Landfast ice properties over the Beaufort Sea region in 2000–2019 from MODIS and Canadian Ice Service data

Alexander P Trishchenko,Calin Ungureanu,Yi Luo,Junhua Li,Vladimir E Kostylev,Dustin Whalen

doi:10.1139/cjes-2021-0011

Alexander P Trishchenko, Calin Ungureanu + Show 4 more

Open Access

https://doi.org/10.1139/cjes-2021-0011

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Abstract

Two decades (2000–2019) of the landfast ice properties in the Beaufort Sea region in the Canadian Arctic were analyzed at 250 m spatial resolution from two sources: (1) monthly maps derived at the Canada Centre for Remote Sensing from the Moderate Resolution Imaging Spectroradiometer clear-sky satellite image composites; and (2) Canadian Ice Service charts. Detailed comparisons have been conducted for the landfast ice spatial extent, the water depth at, and the distance to the outer seaward edge from the coast in four sub-regions: (1) Alaska coast; (2) Barter Island to Herschel Island; (3) Mackenzie Bay; and (4) Richards Island to Cape Bathurst. The results from both sources demonstrate good agreement. The average spatial extent for the entire region over the April–June period is 48.5 (±5.0) × 103 km2 from Canadian Ice Service data versus 45.1 (±6.1) × 103 km2 from satellite data used in this study (7.0% difference). The correlation coefficient for April–June is 0.73 (p = 2.91 × 10−4). The long-term linear trends of the April–June spatial extent since 2000 demonstrated statistically significant decline: −4.45 (±1.69) × 103 km2/decade and −4.73 (±2.17) × 103 km2/decade from Canadian Ice Service and satellite data, respectively. The landfast ice in the Beaufort Sea region showed the general tendency for an earlier break-up, later onset, and longer ice-free period. The break-up date has decreased by 7.6 days/decade in the Mackenzie Bay region. The western part of the study area did not demonstrate statistically significant changes since 2000.

Highlights

Landfast ice (LFI), known as shore-fast ice, primarily forms in shallow coastal waters
There is higher variability in the Canadian Ice Service (CIS) results relative to the Canada Centre for Remote Sensing (CCRS) time series (Fig.5 a), which can be attributed to the higher temporal frequency of the CIS data, as well as to the different length of data collection interval
A much shorter data collection period may lead to the possible inclusion of nonstabilized ice with high concentration at the outer ice edge into the landfast category because the ice stability can not always be reliably determined using the data collected on a specific date

Summary

Introduction

Landfast ice (LFI), known as shore-fast ice, primarily forms in shallow coastal waters. The definition of the landfast ice is provided by the World Meteorological Organization (WMO) in the document “Sea Ice Nomenclature” (WMO, 2014). The LFI is generally defined as ice that is attached to the shore, to the bottom of the sea or to the ice wall or grounded icebergs. The LFI extends along the entire coast of the Beaufort Sea during the cold season and a large part of the summer and represents an important component of the Beaufort Sea climate system (Mahoney, 2018). It occupies most of the Canadian Arctic archipelago area in the winter season.

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