Detailed wind and temperature profiles.
Temperature profiles and associated wind profiles obtained with Jimsphere/FPS-16 radar system at Cape Kennedy, discussing remote CAT detector assessment
Camp, D. W.↗
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Network ST radar and related measurements at Pennsylvania State University
Mesoscale meteorological measurements, analysis and prediction are some of the principal areas of research in the Department of Meteorology at Penn State. In anticipation of a staged turn-on of the three systems during the Summer and Fall of 1984, the nonconstruction-related efforts have focused on the software development necessary to allow essentially immediate use of network data. A 16-bit microcomputer has been programmed to serve as the network controller, communications interface and, at least for real-time purposes, the operational display system. Insofar as possible we have in this task built upon our substantial accumulated experience in working with the processing and display of Doppler sodar system signals. Once the radar-derived wind and turbulence profiles are communicated to the various interconnected Departmental computers they become just one component of a comprehensive data base which can be applied to a diverse set of ongoing basic and operational research programs.
Thomson, D. W.↗
Atmospheric Boundary Layer Sensors for Application in a Wake Vortex Advisory System
Remote sensing of the atmospheric boundary layer has advanced in recent years with the development of commercial off-the-shelf (COTS) radar, sodar, and lidar wind profiling technology. Radio acoustic sounding systems for vertical temperature profiles of high temporal scales (when compared to routine balloon soundings- (radiosondes) have also become increasingly available as COTS capabilities. Aircraft observations during landing and departures are another source of available boundary layer data. This report provides an updated assessment of available sensors, their performance specifications and rough order of magnitude costs for a potential future aircraft Wake Vortex Avoidance System (WakeVAS). Future capabilities are also discussed. Vertical profiles of wind, temperature, and turbulence are anticipated to be needed at airports in any dynamic wake avoidance system. Temporal and spatial resolution are dependent on the selection of approach and departure corridors to be protected. Recommendations are made for potential configurations of near-term sensor technologies and for testing some of the sensor systems in order to validate performance in field environments with adequate groundtruth.
Zak, J. Allen↗
Hydrometeor Size Distribution Measurements by Imaging the Attenuation of a Laser Spot
The optical extinction of a laser due to scattering of particles is a well-known phenomenon. In a laboratory environment, this physical principle is known as the Beer-Lambert law, and is often used to measure the concentration of scattering particles in a fluid or gas. This method has been experimentally shown to be a usable means to measure the dust density from a rocket plume interaction with the lunar surface. Using the same principles and experimental arrangement, this technique can be applied to hydrometeor size distributions, and for launch-pad operations, specifically as a passive hail detection and measurement system. Calibration of a hail monitoring system is a difficult process. In the past, it has required comparison to another means of measuring hydrometeor size and density. Using a technique recently developed for estimating the density of surface dust dispersed during a rocket landing, measuring the extinction of a laser passing through hail (or dust in the rocket case) yields an estimate of the second moment of the particle cloud, and hydrometeor size distribution in the terrestrial meteorological case. With the exception of disdrometers, instruments that measure rain and hail fall make indirect measurements of the drop-size distribution. Instruments that scatter microwaves off of hydrometeors, such as the WSR-88D (Weather Surveillance Radar 88 Doppler), vertical wind profilers, and microwave disdrometers, measure the sixth moment of the drop size distribution (DSD). By projecting a laser onto a target, changes in brightness of the laser spot against the target background during rain and hail yield a measurement of the DSD's second moment by way of the Beer-Lambert law. In order to detect the laser attenuation within the 8-bit resolution of most camera image arrays, a minimum path length is required. Depending on the intensity of the hail fall rate for moderate to heavy rainfall, a laser path length of 100 m is sufficient to measure variations in optical extinction using a digital camera. For hail fall only, the laser path may be shorter because of greater scattering due to the properties of hailstones versus raindrops. A photodetector may replace the camera in automated installations. Laser-based rain and hail measurement systems are available, but they are based on measuring the interruption of a thin laser beam, thus counting individual hydrometeors. These systems are true disdrometers since they also measure size and velocity. The method reported here is a simple method, requiring far less processing, but it is not a disdrometer.
Lane, John↗
The Microwave Radiative Properties of Falling Snow Derived from Nonspherical Ice Particle Models. Part II: Initial Testing Using Radar, Radiometer and In Situ Observations
In this study, two different particle models describing the structure and electromagnetic properties of snow are developed and evaluated for potential use in satellite combined radar-radiometer precipitation estimation algorithms. In the first model, snow particles are assumed to be homogeneous ice-air spheres with single-scattering properties derived from Mie theory. In the second model, snow particles are created by simulating the self-collection of pristine ice crystals into aggregate particles of different sizes, using different numbers and habits of the collected component crystals. Single-scattering properties of the resulting nonspherical snow particles are determined using the discrete dipole approximation. The size-distribution-integrated scattering properties of the spherical and nonspherical snow particles are incorporated into a dual-wavelength radar profiling algorithm that is applied to 14- and 34-GHz observations of stratiform precipitation from the ER-2 aircraft-borne High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) radar. The retrieved ice precipitation profiles are then input to a forward radiative transfer calculation in an attempt to simulate coincident radiance observations from the Conical Scanning Millimeter-Wave Imaging Radiometer (CoSMIR). Much greater consistency between the simulated and observed CoSMIR radiances is obtained using estimated profiles that are based upon the nonspherical crystal/aggregate snow particle model. Despite this greater consistency, there remain some discrepancies between the higher moments of the HIWRAP-retrieved precipitation size distributions and in situ distributions derived from microphysics probe observations obtained from Citation aircraft underflights of the ER-2. These discrepancies can only be eliminated if a subset of lower-density crystal/aggregate snow particles is assumed in the radar algorithm and in the interpretation of the in situ data.
Ice particles; Radiances; Radiative transfer; Airc↗
Atmospheric motion investigation for vapor trails and radio meteors
The dynamics are investigated of the lower thermosphere through comparison of optical observations of motions of ejected vapor trails with radar observations of motions of ionized meteor trails. In particular, the winds obtained from a series of vapor trail observations which occurred at Wallops Island, Virginia during the night of 14-15 December 1970 are to be compared with wind data deduced from radar observations of meteor trails during the same period. The comparison of these data is considered important for two reasons. First, the most widely used methods of measuring winds in the lower thermosphere are the vapor trails and the radar meteors. However, the two techniques differ markedly and the resultant sets of data have been analyzed and presented in different formats. Secondly, and possibly of greater immediate concern is the fact that the radar meteor method appears to be an appropriate approach to the synoptic measurement of winds. During the night of 14-15 December 1970, five vapor trails were ejected from Nike Apache rockets over Wallops Island, Virginia from 2208 EST through 0627 EST. The wind data which were obtained from these trails are presented, and features of the wind profiles which relate to the radar meteor trails results are discussed.
Bedinger, J.↗
The INSU and DMN network of ST radars
Due to their capabilities of measuring wind profiles with good time and height resolution, Stratosphere-Troposphere (ST) are well adapted to carry out atmospheric research. In France, a Very High Frequency (VHF) and an Ultrahigh Frequency (UHF) ST radar are working for research purposes. The INSU (Institut National des Sciences de l'Univers) and the DMN (Direction de la Meteorologie Nationale) networks are discussed.
Petitdidier, M.↗
Radar - ARL Wind Profilerwith RASS, Boardman - Reviewed Data
Wind Profiler with Radio Acoustic Sounding System (RASS) data.
17 WIND ENERGY↗
Special observations
The wind or temperature profiler is a new special observation device designed to supplement traditional atmospheric measurement and provide more accurate middle-range forecasts, including aviation and space applications. Radar is most useful in the short, nowcast time frame. Satellites and surface observations are also most useful for short-range forecasts but have less impact on the longer range. The radiosonde network, on the other hand, only starts to be very important after about six hours and has greatest impact at lead times of 12 hours or more. In the wind profiler, wind is measured by using clear-air Doppler radar principles, Two fixed beams, pointing 15 deg to the north and 15 deg to the east, sense the Doppler shift. The resulting wind vectors are then rotated to the horizontal and combined to give total wind. The temperature profiler measures temperature and humidity by using passive radiometers. Development on the profiler is 95 percent complete, and on the temperature profiler 75 percent complete.
Beran, Donald↗
High resolution vertical profiles of wind, temperature and humidity obtained by computer processing and digital filtering of radiosonde and radar tracking data from the ITCZ experiment of 1977
Results are presented from computer processing and digital filtering of radiosonde and radar tracking data obtained during the ITCZ experiment when coordinated measurements were taken daily over a 16 day period across the Panama Canal Zone. The temperature relative humidity and wind velocity profiles are discussed.
Danielson, E. F.↗
Adaptation of Mesoscale Weather Models to Local Forecasting
Methodologies have been developed for (1) configuring mesoscale numerical weather-prediction models for execution on high-performance computer workstations to make short-range weather forecasts for the vicinity of the Kennedy Space Center (KSC) and the Cape Canaveral Air Force Station (CCAFS) and (2) evaluating the performances of the models as configured. These methodologies have been implemented as part of a continuing effort to improve weather forecasting in support of operations of the U.S. space program. The models, methodologies, and results of the evaluations also have potential value for commercial users who could benefit from tailoring their operations and/or marketing strategies based on accurate predictions of local weather. More specifically, the purpose of developing the methodologies for configuring the models to run on computers at KSC and CCAFS is to provide accurate forecasts of winds, temperature, and such specific thunderstorm-related phenomena as lightning and precipitation. The purpose of developing the evaluation methodologies is to maximize the utility of the models by providing users with assessments of the capabilities and limitations of the models. The models used in this effort thus far include the Mesoscale Atmospheric Simulation System (MASS), the Regional Atmospheric Modeling System (RAMS), and the National Centers for Environmental Prediction Eta Model ( Eta for short). The configuration of the MASS and RAMS is designed to run the models at very high spatial resolution and incorporate local data to resolve fine-scale weather features. Model preprocessors were modified to incorporate surface, ship, buoy, and rawinsonde data as well as data from local wind towers, wind profilers, and conventional or Doppler radars. The overall evaluation of the MASS, Eta, and RAMS was designed to assess the utility of these mesoscale models for satisfying the weather-forecasting needs of the U.S. space program. The evaluation methodology includes objective and subjective verification methodologies. Objective (e.g., statistical) verification of point forecasts is a stringent measure of model performance, but when used alone, it is not usually sufficient for quantifying the value of the overall contribution of the model to the weather-forecasting process. This is especially true for mesoscale models with enhanced spatial and temporal resolution that may be capable of predicting meteorologically consistent, though not necessarily accurate, fine-scale weather phenomena. Therefore, subjective (phenomenological) evaluation, focusing on selected case studies and specific weather features, such as sea breezes and precipitation, has been performed to help quantify the added value that cannot be inferred solely from objective evaluation.
Manobianco, John T.↗
High resolution system for upper air (troposphere) wind and temperature profile measurements
The Jimsphere/Jimsonde system is described and some possible applications of the system for air-sea interface measurements are presented. As space vehicles became larger and more sophisticated, an improved method for obtaining wind profile data had to be found. To satisfy this need the FPS-16 radar/Jimsphere system was developed. The Jimsphere is an aluminized mylar spherical balloon, two meters in diameter. The balloon is under superpressure, and is tracked with a high precision radar system. The development of this detailed wind profile system was started in 1963, and the present design was established in 1964. To improve the system, a program was initiated in 1965 to obtain high resolution temperature data simultaneously with the wind profile data.
Camp, D. W.↗
Use of ground-based wind profiles in mesoscale forecasting
A brief review is presented of recent uses of ground-based wind profile data in mesoscale forecasting. Some of the applications are in real time, and some are after the fact. Not all of the work mentioned here has been published yet, but references are given wherever possible. As Gage and Balsley (1978) point out, sensitive Doppler radars have been used to examine tropospheric wind profiles since the 1970's. It was not until the early 1980's, however, that the potential contribution of these instruments to operational forecasting and numerical weather prediction became apparent. Profiler winds and radiosonde winds compare favorably, usually within a few m/s in speed and 10 degrees in direction (see Hogg et al., 1983), but the obvious advantage of the profiler is its frequent (hourly or more often) sampling of the same volume. The rawinsonde balloon is launched only twice a day and drifts with the wind. In this paper, I will: (1) mention two operational uses of data from a wind profiling system developed jointly by the Wave Propagation and Aeronomy Laboratories of NOAA; (2) describe a number of displays of these same data on a workstation for mesoscale forecasting developed by the Program for Regional Observing and Forecasting Services (PROFS); and (3) explain some interesting diagnostic calculations performed by meteorologists of the Wave Propagation Laboratory.
Schlatter, Thomas W.↗
Wind Retrieval Algorithms for the IWRAP and HIWRAP Airborne Doppler Radars with Applications to Hurricanes
Algorithms for the retrieval of atmospheric winds in precipitating systems from downward-pointing, conically-scanning airborne Doppler radars are presented. The focus in the paper is on two radars: the Imaging Wind and Rain Airborne Profiler(IWRAP) and the High-altitude IWRAP (HIWRAP). The IWRAP is a dual-frequency (Cand Ku band), multi-beam (incidence angles of 30 50) system that flies on the NOAAWP-3D aircraft at altitudes of 2-4 km. The HIWRAP is a dual-frequency (Ku and Kaband), dual-beam (incidence angles of 30 and 40) system that flies on the NASA Global Hawk aircraft at altitudes of 18-20 km. Retrievals of the three Cartesian wind components over the entire radar sampling volume are described, which can be determined using either a traditional least squares or variational solution procedure. The random errors in the retrievals are evaluated using both an error propagation analysis and a numerical simulation of a hurricane. These analyses show that the vertical and along-track wind errors have strong across-track dependence with values of 0.25 m s-1 at nadir to 2.0 m s-1 and 1.0 m s-1 at the swath edges, respectively. The across-track wind errors also have across-track structure and are on average, 3.0 3.5 m s-1 or 10 of the hurricane wind speed. For typical rotated figure four flight patterns through hurricanes, the zonal and meridional wind speed errors are 2 3 m s-1.Examples of measured data retrievals from IWRAP during an eyewall replacement cycle in Hurricane Isabel (2003) and from HIWRAP during the development of Tropical Storm Matthew (2010) are shown.
atmospheric winds↗
Scientific reasons for a network of ST radars and cooperative campaigns
Due to their capabilities of measuring wind profiles in the troposphere and stratosphere with good time and height resolution, whatever the weather conditions, stratosphere-troposphere (ST) radars are well adapted to carry out atmospheric research in many fields as well as to fulfill the meteorological forecasting needs. Examples are presented from previous and future national or international campaigns planned in France. The ST radars were used first by themselves with the adjunction of radiosonde data. Then networks were built and used to get horizontal parameters. It appears that ST radar networks should naturally be included in cooperative campaigns.
Petitdidier, M.↗
Generation of pseudo-waves in the middle atmosphere by flow accelerations due to breaking gravity waves?
Low frequency, large amplitude waves are often observed at mesospheric heights in radar and lidar wind measurements. A series of individual profiles of 1-hr averages of velocity data that were taken in October 1981 using the MST radar at Poker Flat, Alaska are presented. The vertical wavelength of this wave-like event is about 15 km and has a period close to 10 hours. A clear downward phase propagation can be seen, and so these oscillations are usually, and probably correctly, interpreted as being gravity wave flow perturbations. We investigate an alternative explanation that may also be possible; specifically, we investigate the possibility that the perturbed flow is a pseudo-wave structure produced by mean flow acceleration due to gravity waves propagating upward from below and breaking in the mesosphere. The question is whether effects similar to those that produce the much longer period Quasi-Biennial Oscillation (QBO) in the equatorial stratosphere can produce mesospheric pseudo-waves (MPW) at much shorter periods.
Jacobson, Raymond A.↗
Improved Hurricane Boundary Layer Observations with the Imaging Wind and Rain Airborne Profiler
During the NOAA/NESDIS 2005 Hurricane Season (HS2005) and the 2006 Winter Experiment, the University of Massachusetts (UMass) installed two instruments on the NOAA N42RF WP-3D research aircraft: the Imaging Wind and Rain Airborne Profiler (IWRAP) and the Simultaneous Frequency Microwave Radiometer (SFMR). IWRAP is a dual-band (C- and Ku), dual-polarized pencil-beam airborne radar that profiles the volume backscatter and Doppler velocity from rain and that also measures the ocean backscatter response. It simultaneously profiles along four separate incidence angles while conically scanning at 60 RPM. SFMR is a C-band nadir viewing radiometer that measures the emission from the ocean surface and intervening atmosphere simultaneously at six frequencies. It is designed to obtain the surface wind speed and the column average rain rate. Both instruments have previously been flown during the 2002, 2003 and 2004 hurricane seasons. For the HS2005, the IWRAP system was modified to implement a raw data acquisition system. The importance of the raw data system arises when trying to profile the atmosphere all the way down to the surface with a non-nadir looking radar system. With this particular geometry, problems arise mainly from the fact that both rain and ocean provide a return echo coincident in time through the antenna s main lobe. This paper shows how this limitation has been removed and presents initial results demonstrating its new capabilities to derive the atmospheric boundary layer (ABL) wind field within the inner core of hurricanes to much lower altitudes than the ones the original system was capable of, and to analyze the spectral response of the ocean backscatter and the rain under different wind and rain conditions.
tropical cyclones↗
High-resolution system for tropospheric wind and temperature profile measurements
This paper briefly describes the Jimsphere/Jimsonde system and presents some possible applications of the system. As space vehicles became larger and more sophisticated, an improved method for obtaining wind-profile data had to be found. To satisfy this need, the FPS-16 radar/Jimsphere system was developed. The Jimsphere is an aluminized mylar spherical balloon 2 m in diameter. The balloon is under superpressure and is tracked with a high-precision radar system. The development of this detailed wind-profile system was started in 1963, and the present design was established in 1964. To improve the system, a program was initiated in 1965 to obtain high-resolution temperature data simultaneously with the wind-profile data.
Camp, D. W.↗