Passive Microwave Melt Onset Retrieval Based on a Variable Threshold: Assessment in the Canadian Arctic Archipelago
The Canadian Arctic Archipelago (CAA) presents unique challenges to the determination of melt onset (MO) using remote sensing data. High spatial resolution data is required to discern melt onset among the islands and narrow waterways of the region. Current passive microwave retrievals use daily aver...
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MDPI AG
2019-05-01
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Online Access: | https://www.mdpi.com/2072-4292/11/11/1304 |
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author | Stephen Marshall K. Andrea Scott Randall K. Scharien |
author_facet | Stephen Marshall K. Andrea Scott Randall K. Scharien |
author_sort | Stephen Marshall |
collection | DOAJ |
description | The Canadian Arctic Archipelago (CAA) presents unique challenges to the determination of melt onset (MO) using remote sensing data. High spatial resolution data is required to discern melt onset among the islands and narrow waterways of the region. Current passive microwave retrievals use daily averaged 19 GHz and 37 GHz data from the multi-channel microwave radiometer (SMMR) and/or the special sensor microwave/imager (SSM/I). The development of a new passive microwave melt onset method capable of using higher resolution data is desirable. The new passive microwave melt onset method described here, named the Dynamic Threshold Variability Method (DTVM), uses higher resolution data from the 37 GHz vertically-polarized channel from the advanced microwave scanning radiometers (AMSR-E and AMSR-2). The DTVM MO detection methodology differs from previously presented passive microwave Arctic MO methods in that it does not use a fixed threshold of a brightness temperature parameter. Instead, the DTVM determines MO dates based on the distribution of dates corresponding to the exceedance of a range of brightness temperature variability thresholds. The method also uses swath data instead of daily averaged brightness temperatures, which is found to lead to improved melt detection. Two current passive microwave MO methods are compared and evaluated for applicability in the CAA alongside the DTVM. The DTVM provides MO dates at a higher spatial resolution than earlier methods in addition to higher correlation with MO dates from surface air temperature (SAT) reanalyses. It is found that, for some years, MO dates in the CAA exhibit a latitudinal dependence, while in other years the MO dates in the CAA are relatively uniform across the domain. |
first_indexed | 2024-04-11T19:57:07Z |
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id | doaj.art-85c8ce764a4e4acaaafe1186d9f0f0f2 |
institution | Directory Open Access Journal |
issn | 2072-4292 |
language | English |
last_indexed | 2024-04-11T19:57:07Z |
publishDate | 2019-05-01 |
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series | Remote Sensing |
spelling | doaj.art-85c8ce764a4e4acaaafe1186d9f0f0f22022-12-22T04:05:59ZengMDPI AGRemote Sensing2072-42922019-05-011111130410.3390/rs11111304rs11111304Passive Microwave Melt Onset Retrieval Based on a Variable Threshold: Assessment in the Canadian Arctic ArchipelagoStephen Marshall0K. Andrea Scott1Randall K. Scharien2Department of Systems Design Engineering, University of Waterloo, Waterloo, ON N2L 3G1, CanadaDepartment of Systems Design Engineering, University of Waterloo, Waterloo, ON N2L 3G1, CanadaDepartment of Geography, University of Victoria, Victoria, BC V8P 5C2, CanadaThe Canadian Arctic Archipelago (CAA) presents unique challenges to the determination of melt onset (MO) using remote sensing data. High spatial resolution data is required to discern melt onset among the islands and narrow waterways of the region. Current passive microwave retrievals use daily averaged 19 GHz and 37 GHz data from the multi-channel microwave radiometer (SMMR) and/or the special sensor microwave/imager (SSM/I). The development of a new passive microwave melt onset method capable of using higher resolution data is desirable. The new passive microwave melt onset method described here, named the Dynamic Threshold Variability Method (DTVM), uses higher resolution data from the 37 GHz vertically-polarized channel from the advanced microwave scanning radiometers (AMSR-E and AMSR-2). The DTVM MO detection methodology differs from previously presented passive microwave Arctic MO methods in that it does not use a fixed threshold of a brightness temperature parameter. Instead, the DTVM determines MO dates based on the distribution of dates corresponding to the exceedance of a range of brightness temperature variability thresholds. The method also uses swath data instead of daily averaged brightness temperatures, which is found to lead to improved melt detection. Two current passive microwave MO methods are compared and evaluated for applicability in the CAA alongside the DTVM. The DTVM provides MO dates at a higher spatial resolution than earlier methods in addition to higher correlation with MO dates from surface air temperature (SAT) reanalyses. It is found that, for some years, MO dates in the CAA exhibit a latitudinal dependence, while in other years the MO dates in the CAA are relatively uniform across the domain.https://www.mdpi.com/2072-4292/11/11/1304sea icemelt onsetpassive microwave |
spellingShingle | Stephen Marshall K. Andrea Scott Randall K. Scharien Passive Microwave Melt Onset Retrieval Based on a Variable Threshold: Assessment in the Canadian Arctic Archipelago Remote Sensing sea ice melt onset passive microwave |
title | Passive Microwave Melt Onset Retrieval Based on a Variable Threshold: Assessment in the Canadian Arctic Archipelago |
title_full | Passive Microwave Melt Onset Retrieval Based on a Variable Threshold: Assessment in the Canadian Arctic Archipelago |
title_fullStr | Passive Microwave Melt Onset Retrieval Based on a Variable Threshold: Assessment in the Canadian Arctic Archipelago |
title_full_unstemmed | Passive Microwave Melt Onset Retrieval Based on a Variable Threshold: Assessment in the Canadian Arctic Archipelago |
title_short | Passive Microwave Melt Onset Retrieval Based on a Variable Threshold: Assessment in the Canadian Arctic Archipelago |
title_sort | passive microwave melt onset retrieval based on a variable threshold assessment in the canadian arctic archipelago |
topic | sea ice melt onset passive microwave |
url | https://www.mdpi.com/2072-4292/11/11/1304 |
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