Search NASA⌕ Search

SEARCH · Search NASA

Results for “severe storms”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17

Radar/radiometer facilities for precipitation measurements

The OSU ElectroScience Laboratory Radar/Radiometer Facilities are described. This instrumentation includes a high-resolution radar/radiometer system, a fully automated low-resolution radar system, and a small surveillance radar system. The high-resolution radar/radiometer system operates at 3, 9, and 15 GHz using two 9.1 m and one 4.6 m parabolic antennas, respectively. The low-resolution and surveillance radars operate at 9 and 15 GHz, respectively. Both the high- and low-resolution systems are interfaced to real-time digital processing and recording systems. This capability was developed for the measurement of the temporal and spatial characteristics of precipitation in conjunction with millimeter wavelength propagation studies utilizing the Advanced Technology Satellites. Precipitation characteristics derived from these measurements could also be of direct benefit in such diverse areas as: the atmospheric sciences, meteorology, water resources, flood control and warning, severe storm warning, agricultural crop studies, and urban and regional planning.

Hodge, D. B.↗

Meteorological measurements from satellite platforms

Quantitative exploitation of meteorological data from geosynchronous satellites is starting to move from the laboratory to operational practice. Investigations of the data applications portion of the total meteorological satellite system include: (1) tropospheric wind shear and the related severe storm circulations; (2) kinematic properties of the tropical atmosphere as derived from cloud motion vectors; (3) application of a geostationary satellite rake system to measurements of rainfall; and (4) pointing error analysis of geosynchronous satellites.

Suomi, V. E.↗

Overshooting thunderheads observed from ATS and Learjet

Overshooting tops of thunderstorms were photographed simultaneously from both ATS and a Learjet during the cloud-truth experiment over the Midwest in the Spring of 1972 and 1973. The characteristics of overshooting tops were studied in various time and space scales, revealing that the horizontal dimensions of overshooting tops vary between 1000 ft and about 10 miles. The period of overshooting turrets with horizontal dimensions of less than 1 mile is found to be comparable to the Brunt-Vaisalla frequency of gravity waves at the lowermost stratosphere. The up-and-down motion of an overshooting dome, consisting of a number of turrets, is much slower than that of individual turrets. It is assumed that the height of a dome is closely related to the intensity of the up and downdrafts beneath the dome. Emphasis is placed upon the importance of the investigation of overshooting domes toward the identification of severe storm characteristics from satellites.

Fujita, T. T.↗

Solar modulation of atmospheric electrification through variation of the conductivity over thunderstorms

Variations of the current in the global atmospheric electrical circuit can be produced through regulation of the resistance between the tops of thunderclouds and the ionosphere. Long-and short-term changes in the conductivity of this region occur due to changes in the ionization rate resulting from solar activity. Previous suggestions that the phenomena might be due to conductivity variations in the fair weather part of the world or an influx of space charge to the upper atmosphere are considered unlikely. It might be possible to test the proposed mechanism by measuring the temporal variation of the ionospheric potential during disturbed solar periods. Another approach would be to measure simultaneously the variation in ionization rate and electric current over thunder-storms. Several ways in which changes in atmospheric electrification might influence other meteorological phenomena are mentioned.

Markson, R.↗

Interactive image processing for meteorological applications at NASA/Goddard Space Flight Center

The meteorological data processing program at the space center is centered on the analysis of geostationary satellite data. Its objectives are to detect and predict severe storms, to improve short range and long range global numerical weather forecasting models, and to develop improved satellite systems. The Image Display and Manipulation System (IDAMS) for earth resources satellite data processing is described, as is the special purpose software package, METPAK, for performing meteorology operations on IDAMS. The Atmospheric and Oceanographic Information Processing System (AOIPS), a dual terminal multiprocessor is also described.

Billingsley, J. B.↗

Planetary meteorology - A new perspective on the earth's weather

Meteorological observations of other planets which may contribute to an understanding of the meteorological processes on the earth are discussed. The high solar input and extremely low rotation rate of Venus simplify the analysis of the interaction of solar energy with the atmosphere. The dust present in the atmosphere of Mars may provide a useful model for studying the effects of anthropogenic aerosols in the atmosphere of earth. Observations of Mars may also be expected to yield information on the evolution of severe storms and on atmospheric tides. The belts and zones in the Jovian atmosphere bear some similarities to cyclones on earth, although they are produced differently; careful modeling of Jupiter's atmosphere may cast light on terrestrial cyclonic activity.

Joels, K.↗

Distress detection, location, and communications using advanced space technology

This paper briefly introduces a concept for low-cost, global, day-night, all-weather disaster warning and assistance. Evolving, advanced space technology with passive radio frequency reflectors in conjunction with an imaging synthetic aperture radar is employed to detect, identify, locate, and provide passive communication with earth users in distress. This concept evolved from a broad NASA research on new global search and rescue techniques. Appropriate airborne radar test results from this research are reviewed and related to potential disaster applications. The analysis indicates the approach has promise for disaster communications relative to floods, droughts, earthquakes, volcanic eruptions, and severe storms.

Sivertson, W. E., Jr.↗

Investigations with satellite data. 2: Temperature retrievals

A method for retrieving atmospheric temperatures in a severe storm situation was investigated. Retrieval was accomplished through the aid of satellite radiance measurements and nearby radiosondes. A set of coefficients was derived which when multiplied by the measured radiances, yielded smaller temperature retrieval errors than the minimum-information retrieval method.

Fritz, S.↗

Weather assessment and forecasting

Data management program activities centered around the analyses of selected far-term Office of Applications (OA) objectives, with the intent of determining if significant data-related problems would be encountered and if so what alternative solutions would be possible. Three far-term (1985 and beyond) OA objectives selected for analyses as having potential significant data problems were large-scale weather forecasting, local weather and severe storms forecasting, and global marine weather forecasting. An overview of general weather forecasting activities and their implications upon the ground based data system is provided. Selected topics were specifically oriented to the use of satellites.

Source record↗

RF radiation from lightning

Radiation from lightning in the RF band from 3-300 MHz were monitored. Radiation in this frequency range is of interest as a potential vehicle for monitoring severe storms and for studying the lightning itself. Simultaneous measurements were made of RF radiation and fast and slow field changes. Continuous analogue recordings with a system having 300 kHz of bandwidth were made together with digital records of selected events (principally return strokes) at greater temporal resolution. The data reveal patterns in the RF radiation for the entire flash which are characteristic of flash type and independent of the frequency of observation. Individual events within the flash also have characteristic RF patterns. Strong radiation occurs during the first return strokes, but delayed about 20 micron sec with respect to the begining of the return stroke; whereas, RF radiation from subsequent return strokes tends to be associated with cloud processes preceding the flash with comparatively little radiation occurring during the return stroke itself.

Levine, D. M.↗

Studies of satellite support to weather modification in the western US region

The applications of meteorological satellite data to both summer and winter weather modification programs are addressed. Appraisals of the capability of satellites to assess seedability, to provide real-time operational support, and to assist in the post-experiment analysis of a seeding experiment led to the incorporation of satellite observing systems as a major component in the Bureau of Reclamations weather modification activities. Satellite observations are an integral part of the South Park Area cumulus experiment (SPACE) which aims to formulate a quantitative hypothesis for enhancing precipitation from orographically induced summertime mesoscale convective systems (orogenic mesoscale systems). Progress is reported in using satellite observations to assist in classifying the important mesoscale systems, and in defining their frequency and coverage, and potential area of effect. Satellite studies of severe storms are also covered.

Cotton, W. R.↗

Geosynchronous Microwave Atmospheric Sounding Radiometer (MASR) feasibility studies. Volume 1: Management summary

The mission of the microwave atmospheric sounding radiometer (MASR) is to collect data to aid in the observation and prediction of severe storms. The geosynchronous orbit allows the continuous atmospheric measurement needed to resolve mesoscale dynamics. The instrument may operate in conjunction with this document, Volume 1 - Management, which summarizes the highlights of final reports on both the radiometer instrument and antenna studies. The radiometer instrument summary includes a synopsis of Volume 2 - Radiometer Receiver Feasibility, including design, recommended configuration, performance estimates, and weight and power estimates. The summary of the antenna study includes a synopsis of Volume 3 - Antenna Feasibility, including preliminary design tradeoffs, performance of selected design, and details of the mechanical/thermal design.

Source record↗

Geosynchronous Microwave Atmospheric Sounding Radiometer (MASR) antenna feasibility study. Volume 3: Antenna feasibility

Antenna systems capable of operating with a multichannel microwave radiometer intended for mapping severe storm activity over patches on the surface of the earth 750 km square were compared. These systems included a paraboloidal reflector with an offset focal point feed, and a symmetrical Cassegrain reflector system. Both systems are acceptable from the point of view of beam efficiency, however, from the point of view of maintaining the required positional accuracies and surface tolerances, as well as from the point of view of manufacturability, cost effectiveness, and technical risk, the symmetrical Casegrain was selected as the preferred configuration. Performance characteristics were calculated and a mechanical design study was conducted to provide estimates of the technical risk, costs, and development time required for the construction of such an antenna system.

Villeneuve, A. T.↗

Classification and machine recognition of severe weather patterns

Forecasting and warning of severe weather conditions are treated from the vantage point of pattern recognition by machine. Pictorial patterns and waveform patterns are distinguished. Time series data on sferics are dealt with by considering waveform patterns. A severe storm patterns recognition machine is described, along with schemes for detection via cross-correlation of time series (same channel or different channels). Syntactic and decision-theoretic approaches to feature extraction are discussed. Active and decayed tornados and thunderstorms, lightning discharges, and funnels and their related time series data are studied.

Wang, P. P.↗

Satellite-based thunderstorm intensity parameters

Thunderstorm growth rates are investigated through use of infrared data furnished by the Synchronous Meteorological Satellite. Blackbody temperature isotherms provide an accurate method of delineating the areal expansion of cold areas; the blackbody temperature isotherms are valuable analytical tools even in cases when there is very little decrease with time of the minimum cloud top temperature. In an application of the severe storm monitoring technique, the origin of tornadoes is found to be closely linked to a rapid expansion of cold areas in seven out of eight cases.

Adler, R. F.↗

Thunderstorm-associated cloud motions as computed from 5-minute SMS pictures

The five-minute rapid-scan imagery from the Synchronous Meteorological Satellite is employed to study cloud motions associated with the Omaha tornado of May 6, 1975. Cloud-motion vectors derived from automated and man-machine interactive systems provide an account of the mesoscale phenomena. In addition to the geostationary satellite data, aerial photography obtained during a cloud-truth mission is used in the severe storm investigation. For tracking overland cumuli with short half-lives, a three-minute scan interval appears necessary for the satellite imagery.

Tecson, J. J.↗