Estimation of Sea Ice Production in the North Water Polynya Based on Ice Arch Duration in Winter During 2006–2019. Issue 10 (13th October 2022)

• Record Type: Journal Article
• Authors: Ren, Haiyi; Shokr, Mohammed; Li, Xinqing; Zhang, Zhilun; Hui, Fengming; Cheng, Xiao
• Is Part Of: Journal of geophysical research. Volume 127:Issue 10(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-10-13
• Subjects: the ice arch -- the North Water Polynya -- the heat flux -- the ice production; Oceanography -- Periodicals; 551.4605
• DOI: 10.1029/2022JC018764
• Languages: English
• ISSNs: 2169-9275

Abstract

Abstract: The North Water Polynya (NOW) is the largest recurrent Arctic coastal polynya. The formation of the NOW is critically dependent on the development of an ice arch that defines its northern boundary. In this study, high‐resolution ENVISAT Advanced Synthetic Aperture Radar data, Sentinel‐1A data, and Moderate Resolution Imaging Spectroradiometer data were employed to identify the spatio‐temporal characteristics of the ice arch during 2006–2019. Polynya pixels were identified based on the thin ice thickness (TIT), using a threshold of TIT <0.2 m, from which the polynya extent, heat flux, and ice production (IP) were estimated. The results show the different locations of the ice arch in different years, with a mean duration of 132 ± 69 days. The average annual polynya extent over the 14 years is ∼38.8 ± 8 × 10 3 km 2, and we found that it is more closely correlated with wind speed during the winter and air temperature during early spring. The average heat flux drops from about 248 W/m 2 in the winter months to about 34 W/m 2 in May. The average accumulated IP varies significantly every year, with an average of 144 ± 103 km 3, and peak values in March in most years. No apparent interannual trends are shown for the polynya area, heat flux, and IP during 2006–2019. The results also show that IP calculated based on the ice arch data is approximately 25% lower than that obtained by assuming a fixed time, location, and duration for the polynya. Plain Language Summary: The North Water Polynya (NOW) is the area of the highest ice production (IP) in the Arctic. The ice arch is critical to the formation of the NOW. In this study, we used high‐resolution satellite data to identify the spatio‐temporal characteristics of the ice arch during 2006–2019. Then, for the first time, we estimated the IP based on the variable location and duration of the ice arch, and we analyzed the difference with the results previously obtained based on a fixed location and period (FLP) for the polynya. Our results show that the ice arch may locate at the entrance to the Robeson Channel, Smith Sound, or the middle of Kane Basin, and its duration is highly variable. Hence, the heat flux and IP of the NOW fluctuate considerably. Furthermore, the heat flux and IP in our results are approximately 34% and 25% lower than those previously obtained based on FLP, respectively. In addition, we found that air temperature has a greater effect on the polynya extent than wind speed in spring while wind had greater effect in winter. The results of this study will provide more accurate conditions for coupled regional atmosphere‐ice‐ocean models in the Arctic. Key Points: The spatio‐temporal characteristics of the ice arch is identified from high‐resolution Synthetic Aperture Radar and Moderate Resolution Imaging Spectroradiometer data The ice production in the North Water Polynya estimated based on the variable location and duration of the ice arch are presented Analysis of the difference with the results estimated based on the fixed location and duration (from December and March)