Ice Production in Ross Ice Shelf Polynyas during 2017–2018 from Sentinel–1 SAR Images

High sea ice production (SIP) generates high-salinity water, thus, influencing the global thermohaline circulation. Estimation from passive microwave data and heat flux models have indicated that the Ross Ice Shelf polynya (RISP) may be the highest SIP region in the Southern Oceans. However, the coa...

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Bibliographic Details
Published in:Remote Sensing
Main Authors: Liyun Dai, Hongjie Xie, Stephen F. Ackley, Alberto M. Mestas-Nuñez
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2020
Subjects:
polynya ice production
SAR
Sentinel-1
sea ice
AMSR-2
Science
Q
Ross Sea
McMurdo Sound
Ross Ice Shelf
The Sentinel
Ice Shelf
Sea ice
Online Access:https://doi.org/10.3390/rs12091484
https://doaj.org/article/6ca8577c7dcb474c8a8e10f6e53a33c5
Description
Summary:High sea ice production (SIP) generates high-salinity water, thus, influencing the global thermohaline circulation. Estimation from passive microwave data and heat flux models have indicated that the Ross Ice Shelf polynya (RISP) may be the highest SIP region in the Southern Oceans. However, the coarse spatial resolution of passive microwave data limited the accuracy of these estimates. The Sentinel-1 Synthetic Aperture Radar dataset with high spatial and temporal resolution provides an unprecedented opportunity to more accurately distinguish both polynya area/extent and occurrence. In this study, the SIPs of RISP and McMurdo Sound polynya (MSP) from 1 March–30 November 2017 and 2018 are calculated based on Sentinel-1 SAR data (for area/extent) and AMSR2 data (for ice thickness). The results show that the wind-driven polynyas in these two years occurred from the middle of March to the middle of November, and the occurrence frequency in 2017 was 90, less than 114 in 2018. However, the annual mean cumulative SIP area and volume in 2017 were similar to (or slightly larger than) those in 2018. The average annual cumulative polynya area and ice volume of these two years were 1,040,213 km 2 and 184 km 3 for the RSIP, and 90,505 km 2 and 16 km 3 for the MSP, respectively. This annual cumulative SIP (volume) is only 1/3–2/3 of those obtained using the previous methods, implying that ice production in the Ross Sea might have been significantly overestimated in the past and deserves further investigations.

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