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Changing river ice seasonality and impacts on interior Alaskan communities
Dana
Brown, University of Alaska, drbrown11@alaska.edu
Subsistence harvesters in the North rely on frozen rivers for winter access to local resources. Interior Alaskan residents have observed changes in river ice regimes that are significant hindrances to travel and subsistence practices. In this study, remote sensing and local observations were used to examine changes in seasonality of break-up and freeze-up seasons on major rivers in interior Alaska and assess the implications for subsistence harvesters. Spring and autumn air temperatures, respectively, were found to impact timing of break-up (-2.0 days/˚C) and freeze-up (+2.0 days/˚C). Spring air temperatures have increased by 0.02-0.06 ˚C/year over the last ~53-93 years. Accordingly, the break-up season has advanced by 6 days over the last century. The beginning of safe travel on river ice has been delayed by 10 days over the last century. Freeze-up timing was positively related to both air temperature and river discharge. Fall river discharge increased by 920 m3/s over the last 40 years, and was unrelated to precipitation change. Changing hydrology resulting from climate-related permafrost thaw and glacial melt may have contributed to the delay in freeze-up. The duration of river inaccessibility during freeze-up was double to triple that of the break-up, thus, understanding controls over freeze-up remains an important goal. The duration of safe travel on river ice has declined over the last century, and is expected to decline further as the climate continues to warm, thereby presenting new challenges to accessing subsistence resources at traditional times of the year. The mismatch in timing will necessitate community adaptation. Associated Project(s): Poster Location ID: 62 Session Assigned: Wildlife and Ecosystem Services
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