Retrieval of Effective Correlation Length and Snow Water Equivalent from Radar and Passive Microwave Measurements
Current methods for retrieving SWE (snow water equivalent) from space rely on passive microwave sensors. Observations are limited by poor spatial resolution, ambiguities related to separation of snow microstructural properties from the total snow mass, and signal saturation when snow is deep (~>8...
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ftmdpi:oai:mdpi.com:/2072-4292/10/2/170/ 2023-08-20T04:08:44+02:00 Retrieval of Effective Correlation Length and Snow Water Equivalent from Radar and Passive Microwave Measurements Juha Lemmetyinen Chris Derksen Helmut Rott Giovanni Macelloni Josh King Martin Schneebeli Andreas Wiesmann Leena Leppänen Anna Kontu Jouni Pulliainen agris 2018-01-25 application/pdf https://doi.org/10.3390/rs10020170 EN eng Multidisciplinary Digital Publishing Institute https://dx.doi.org/10.3390/rs10020170 https://creativecommons.org/licenses/by/4.0/ Remote Sensing; Volume 10; Issue 2; Pages: 170 snow water equivalent passive microwave radar snow correlation length Text 2018 ftmdpi https://doi.org/10.3390/rs10020170 2023-07-31T21:21:53Z Current methods for retrieving SWE (snow water equivalent) from space rely on passive microwave sensors. Observations are limited by poor spatial resolution, ambiguities related to separation of snow microstructural properties from the total snow mass, and signal saturation when snow is deep (~>80 cm). The use of SAR (Synthetic Aperture Radar) at suitable frequencies has been suggested as a potential observation method to overcome the coarse resolution of passive microwave sensors. Nevertheless, suitable sensors operating from space are, up to now, unavailable. Active microwave retrievals suffer, however, from the same difficulties as the passive case in separating impacts of scattering efficiency from those of snow mass. In this study, we explore the potential of applying active (radar) and passive (radiometer) microwave observations in tandem, by using a dataset of co-incident tower-based active and passive microwave observations and detailed in situ data from a test site in Northern Finland. The dataset spans four winter seasons with daily coverage. In order to quantify the temporal variability of snow microstructure, we derive an effective correlation length for the snowpack (treated as a single layer), which matches the simulated microwave response of a semi-empirical radiative transfer model to observations. This effective parameter is derived from radiometer and radar observations at different frequencies and frequency combinations (10.2, 13.3 and 16.7 GHz for radar; 10.65, 18.7 and 37 GHz for radiometer). Under dry snow conditions, correlations are found between the effective correlation length retrieved from active and passive measurements. Consequently, the derived effective correlation length from passive microwave observations is applied to parameterize the retrieval of SWE using radar, improving retrieval skill compared to a case with no prior knowledge of snow-scattering efficiency. The same concept can be applied to future radar satellite mission concepts focused on retrieving SWE, exploiting ... Text Northern Finland MDPI Open Access Publishing Remote Sensing 10 2 170 |
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MDPI Open Access Publishing |
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English |
topic |
snow water equivalent passive microwave radar snow correlation length |
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snow water equivalent passive microwave radar snow correlation length Juha Lemmetyinen Chris Derksen Helmut Rott Giovanni Macelloni Josh King Martin Schneebeli Andreas Wiesmann Leena Leppänen Anna Kontu Jouni Pulliainen Retrieval of Effective Correlation Length and Snow Water Equivalent from Radar and Passive Microwave Measurements |
topic_facet |
snow water equivalent passive microwave radar snow correlation length |
description |
Current methods for retrieving SWE (snow water equivalent) from space rely on passive microwave sensors. Observations are limited by poor spatial resolution, ambiguities related to separation of snow microstructural properties from the total snow mass, and signal saturation when snow is deep (~>80 cm). The use of SAR (Synthetic Aperture Radar) at suitable frequencies has been suggested as a potential observation method to overcome the coarse resolution of passive microwave sensors. Nevertheless, suitable sensors operating from space are, up to now, unavailable. Active microwave retrievals suffer, however, from the same difficulties as the passive case in separating impacts of scattering efficiency from those of snow mass. In this study, we explore the potential of applying active (radar) and passive (radiometer) microwave observations in tandem, by using a dataset of co-incident tower-based active and passive microwave observations and detailed in situ data from a test site in Northern Finland. The dataset spans four winter seasons with daily coverage. In order to quantify the temporal variability of snow microstructure, we derive an effective correlation length for the snowpack (treated as a single layer), which matches the simulated microwave response of a semi-empirical radiative transfer model to observations. This effective parameter is derived from radiometer and radar observations at different frequencies and frequency combinations (10.2, 13.3 and 16.7 GHz for radar; 10.65, 18.7 and 37 GHz for radiometer). Under dry snow conditions, correlations are found between the effective correlation length retrieved from active and passive measurements. Consequently, the derived effective correlation length from passive microwave observations is applied to parameterize the retrieval of SWE using radar, improving retrieval skill compared to a case with no prior knowledge of snow-scattering efficiency. The same concept can be applied to future radar satellite mission concepts focused on retrieving SWE, exploiting ... |
format |
Text |
author |
Juha Lemmetyinen Chris Derksen Helmut Rott Giovanni Macelloni Josh King Martin Schneebeli Andreas Wiesmann Leena Leppänen Anna Kontu Jouni Pulliainen |
author_facet |
Juha Lemmetyinen Chris Derksen Helmut Rott Giovanni Macelloni Josh King Martin Schneebeli Andreas Wiesmann Leena Leppänen Anna Kontu Jouni Pulliainen |
author_sort |
Juha Lemmetyinen |
title |
Retrieval of Effective Correlation Length and Snow Water Equivalent from Radar and Passive Microwave Measurements |
title_short |
Retrieval of Effective Correlation Length and Snow Water Equivalent from Radar and Passive Microwave Measurements |
title_full |
Retrieval of Effective Correlation Length and Snow Water Equivalent from Radar and Passive Microwave Measurements |
title_fullStr |
Retrieval of Effective Correlation Length and Snow Water Equivalent from Radar and Passive Microwave Measurements |
title_full_unstemmed |
Retrieval of Effective Correlation Length and Snow Water Equivalent from Radar and Passive Microwave Measurements |
title_sort |
retrieval of effective correlation length and snow water equivalent from radar and passive microwave measurements |
publisher |
Multidisciplinary Digital Publishing Institute |
publishDate |
2018 |
url |
https://doi.org/10.3390/rs10020170 |
op_coverage |
agris |
genre |
Northern Finland |
genre_facet |
Northern Finland |
op_source |
Remote Sensing; Volume 10; Issue 2; Pages: 170 |
op_relation |
https://dx.doi.org/10.3390/rs10020170 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3390/rs10020170 |
container_title |
Remote Sensing |
container_volume |
10 |
container_issue |
2 |
container_start_page |
170 |
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1774721176439881728 |