{"id":348,"date":"2019-03-01T11:43:47","date_gmt":"2019-03-01T15:43:47","guid":{"rendered":"https:\/\/storm.uml.edu\/~metweb\/Blog\/?p=348"},"modified":"2021-09-16T16:43:16","modified_gmt":"2021-09-16T16:43:16","slug":"recent-stratospheric-polar-vortex-breakdown-and-recovery","status":"publish","type":"post","link":"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/2019\/03\/01\/recent-stratospheric-polar-vortex-breakdown-and-recovery\/","title":{"rendered":"Recent Stratospheric Polar Vortex Breakdown and Recovery"},"content":{"rendered":"\n<p>by Mathew Barlow, UML Professor of Climate Science<\/p>\n\n\n\n<p>During the 2018-2019 Northern Hemisphere winter, a major Sudden Stratospheric Warming (SSW) occurred in association with the breakdown of the Polar Stratospheric Vortex.<\/p>\n\n\n\n<p>The following video shows the evolution of the vortex starting from a strong circulation in late Dec 2018, through the breakdown in early Jan 2019, and into recovery by the end of Feb 2019. &nbsp;The evolution is shown in terms of potential vorticity and winds on the 850K isentropic surface (about 30km up, in the middle of the stratosphere).<\/p>\n\n\n\n<style>\n#wrapper { width: 1200px; height: 800px; padding: 0; overflow: hidden; align:center;}\n#scaled-frame { width: 1200px; height: 1200px; border: 0px; }\n#scaled-frame {\n    zoom: 0.51;\n    -moz-transform: scale(0.51);\n    -moz-transform-origin: 0 0;\n    -o-transform: scale(0.51);\n    -o-transform-origin: 0 0;\n    -webkit-transform: scale(0.51);\n    -webkit-transform-origin: 0 0;\n}\n\n@media screen and (-webkit-min-device-pixel-ratio:0) {\n #scaled-frame  { zoom: 1;  }\n}\n<\/style>\n\n<div id=\"wrapper\"><iframe id=\"scaled-frame\" src=\"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/03\/spv_wind-2.gif\" scrolling=\"no\"><\/iframe><\/div>\n\n\n\n<p>Potential vorticity is a measure of rotation in a fluid that accounts for both speed of rotation and distribution of mass, analogous to angular momentum. A brief, equation-free introduction to potential vorticity is available at:<\/p>\n\n\n\n<p>&nbsp;<a href=\"https:\/\/storm.uml.edu\/~metweb\/Blog\/?p=330\">https:\/\/storm.uml.edu\/~metweb\/Blog\/?p=330<\/a> .<\/p>\n\n\n\n<p>Note that the winds show a counter-clockwise (cyclonic) rotation around the highest values of potential vorticity (yellow colors).<\/p>\n\n\n\n<p>Here are three snapshots of the vortex before, during, and after the breakdown:<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><a href=\"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/03\/spv_2018-2019.png\"><img loading=\"lazy\" decoding=\"async\" width=\"2160\" height=\"880\" src=\"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/03\/spv_2018-2019.png\" alt=\"\" class=\"wp-image-365\" srcset=\"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/03\/spv_2018-2019.png 2160w, https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/03\/spv_2018-2019-300x122.png 300w, https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/03\/spv_2018-2019-1024x417.png 1024w, https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/03\/spv_2018-2019-768x313.png 768w, https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/03\/spv_2018-2019-1536x626.png 1536w, https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/03\/spv_2018-2019-2048x834.png 2048w, https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/03\/spv_2018-2019-1568x639.png 1568w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/a><\/figure><\/div>\n\n\n\n<p>&nbsp;<a href=\"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/03\/spv_2018-2019.pdf\">spv_2018-2019<\/a>&nbsp;<\/p>\n\n\n\n<p>Before the breakdown there is a single large area of cyclonic rotation close the North Pole &#8211; this is the Stratospheric Polar Vortex. &nbsp;This circulation splits into three smaller pieces that move around and interact, with the two larger pieces eventually merging via a Fujiwhara-like interaction. &nbsp;During the breakdown, the winds are circulating clock-wise around the pole, which is opposite to their usually direction. Eventually, a strong vortex redevelops. &nbsp;The values of potential vorticity are not as high in the recovered vortex as in the initial vortex, but are typical for that time of year.<\/p>\n\n\n\n<p>The data is from NOAA&#8217;s CFSv2 operational analysis at 6-hour intervals, which is available online: &nbsp;<\/p>\n\n\n\n<figure class=\"wp-block-embed\"><div class=\"wp-block-embed__wrapper\">\nhttps:\/\/www.ncdc.noaa.gov\/data-access\/model-data\/model-datasets\/climate-forecast-system-version2-cfsv2.\n<\/div><\/figure>\n\n\n\n<p>For more information on polar vortex terminology:<\/p>\n\n\n\n<p><a href=\"https:\/\/journals.ametsoc.org\/doi\/10.1175\/BAMS-D-15-00212.1\">https:\/\/journals.ametsoc.org\/doi\/10.1175\/BAMS-D-15-00212.1 .<\/a><\/p>\n\n\n\n<p>The average surface impacts associated with sudden stratospheric warmings (SSWs) can be explored at:&nbsp;<\/p>\n\n\n\n<p><a href=\"https:\/\/www.esrl.noaa.gov\/csd\/groups\/csd8\/sswcompendium\/\">https:\/\/www.esrl.noaa.gov\/csd\/groups\/csd8\/sswcompendium\/ .<\/a><\/p>\n\n\n\n<p>For instance, here is the average surface temperature anomalies observed in the 30 day-period after past SSWs.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><a href=\"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/02\/SSWC_tsfcAnom30_ERA40_compOnly.png\"><img loading=\"lazy\" decoding=\"async\" width=\"1174\" height=\"1128\" src=\"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/02\/SSWC_tsfcAnom30_ERA40_compOnly.png\" alt=\"\" class=\"wp-image-356\" srcset=\"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/02\/SSWC_tsfcAnom30_ERA40_compOnly.png 1174w, https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/02\/SSWC_tsfcAnom30_ERA40_compOnly-300x288.png 300w, https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/02\/SSWC_tsfcAnom30_ERA40_compOnly-1024x984.png 1024w, https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-content\/uploads\/2019\/02\/SSWC_tsfcAnom30_ERA40_compOnly-768x738.png 768w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/a><\/figure>\n\n\n\n<p>This average pattern of surface temperature anomalies does not occur after every SSW, however. &nbsp;The predictability of the tropospheric impacts of SSWs is examined in:<\/p>\n\n\n\n<figure class=\"wp-block-embed\"><div class=\"wp-block-embed__wrapper\">\nhttps:\/\/rmets.onlinelibrary.wiley.com\/doi\/full\/10.1002\/qj.3017.\n<\/div><\/figure>\n\n\n\n<p><em><strong>Acknowledgements<\/strong><\/em><\/p>\n\n\n\n<p>This discussion is part of outreach efforts for NSF AGS-1657921.<\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>by Mathew Barlow, UML Professor of Climate Science During the 2018-2019 Northern Hemisphere winter, a major Sudden Stratospheric Warming (SSW) occurred in association with the breakdown of the Polar Stratospheric Vortex. The following video shows the evolution of the vortex starting from a strong circulation in late Dec 2018, through the breakdown in early Jan [&hellip;]<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-348","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-json\/wp\/v2\/posts\/348","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-json\/wp\/v2\/comments?post=348"}],"version-history":[{"count":1,"href":"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-json\/wp\/v2\/posts\/348\/revisions"}],"predecessor-version":[{"id":953,"href":"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-json\/wp\/v2\/posts\/348\/revisions\/953"}],"wp:attachment":[{"href":"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-json\/wp\/v2\/media?parent=348"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-json\/wp\/v2\/categories?post=348"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/storm.uml.edu\/~metweb\/newBlog\/wordpress\/wp-json\/wp\/v2\/tags?post=348"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}