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Results for “CLOUD SEEDING”

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.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Monitor weather conditions for cloud seeding control

The author has identified the following significant results. The near real-time DCS platform data transfer to the time-share compare is a working reality. Six stations are now being automatically monitored and displayed with a system delay of 3 to 8 hours from time of data transmission to time of data accessibility on the computer. The DCS platform system has proven itself a valuable tool for near real-time monitoring of mountain precipitation. Data from Wolf Creek Pass were an important input in making the decision when to suspend seeding operations to avoid exceeding suspension criteria in that area. The DCS platforms, as deployed in this investigation, have proven themselves to be reliable weather resistant systems for winter mountain environments in the southern Colorado mountains.

Kahan, A. M.↗
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 NTRS1982

Clarification of confirmation in the FACE-2 experiment

Definitions of the data acquisition and interpretation goals which were sought in the Florida Area Cumulus Experiment (FACE) phase-II experiment as confirmation of results from FACE-I are presented. The FACE-1 trials in cloud seeding to increase rainfall were conducted in 1970, '71, '73, '75, and '76 and phase II proceeded from June 1978-August 1980. The data from the second set were to be treated with a block randomization scheme using the mean vector wind speed and direction and superposition of rainfall data, considering fixed and floating target clouds. A first level of probability was configured to eliminate cells from further investigation, and then two other levels are included in the analyses, each of continually increasing levels of likelihood. The instances of rainfall with seeding cover periods of either 60 or more or 60 or less seeding flares being ignited.

Woodley, W. L.↗
DOE OSTI2026

Large Aerosol Particles Favor Haze Conditions Through Limitations on Water Budget and Activation Kinetics

Experiments in the Pi Convection‐Cloud Chamber conducted by systematically changing the diameter of injected dry aerosol particles while holding the temperature difference constant demonstrate that dry diameter strongly influences the onset of haze‐dominated conditions. Two factors contribute: the system becomes water‐limited, resulting in reduction of supersaturation by growing aerosol particles to the activation diameter; and the activation process becomes kinetically limited. Dry aerosol diameter exerts a strong influence on activation time, with a power‐law exponent of 9/2. Kinetically limited activation occurs when the ratio of the activation and droplet residence times is greater than unity. The findings demonstrate that a haze‐dominated state, where cloud formation is suppressed, can be achieved not only with weak supersaturation forcing and high aerosol concentration but also with large, hygroscopic aerosol particles. These results have implications for cloud formation in polluted environments, fog development near the ocean, and hygroscopic cloud seeding.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

Atmospheric Composition and Radiative Forcing Effects due to UN International Ship Emissions Regulations (ACRUISE) Field Campaign Report

Aerosols, or atmospheric particulates, are long known to be able to seed clouds and modify their characteristics (e.g., cloud brightness, coverage, lifetime). However, the impact of aerosols on clouds is highly complex and non-linear. As a result, aerosol-cloud interaction remains the largest uncertainty in our understanding of the Earth’s radiative balance and in any future climate projections. Aerosols are also a principal component of air pollution and are known to adversely affect respiratory and cardiovascular health.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1972

Government and technological innovation - Weather modification as a case in point.

The principal technology on which all forms of intentional, local weather modification ultimately rest is that of cloud seeding. There are three primary milestones in the evolution of such a new technology including invention, development, and introduction to society on an operational basis. It is shown that government has been deeply involved in each of the first two phases of weather modification's evolution. The agencies involved include the military agencies, the Weather Bureau, the National Science Foundation, and the Bureau of Reclamation. It is pointed out that weather modification will require some unusually flexible and open administrative devices if it is to advance in the public interest.

Lambright, W. H.↗
NASA NTRS1975

Use of the LANDSAT-2 Data Collection System in the Colorado River Basin Weather Modification Program

The author has identified the following significant results. The LANDSAT data collection system has proven itself to be a valuable tool for control of cloud seeding operations and for verification of weather forecasts. These platforms have proven to be reliable weather resistant units suitable for the collection of hydrometeorological data from remote severe weather environments. The detailed design of the wind speed and direction system and the wire-wrapping of the logic boards were completed.

Kahan, A. M.↗
NASA NTRS1973

Use of meteorological satellite observations in weather modification programs

The potential value of weather satellite data in field operations of weather modification is appraised. It was found that satellites could play a useful role in operational weather modification projects, particularly in the recognition of treatment opportunities. Satellite cloud photographs and infrared observations appear promising in the identification of treatment opportunities in seeding orographic cloud systems for increased snowpack, in seeding convective clouds for increased rainfall, in identifying hail threats, and in tracking and observing hurricanes as an aid to timing and location of seeding treatments. It was concluded that the potential value of satellite data in the treatment and evaluation phases of operational projects is not as great as in the recognition of treatment opportunity.

Dennis, A. S.↗
DOE OSTI2026

Occurrence of seeding multi-layer clouds in the Arctic from ground-based observations

Studies of Arctic clouds often focus on low-level single-layer clouds (SLCs). Here, we use combined observations of soundings and cloud radar during the MOSAiC, ACSE, and AO2018 research cruises as well as from long-term observations at Ny-Ålesund, Svalbard and Utqiagvik, Alaska to investigate the occurrence of SLCs and multi-layer clouds (MLCs) in the Arctic and to assess the rate of ice-crystal seeding in cold MLCs. MOSAiC observations show cloudy conditions in between 70 % and 90 % of sounding-radar cases. SLCs show occurrence rates of 30 % to 40 % with the highest value of 45 % during October. Cold MLCs are most abundant from November to June (40 % to 55 % of cases). Seeding occurs in about half to two thirds of the identified cold MLCs during MOSAiC for which the sub-saturated layer extends between 100 and 1000 m. The seeding rate increases by as much as 20 percentage points as the assumed size of the falling ice crystals is increased from 100 to 400 µm. The observations reveal a stable rate of cloud-free conditions of around 20 % over the covered latitude range. Cloud occurrence during MOSAiC and at Ny-Ålesund in July, when the geographical distance between observations was minimal, shows reasonable agreement. Comparisons of MOSAiC and other research cruises to the central Arctic also indicate consistent occurrence rates of different cloud types despite the likely effect of year-to-year variability. The comparison of data from ship campaigns and land sites suggests that the latter are not necessarily a good indicator of cloud occurrence in the high Arctic.

Achtert, Peggy [Leipzig Univ. (Germany); Meteorolo↗
DOE OSTI2026

Polar primary aerosols across the ocean-sea ice-snow-atmosphere interface: From sources to impacts

Primary aerosols play a critical role in polar climate systems, influencing cloud formation, precipitation, radiative balance, and surface energy budgets. This paper provides a comprehensive synthesis of primary aerosol sources, transformation and removal processes, and broader atmospheric impacts in polar regions, emphasizing their links to ocean and sea ice biogeochemistry. These aerosols (including sea salt, primary organic aerosol, and primary biological aerosol particles) originate from marine and cryospheric environments and are emitted through physical processes, such as wave breaking, bubble bursting, and blowing snow. Emission sources include seawater, sea ice, snow, and freshwater from river discharge and glacial runoff. Once airborne, these particles can serve as a chemical reservoir, influencing atmospheric composition and reactivity, and as seeds for cloud droplet and ice crystal formation, influencing cloud microphysics and polar climate. Despite their importance, many of the processes governing primary aerosol emissions and transformations remain poorly constrained. The most pressing knowledge gaps pertain to emission processes, limited spatiotemporal observational coverage, instrumentation constraints, parameterization development, and the integration of interdisciplinary expertise. To improve our understanding of primary aerosol drivers and their response to climate, future research efforts should prioritize strategically coordinated and cross-disciplinary process studies, advancements in measurement technologies and coverage, and close collaboration between modelers and observational scientists to inform and refine model parameterizations. As polar regions continue to undergo profound changes marked by increased precipitation, reduced sea and land ice, freshening oceans, and shifting ecosystem dynamics, characterizing present-day primary aerosol populations is vital. Improved understanding will be essential for anticipating future changes in aerosol-radiation and aerosol-cloud interactions and their implications for polar and global climate systems.

Aerosol-cloud↗