Estimating melt onset over Arctic sea ice from time series multi-sensor Sentinel-1 and RADARSAT-2 backscatter
Information on the timing of melt onset over sea ice is important for understanding the Arctic's changing climate. The daily temporal resolution of passive microwave brightness temperatures provides the most widely utilized observations to detect melt onset but are limited to a spatial resoluti...
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ftunivzuerich:oai:www.zora.uzh.ch:171432 2024-06-23T07:48:38+00:00 Estimating melt onset over Arctic sea ice from time series multi-sensor Sentinel-1 and RADARSAT-2 backscatter Howell, Stephen E L Small, David Rohner, Christoph Mahmud, Mallik S Yackel, John J Brady, Michael 2019-08-01 application/pdf https://www.zora.uzh.ch/id/eprint/171432/ https://www.zora.uzh.ch/id/eprint/171432/1/2019_1-s2.0-S0034425719301828-main.pdf https://doi.org/10.5167/uzh-171432 https://doi.org/10.1016/j.rse.2019.04.031 eng eng Elsevier https://www.zora.uzh.ch/id/eprint/171432/1/2019_1-s2.0-S0034425719301828-main.pdf doi:10.5167/uzh-171432 doi:10.1016/j.rse.2019.04.031 urn:issn:0034-4257 info:eu-repo/semantics/openAccess Creative Commons: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) http://creativecommons.org/licenses/by-nc-nd/4.0/ Howell, Stephen E L; Small, David; Rohner, Christoph; Mahmud, Mallik S; Yackel, John J; Brady, Michael (2019). Estimating melt onset over Arctic sea ice from time series multi-sensor Sentinel-1 and RADARSAT-2 backscatter. Remote Sensing of Environment, 229:48-59. Institute of Geography 910 Geography & travel Computers in Earth Sciences Soil Science Geology Journal Article PeerReviewed info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2019 ftunivzuerich https://doi.org/10.5167/uzh-17143210.1016/j.rse.2019.04.031 2024-06-05T00:23:24Z Information on the timing of melt onset over sea ice is important for understanding the Arctic's changing climate. The daily temporal resolution of passive microwave brightness temperatures provides the most widely utilized observations to detect melt onset but are limited to a spatial resolution of 25 km. Wide-swath synthetic aperture radar (SAR) imagery provides a much higher spatial resolution (20–100 m) but melt onset detection remains challenging because of i) insufficient temporal resolution to facilitate accurate melt onset detection, ii) inconsistent viewing geometries and iii) limited image availability across the Arctic. Here, we construct high temporal resolution composite gamma nought backscatter products (1 day, 1–2 day and 2–4 day) using Sentinel-1 and RADARSAT-2 over a close-to-seamless revisit region located in northern Canadian Arctic and Greenland for estimating melt onset over Arctic sea ice in 2016 and 2017. We employ the necessary radiometric terrain flattening and local resolution weighting techniques to generate normalised backscatter over the entire study region, removing restrictions limiting analysis to a single sensor or track's swath width by integrating both ascending and descending passes into the composite products. Results indicate that higher temporal resolution multi-sensor composite gamma nought products (1 day) that make use of the most imagery provide a robust temporal evolution of the backscatter. This allows for more representative estimates of melt onset as it is easier to separate the melt onset threshold from winter variability that is otherwise a considerable challenge for SAR based melt onset algorithms because of inconsistent temporal resolution. Multi-sensor composite gamma naught melt onset detection is in good agreement with melt onset estimates derived from the Advance Scatterometer (ASCAT) backscatter values and passive microwave brightness temperatures over homogenous sea ice regions but very noticeable improvement was found within narrow channels and regions ... Article in Journal/Newspaper Arctic Arctic Greenland Sea ice University of Zurich (UZH): ZORA (Zurich Open Repository and Archive Arctic Greenland |
institution |
Open Polar |
collection |
University of Zurich (UZH): ZORA (Zurich Open Repository and Archive |
op_collection_id |
ftunivzuerich |
language |
English |
topic |
Institute of Geography 910 Geography & travel Computers in Earth Sciences Soil Science Geology |
spellingShingle |
Institute of Geography 910 Geography & travel Computers in Earth Sciences Soil Science Geology Howell, Stephen E L Small, David Rohner, Christoph Mahmud, Mallik S Yackel, John J Brady, Michael Estimating melt onset over Arctic sea ice from time series multi-sensor Sentinel-1 and RADARSAT-2 backscatter |
topic_facet |
Institute of Geography 910 Geography & travel Computers in Earth Sciences Soil Science Geology |
description |
Information on the timing of melt onset over sea ice is important for understanding the Arctic's changing climate. The daily temporal resolution of passive microwave brightness temperatures provides the most widely utilized observations to detect melt onset but are limited to a spatial resolution of 25 km. Wide-swath synthetic aperture radar (SAR) imagery provides a much higher spatial resolution (20–100 m) but melt onset detection remains challenging because of i) insufficient temporal resolution to facilitate accurate melt onset detection, ii) inconsistent viewing geometries and iii) limited image availability across the Arctic. Here, we construct high temporal resolution composite gamma nought backscatter products (1 day, 1–2 day and 2–4 day) using Sentinel-1 and RADARSAT-2 over a close-to-seamless revisit region located in northern Canadian Arctic and Greenland for estimating melt onset over Arctic sea ice in 2016 and 2017. We employ the necessary radiometric terrain flattening and local resolution weighting techniques to generate normalised backscatter over the entire study region, removing restrictions limiting analysis to a single sensor or track's swath width by integrating both ascending and descending passes into the composite products. Results indicate that higher temporal resolution multi-sensor composite gamma nought products (1 day) that make use of the most imagery provide a robust temporal evolution of the backscatter. This allows for more representative estimates of melt onset as it is easier to separate the melt onset threshold from winter variability that is otherwise a considerable challenge for SAR based melt onset algorithms because of inconsistent temporal resolution. Multi-sensor composite gamma naught melt onset detection is in good agreement with melt onset estimates derived from the Advance Scatterometer (ASCAT) backscatter values and passive microwave brightness temperatures over homogenous sea ice regions but very noticeable improvement was found within narrow channels and regions ... |
format |
Article in Journal/Newspaper |
author |
Howell, Stephen E L Small, David Rohner, Christoph Mahmud, Mallik S Yackel, John J Brady, Michael |
author_facet |
Howell, Stephen E L Small, David Rohner, Christoph Mahmud, Mallik S Yackel, John J Brady, Michael |
author_sort |
Howell, Stephen E L |
title |
Estimating melt onset over Arctic sea ice from time series multi-sensor Sentinel-1 and RADARSAT-2 backscatter |
title_short |
Estimating melt onset over Arctic sea ice from time series multi-sensor Sentinel-1 and RADARSAT-2 backscatter |
title_full |
Estimating melt onset over Arctic sea ice from time series multi-sensor Sentinel-1 and RADARSAT-2 backscatter |
title_fullStr |
Estimating melt onset over Arctic sea ice from time series multi-sensor Sentinel-1 and RADARSAT-2 backscatter |
title_full_unstemmed |
Estimating melt onset over Arctic sea ice from time series multi-sensor Sentinel-1 and RADARSAT-2 backscatter |
title_sort |
estimating melt onset over arctic sea ice from time series multi-sensor sentinel-1 and radarsat-2 backscatter |
publisher |
Elsevier |
publishDate |
2019 |
url |
https://www.zora.uzh.ch/id/eprint/171432/ https://www.zora.uzh.ch/id/eprint/171432/1/2019_1-s2.0-S0034425719301828-main.pdf https://doi.org/10.5167/uzh-171432 https://doi.org/10.1016/j.rse.2019.04.031 |
geographic |
Arctic Greenland |
geographic_facet |
Arctic Greenland |
genre |
Arctic Arctic Greenland Sea ice |
genre_facet |
Arctic Arctic Greenland Sea ice |
op_source |
Howell, Stephen E L; Small, David; Rohner, Christoph; Mahmud, Mallik S; Yackel, John J; Brady, Michael (2019). Estimating melt onset over Arctic sea ice from time series multi-sensor Sentinel-1 and RADARSAT-2 backscatter. Remote Sensing of Environment, 229:48-59. |
op_relation |
https://www.zora.uzh.ch/id/eprint/171432/1/2019_1-s2.0-S0034425719301828-main.pdf doi:10.5167/uzh-171432 doi:10.1016/j.rse.2019.04.031 urn:issn:0034-4257 |
op_rights |
info:eu-repo/semantics/openAccess Creative Commons: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) http://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_doi |
https://doi.org/10.5167/uzh-17143210.1016/j.rse.2019.04.031 |
_version_ |
1802638976047120384 |