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Delnore, V. E.

Publications and source records attributed to Delnore, V. E..

Integrated display of multi-sensor geophysical and electromagnetic flight data

Low-altitude wind shear has been identified by several aviation interests as a significant hazard to the safety of flying. The hazard may be greatest when the wind shear is due to an unpredicted and short-lived microburst occurring in the immediate flight path of an aircraft during takeoff or landing. Researchers from the NASA Langley Research Center have investigated wind shear by developing a suite of remote sensing instruments and then using these instruments in an airborne wind shear detection flight program. Among these instruments were a Doppler radar, a lidar, and an infrared sensor; these were supported by in situ measurements of aircraft and environmental parameters and by ground-based Doppler radars. The basic problem addressed was the airborne detection and measurement of meteorologically-induced wind shear sufficiently ahead of the aircraft to allow avoidance. If the remote measurements of the shear and its associated radar reflectivity did not exceed set limits, the airplane then continued through the wind shear so that in situ measurements could be made for comparison. Initial detection and vectoring to the wind shear was normally given from a ground-based Doppler weather radar and most of the wind shear events were due to microbursts, both wet and dry. This paper considers the problems of sampling the wind shear event, time and space registration among the various sensors, coordination of the various sensors' beams and sampling volumes, and also various techniques for portraying the data, both for research and for presentation. Examples are given based on data from the 1991 and 1992 NASA/FAA wind shear flights, and the results and conclusions are generalized to other flight experiments involving multi-sensor electromagnetic data sets.

Delnore, V. E.

Wind shear detection. Forward-looking sensor technology

A meeting took place at NASA Langley Research Center in February 1987 to discuss the development and eventual use of forward-looking remote sensors for the detection and avoidance of wind shear by aircraft. The participants represented industry, academia, and government. The meeting was structured to provide first a review of the current FAA and NASA wind shear programs, then to define what really happens to the airplane, and finally to give technology updates on the various types of forward-looking sensors. This document is intended to informally record the essence of the technology updates (represented here through unedited duplication of the vugraphs used), and the floor discussion following each presentation. Also given are key issues remaining unresolved.

Bracalente, E. M.

Active and passive microwave measurements in Hurricane Allen

The NASA Langley Research Center analysis of the airborne microwave remote sensing measurements of Hurricane Allen obtained on August 5 and 8, 1980 is summarized. The instruments were the C-band stepped frequency microwave radiometer and the Ku-band airborne microwave scatterometer. They were carried aboard a NOAA aircraft making storm penetrations at an altitude of 3000 m and are sensitive to rain rate, surface wind speed, and surface wind vector. The wind speed is calculated from the increase in antenna brightness temperature above the estimated calm sea value. The rain rate is obtained from the difference between antenna temperature increases measured at two frequencies, and wind vector is determined from the sea surface normalized radar cross section measured at several azimuths. Comparison wind data were provided from the inertial navigation systems aboard both the C-130 aircraft at 3000 m and a second NOAA aircraft (a P-3) operating between 500 and 1500 m. Comparison rain rate data were obtained with a rain radar aboard the P-3. Evaluation of the surface winds obtained with the two microwave instruments was limited to comparisons with each other and with the flight level winds. Two important conclusions are drawn from these comparisons: (1) the radiometer is accurate when predicting flight level wind speeds and rain; and (2) the scatterometer produces well behaved and consistent wind vectors for the rain free periods.

Delnore, V. E.

The pushbroom microwave radiometer and aircraft measurement of soil moisture

Soil moisture has been identified as a controlling parameter in the occurrence of atmospheric variations and crop vigor. Evapotranspiration rates impact local temperature, precipitation and motion fields of the atmosphere. The multiple beam pushbroom microwave radiometer (MBPMR) is a candidate for moisture monitoring on the Earth Observation System. A prototype MBPMR has been devised for airborne technology evaluations of pushbroom scanning capabilities. The instrument scans at 1.4 GHz with a Diche radiometer. Test flights on a NASA aircraft with the antenna mounted on the bottom of the fuselage have generated soil moisture data over crop areas for which ground truth data were gathered. Large antennas deployed from the Orbiter could collect sufficient data for mapping the global soil moisture in 6 days.

Harrington, R. F.

Beaufort/Bering 1979 microwave remote sensing data catalog report, 14-24 March 1979

The airborne microwave remote sending measurements obtained by the Langley Research Center in support of the 1979 Sea-Ice Radar Experiment (SIRE) in the Beaufort and Bering Seas are discussed. The remote sensing objective of SIRE was to define correlations between both active and passive microwave signatures and ice phenomena assocated with practical applications in the Arctic. The instruments used by Langley during SIRE include the stepped frequency microwave radiometer (SFMR), the airborne microwave scatterometer (AMSCAT), the precision radiation thermometer (PRT-5), and metric aerial photography. Remote sensing data are inventoried and cataloged in a user-friendly format. The data catalog is presented as time-history plots when and where data were obtained as well as the sensor configuration.

Hirstein, W. S.

Greenland 1979 microwave remote sensing data catalog report, 14-15 October 1979

Microwave remote sensing measurements were cataloged for active and passive instruments in support of the 1979 Greenland Remote Sensing Experiment. Instruments used in this field experiment include the stepped frequency microwave radiometer (4 to 8 GHz) and the airborne microwave scatterometer (14.6 GHz). The microwave signature data are inventoried and cataloged in a user friendly format and are available on 9 track computer compatible tapes upon request.

Hennigar, H. F.

The study of mesoscale ocean winds

SAR data gathered over the U.S. East Coast are used to infer near-surface wind speed, using a simplified model to relate the strength of the 30 to 40 cm SAR backscatter to surface wind speed. It is found that the SAR backscatter is nearly isotropic with a wind speed exponent of 0.4. Using this exponent, the model is tested against an independent data set. Subsequent agreement between wind speeds simultaneously determined by SAR and the Seasat-A Satellite Scatterometer (SASS) is within 0.7 m/s rms. A one-dimensional Fourier transform of the SAR-derived wind field shows an increasing energy content in rough agreement with the Van der Hoven spectrum.

Jones, W. L.