{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,28]],"date-time":"2026-06-28T07:07:41Z","timestamp":1782630461350,"version":"3.54.5"},"reference-count":48,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2018,8,20]],"date-time":"2018-08-20T00:00:00Z","timestamp":1534723200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Ice-wedge polygons are widespread and conspicuous surficial expressions of ground-ice in permafrost landscapes. Thawing of ice wedges triggers differential ground subsidence, local ponding, and persistent changes to vegetation and hydrologic connectivity across the landscape. Here we characterize spatio-temporal patterns of ice-wedge degradation since circa 1950 across environmental gradients on Alaska\u2019s North Slope. We used a spectral thresholding approach validated by field observations to map flooded thaw pits in high-resolution images from circa 1950, 1982, and 2012 for 11 study areas (1577\u20134460 ha). The total area of flooded pits increased since 1950 at 8 of 11 study areas (median change +3.6 ha; 130.3%). There were strong regional differences in the timing and extent of degradation; flooded pits were already extensive by 1950 on the Chukchi coastal plain (alluvial-marine deposits) and subsequent changes there indicate pit stabilization. Degradation began more recently on the central Beaufort coastal plain (eolian sand) and Arctic foothills (yedoma). Our results indicate that ice-wedge degradation in northern Alaska cannot be explained by late-20th century warmth alone. Likely mechanisms for asynchronous onset include landscape-scale differences in surficial materials and ground-ice content, regional climate gradients from west (maritime) to east (continental), and regional differences in the timing and magnitude of extreme warm summers after the Little Ice Age.<\/jats:p>","DOI":"10.3390\/rs10081312","type":"journal-article","created":{"date-parts":[[2018,8,20]],"date-time":"2018-08-20T11:23:06Z","timestamp":1534764186000},"page":"1312","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":37,"title":["Regional Patterns and Asynchronous Onset of Ice-Wedge Degradation since the Mid-20th Century in Arctic Alaska"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5134-0334","authenticated-orcid":false,"given":"Gerald V.","family":"Frost","sequence":"first","affiliation":[{"name":"ABR, Inc.\u2014Environmental Research &amp; Services, P.O. Box 80410, Fairbanks, AK 99708, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tracy","family":"Christopherson","sequence":"additional","affiliation":[{"name":"ABR, Inc.\u2014Environmental Research &amp; Services, P.O. Box 240268, Anchorage, AK 99518, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M. Torre","family":"Jorgenson","sequence":"additional","affiliation":[{"name":"Alaska Ecoscience, 2332 Cordes Way, Fairbanks, AK 99709, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna K.","family":"Liljedahl","sequence":"additional","affiliation":[{"name":"Water and Environmental Research Center, University of Alaska Fairbanks, Fairbanks, AK 99775, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2808-208X","authenticated-orcid":false,"given":"Matthew J.","family":"Macander","sequence":"additional","affiliation":[{"name":"ABR, Inc.\u2014Environmental Research &amp; Services, P.O. Box 80410, Fairbanks, AK 99708, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Donald A.","family":"Walker","sequence":"additional","affiliation":[{"name":"Alaska Geobotany Center, University of Alaska Fairbanks, Fairbanks, AK 99775, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aaron F.","family":"Wells","sequence":"additional","affiliation":[{"name":"ABR, Inc.\u2014Environmental Research &amp; Services, P.O. Box 240268, Anchorage, AK 99518, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2018,8,20]]},"reference":[{"key":"ref_1","unstructured":"Washburn, A.L. (1980). Geocryology: A Survey of Periglacial Processes and Environments, John Wiley & Sons, Inc."},{"key":"ref_2","unstructured":"French, H.M. (2007). The Periglacial Environment, John Wiley & Sons, Ltd."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"De Koven Leffingwell, E. (1919). 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