150 likes | 160 Views
What drives the vortex?. Vortex explanation. mid-May - onset SH winter Antarctic stratosphere cools descends closer to the surface Coriolis effect - sets up strong westerly circulation (@ SP) forms oblong vortex temperatures - lower stratosphere cool < -80C PCS’s. South American Ozone.
E N D
What drives the vortex? www.assignmentpoint.com
Vortex explanation • mid-May - onset SH winter • Antarctic stratosphere cools • descends closer to the surface • Coriolis effect - sets up strong westerly circulation (@ SP) • forms oblong vortex • temperatures - lower stratosphere cool < -80C PCS’s www.assignmentpoint.com
South American Ozone • The Ozone hole has reached Argentina, Chile and The Falkland Islands since the 1990's. • Ozone levels dropped down 70% in some areas. • The protective level of ozone dropped below 150 DU in some areas. www.assignmentpoint.com
Arctic ozone hole? www.assignmentpoint.com
What does this look like on population density map? www.assignmentpoint.com
Any satellite evidence? May 25, 2000 – “low ozone event” www.assignmentpoint.com
What do these clouds look like? www.assignmentpoint.com
Implications of ‘low ozone event’ • Could be blown south by high-altitude winds across heavily populated regions • 10% reduction ozone layer 25% imcr non-melanoma skin cancer – temperate climates by 2050 • Arctic ozone recovery may not be as quick as Antarctic www.assignmentpoint.com
Why the different response? • Polar stratospheric clouds surfaces where benign forms of chlorine reactive ozone-destroying forms • Remove nitrogen compounds that moderate destructive impact of chlorine - Dr. Phil De Cola, Atmospheric Chemistry Program Manager, NASA Headquarters, Washington, DC. • Presently – nitric acid stays longer in Arctic – reduces amount reactive chlorine www.assignmentpoint.com
Any links with global warming? • Upper atmosphere is getting colder – due to • Ozone loss • Greenhouse gases warming at surface cooling upper atmosphere • Arctic ozone hole forming within 20y Professor Jonathan Shanklin,The British Antarctic Study www.assignmentpoint.com
Ozone losses in mid-latitudes • What causes these losses? • Are losses over poles linked with those of mid latitudes? • Are CFC’s and bromine also responsible? www.assignmentpoint.com
European Ozone • Upper atmospheric conditions in The Northern Hemisphere are becoming similar to those of the Antarctic. The result of this could be the formation of an "Arctic Ozone Hole" or more correctly termed "low ozone event". • 10% ozone decr – winter • 5% ozone decr - summer www.assignmentpoint.com
November 11,2001 • Levels of ozone - fall to 60-70% of the seasonal average -Climate Research Centre, KNMI, The Netherlands. Low ozone event maybe caused by unusual air currents – not chemicals as Antarctic ozone hole www.assignmentpoint.com