17:15 〜 18:30
[MIS01-P07] Ice-free period duration changes in the coastal zone of the Kara sea using satellite data
キーワード：sea ice, arctic coastal zone, climate change
Rapid arctic sea ice reduction in the XXI century is a clear example of the global warming process. The seasonal evolution of Arctic sea ice could be described by the timing of key dates of sea ice concentration change during its annual retreat and advance cycle. Sea ice area decrease leads to an ice-free period duration increase in the Arctic ocean seas. Changes in the characteristics of the ice-free period, such as day of the retreat, day of advance, and total duration, significantly influence coastal infrastructure, navigation, and coastal ecosystems. Satellite datasets allow us to analyze the long-term state and dynamics of the sea ice cover in the arctic coastal zone in Russia.
In this paper, we explore whether and how the ice-free period characteristics over the Kara sea coastal zone have changed during the satellite data record period of 1979–2019 and examine the sensitivity decadal trends of ice-free period duration to sea ice concentration datasets in the Kara sea coastal zone.
The threshold-based ice-free period detection method was modified with a focus on seasonal gradients in the sea ice concentrations time series and adapted for the coastal data. The annual estimates of ice-free period characteristics for the coastal zone of the Kara sea were obtained using ensemble estimations, calculated from the satellite sea ice concentration datasets provided by JASMES, NSIDC, and OSI SAF services for the time period 1979-2019.
A detailed description of the Kara sea coastal zone of the means and trends in the ice-free period characteristics is performed. It was found that the duration of the ice-free period in the coastal zone of the Kara sea has increased significantly over the last decades. The duration increase is due to both dates of retreat shifts to earlier periods (the average rate is -8 days/decade) and dates of advance shifts to later periods (the average rate is +4+5 days/decade). The total ice-free period duration average rate was estimated as +12+13 days/decade during the period 1979-2019. At the same time, the leading contribution to the total duration of the ice-free period is made by the dates of retreat dynamics, which has high interannual variability and large spatial diversity over the Kara sea coast.
In this paper, we explore whether and how the ice-free period characteristics over the Kara sea coastal zone have changed during the satellite data record period of 1979–2019 and examine the sensitivity decadal trends of ice-free period duration to sea ice concentration datasets in the Kara sea coastal zone.
The threshold-based ice-free period detection method was modified with a focus on seasonal gradients in the sea ice concentrations time series and adapted for the coastal data. The annual estimates of ice-free period characteristics for the coastal zone of the Kara sea were obtained using ensemble estimations, calculated from the satellite sea ice concentration datasets provided by JASMES, NSIDC, and OSI SAF services for the time period 1979-2019.
A detailed description of the Kara sea coastal zone of the means and trends in the ice-free period characteristics is performed. It was found that the duration of the ice-free period in the coastal zone of the Kara sea has increased significantly over the last decades. The duration increase is due to both dates of retreat shifts to earlier periods (the average rate is -8 days/decade) and dates of advance shifts to later periods (the average rate is +4+5 days/decade). The total ice-free period duration average rate was estimated as +12+13 days/decade during the period 1979-2019. At the same time, the leading contribution to the total duration of the ice-free period is made by the dates of retreat dynamics, which has high interannual variability and large spatial diversity over the Kara sea coast.