{"id":7,"date":"2023-04-11T13:28:50","date_gmt":"2023-04-11T13:28:50","guid":{"rendered":"https:\/\/teams.issibern.ch\/antarcticseaice\/?page_id=7"},"modified":"2023-05-22T12:20:19","modified_gmt":"2023-05-22T12:20:19","slug":"scientific-rationale","status":"publish","type":"page","link":"https:\/\/teams.issibern.ch\/antarcticseaice\/scientific-rationale\/","title":{"rendered":"Scientific Rationale"},"content":{"rendered":"<p><span style=\"font-weight: 400\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft  wp-image-58\" src=\"https:\/\/teams.issibern.ch\/antarcticseaice\/wp-content\/uploads\/sites\/74\/2023\/05\/MIZ_Continent-1024x987-1.png\" alt=\"\" width=\"536\" height=\"516\" srcset=\"https:\/\/teams.issibern.ch\/antarcticseaice\/wp-content\/uploads\/sites\/74\/2023\/05\/MIZ_Continent-1024x987-1.png 1024w, https:\/\/teams.issibern.ch\/antarcticseaice\/wp-content\/uploads\/sites\/74\/2023\/05\/MIZ_Continent-1024x987-1-300x289.png 300w, https:\/\/teams.issibern.ch\/antarcticseaice\/wp-content\/uploads\/sites\/74\/2023\/05\/MIZ_Continent-1024x987-1-768x740.png 768w\" sizes=\"auto, (max-width: 536px) 100vw, 536px\" \/>State-of-the-art ocean\/sea-ice\/climate (coupled) models have consistently underestimated the recent reduction in Antarctic sea-ice. Information on sea-ice thickness and snow depth-on-sea-ice are required to explore this mismatch and improve the model physics of both thermodynamic and dynamic processes. <\/span><\/p>\n<p><span style=\"font-weight: 400\">Sea-ice thickness provides an integrated measure of changes in the global energy budget. Snow on sea-ice adds an insulating layer and, in Antarctica, contributes to sea-ice volume via snow-ice formation. Whilst not readily observed, information about both sea-ice thickness and snow on sea-ice thickness are critical for forecasting and navigation.<\/span><\/p>\n<p><span style=\"font-weight: 400\">Accurate estimates of snow on sea-ice are crucial to improve satellite-derived estimates of sea-ice thickness and estimate energy fluxes for Numerical Weather Prediction. At present, <a href=\"https:\/\/cds.climate.copernicus.eu\/toolbox\/doc\/how-to\/13_how_to_calculate_climatologies_and_anomalies\/13_how_to_calculate_climatologies_and_anomalies.html\">climatologies<\/a> are used to estimate snow on sea-ice when retrieving sea-ice thickness from altimetry, which is a sub-optimal approach when computing long-term trends: Uncertainty associated with spatio-temporal distribution of snow depth is the largest individual source of error in altimetry-based sea-ice thickness retrievals. In conjunction with<\/span><span style=\"font-weight: 400\">\u00a0snow properties, knowledge of underlying sea-water and sea-ice properties are needed to translate any RADAR or LIDAR surface elevation into sea-ice thickness. In summary, the greatest potential sources of uncertainty in calculations of Antarctic sea-ice thickness and thus volume are:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Snow thickness and density.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Their temporal and regional evolution.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">The densities of sea-ice and sea-water.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-59 alignright\" src=\"https:\/\/teams.issibern.ch\/antarcticseaice\/wp-content\/uploads\/sites\/74\/2023\/05\/MIZ_Cycle-1024x782-1.png\" alt=\"\" width=\"507\" height=\"387\" srcset=\"https:\/\/teams.issibern.ch\/antarcticseaice\/wp-content\/uploads\/sites\/74\/2023\/05\/MIZ_Cycle-1024x782-1.png 1024w, https:\/\/teams.issibern.ch\/antarcticseaice\/wp-content\/uploads\/sites\/74\/2023\/05\/MIZ_Cycle-1024x782-1-300x229.png 300w, https:\/\/teams.issibern.ch\/antarcticseaice\/wp-content\/uploads\/sites\/74\/2023\/05\/MIZ_Cycle-1024x782-1-768x587.png 768w\" sizes=\"auto, (max-width: 507px) 100vw, 507px\" \/>Freeboard (height above sea-level)-to-ice-thickness retrievals have been proposed and used successfully for Arctic conditions. However, they do not work (well) for Antarctic sea-ice due to it&#8217;s highly dynamic and seasonal nature, hence low sea-ice thickness. The comparatively thick and highly variable snow cover over Antarctic sea-ice, associated with processes such as flooding at the ice-snow interface and rapid weather-induced snow metamorphism hamper the retrieval of sea-ice thickness from observed freeboard data. The influence of these factors on physical snow and sea-ice properties relevant for satellite remote sensing of sea-ice thickness has thus far inhibited accurate routine estimates of sea-ice thickness distribution in the Southern Ocean.<\/span><\/p>\n<p><span style=\"font-weight: 400\">The primary objective of this ISSI team is to identify and proto-type a processing chain to derive Antarctic sea-ice thickness from a range of remotely-sensed observations to understand its spatial-temporal characteristics in response to change and variability in external forcing. While the areal extent of sea-ice is routinely monitored by satellite passive-microwave sensors, deriving sea-ice (or snow) thickness from remote observations presents a matter of urgency in informing sea-ice and climate research.\u00a0<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>State-of-the-art ocean\/sea-ice\/climate (coupled) models have consistently underestimated the recent reduction in Antarctic sea-ice. Information on sea-ice thickness and snow depth-on-sea-ice are required to explore this mismatch and improve the model physics of both thermodynamic and dynamic processes. Sea-ice thickness provides an integrated measure of changes in the global energy budget. Snow on sea-ice adds an [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-7","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/teams.issibern.ch\/antarcticseaice\/wp-json\/wp\/v2\/pages\/7","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/teams.issibern.ch\/antarcticseaice\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/teams.issibern.ch\/antarcticseaice\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/teams.issibern.ch\/antarcticseaice\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/teams.issibern.ch\/antarcticseaice\/wp-json\/wp\/v2\/comments?post=7"}],"version-history":[{"count":5,"href":"https:\/\/teams.issibern.ch\/antarcticseaice\/wp-json\/wp\/v2\/pages\/7\/revisions"}],"predecessor-version":[{"id":60,"href":"https:\/\/teams.issibern.ch\/antarcticseaice\/wp-json\/wp\/v2\/pages\/7\/revisions\/60"}],"wp:attachment":[{"href":"https:\/\/teams.issibern.ch\/antarcticseaice\/wp-json\/wp\/v2\/media?parent=7"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}