Sentences with phrase «ice nuclei in»

These studies concern the formation of ice nuclei in supercooled vapours at low temperatures.

The presence of cloud condensation and ice nuclei in air parcels is tested by using cloud chambers in which controlled temperatures and relative humidities are specified.

Methods: Scientists have known since the 1940s that seeding with silver and lead iodide can produce artificial ice nuclei in cirrus clouds.

These studies concern the formation of ice nuclei in supercooled vapours at low temperatures.

Not exact matches

While in the air, he tested the samples to see whether he could make the dust particles in them create ice nuclei again, inside his instrument.

The ability to essentially re-create in the aircraft what the researchers believed was happening out in the cloud further confirmed that the dust particles were creating ice nuclei.

In the cool upper atmosphere, ice crystals would have formed around tiny nuclei of volcanic dust, before falling back to Earth.

The oxygen levels also varied in step with water levels as Rosetta flew around the comet, suggesting that ice and oxygen in 67P's atmosphere are coming from the same places in its nucleus.

Comet Siding Spring's nucleus — a nugget of ice and rock measuring no more than half a kilometer (about 1/3 mile)-- is small, but the coma is expansive, stretching out a million kilometers (more than 600,000 miles) in every direction.

This stunning achievement shows that, contrary to popular belief, the ice crystals that form in frozen tissue do not necessarily damage the cell nuclei that hold genetic material.

Circling the South Pole, ANITA's antennas will scan a million cubic kilometers of ice at a time, looking for the telltale radio waves emitted when an ultrahigh - energy neutrino hits a nucleus in ice.

Researchers from the IceCube project will place a string of Digital Optical Modules into this hole, which can detect the faint signal produced on the rare occasion when a neutrino collides directly with the nucleus of an atom in a molecule of ice.

When a neutrino collides with an atomic nucleus, a new particle called a muon is produced, which emits a faint blue glow in the transparent ice that the DOMs can detect.

ANITA will exploit a phenomenon known as the Askaryan effect, whereby high - energy neutrinos streaming through ice, salt or sand produce a cone of radio waves when they collide with a nucleus in the material.

The team found there were much fewer of these ice nuclei than there were actual ice crystals in the clouds.

Ice nuclei, a type of aerosol particle in the atmosphere, form the ice crystals in mixed - phase clouIce nuclei, a type of aerosol particle in the atmosphere, form the ice crystals in mixed - phase clouice crystals in mixed - phase clouds.

nucleus (in astronomy) The rocky body of a comet, sometimes carrying a jacket of ice or frozen gases.

Airborne particles in the form of naturally occurring dusts and human - produced aerosols can serve as ice nuclei, sites around which water vapor condenses into clouds.

The vapor pressure in equilibrium with supercooled droplets (liquid H2O) is higher than that in equilibrium with solid H2O at the same temperature, so liquid droplets will evaporate to feed deposition on an effective ice nucleus.

While cloud condensation nuclei are always readily available in the atmosphere, ice nuclei are often scarce.

In contrast to cloud condensation nuclei, the most effective ice nuclei are hydrophobic (having a low affinity for water) with molecular spacings and a crystallographic structure close to that of ice.

In addition, naturally occurring bacteria found in decayed leaf litter can serve as ice nuclei at temperatures of less than about − 4 °C (24.8 °FIn addition, naturally occurring bacteria found in decayed leaf litter can serve as ice nuclei at temperatures of less than about − 4 °C (24.8 °Fin decayed leaf litter can serve as ice nuclei at temperatures of less than about − 4 °C (24.8 °F).

It has empirically derived dependencies on the chemistry and surface area of multiple species of ice nucleus (IN) aerosols.

In a process called cloud seeding, silver iodide, with effective ice - nucleating temperatures of less than − 4 °C, has been used for years in attempts to convert supercooled water to ice crystals in regions with a scarcity of natural ice nucleIn a process called cloud seeding, silver iodide, with effective ice - nucleating temperatures of less than − 4 °C, has been used for years in attempts to convert supercooled water to ice crystals in regions with a scarcity of natural ice nuclein attempts to convert supercooled water to ice crystals in regions with a scarcity of natural ice nuclein regions with a scarcity of natural ice nuclei.

Contact and freezing nuclei, in contrast, are associated with the conversion of supercooled water to ice.

In the absence of any ice nuclei, the freezing of supercooled water droplets of a few micrometres in radius, in a process called homogeneous ice nucleation, requires temperatures at or lower than − 39 °C (− 38 °FIn the absence of any ice nuclei, the freezing of supercooled water droplets of a few micrometres in radius, in a process called homogeneous ice nucleation, requires temperatures at or lower than − 39 °C (− 38 °Fin radius, in a process called homogeneous ice nucleation, requires temperatures at or lower than − 39 °C (− 38 °Fin a process called homogeneous ice nucleation, requires temperatures at or lower than − 39 °C (− 38 °F).

Deposition nuclei are analogous to condensation nuclei in that water vapour directly deposits as ice crystals on the aerosol.

Including aggregation, in addition to quadrupled ice nucleus concentrations aloft or an ice nucleus reservoir below, allowed the simulations to roughly match the in situ properties when assuming the presence of low - density dendrites and their aggregates (Fig. 2).

We also note that agreement between observed and simulated ice crystal number concentrations in our study required the concentration of entrained ice nuclei to be much greater than the number concentration of ice crystals, which conflicts with studies that indicate that entrained ice nucleus concentrations are equal to in - cloud ice crystal concentrations.

However, we caution that these results do not imply that the ice formation problem is solved because several unique conditions favored agreement between simulated and observed ice crystal number concentrations in this case: overlying ice nucleus concentrations much greater than in - cloud ice crystal concentrations, very slow - falling ice crystals, and the possible presence of an ice nucleus reservoir below a decoupled surface layer.

The aircraft also made in situ measurements of cloud microphysics and ice nuclei, as well as meteorological state parameters and radiative fluxes, which were important study inputs.

We found that without crystal aggregation, our simulations using low - density dendrites were able to predominantly match the in situ measurements, but this rough match required either increasing the overlying ice nucleus concentration fourfold or assuming a reservoir of ice nuclei from the surface layer to be entrained from the underlying, decoupled surface layer (both conceivable; see paper for details).

However, past studies of such Arctic mixed - phase clouds have been unable to explain the measured abundance of ice crystals larger than 100 micrometers in maximum dimension (the size range where measurements are available), given observed environmental conditions and the measured concentrations of ice nuclei that could be entrained into the observed shallow cloud layers from aloft.

Simulations include possible quadrupled ice nucleus concentration aloft (top four panels; see paper for details) or a possible ice nucleus reservoir in the surface layer (bottom four panels).

On the other hand, if some of the anthropogenic aerosols act as ice nuclei, supercooled clouds could be converted into ice clouds by the glaciation indirect effect (Lohmann, 2002), resulting in more efficient precipitation formation.

Aerosols may influence climate in several ways: directly through scattering and absorbing radiation (see Aerosol — radiation interaction) and indirectly by acting as cloud condensation nuclei or ice nuclei, modifying the optical properties and lifetime of clouds (see Aerosol — cloud interaction).

Their freezing can either be triggered by aerosol particles acting as a so - called ice nuclei (IN), or occur homogeneously (without IN) at about − 38 ◦ C The goal of many laboratory studies was and is to assess the ice nucleation ability of selected aerosol particles of a... http://search.proquest.com/openview/421dd0783b387a8e030902328dcc6f23/1.pdf?pq-origsite=gscholar&cbl=105744

Interactions with the hydrological cycle, and additional impacts on the radiation budget, occur through the role of aerosols in cloud microphysical processes, as aerosol particles act as cloud condensation nuclei (CCN) and ice nuclei (INin cloud microphysical processes, as aerosol particles act as cloud condensation nuclei (CCN) and ice nuclei (ININ).

When endothermic reacting (toxic) ice nucleating materials are utilized on a massive scale for climate intervention / modification programs, convection is greatly impacted, too many condensation nuclei are present, and precipitation is generally greatly reduced (from what it would have otherwise been) in the core of the engineered chemical cool - down zones.