Articles | Volume 15, issue 11
© Author(s) 2021. This work is distributed underthe Creative Commons Attribution 4.0 License.
Supraglacial lake bathymetry automatically derived from ICESat-2 constraining lake depth estimates from multi-source satellite imagery
- Final revised paper (published on 12 Nov 2021)
- Supplement to the final revised paper
- Preprint (discussion started on 29 Jan 2021)
- Supplement to the preprint
Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor |
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RC1: 'Reviewer response to tc-2021-4', Jennifer Arthur, 22 Feb 2021
- AC1: 'Reply on RC1', Rajashree Datta, 11 May 2021
RC2: 'Reviewer comments on tc-2021-4, "Supraglacial lake bathymetry automatically derived from ICESat-2 constraining lake depth estimates from multi-source satellite imagery"', Anonymous Referee #2, 11 Mar 2021
- AC2: 'Reply on RC2', Rajashree Datta, 11 May 2021
Peer review completion
AR: Author's response | RR: Referee report | ED: Editor decision
ED: Reconsider after major revisions (further review by editor and referees) (31 May 2021) by Louise Sandberg Sørensen
AR by Rajashree Datta on behalf of the Authors (12 Jul 2021)  Author's response Author's tracked changes Manuscript
ED: Referee Nomination & Report Request started (20 Jul 2021) by Louise Sandberg Sørensen
RR by Anonymous Referee #2 (13 Aug 2021)
ED: Publish subject to minor revisions (review by editor) (01 Sep 2021) by Louise Sandberg Sørensen
AR by Rajashree Datta on behalf of the Authors (11 Sep 2021)  Author's response Author's tracked changes
ED: Publish subject to technical corrections (08 Oct 2021) by Louise Sandberg Sørensen
AR by Rajashree Datta on behalf of the Authors (16 Oct 2021)  Author's response Manuscript
This manuscript presents a new algorithm, ‘Watta’, for automatically extracting supraglacial lake depth estimates using ICESat-2 geolocated photon heights (ATL03) which are then used to validate empirically-derived lake depths from Landsat 8, Sentinel-2, Planet Labs Skysat and PlanetScope imagery. The authors test the algorithm performance on 46 supraglacial lakes near Jakobshavn Glacier in West Greenland during an intense melt season (2019). Finally, they use this stacked dataset in combination with Operation IceBridge imagery to track volume, drainage mechanisms and ice cover evolution of two individual lakes in this region.
Supraglacial lakes form in the ablation zones of Greenland and Antarctica during the summer melt season and can impact ice sheet dynamics, making lake detection and depth retrieval important. However, lake volumes have been difficult to quantify due to a lack of in-situ measurements and uncertainties associated with image-based methods. This manuscript builds upon other recent studies by applying a novel method for lake depth extraction, which is the first application of high-resolution Planet Labs satellite imagery to calculate supraglacial lake depths in combination with other imagery sources and ICESat-2 heights. It also provides useful insight into lake dynamics and ice cover evolution, which to date have been limited by the comparatively coarse resolution of publicly-available satellite datasets (Sentinel, Landsat).
Therefore, it is my view that the findings are of broad interest to the cryospheric community and represent a promising step forward for studying supraglacial hydrology and dynamics. I look forward to seeing further development of this method and its applications elsewhere on the Greenland and Antarctic ice sheets, particularly on floating ice shelves.
In general, this is a well-written manuscript and most of my comments are relatively minor. I would like to see in places some additional detail around the discussion of lake depth retrieval methods (see specific comments attached).
Lastly, The Cryosphere’s data policy states that “Authors are required to provide a statement on how their underlying research data can be accessed. This must be placed as the section "Data availability" at the end of the manuscript.” Although the authors state at the end of the manuscript that the Matlab code will be converted and shared publicly, I would like to see this section added including statements of how Landsat, Sentinel and Planet imagery can be accessed.
Once the authors address these points and my comments below, I can therefore recommend that this manuscript is suitable for publication in The Cryosphere.