a hybrid system that places the components on separate aircraft platforms to reduce complexity.
Carl Nardell spoke on the Molecular Optical Air Data System (MOADS) lidar status and flight plans. The MOADS is a direct detection, 266-nm system intended for measurements just a few meters ahead of a host aircraft. Velocity and temperature measurements have been verified in a wind tunnel; flight tests are planned this summer.
Bob Brown (University of Washington) presented a paper on the benefits of having two SeaWinds in orbit. He emphasized that a general circulation model that includes the PBL needs satellite data ‚ scatterometry, WindSat, SAR, altimeters, SSMI, and lidar to overcome the limitations of surface data from ships and buoys.
Phil Gatt (Coherent Technologies Inc.) discussed DWL projects being supported by CTI. These include both surface and aircraft based instruments, including van-based systems for the USAF and the laser for Dave Emmittís aircraft experiments.
Gary Uyeno (Raytheon) reviewed Raytheonís long history in providing laser and lidar technology (over 28,000 laser systems delivered) and standing interest in working towards a space-based DWL mission. He described the new partnership with MAC and UNH for BalloonWinds as a risk-reduction mission for space-based DWL.
Farzin Amzajerdian (NASA/LaRC) reported on advances made in risk reduction of laser diodes. He emphasized work that would support coherent detection DWL systems.
Dave Emmitt discussed cooperative studies being conducted via the National Institute of Aerospace (NIA) at LaRC. These include IMPs, DIAL, and DWL. A Workshop on the development of a network for the detection of stratospheric change is being planned at NIA for June 2003.
Rod Frehlich (University of Colorado) presented a paper on the prediction of wind variability using the FSL RUC model. He noted the difficulty and importance of this issue, as representative error varies greatly as a consequence of atmospheric turbulence.
Stephan Rahm gave a status report on the ADM. He reviewed the mission objectives, instrument design, and sampling strategies. Ground and airborne instruments are being developed and characterized for cal/val. These will be tested actively in the 2004 ‚ 2006 time frame. He noted that the ADM goal of staring to the dark side of the terminator, while desirable for avoiding noise photons originating outside the ADM laser, may prove more difficult to achieve than anticipated.