Fandom

Gravity Wiki

Polar stratospheric cloud

771pages on
this wiki
Add New Page
Talk0 Share
No Title
No Title
No information

Polar stratospheric clouds (PSCs), also known as nacreous clouds, are clouds in the winter polar stratosphere at altitudes of 15,000–25,000 metres (50,000–80,000 ft). They are implicated in the formation of ozone holes;[1] their effects on ozone depletion arise because they support chemical reactions that produce active chlorine which catalyzes ozone destruction, and also because they remove gaseous nitric acid, perturbing nitrogen and chlorine cycles in a way which increases ozone destruction.[2]

FormationEdit

The stratosphere is very dry; unlike the troposphere, it rarely allows clouds to form. In the extreme cold of the polar winter, however, stratospheric clouds of different types may form, which are classified according to their physical state and chemical composition.

Due to their high altitude and the curvature of the surface of the Earth, these clouds will receive sunlight from below the horizon and reflect it to the ground, shining brightly well before dawn or after dusk.

PSCs form at very low temperatures, below −78 °C. These temperatures can occur in the lower stratosphere in polar winter. In the Antarctic, temperatures below −88 °C frequently cause type II PSCs. Such low temperatures are rarer in the Arctic. In the Northern hemisphere, the generation of lee waves by mountains may locally cool the lower stratosphere and lead to the formation of PSCs.

Types of PSC Edit

PSCs are classified into three types Ia, Ib and II according to their chemical composition.

See also Edit

ReferencesEdit

  1. United States Environmental Protection Agency — see [1]
  2. World Meteorological Organization Scientific Assessment of Ozone Depletion (2002), particularly section 3.2.2 (pages 3.21, i.e. 195 of the PDF file, and following).

External links Edit

ResearchEdit

News reportsEdit

cs:Nacreousnl:Parelmoerwolkno:Perlemorskyer

nn:Perlemorskyer pl:Polarne chmury stratosferycznefi:Helmiäispilvi sv:Pärlemormoln vi:Mây xà cừ

Ad blocker interference detected!


Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.