Results for “weathering” — Page 50

DOE OSTI2025

Synoptic Weather Regime Classifications for March, April and May, from 2000 to 2025

The synoptic weather regime classification has become a highly demanded product for the ARM site in recent years. This type of regime classification has shown applications in various studies and topics, including aerosol-cloud interactions, land-atmosphere interactions, and cloud radiative effects. The VAP employs an unsupervised machine learning method, Self-organizing map (SOM), to classify weather regimes for each day of the AMF campaigns and fixed sites, using ERA5 data. This idea is mainly based on our published study for TRACER in Wang et al. (2022, JGR-A).

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DOE OSTI2025

Synoptic Weather Regime Classifications for June, July and August, from 2000 to 2025

The synoptic weather regime classification has become a highly demanded product for the ARM site in recent years. This type of regime classification has shown applications in various studies and topics, including aerosol-cloud interactions, land-atmosphere interactions, and cloud radiative effects. The VAP employs an unsupervised machine learning method, Self-organizing map (SOM), to classify weather regimes for each day of the AMF campaigns and fixed sites, using ERA5 data. This idea is mainly based on our published study for TRACER in Wang et al. (2022, JGR-A).

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DOE OSTI2025

Synoptic Weather Regime Classifications for December, January and February, from 2000 to 2025

The synoptic weather regime classification has become a highly demanded product for the ARM site in recent years. This type of regime classification has shown applications in various studies and topics, including aerosol-cloud interactions, land-atmosphere interactions, and cloud radiative effects. The VAP employs an unsupervised machine learning method, Self-organizing map (SOM), to classify weather regimes for each day of the AMF campaigns and fixed sites, using ERA5 data. This idea is mainly based on our published study for TRACER in Wang et al. (2022, JGR-A).

{node_som_ml,synop_wea_reg}↗

DOE OSTI2025

Synoptic Weather Regime Classifications for September, October and November, from 2000 to 2025

The synoptic weather regime classification has become a highly demanded product for the ARM site in recent years. This type of regime classification has shown applications in various studies and topics, including aerosol-cloud interactions, land-atmosphere interactions, and cloud radiative effects. The VAP employs an unsupervised machine learning method, Self-organizing map (SOM), to classify weather regimes for each day of the AMF campaigns and fixed sites, using ERA5 data. This idea is mainly based on our published study for TRACER in Wang et al. (2022, JGR-A).

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NASA NTRS1972

Potential value of satellite cloud pictures in weather modification projects

Satellite imagery for one project season of cloud seeding programs in the northern Great Plains has been surveyed for its probable usefulness in weather modification programs. The research projects and the meteorological information available are described. A few illustrative examples of satellite imagery analysis are cited and discussed, along with local observations of weather and the seeding decisions made in the research program. This analysis indicates a definite correlation between satellite-observed cloud patterns and the types of cloud seeding activity undertaken, and suggests a high probability of better and/or earlier decisions if the imagery is available in real time. Infrared imagery provides better estimates of cloud height which can be useful in assessing the possibility of a hail threat. The satellite imagery appears to be of more value to area-seeding projects than to single-cloud seeding experiments where the imagery is of little value except as an aid in local forecasting and analysis.

Biswas, K. R.↗

NASA NTRS1973

Solar activity and the weather

Some evidence that the weather is influenced by solar activity is reviewed. It appears that the solar magnetic sector structure is related to the circulation of the earth's atmosphere during local winter. About 31/2 days after the passage of a sector boundary the maximum effect is seen: apparently the height of all pressure surfaces increases in high latitudes leading to anticyclogenesis, whereas at midlatitudes the height of the pressure surfaces decreases leading to low pressure systems or to deepening of existing systems. This later effect is clearly seen as an increase in the area of the base of air with absolute vorticity exceeding a given threshold. Since the increase of geomagnetic activity generally is small at a sector boundary, it is speculated that geomagnetic activity as such is not the cause of the response to the sector structure, but that both weather and geomagnetic activity are influenced by the same (unknown) mechanism.

Svalgaard, L.↗

NASA NTRS1973

Losses due to weather phenomena in the bituminous concrete construction industry in Wisconsin

The losses (costs) due to weather phenomena as they affect the bituminous concrete industry in Wisconsin were studied. The bituminous concrete industry's response to precipitation, in the form of rain, is identified through the use of a model, albeit crude, which identifies a typical industry decision-response mechanism. Using this mechanism, historical weather data and 1969 construction activity, dollar losses resulting from rain occurrences were developed.

Kuhn, H. A. J.↗

NASA NTRS1974

Salt weathering on Mars

Mariner 9 photographs of Mars indicate that significant erosion has occurred on that planet. Although several possible erosion mechanisms have been proposed, most terrestrial weathering mechanisms cannot function in the present Martian environment. Salt weathering, believed to be active in the Antarctic dry valleys, is especially suited to Mars, given the presence of salts and small amounts of water. Volcanic salts are probably available, and the association of salts and water is likely from both thermodynamic and geologic considerations.

Malin, M. C.↗

NASA NTRS1974

Systems Study of an Automated Fire Weather Data System

A sensor system applicable to an automated weather station was developed. The sensor provides automated fire weather data which correlates with manual readings. The equipment and methods are applied as an aid to the surveillance and protection of wildlands from fire damage. The continuous readings provided by the sensor system make it possible to determine the periods of time that the wilderness areas should be closed to the public to minimize the possibilities of fire.

Nishioka, K.↗

NASA NTRS1975

Great Lakes all-weather ice information system

A system is described which utilizes an X-band Side-Looking-Airborne-Radar (SLAR) for determining type, location, and aerial distribution of the ice cover in the Great Lakes and an airborne, S-band, short pulse radar for obtaining ice thickness. The SLAR system is currently mounted aboard a U.S. Coast Guard C-130B aircraft. Digitized SLAR data are relayed in real-time via the NOAA-GOES-1 satellite in geosynchronous orbit to the U.S. Coast Guard Ice Center in Cleveland, Ohio. SLAR images along with hand-drawn interpretative ice charts for various winter shipping areas in the Great Lakes are broadcast to facsimile recorders aboard Great Lakes vessels. The operational aspects of this ice information system are being demonstrated by NASA, U.S. Coast Guard, and NOAA/National Weather Service. Results from the 1974-75 winter season demonstrated the ability of this system to provide all-weather ice information to shippers in a timely manner.

Schertler, R. J.↗

NASA NTRS1974

Solar activity and the weather

Some new evidence that the weather is influenced by solar activity is reviewed. It appears that the solar magnetic sector structure is related to the circulation of the earth's atmosphere during local winter. About 3 1/2 days after the passage of a sector boundary the maximum effect is seen; apparently the height of all pressure surfaces increases in high latitudes leading to anticyclogenesis, whereas at midlatitudes the height of the pressure surfaces decreases leading to low pressure systems or to deepening of existing systems. This later effect is clearly seen as an increase in the area of the base of air with absolute vorticity exceeding a given threshold. Since the increase of geomagnetic activity generally is small at a sector boundary it is speculated that geomagnetic activity as such is not the cause of the response to the sector structure but that both weather and geomagnetic activity are influenced by the same (unknown) mechanism.

Svalgaard, L.↗

NASA NTRS1974

Satellite observations of weather and climate

The SEASAT-A program is viewed as a new way to obtain atmospheric observations for weather and climatic studies in the framework of the Global Atmospheric Research Program (GARP). Total information derived from SEASAT-A sensor package provides a synoptic picture of the upper parts of the world's oceans as a prerequisite to the development of dynamic ocean models and combined ocean/atmospheric models for weather forecasting requirements.

Kellogg, W. W.↗

NASA NTRS1976

Solar structure and terrestrial weather

The possibility that solar activity has discernible effects on terrestrial weather is considered. Research involving correlation of weather conditions with solar and geomagnetic activity is discussed.

Wilcox, J. M.↗

NASA NTRS1976

Some effects of adverse weather conditions on performance of airplane antiskid braking systems

The performance of current antiskid braking systems operating under adverse weather conditions was analyzed in an effort to both identify the causes of locked-wheel skids which sometimes occur when the runway is slippery and to find possible solutions to this operational problem. This analysis was made possible by the quantitative test data provided by recently completed landing research programs using fully instrumented flight test airplanes and was further supported by tests performed at the Langley aircraft landing loads and traction facility. The antiskid system logic for brake control and for both touchdown and locked-wheel protection is described and its response behavior in adverse weather is discussed in detail with the aid of available data. The analysis indicates that the operational performance of the antiskid logic circuits is highly dependent upon wheel spin-up acceleration and can be adversely affected by certain pilot braking inputs when accelerations are low. Normal antiskid performance is assured if the tire-to-runway traction is sufficient to provide high wheel spin-up accelerations or if the system is provided a continuous, accurate ground speed reference. The design of antiskid systems is complicated by the necessity for tradeoffs between tire braking and cornering capabilities, both of which are necessary to provide safe operations in the presence of cross winds, particularly under slippery runway conditions.

Horne, W. B.↗

NASA NTRS1975

Observation of severe weather activities by Doppler sounder array

A three-dimensional, nine-element, high-frequency CW Doppler sounder array has been used to detect ionospheric disturbances during periods of severe weather, particularly during periods with severe thunderstorms and tornadoes. One typical disturbance recorded during a period of severe thunderstorm activity and one during a period of tornado activity have been chosen for analysis in this note. The observations indicate that wave-like disturbances possibly generated by the severe weather have wave periods in the range 2-8 min which place them in the infrasonic wave category.

Smith, R. E.↗

NASA NTRS1975

Great Lakes all-weather ice information system

The all-weather ice information system described uses the X-band side-looking airborne radar to determine the aerial distribution, location, and type of ice cover in the Great Lakes and an airborne S-band short-pulse radar to determine the ice thickness. Results from the 1974-1975 winter season demonstrated the ability of the system to provide all-weather ice information to shippers at the required time.

Schertler, R. J.↗

NASA NTRS1976

Al-26 losses from weathered chondrites

Analysis of Al-26 and noble gases were conducted in a study of samples of two heavily weathered meteorites. The analyses were performed in accordance with procedures described by Cressy (1970) and by Herzog and Cressy (1974). The analytic data are presented in tables. Evidence is presented which implicates weathering as the most probable cause of the observed variation of Al-26 and the rare gas contents.

Herzog, G. F.↗

NASA NTRS1978

Inertially-aided, all-weather landing systems for C/TOL

Ways to improve significantly all-weather landing systems technology for conventional take-off and landing vehicles, primarily, the large commercial jets, were studied. It was concluded that there is a great deal to be gained by extensive use of inertial navigation system derived information, primarily, the translational information inherent in an inertial navigator, for improving all-weather landing system performance.

Pawlak, R. J.↗