{"id":1820,"date":"2013-04-04T10:40:44","date_gmt":"2013-04-04T15:40:44","guid":{"rendered":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/?p=1820"},"modified":"2013-04-04T10:40:44","modified_gmt":"2013-04-04T15:40:44","slug":"nssl-partners-thin-low-arctic-clouds-played-an-important-role-in-the-massive-2012-greenland-ice-melt","status":"publish","type":"post","link":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/2013\/04\/nssl-partners-thin-low-arctic-clouds-played-an-important-role-in-the-massive-2012-greenland-ice-melt\/","title":{"rendered":"NSSL, partners: Thin, low Arctic clouds played an important role in the massive 2012 Greenland ice melt"},"content":{"rendered":"
\"Thin<\/a>
Thin low clouds over Greenland caused unusual melting.<\/figcaption><\/figure>\n

Better understanding of Arctic clouds will help improve climate and weather forecasts<\/i><\/p>\n

Clouds over the central Greenland Ice Sheet last July were \u201cjust right\u201d for driving surface temperatures there above the melting point, according to a new study by scientists at NOAA and the Universities of Wisconsin, Idaho and Colorado. The study, published today in Nature<\/i>, found that thin, low-lying clouds allowed the sun\u2019s energy to pass through and warm the surface of the ice, while at the same time trapping heat near the surface of the ice cap. This combination played a significant role in last summer’s record-breaking melt.<\/p>\n

\u201cThicker cloud conditions would not have led to the same amount of surface warming,\u201d said Matthew Shupe, research meteorologist with NOAA\u2019s Cooperative Institute for Research in Environmental Sciences at the University of Colorado and the NOAA Earth System Research Laboratory. \u201cTo understand the region\u2019s future, you\u2019ll need to understand its clouds. Our finding has implications for the fate of ice throughout the Arctic.\u201d<\/p>\n

Scientists around the world are trying to understand how quickly Greenland is warming because ice melt there contributes to sea level rise globally. The Greenland Ice Sheet is second only to Antarctica in ice volume. In July, more than 97 percent of the Greenland Ice Sheet surface experienced some degree of melting, including at the National Science Foundation\u2019s Summit Station, high atop the ice sheet. According to ice core records, the last time the surface at Summit experienced any degree of melting was in 1889, but it is not known whether this extended across the entire ice sheet.<\/p>\n

To investigate whether clouds contributed to, or counteracted, the surface warming that melted the ice, the authors modeled the near-surface conditions. The model was based on observations from a suite of sophisticated atmospheric sensors operated as part of a study called the Integrated Characterization of Energy, Clouds, Atmospheric State and Precipitation at Summit<\/i>.<\/p>\n

\u201cThe July 2012 ice melt was triggered by an influx of unusually warm air sweeping in from North America, but that was only one factor,\u201d said David Turner, research meteorologist with the NOAA National Severe Storms Laboratory and one of the lead investigators. \u201cIn our paper, we show that low-lying clouds containing a low amount of condensed water were instrumental in pushing surface air temperatures up above freezing and causing the surface ice to melt.\u201d<\/p>\n

Clouds can cool the surface by reflecting solar energy back into space, and can warm it by radiating heat energy back down to the surface. The balance of those two processes depends on many factors, including wind speed, turbulence, humidity and cloud \u201cthickness,\u201d or liquid water content.<\/p>\n

In certain conditions, these clouds can be thin enough to allow some solar radiation to pass through, while still \u201ctrapping\u201d infrared radiation at ground level. That is exactly what happened last July: the clouds were just right for maximum surface warming. Thicker clouds would have reflected away more solar radiation; thinner ones couldn\u2019t have trapped as much heat, and in either of those cases, there would have been less surface warming.<\/p>\n

The researchers also found these thin, low-lying liquid clouds occur 30 to 50 percent of the time in summer, both over Greenland and across the Arctic. Current climate models tend to underestimate their occurrence\u00a0<\/b>in the Arctic, which limits those models\u2019 ability to predict how clouds and their warming or cooling effects may respond to climate change.<\/p>\n

\u201cThe cloud properties and atmospheric processes observed with the Summit Station instrument array provide a unique dataset to answer the large range of scientific questions we want to address,\u201d said Turner. \u201cClouds play a big role in the surface mass and energy budgets over the Greenland Ice Sheet. Melting of the world\u2019s major ice sheets can significantly impact human and environmental conditions via its contribution to sea-level rise.\u201d<\/p>\n

Better understanding of clouds also improves climate and weather models.<\/p>\n

\u201cOur results may help to explain some of the difficulties that current global climate models have in simulating the Arctic surface energy budget, including the contributions of clouds,\u201d said Ralf Bennartz, lead author for the study and professor at the University of Wisconsin-Madison. \u201cAbove all, this study highlights the importance of continuous and detailed ground-based observations over the Greenland Ice Sheet and elsewhere. Only such detailed observations will lead to a better understanding of the processes that drive Arctic climate.\u201d<\/p>\n

NOAA\u2019s mission is to understand and predict changes in the Earth’s environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources.<\/p>\n

Contact:<\/b><\/p>\n

Keli Pirtle\u00a0\u00a0 405-325-6933<\/p>\n

keli.pirtle@noaa.gov<\/p>\n","protected":false},"excerpt":{"rendered":"

A team of scientists, including NSSL’s Dave Turner published a new study in Nature that showed how clouds over the central Greenland Ice Sheet last July were \u201cjust right\u201d for driving surface temperatures there above the melting point.<\/p>\n","protected":false},"author":38,"featured_media":1821,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_eb_attr":"","ghostkit_customizer_options":"","ghostkit_custom_css":"","ghostkit_custom_js_head":"","ghostkit_custom_js_foot":"","ghostkit_typography":"","footnotes":""},"categories":[4,12],"tags":[165,195,244,291],"class_list":["post-1820","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-forecast","category-research-news","tag-greenland","tag-icecaps","tag-issue-spring-2013","tag-melting"],"acf":[],"wps_subtitle":"","_links":{"self":[{"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/posts\/1820","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/users\/38"}],"replies":[{"embeddable":true,"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/comments?post=1820"}],"version-history":[{"count":0,"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/posts\/1820\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/media\/1821"}],"wp:attachment":[{"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/media?parent=1820"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/categories?post=1820"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/tags?post=1820"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}