130 Matching Results

Search Results

Advanced search parameters have been applied.

Effective Use of Molecular Recognition in Gas Sensing: Results from Acoustic Wave and In-Situ FTIR Measurements

Description: To probe directly the analyte/film interactions that characterize molecular recognition in gas sensors, we recorded changes to the in-situ surface vibrational spectra of specifically fictionalized surface acoustic wave (SAW) devices concurrently with analyte exposure and SAW measurement of the extent of sorption. Fourier-lmnsform infrared external- reflectance spectra (FTIR-ERS) were collected from operating 97-MH2 SAW delay lines during exposure to a range of analytes as they interacted with thin-film coatings previously shown to be selective: cyclodextrins for chiral recognition, Ni-camphorates for Lewis bases such as pyridine and organophosphonates, and phthalocyanines for aromatic compounds. In most cases where specific chemical interactions-metal coordination, "cage" compound inclusion, or z stacking-were expected, analyte dosing caused distinctive changes in the IR spectr~ together with anomalously large SAW sensor responses. In contrast, control experiments involving the physisorption of the same analytes by conventional organic polymers did not cause similar changes in the IR spectra, and the SAW responses were smaller. For a given conventional polymer, the partition coefficients (or SAW sensor signals) roughly followed the analyte fraction of saturation vapor pressure. These SAW/FTIR results support earlier conclusions derived from thickness-shear mode resonator data.
Date: December 9, 1998
Creator: Bodenhofer, K,; Gopel, W.; Hierlemann, A. & Ricco, A.J.
Partner: UNT Libraries Government Documents Department

Acoustic noise associated with the MOD-1 wind turbine: its source, impact, and control

Description: This report summarizes extensive research by staff of the Solar Energy Research Institute and its subcontractors conducted to establish the origin and possible amelioration of acoustic disturbances associated with the operation of the DOE/NASA MOD-1 wind turbine installed in 1979 near Boone, North Carolina. Results have shown that the source of this acoustic annoyance was the transient, unsteady aerodynamic lift imparted to the turbine blades as they passed through the lee wakes of the large, cylindrical tower supports. Nearby residents were annoyed by the low-frequency, acoustic impulses propagated into the structures in which the complainants lived. The situation was aggravated further by a complex sound propagation process controlled by terrain and atmospheric focusing. Several techniques for reducing the abrupt, unsteady blade load transients were researched and are discussed in the report.
Date: February 1, 1985
Creator: Kelley, N.D.; McKenna, H.E.; Hemphill, R.R.; Etter, C.L.; Garrelts, R.L. & Linn, N.C.
Partner: UNT Libraries Government Documents Department

BBN technical memorandum W1310 hydroacoustic network capability studies

Description: This report summarizes work performed under contract to Lawrence Livermore National Laboratory during the period 1 August to 30 November 1997. Four separate tasks were undertaken during this period which investigated various aspects of hydroacoustic network performance using the Hydroacoustic Coverage Assessment Model (HydroCAM). The purpose of this report is to document each of these tasks.
Date: December 1, 1997
Creator: Angell, J., LLNL
Partner: UNT Libraries Government Documents Department

The design and operation of infrasonic microphones

Description: This report is intended as a guide to the design and operation of infrasonic microphones. It will emphasize general principles and the effects of parameter choices upon performance but will not provide details of design for specific microphones. The report will consider primarily the mechanical aspects that control the acoustic properties; it will not discuss the features of electronic design, which vary greatly among microphones. Here the authors define infrasonic microphones as sensors capable of detecting pressure variations in the period range of about 0.1 s to 1000 s with changes from about 0.1 {mu}bar (microbar = 1 dyne cm{sup {minus}2}) to about 1 mbar.
Date: May 1, 1997
Creator: Mutschlecner, J.P. & Whitaker, R.W.
Partner: UNT Libraries Government Documents Department

Ultrasonic evaluation of flood gate tendons

Description: Our water resources infrastructure is susceptible to aging degradation just like the rest of this country`s infrastructure. A critical component of the water supply system is the flood gate that controls the outflow from dams.Long steel rods called tendons attach these radial gates to the concrete in the dam. The tendons are typically forty feet long and over one inch in diameter. Moisture may seep into the grout around the tendons and cause corrosion. Lawrence Livermore National Laboratory is working with the California Department of Water Resources to develop advanced ultrasonic techniques for nondestructively inspecting their tendons. A unique transducer was designed and fabricated to interrogate the entire tendon. A robust,portable unit was assembled that included a computer controlled data acquisition system and specialized data processing software to analyze the ultrasonic signals. This system was tested on laboratory specimens and is presently being fielded at two dam sites.
Date: October 1, 1997
Creator: Thomas, G. & Brown, A.
Partner: UNT Libraries Government Documents Department

Rationale and summary of methods for determining ultrasonic properties of materials at Lawrence Livermore National Laboratory

Description: This report is a summary of the methods used to determine ultrasonic velocities through the many materials tested at the Acoustic Properties of Materials Laboratory. Ultrasonic velocity techniques enable the determination of material properties, including elastic moduli, without harming the materials being tested, an advantage some over mechanical methods. Ultrasonic modulus determination has other advantages as well: (1) relative ease and low cost of material preparation; and (2) comparative analysis to physical testing as a function of material loading rate dependence. In addition, ultrasonic measurement provides clues to determine grain size and orientation, and provides a relative indication of material anisotropy with respect to the material geometry. The authors usually perform ultrasonic measurements on materials in ambient atmospheric conditions, and in a relatively free-free condition. However, the authors can perform them in other environments, as required. This paper describes some of the techniques used in this laboratory and shows how ultrasonic velocities are used to establish elastic constants. It also includes a sample test report for a homogeneous isotropic solid, along with a list of references.
Date: February 9, 1995
Creator: Brown, A. E.
Partner: UNT Libraries Government Documents Department

Report on the test and evaluation of the Chaparral Physics Model 4.1.1 prototype microbarograph for CTBT infrasound array application

Description: The Sandia National Laboratories has tested and evaluated the Chaparral Physics Model 4.1.1 prototype infrasound sensor to CTBT specifications. The sensor was characterized by using a piston-phone chamber to set and measure sensor sensitivity. Multiple sensor side-by-side coherence analysis testing provided a measure of sensor relative gain and phase; sensor self-noise was computed using this technique. The performance of the sensor calibration circuitry was evaluated. Sensor performance was compared to CTBT specifications. The Chaparral sensor met or exceeded all CTBT specifications.
Date: January 1, 1998
Creator: Kromer, R.P. & McDonald, T.S.
Partner: UNT Libraries Government Documents Department

Progress report of FY 1998 activities: Continued development of an integrated sounding system in support of the DOE/ARM experimental program

Description: Both during September 15-30, 1996 and September 15-October 5, 1997, the Environmental Technology Laboratory (ETL) participated in an experiment at the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) site that was designed to study many of the ways that ARM is measuring water vapor. These experiments, called the Water Vapor Intensive Operating Periods (WVIOPs), produced some results of significant importance to ARM water vapor measurements. We have spent the major portion of this years activities in analyzing results of these experiments, and improving algorithms for improving the measurement of precipitable water vapor (PWV) from instruments available at ARM. The most important ARM instrument for this measurement continues to be the Microwave Radiometer (MWR). Measurements of water vapor at the North Slope of Alaska and Adjacent Arctic Ocean (NSA/AAO) CART site in Barrow, Alaska, area potential problem because of the difficulty of radiosondes to measure low amounts of vapor during cold and extremely dry conditions. The applicability of MWR scaling to radiosondes is questionable because of the low sensitivity of these instrument during dry conditions. It has been suggested by the ARM Instantaneous Radiative Flux Working Group and others that measurements of brightness temperature around 183 GHz could be used to scale during the coldest and driest periods. However, the millimeter wavelengths are vulnerable to cloud effects from both liquid and ice. We have participated in the planning and will participate in the Millimeter wave Arctic Experiment that will evaluate microwave and millimeter wave radiometers during extremely cold conditions. ETL has tested, both in an experiment at the Boulder Atmospheric Observatory and during the two Water Vapor Intensive Operating Periods in 1996 and 1997, a 5-mm scanning radiometer that measures low-altitude temperature profiles; both profiles of lapse rate and absolute temperature can be measured with the instrument. The technique ...
Date: September 6, 1998
Creator: Westwater, Edgeworth R.; Han, Yong & Leuskiy, Vladimir
Partner: UNT Libraries Government Documents Department

Progress report: Continued development of an integrated sounding system in support of the DOE/ARM experimental program

Description: From January 6 to February 28, 1993, the second phase of the Prototype Radiation Observation Experiment (PROBE) was conducted in Kavieng, Papua New Guinea. Data taken during PROBE included frequent radiosondes, 915 MHz Wind profiler/Radio Acoustic Sounding System (RASS) observations of winds and temperatures, and lidar measurements of cloud-base heights. In addition, a dual-channel Microwave Water Substance Radiometer (MWSR) at 23.87 and 31.65 GHz and a Fourier Transform Infrared Radiometer (FTIR) were operated. The FTIR operated between 500 and 2000 cm{sup -1} and measured some of the first high spectral resolution (1 cm{sup -1}) radiation data taken in the tropics. The microwave radiometer provided continuous measurements with 30-second resolution of precipitable water vapor (PWV) and integrated cloud liquid (ICL), the RASS measured virtual temperature profiles every 30 minutes, and the cloud lidar provided episodic measurements of clouds every minute. The RASS, MWSR, and FTIR data taken during PROBE were compared with radiosonde data. Broadband longwave and shortwave irradiance data and lidar data were used to identify the presence of cirrus clouds and clear conditions. Comparisons were made between measured and calculated radiance during clear conditions, using radiosonde data as input to a Line-By-Line Radiative Transfer Model. Comparisons of RASS-measured virtual temperature with radiosonde data revealed a significant cold bias below 500 m.
Date: September 6, 1996
Creator: Westwater, Edgeworth R.; Gage, Kenneth S.; Han, Yong; Shaw, Joseph A. & Churnside, Jim H.
Partner: UNT Libraries Government Documents Department

SURFACE ACOUSTIC WAVE MERCURY VAPOR SENSOR

Description: Sensor Research and Development Corporation (SRD) has been contracted to develop and deliver a prototype instrument capable of the in situ detection and measurement of low levels of gaseous mercury for use in thermal waste treatment continuous emissions monitoring. The goal is to develop a fast, simple, inexpensive and reliable in situ sensor instrument for detecting and monitoring vaporized mercury that should be able to react to low (less than 5 mg/m 3 ) levels of mercury vapor, should be site deployable and provide continuous data on either cumulative mercury exposure or instantaneous concentration. Over the course of the reporting period, sensor responses were measured and analyzed for a wide range of sensing film thicknesses, operating temperatures, and adhesion layers. From this data, an optimal combination of those parameters was chosen. The film was then incorporated into the SAW sensing element, and rigorous testing has begun. To date, sensor responses to wide concentration ranges (0.7 ppb to 500 ppb) have been measured. Furthermore, a contract modification to include measurement of total mercury (both in elemental and reacted forms) has been requested and is expected to be finalized before the end of November, 1998. Finally, plans have been made for initial visits to the TSCA facility in Oak Ridge, TN and the University of North Dakota�s EERC facility to gather information required for the construction of the prototype instrument and to discuss possible future collaborations and field testing.
Date: September 2, 1998
Creator: CARON, JOSHUA
Partner: UNT Libraries Government Documents Department

Sonic Temperature Sensor for Food Processing

Description: The lack of adequate temperature measurement is the major barrier to the development of more efficient and better quality food processing methods. The objective of the sonic temperature sensor for food processing project is to develop a prototype sensor system to noninvasively measure the interior temperature of particulate foods during processing. The development of the prototype sensor is a collaborative project with the National Food Processors Association. The project is based on the property of materials that involves a change in the temperature of a material having a corresponding change in the speed of sound. The approach for the sonic sensor system is to determine the speed of sound through particulate foods using a tomographic reconstruction process.
Date: September 1, 1997
Creator: Akers, D. W.; Porter, A. M. & Tow, D. M.
Partner: UNT Libraries Government Documents Department

Seismic monitoring of roadbeds for traffic flow, vehicle characterization, and pavement deterioration

Description: A road-side seismic monitoring system has been developed that includes not only instrumentation and fielding methods, but also data analysis methods and codes. The system can be used as either a passive or active monitoring system. In the passive mode, seismic signals generated by passing vehicles are recorded. Analysis of these signals provides information on the location, speed, length, and weight of the vehicle. In the active mode, designed for monitoring pavement degradation, a vibrating magnetostrictive source is coupled to the shoulder of the road and signals generated are recorded on the opposite side of the road. Analysis of the variation in surface wave velocity at various frequencies (dispersion) is used in an attempt to develop models of the near-surface pavement velocity structure. The monitoring system was tested at two sites in New Mexico, an older two-lane road and a newly-paved section of interstate highway. At the older site, the system was able to determine information about vehicle velocity, wheel-base length and weight. The sites showed significant differences in response and the results indicate the need for further development of the method to extract the most information possible for each site investigated.
Date: January 1, 1998
Creator: Elbring, G.J.; Ormesher, R.C. & Holcomb, D.J.
Partner: UNT Libraries Government Documents Department

Acoustic imaging of underground storage tank wastes

Description: Acoustics is a potential tool to determine the properties of high level wastes stored in Underground Storage Tanks. Some acoustic properties were successfully measured by a limited demonstration conducted in 114-TX. This accomplishment provides the basis for expanded efforts to qualify techniques which depend on the acoustic properties of tank wastes. This work is being sponsored by the Department of Energy under the Office of Science and Technology. In FY-1994, limited Tank Waste Remediation Systems EM-30 support was available at Hanford and Los Alamos National Laboratory. The Massachusetts Institute of Technology (MIT) and Earth Resources Laboratory (ERL) were engaged for analysis support, and Elohi Geophysics, Inc. for seismic testing services. Westinghouse-Hanford Company provided the testing and training, supplied the special engineering and safety analysis equipment and procedures, and provided the trained operators for the actual tank operations. On 11/9/94, limited in-tank tests were successfully conducted in tank 114-TX. This stabilized Single Shell Tank was reported as containing 16.8 feet of waste, the lower 6.28 feet of which contained interstitial liquid. Testing was conducted over the lower 12 feet, between two Liquid Observation Wells thirty feet apart. The ``quick-look`` data was reviewed on-site by MIT and Elohi.
Date: September 1, 1995
Creator: Mech, S.J.
Partner: UNT Libraries Government Documents Department

Improving Ventilation and Saving Energy: Relocatable ClassroomField Study Interim Report

Description: The primary goals of this research effort are to develop, evaluate, and demonstrate a very practical HVAC system for classrooms that consistently provides classrooms with the quantity of ventilation in current minimum standards, while saving energy, and reducing HVAC-related noise levels. This research is motivated by the public benefits of energy efficiency, evidence that many classrooms are under-ventilated, and public concerns about indoor environmental quality in classrooms. This report presents an interim status update and preliminary findings from energy and indoor environmental quality (IEQ) measurements in sixteen relocatable classrooms in California. The field study includes measurements of HVAC energy use, ventilation rates, and IEQ conditions. Ten of the classrooms were equipped with a new HVAC technology and six control classrooms were equipped with a standard HVAC system. Energy use and many IEQ parameters have been monitored continuously, while unoccupied acoustic measurements were measured in one of four planned seasonal measurement campaigns. Continuously monitored data are remotely accessed via a LonWorks{reg_sign} network and stored in a relational database at LBNL. Preliminary results are presented here.
Date: September 1, 2005
Creator: Apte, Michael G.; Buchanan, Ian S.; Faulkner, David; Hotchi,Toshifumi; Spears,Michael; Sullivan, Douglas P. et al.
Partner: UNT Libraries Government Documents Department

DEVELOPMENT OF AN EMAT IN-LINE INSPECTION SYSTEM FOR DETECTION, DISCRIMINATION, AND GRADING OF STRESS CORROSION CRACKING IN PIPELINES

Description: This report describes progress, experiments, and results for a project to develop a pipeline inline inspection tool that uses electromagnetic acoustic transducers (EMATs) to detect and grade stress corrosion cracking (SCC). There is a brief introduction that gives background material about EMATs and relevant previous Tuboscope work toward a tool. This work left various choices about the modes and transducers for this project. The experimental section then describes the lab systems, improvements to these systems, and setups and techniques to narrow the choices. Improvements, which involved transducer matching networks, better magnetic biasing, and lower noise electronics, led to improved signal to noise (SNR) levels. The setups permitted transducer characterizations and interaction measurements in plates with man-made cracks, pipeline sections with SCC, and a full pipe with SCC. The latter were done with a moveable and compact EMAT setup, called a lab mouse, which is detailed. Next, the results section justifies the mode and transducer choices. These were for magnetostrictive EMATs and the use of EMAT launched modes: SH0 (at 2.1 MHz-mm) and SV1 (at 3.9 MHz-mm). This section then gives details of measurements on these modes. The measurements consisted of signal to noise ratio, insertion loss, magnetic biasing sensitivities crack reflection and transmission coefficients, beam width, standoff and tilt sensitivities. For most of the measurements the section presents analysis curves, such as reflection coefficient versus crack depth. Some notable results for the chosen modes are: that acceptable SNRs were generated in a pipe with magnetostrictive EMATs, that optimum bias for magnetostrictive transmitters and receivers is magnetic saturation, that crack reflection and transmission coefficients from crack interactions agree with 2 D simulations and seem workable for crack grading, and that the mouse has good waveform quality and so is ready for exhaustive measurement EMAT scans of SCC interactions. This section also ...
Date: July 1, 2003
Creator: Aron, Jeff; Jon Gore, Roger Dalton; Eaton, Stuart; Bowles, Adrian; Thomas, Owen & Jarman, Tim
Partner: UNT Libraries Government Documents Department

Acoustic Doppler Current Profiler Surveys of Velocity Downstream of Albeni Falls Dam

Description: The U.S. Army Corps of Engineers (USACE), Seattle District, is studying the potential to locate fish bypass systems at Albeni Falls Dam. The USACE requested Pacific Northwest National Laboratory (PNNL) to survey velocity magnitude and direction in the dam tailrace. The empirical data collected will be used to support future numerical modeling, physical modeling, and evaluation of fish bypass system alternatives. In May 2010, PNNL conducted velocity surveys of the Albeni Falls Dam using a boat-mounted acoustic Doppler current profiler. The surveys were conducted over three days (May 25 through 27). During the survey period, total river discharge at the dam varied between 30.2 and 31.0 kcfs. A small amount of spill discharge, 2 kcfs, was present on two days (May 26 and 27). This report presents data plots showing measured velocity direction and magnitude averaged over the entire depth and over 5-ft depth increments from 5 to 30 ft.
Date: September 30, 2010
Creator: Perkins, William A.; Titzler, P. Scott; Richmond, Marshall C.; Serkowski, John A.; Kallio, Sara E. & Bellgraph, Brian J.
Partner: UNT Libraries Government Documents Department

Development of Millimeter-Wave Velocimetry and Acoustic Time-of-Flight Tomography for Measurements in Densely Loaded Gas-Solid Riser Flow

Description: The MFDRC was formed in 1998 to advance the state-of-the-art in simulating multiphase turbulent flows by developing advanced computational models for gas-solid flows that are experimentally validated over a wide range of industrially relevant conditions. The goal was to transfer the resulting validated models to interested US commercial CFD software vendors, who would then propagate the models as part of new code versions to their customers in the US chemical industry. Since the lack of detailed data sets at industrially relevant conditions is the major roadblock to developing and validating multiphase turbulence models, a significant component of the work involved flow measurements on an industrial-scale riser contributed by Westinghouse, which was subsequently installed at SNL. Model comparisons were performed against these datasets by LANL. A parallel Office of Industrial Technology (OIT) project within the consortium made similar comparisons between riser measurements and models at NETL. Measured flow quantities of interest included volume fraction, velocity, and velocity-fluctuation profiles for both gas and solid phases at various locations in the riser. Some additional techniques were required for these measurements beyond what was currently available. PNNL’s role on the project was to work with the SNL experimental team to develop and test two new measurement techniques, acoustic tomography and millimeter-wave velocimetry. Acoustic tomography is a promising technique for gas-solid flow measurements in risers and PNNL has substantial related experience in this area. PNNL is also active in developing millimeter wave imaging techniques, and this technology presents an additional approach to make desired measurements. PNNL supported the advanced diagnostics development part of this project by evaluating these techniques and then by adapting and developing the selected technology to bulk gas-solids flows and by implementing them for testing in the SNL riser testbed.
Date: April 1, 2007
Creator: Fort, James A.; Pfund, David M.; Sheen, David M.; Pappas, Richard A. & Morgen, Gerald P.
Partner: UNT Libraries Government Documents Department

Acoustic Telemetry Evaluation of Juvenile Salmonid Passage and Survival at John Day Dam with Emphasis on the Prototype Surface Flow Outlet, 2008

Description: The main purpose of the study was to evaluate the performance of Top Spill Weirs installed at two spillbays at John Day Dam and evaluate the effectiveness of these surface flow outlets at attracting juvenile salmon away from the powerhouse and reducing turbine passage. The Juvenile Salmonid Acoustic Telemetry System (JSATS) was used to estimate survival of juvenile salmonids passing the dam and also for calculating performance metrics used to evaluate the efficiency and effectiveness of the dam at passing juvenile salmonids.
Date: December 1, 2009
Creator: Weiland, Mark A.; Ploskey, Gene R.; Hughes, James S.; Deng, Zhiqun; Fu, Tao; Monter, Tyrell J. et al.
Partner: UNT Libraries Government Documents Department

Progress report of FY 1999 activities: The application of Kalman filtering to derive water vapor profiles from combined ground-based sensors: Raman lidar, microwave radiometers, GPS, and radiosondes

Description: Previously, the proposers have delivered to ARM a documented algorithm, that is now applied operationally, and which derives water vapor profiles from combined remote sensor measurements of water vapor radiometers, cloud-base ceilometers, and radio acoustic sounding systems (RASS). With the expanded deployment of a Raman lidar at the CART Central Facility, high quality, high vertical-resolution, water vapor profiles will be provided during nighttime clear conditions, and during clear daytime conditions, to somewhat lower altitudes. The object of this effort is to use Kalman Filtering, previously applied to the combination of nighttime Raman lidar and microwave radiometer data, to derive high-quality water vapor profiles, during non-precipitating conditions, from data routinely available at the CART site. Input data to the algorithm would include: Raman lidar data, highly quality-controlled data of integrated moisture from microwave radiometers and GPS, RASS, and radiosondes. While analyzing data obtained during the Water Vapor Intensive Operating Period'97 at the SGP CART site in central Oklahoma, several questions arose about the calibration of the ARM microwave radiometers (MWR). A large portion of this years effort was a thorough analysis of the many factors that are important for the calibration of this instrument through the tip calibration method and the development of algorithms to correct this procedure. An open literature publication describing this analysis has been accepted.
Date: September 10, 1999
Creator: Westwater, Edgeworth R. & Han, Yong
Partner: UNT Libraries Government Documents Department

Progress report of FY 1998 activities: The application of Kalman filtering to derive water vapor profiles from combined ground-based sensors: Raman lidar, microwave radiometers, GPS, and radiosondes

Description: Previously, the proposers have delivered to ARM a documented algorithm, that is now applied operationally, and which derives water vapor profiles from combined remote sensor measurements of water vapor radiometers, cloud-base ceilometers, and radio acoustic sounding systems (RASS). With the expanded deployment of a Raman lidar at the CART Central Facility, high quality, high vertical-resolution, water vapor profiles will be provided during nighttime clear conditions, and during clear daytime conditions, to somewhat lower altitudes. The object of this effort is to use Kalman Filtering, previously applied to the combination of nighttime Raman lidar and microwave radiometer data, to derive high-quality water vapor profiles, during non-precipitating conditions, from data routinely available at the CART site. Input data to the algorithm would include: Raman lidar data, highly quality-controlled data of integrated moisture from microwave radiometers and GPS, RASS, and radiosondes. The focus of this years activities has been on the intercomparison of data obtained during the Water Vapor Intensive Operating Period'97 at the SGP CART site in central Oklahoma.
Date: October 1, 1999
Creator: Westwater, Edgeworth R. & Han, Yong
Partner: UNT Libraries Government Documents Department

A Methodology to Integrate Magnetic Resonance and Acoustic Measurements for Reservoir Characterization

Description: The objective of this project was to develop an advanced imaging method, including pore scale imaging, to integrate NMR techniques and acoustic measurements to improve predictability of the pay zone in hydrocarbon reservoirs. This is accomplished by extracting the fluid property parameters using NMR laboratory measurements and the elastic parameters of the rock matrix from acoustic measurements to create poroelastic models of different parts of the reservoir. Laboratory measurement techniques and core imaging are being linked with a balanced petrographical analysis of the core and theoretical model.
Date: January 29, 2002
Creator: Parra, Jorge O.; Hackert, Chris L.; Collier, Hughbert A. & Bennett, Michael
Partner: UNT Libraries Government Documents Department

Progress report of FY 1997 activities: The application of Kalman filtering to derive water vapor profiles from combined ground-based sensors: Raman lidar, microwave radiometers, GPS, and radiosondes

Description: Previously, the proposers have delivered to ARM a documented algorithm, that is now applied operationally, and which derives water vapor profiles from combined remote sensor measurements of water vapor radiometers, cloud-base ceilometers, and radio acoustic sounding systems (RASS). With the expanded deployment of a Raman lidar at the CART Central Facility, high quality, high vertical-resolution, water vapor profiles will be provided during nighttime clear conditions, and during clear daytime conditions, to somewhat lower altitudes. The object of this proposal was to use Kalman Filtering, previously applied to the combination of nighttime Raman lidar and microwave radiometer data, to derive high-quality water vapor profiles, during non-precipitating conditions, from data routinely available at the CART site. Input data to the algorithm would include: Raman lidar data, highly quality-controlled data of integrated moisture from microwave radiometers and GPS, RASS, and radiosondes. The algorithm will include recently-developed quality control procedures for radiometers. The focus of this years activities has been on the intercomparison of data obtained during an intensive operating period at the SGP CART site in central Oklahoma.
Date: October 5, 1997
Creator: Westwater, Edgeworth R. & Han, Yong
Partner: UNT Libraries Government Documents Department