Bottomfast Ice Mapping and the Measurement of Ice Thickness on Tundra Lakes Using C‐Band Synthetic Aperture Radar Remote Sensing¹

Abstract

Industrial activity in Canada's north is increasing, placing demands on the use of water from lakes to build ice roads. Winter water withdrawal from these lakes has the potential to impact overwintering fish. Removal of water from small lakes can decrease oxygen and habitat available to fish. To address this issue, a protocol has been developed by the Department of Fisheries and Oceans outlining water withdrawal thresholds. Bathymetric surveys are the traditional method to determine lake depth, but are costly given the remoteness of northern lakes. This paper investigates the use of satellite C-band synthetic aperture radar (SAR) remote sensing technology as a potential alternative or complement to traditional survey methods. Previous research has shown that a SAR can detect the transition from grounded to floating ice on lakes, or if a lake is completely frozen. Grounded ice has a dark signature while floating ice appears very bright in contrast. Similar results were observed for the datasets acquired in the study area. This suggests that lakes that freeze completely to the bottom can be identified using SAR. Such water bodies would not be viable fish overwintering habitat and can therefore be used as water sources without thresholds necessary. However, attempts to accurately calculate the depth of the ice at the grounded-floating ice boundary using bathymetric profiles acquired in the summer and lake ice thickness measurements from a reference lake near Inuvik proved to be unreliable.

Monitoring Bedfast Ice and Ice Phenology in Lakes of the Lena River Delta Using TerraSAR-X Backscatter and Coherence Time Series

“…However, the relatively low spatial resolution of SAR data used in these studies (240 m pixel size) confined the analysis to relatively large lakes, omitting the abundant number of water bodies smaller than the resolution. Advancements in technology have allowed for lake ice studies using higher spatial resolution (100 m or better) data from C-band RADARSAT-1, ERS-1 and ENVISAT ASAR [12,13,[27][28][29]. One of the main constraints for SAR-based investigations to date has been the insufficient temporal resolution of time series, so that acquisitions obtained with different incidence angles or a multi-sensor approach must be employed [20,27].…”

“…SAR-derived timing of ice grounding in combination with bathymetry information can be used as a proxy for the estimation of ice growth [28,29]. Another approach is to use a numerical ice growth model: SAR-derived date of ice grounding can be assigned to a simulated ice thickness on that date, which, in turn, provides information on the depth of a lake (i.e., bathymetry) [26,32].…”

Investigating the Influence of Variable Freshwater Ice Types on Passive and Active Microwave Observations

“…Economically, snow is a source of sustenance and electricity, providing drinking water to northern communities and fueling hydroelectric dams, bringing a considerable economic benefit [1,2]. Concurrently, the presence (phenology) and knowledge of ice thickness allows for winter transport to remote locations that otherwise lack land-based access [3]. Accurate snow and ice datasets including snow extent, snow water equivalent (SWE), and lake-ice phenology and thickness are important to assess output from regional climate models, and are also key indicators for global climate assessment research [4][5][6][7].…”

Circumpolar Mapping of Ground-Fast Lake Ice

“…While initial studies on mapping ground-fast ice at high latitudes were undertaken with airborne measurements in the 1970s (Surdu et al, 2014), investigations based on satellite data were first enabled with the availability of C-Band ERS (European Remote Sensing satellite) data in the 1990s (e.g., Jeffries et al, 1994;Duguay et al, 2002). Studies have been published for the North Slope of Alaska (Wakabayashi et al, 1993;Jeffries et al, 1994;Arp et al, 2011Arp et al, , 2012Engram et al, 2013;Surdu et al, 2014;Arp et al, 2015), Seward peninsula in Alaska (Engram et al, 2013), Manitoba (Duguay et al, 2002) and the MacKenzie Delta (Hirose et al, 2008;Yue et al, 2013) in Canada. Furthermore, the application of X-and L-band measurements for the detection of ground-fast ice has also been demonstrated over the North Slope (Engram et al, 2013;Jones et al, 2013).…”