{"id":736,"date":"2026-08-20T12:14:01","date_gmt":"2026-08-20T12:14:01","guid":{"rendered":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/?p=736"},"modified":"2026-08-20T12:17:22","modified_gmt":"2026-08-20T12:17:22","slug":"atmospheric-optical-phenomena-nacreous-clouds","status":"publish","type":"post","link":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/2026\/08\/20\/atmospheric-optical-phenomena-nacreous-clouds\/","title":{"rendered":"Optical Phenomena in Antarctica: Nacreous Clouds"},"content":{"rendered":"\n

Welcome back to what is likely my last post in the atmospheric optical phenomena in Antarctica series. This post will be centered on nacreous clouds. Nacreous clouds are a type of polar stratospheric cloud. Polar stratospheric clouds are clouds made of ice that occur high in the atmosphere (in the stratosphere) at very cold temperatures, typically near -85\u00ba C or -121\u00ba F, which is colder than the average stratospheric temperature. Since such cold conditions are required, these clouds typically are only found in polar regions (Arctic and Antarctic).<\/p>\n\n\n\n

Most clouds form below 10 km, however polar stratospheric clouds form between 15 and 25 km, much higher up in the atmosphere (where the temperature can drop low enough for formation). There are two types of polar stratospheric clouds, those with ice crystals made of water and a contaminant (usually nitric acid or sometimes sulfuric acid), and those with ice composed purely of water. Nacreous clouds are the type made of pure water.<\/p>\n\n\n\n

We can see polar stratospheric clouds in our lidar signal since they diffuse the beam. In winter, when the temperatures are coldest, we typically see interference with the lidar around 20-25 km (occasionally as low as 15-18 km). In the dark of winter, you can typically only see these clouds with the naked eye when they drift near the moon. However, now that we’re in winfly season and the sun has started to return, we can see them by eye and we were lucky enough to catch a very special set of nacreous clouds today.<\/p>\n\n\n\n

Nacreous clouds typically look like pale cirrus clouds and feel like normal clouds, however when the sun is a few degrees below the horizon and catches the clouds at the right angle, it can produce stunning mother of pearl like colors. Since the sun was below the horizon for most of the day, the nacreous clouds lit up and put on a stunning show for us all day. The pictures can only capture a small part of what it felt like to stand beneath these alien skies. It was truly a magical experience. Many returners said it was the finest display of nacreous clouds they’d ever seen in the years they’d been working here.<\/p>\n\n\n\n

While nacreous clouds are most common in Antarctica, they can also occur in Alaska, northern Canada, and Northern Europe. I hope to see them again someday, since it may have been the most beautiful sky I’ve ever seen.<\/p>\n\n\n\n

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Welcome back to what is likely my last post in the atmospheric optical phenomena in Antarctica series. This post will be centered on nacreous clouds. Nacreous clouds are a type of polar stratospheric cloud. Polar stratospheric clouds are clouds made of ice that occur high in the atmosphere (in the stratosphere) at very cold temperatures,… Read More<\/a><\/p>\n","protected":false},"author":215,"featured_media":737,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-736","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized"],"publishpress_future_action":{"enabled":false,"date":"2026-11-01 22:56:53","action":"change-status","newStatus":"draft","terms":[],"taxonomy":"category","extraData":[]},"publishpress_future_workflow_manual_trigger":{"enabledWorkflows":[]},"jetpack_featured_media_url":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-content\/uploads\/sites\/73\/2026\/08\/Nacreous-1.jpg","_links":{"self":[{"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/posts\/736","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/users\/215"}],"replies":[{"embeddable":true,"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/comments?post=736"}],"version-history":[{"count":2,"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/posts\/736\/revisions"}],"predecessor-version":[{"id":744,"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/posts\/736\/revisions\/744"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/media\/737"}],"wp:attachment":[{"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/media?parent=736"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/categories?post=736"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/tags?post=736"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}