Sentences with phrase «polar stratospheric»

This could enhance the formation of polar stratospheric clouds, which convert potential ozone - depleting species to their active forms.

Ozone recovery in the tropical stratosphere is expected to be faster and the recovery of the polar ozone hole is expected to be slower because of the CO2 - induced cooling of the stratosphere (and increase the number of polar stratospheric clouds).

Shindell, D.T., D. Rind, and P. Lonergan, 1998: Increased polar stratospheric ozone losses and delayed eventual recovery owing to increasing greenhouse - gas concentrations.

PSC = polar stratospheric cloud?

The process occurs most readily at temperatures below -77 C, at which point a polar stratospheric cloud can develop (UNEP image below).

Consequently, both the solar irradiance and the CR flux appear unconnected to these polar stratospheric cloud changes.

Dubbed «mother - of - pearl» clouds because of their attractive appearance, polar stratospheric clouds form at temperatures below -78 ° C.

An unusual persistence of cold temperatures in the stratosphere into March, allowing longer lifetimes for the polar stratospheric clouds that enable conversion of pollutant gases into ozone - destroying chlorine.

Thus, we come to a dead end: calculations of nucleation become impossible below Tlim with Boltzmann statistics although many cirrus clouds may form at these T (especially in the tropics), polar stratospheric clouds, playing important role in ozone depletion, noctilucent and mesospheric clouds form at even lower T. Vitaly Khvorostyanov

Simple and comprehensive general circulation models (GCMs) indicate that the Hadley cell may widen in response to global warming, warming of the west Pacific, or polar stratospheric cooling.

But it does happen whenever temperatures get cold enough for polar stratospheric clouds to form.

Increased polar stratospheric ozone losses and delayed eventual recovery due to increasing greenhouse gas concentrations.

In the 1980s, Antarctic researchers discovered that these chemical reactions went into overdrive in the super-cold polar stratospheric clouds that formed over the frozen continent.

But last year, Susan Solomon of MIT — who back in the 1980s became one of the world's most celebrated scientists for uncovering the chemistry of the polar stratospheric clouds — declared that she had detected the first «fingerprints» of the hole closing.

Ozone holes are caused by chemical reactions that take place primarily on the surface of polar stratospheric clouds, ice particles, or liquid droplets, which form at high altitudes in the extreme cold of the polar regions.

The stable air that causes the ultra-cold conditions where polar stratospheric clouds form in Antarctica is much less likely.

In both the past two winters, researchers saw polar stratospheric clouds over parts of Britain, said Jonathan Shanklin of the British Antarctic Survey.

It is caused by chemical reactions that take place primarily on the surface of polar stratospheric clouds, ice particles or liquid droplets which form at high altitudes in extreme cold.

Unusually low temperatures in the stratosphere, even cold records, are at fault — creating conditions whereby ice crystals form in so called polar stratospheric clouds.

Subsequently it was shown variation was due to a combination of variation in UV, extremely cold temperatures, formation of polar stratospheric clouds (PSC) and intense atmospheric circulation.

Orton, G. S, L. N. Fletcher, J. Liu, T. Schneider, P. A. Yanamandra - Fisher, I. de Pater, M. Edwards, T. R. Geballe, H. B. Hammel, T. Fujiyoshi, T. Encrenaz, E. Pantin, O. Mousis, T. Fuse, 2012: Recovery and characterization of Neptune's near - polar stratospheric hot spot.

There is nothing «natural» about these extremes of weather over the last 2 years, or about the unprecedented ozone hole in the Arctic last year (troposphere warming from greenhouse gases caused stratospheric cooling to below threshold temperature for polar stratospheric cloud generation and ozone destruction).

large areas of polar stratospheric clouds (PSCs)-- clouds in the ozone layer - were present over the Arctic region at altitudes between 14 and 26 km.

And this one does graph trend lines for polar stratospheric temperature that on average over recent years would correlate to the trend line for area for PSCs in the article being discussed:

Further field work by NASA during the 1987 Airborne Antarctic Ozone Experiment (AAOE) ended up providing definitive evidence in favor of the chlorine hypothesis, with details of the heterogeneous chemistry on polar stratospheric clouds as hypothesized by Susan Solomon and colleagues in 1986.

Increased polar stratospheric ozone losses and delayed eventual recovery owing to increasing greenhouse - gas concentration.

This vortex can isolate polar stratospheric air from mixing with mid-latitude air.

There are more polar stratospheric clouds observed now than ever before.

It normally reaches its widest extent in the southern hemisphere in the spring (August and September), as extreme cold temperatures in the stratosphere facilitate chemical reactions on the surface of polar stratospheric clouds.

large areas of polar stratospheric clouds (PSCs)-- clouds in the ozone layer - were present over the Arctic region at altitudes between 14 and 26 km.

And this one does graph trend lines for polar stratospheric temperature that on average over recent years would correlate to the trend line for area for PSCs in the article being discussed:

To sample polar stratospheric clouds: During winter months, the stratosphere above the Arctic Circle sometimes fills with icy clouds so colorful, they are likened to the aurora borealis.

Particles composed of such hydrates are thought to be the principal component of the polar stratospheric clouds that initiate the destruction of ozone.

Aircraft emissions probably play a crucial role in ozone destruction by fuelling the formation of polar stratospheric clouds.

(Such low air temperatures encourage the formation of icy clouds in the upper atmosphere known as polar stratospheric clouds, which foster the chemical reactions that turn harmless chlorine compounds into ozone eradicators.)

The temperature of the stratosphere is one of the key factors in the springtime depletion of ozone above the Antarctic where in winter it gets colder than anywhere else on Earth, encouraging icy particles to form in polar stratospheric clouds.

On the basis of its intended flight route, the Perlan glider might be able to provide the first direct observations of polar stratospheric clouds, a unique type of ice cloud that forms in the polar stratosphere and helps to deplete ozone, Gong adds.

Of particular importance are vertically extended polar stratospheric clouds that have been observed to cover wide areas of the Arctic.

«For a period of several weeks, wide areas of the Arctic were covered by polar stratospheric clouds between about 14 and 26 kilometers height.

«We were very much surprised to find polar stratospheric clouds down to heights of about 14 km,» Björn - Martin Sinnhuber says.

Chlorine eats away at ozone, but only if light is present and if the atmosphere is cold enough to create polar stratospheric clouds on which chlorine chemistry can occur — a relationship that Solomon was first to characterize in 1986.

Volcanoes don't inject significant chlorine into the stratosphere but they do increase small particles, which increase the amount of polar stratospheric clouds with which the human - made chlorine reacts.

The chemical reactions that break down ozone are particularly intense within cold, acidified clouds called polar stratospheric clouds.

That triggered vast polar stratospheric clouds, some of them as big as the continental United States.

An eerie «polar stratospheric cloud,» which destroys ozone at a rapid rate, hangs above Kiruna, Sweden, in January 2000.

Not exact matches

During these events, a polar vortex of up - to -130-kilometer-per-hour stratospheric winds encircling the Arctic can weaken or change direction (from counterclockwise to clockwise around the North Pole) for up to 2 months.

When the warming extended into the stratosphere, however, disruptions of the stratospheric polar vortex were likely.

Besides its atmospheric chemistry, Perlan 2 will carry instruments to study turbulence in stratospheric mountain waves, and to explore the microphysics of interactions between mountain waves and polar meteorology, which ultimately affect weather variability.

The mechanism behind polar ozone depletion is VERY WELL UNDERSTOOD and has nothing at all to do with solar flares somehow selectively blasting stratospheric ozone molecules into space.

Oinas et al also show that stratospheric dynamics make their contribution in the polar vortex regions to produce local warming in the 1 mb region for the uniformly applied increase in stratospheric water vapor.