[{"awards": "1940473 Banwell, Alison; 1940483 Datta-Barua, Seebany", "bounds_geometry": "POLYGON((166.502 -77.947,166.52630000000002 -77.947,166.5506 -77.947,166.5749 -77.947,166.5992 -77.947,166.6235 -77.947,166.64780000000002 -77.947,166.6721 -77.947,166.6964 -77.947,166.7207 -77.947,166.745 -77.947,166.745 -77.9479,166.745 -77.9488,166.745 -77.9497,166.745 -77.95060000000001,166.745 -77.95150000000001,166.745 -77.9524,166.745 -77.9533,166.745 -77.9542,166.745 -77.9551,166.745 -77.956,166.7207 -77.956,166.6964 -77.956,166.6721 -77.956,166.64780000000002 -77.956,166.6235 -77.956,166.5992 -77.956,166.5749 -77.956,166.5506 -77.956,166.52630000000002 -77.956,166.502 -77.956,166.502 -77.9551,166.502 -77.9542,166.502 -77.9533,166.502 -77.9524,166.502 -77.95150000000001,166.502 -77.95060000000001,166.502 -77.9497,166.502 -77.9488,166.502 -77.9479,166.502 -77.947))", "dataset_titles": null, "datasets": null, "date_created": "Wed, 27 Aug 2025 00:00:00 GMT", "description": "Part I: Nontechnical \r\nGlobal navigation satellite systems (GNSS) such as the Global Positioning System (GPS) are continuously transmitting signals toward Earth. While many people may be familiar with using the GPS signals for positioning and navigation, these signals are also usable for sensing Earth\u2019s environment. Ice and snow surfaces are continuously awash with radio signals broadcast from GNSS. When the signal bounces off the ice or snow surface and then arrives at a receiver, it acts as a form of radar, in which the radar transmitter is free, covers the globe, is always on, and is unaffected by precipitation. This work will build and deploy a GNSS reflectometry (GNSS-R) system specifically to detect reflections off glaciated surfaces. The goal of the work is to find out how the signal changes depending on surface type, and specifically, whether using GNSS as a radar can be effective for monitoring snow and ice melt and freeze on a glaciated surface. In this system, two GNSS antennas and receivers will be used, one facing upward for positioning, and one directed downward to collect the surface reflections. Setting up the GNSS-R system near the ice runways on the McMurdo Ice Shelf, near to the US McMurdo Station, Antarctica, the system will monitor for variations in the signal as it reflects off alternately surface ice, meltwater, and snow. With camera images and lidar surveys at the site will relate the GNSS \u201cradar\u201d signal and the area it bounced from (knowable from geometry because the GNSS satellite and receiver locations are known) to the surface type. If GNSS-R is developed to the point of being comparable to or better than existing ways of characterizing frozen surfaces, it would find a niche in applications ranging from local ablation monitoring to assessment of aircraft runway safety. \r\n\r\nPart II: Technical Description \r\nThe proposed research aspires to answer the question: Can global navigation satellite system (GNSS) reflectometry (GNSS-R) be used to reliably map snow-cover, ice, and surface water in a harsh glaciated environment at high spatio-temporal resolution? Our working hypothesis is that GNSS-R can differentiate among cold snow, wet snow, bare ice, wet ice, and surface water in a way that will yield observations that can inform how glacial surfaces accumulate and ablate. This project will test this hypothesis by conducting GNSS-R instrument design, field trial and signal processing, and comparison with other methods, including the single-antenna interferometric reflectometry (GNSS-IR) method currently in use. The objective is to develop GNSS-R instrumentation and data-processing techniques as an effective high-spatiotemporal-resolution method of characterizing the composition of snow, firn and melting ice surfaces relevant to climate change on the Antarctic Ice Sheet. The GNSS-R receiver system will capture the signal after it has interacted with the surface (glaciated in this case), in order to infer variable compositions of the surface. Passive radar return intensity will be used to characterize the surface type, whether snow, firn, ice, or water. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": 166.745, "geometry": "POINT(166.6235 -77.95150000000001)", "instruments": null, "is_usap_dc": true, "keywords": "Supraglacial Lake; Camera; McMurdo; GNSS; Surface Melt; Remote Sensing; GLACIERS/ICE SHEETS; GPS; LIDAR; Multi-Frequency Passive Remote Sensing", "locations": "McMurdo", "north": -77.947, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Instrumentation and Facilities; Antarctic Instrumentation and Facilities", "paleo_time": null, "persons": "Datta-Barua, Seebany; Banwell, Alison", "platforms": null, "repositories": null, "science_programs": null, "south": -77.956, "title": "EAGER: Collaborative Research: Mapping Melting Glacial Surfaces with GNSS Reflectometry", "uid": "p0010533", "west": 166.502}, {"awards": "1844793 Aksoy, Mustafa", "bounds_geometry": "POLYGON((-180 -60,-144 -60,-108 -60,-72 -60,-36 -60,0 -60,36 -60,72 -60,108 -60,144 -60,180 -60,180 -63,180 -66,180 -69,180 -72,180 -75,180 -78,180 -81,180 -84,180 -87,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -87,-180 -84,-180 -81,-180 -78,-180 -75,-180 -72,-180 -69,-180 -66,-180 -63,-180 -60))", "dataset_titles": "Antarctic Firn Brightness Temperatures Measured by AMSR2 and SSMIS (Concordia, Vostok, and the Entire Ice Sheet)); In-Situ Density, Temperature, Grain Size, and Layer Thickness data for the Antarctic Ice Sheet", "datasets": [{"dataset_uid": "601551", "doi": "10.15784/601551", "keywords": "Antarctica; Antarctic Ice Sheet", "people": "Kar, Rahul; Aksoy, Mustafa; Kaurejo, Dua", "repository": "USAP-DC", "science_program": null, "title": "In-Situ Density, Temperature, Grain Size, and Layer Thickness data for the Antarctic Ice Sheet", "url": "https://www.usap-dc.org/view/dataset/601551"}, {"dataset_uid": "601550", "doi": "10.15784/601550", "keywords": "Antarctica; Antarctic Ice Sheet; Satellite; Vostok", "people": "Kaurejo, Dua; Kar, Rahul; Aksoy, Mustafa", "repository": "USAP-DC", "science_program": null, "title": "Antarctic Firn Brightness Temperatures Measured by AMSR2 and SSMIS (Concordia, Vostok, and the Entire Ice Sheet))", "url": "https://www.usap-dc.org/view/dataset/601550"}], "date_created": "Fri, 25 Jun 2021 00:00:00 GMT", "description": "This project will test the hypothesis that physical and thermal properties of Antarctic firn--partially compacted granular snow in an intermediate stage between snow and glacier ice--can be remotely measured from space. Although these properties, such as internal temperature, density, grain size, and layer thickness, are highly relevant to studies of Antarctic climate, ice-sheet dynamics, and mass balance, their measurement currently relies on sparse in-situ surveys under challenging weather conditions. Sensors on polar-orbiting satellites can observe the entire Antarctic every few days during their years-long lifetime. Consequently, the approaches developed in this study, when coupled with the advancing technologies of small and low-cost CubeSats, aim to contribute to Antarctic science and lead to cost-effective, convenient, and accurate long-term analyses of the Antarctic system while reducing the human footprint on the continent. Moreover, the project will be solely based on publicly-available datasets; thus, while contributing to interdisciplinary undergraduate and graduate research and education at the grantee\u0027s institution, the project will also encourage engagement of citizen scientists through its website. The overarching goal of this project is to characterize Antarctic firn layers in terms of their thickness, physical temperature, density, and grain size through multi-frequency microwave radiometer measurements from space. Electromagnetic penetration depth changes with frequency in ice; thus, multi-frequency radiometers are able to profile firn layer properties versus depth. To achieve its objective, the project will utilize the Global Precipitation Measurement (GPM) satellite constellation as a single multi-frequency microwave radiometer system with 11 frequency channels observing the Antarctic Ice Sheet. Archived in-situ measurements of Antarctic firn density, grain size, temperature, and layer thickness will be collected and separated into training and test datasets. Microwave emissions simulated using the training data will be compared to GPM constellation measurements to evaluate and improve state-of-the-art forward microwave emission models. Based on these models, the project will develop numerical retrieval algorithms for the thermal and physical properties of Antarctic firn. Results of retrievals will be validated using the test dataset, and uncertainty and error analyses will be conducted. Lastly, changes in the thermal and physical characteristics of Antarctic firn will be examined through long-term retrieval studies exploiting GPM constellation measurements. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "AMD; FIRN; Amd/Us; USA/NSF; ICE SHEETS; SNOW DENSITY; Multi-Frequency Passive Remote Sensing; University At Albany; USAP-DC; SNOW/ICE TEMPERATURE; SATELLITES; SNOW/ICE", "locations": "University At Albany", "north": -60.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Aksoy, Mustafa", "platforms": "SPACE-BASED PLATFORMS \u003e EARTH OBSERVATION SATELLITES \u003e SATELLITES", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "Characterization of Antarctic Firn by Multi-Frequency Passive Remote Sensing from Space", "uid": "p0010206", "west": -180.0}]

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EAGER: Collaborative Research: Mapping Melting Glacial Surfaces with GNSS Reflectometry

1940473
1940483

2025-08-27

Datta-Barua, Seebany; Banwell, Alison

No dataset link provided

Part I: Nontechnical Global navigation satellite systems (GNSS) such as the Global Positioning System (GPS) are continuously transmitting signals toward Earth. While many people may be familiar with using the GPS signals for positioning and navigation, these signals are also usable for sensing Earth’s environment. Ice and snow surfaces are continuously awash with radio signals broadcast from GNSS. When the signal bounces off the ice or snow surface and then arrives at a receiver, it acts as a form of radar, in which the radar transmitter is free, covers the globe, is always on, and is unaffected by precipitation. This work will build and deploy a GNSS reflectometry (GNSS-R) system specifically to detect reflections off glaciated surfaces. The goal of the work is to find out how the signal changes depending on surface type, and specifically, whether using GNSS as a radar can be effective for monitoring snow and ice melt and freeze on a glaciated surface. In this system, two GNSS antennas and receivers will be used, one facing upward for positioning, and one directed downward to collect the surface reflections. Setting up the GNSS-R system near the ice runways on the McMurdo Ice Shelf, near to the US McMurdo Station, Antarctica, the system will monitor for variations in the signal as it reflects off alternately surface ice, meltwater, and snow. With camera images and lidar surveys at the site will relate the GNSS “radar” signal and the area it bounced from (knowable from geometry because the GNSS satellite and receiver locations are known) to the surface type. If GNSS-R is developed to the point of being comparable to or better than existing ways of characterizing frozen surfaces, it would find a niche in applications ranging from local ablation monitoring to assessment of aircraft runway safety. Part II: Technical Description The proposed research aspires to answer the question: Can global navigation satellite system (GNSS) reflectometry (GNSS-R) be used to reliably map snow-cover, ice, and surface water in a harsh glaciated environment at high spatio-temporal resolution? Our working hypothesis is that GNSS-R can differentiate among cold snow, wet snow, bare ice, wet ice, and surface water in a way that will yield observations that can inform how glacial surfaces accumulate and ablate. This project will test this hypothesis by conducting GNSS-R instrument design, field trial and signal processing, and comparison with other methods, including the single-antenna interferometric reflectometry (GNSS-IR) method currently in use. The objective is to develop GNSS-R instrumentation and data-processing techniques as an effective high-spatiotemporal-resolution method of characterizing the composition of snow, firn and melting ice surfaces relevant to climate change on the Antarctic Ice Sheet. The GNSS-R receiver system will capture the signal after it has interacted with the surface (glaciated in this case), in order to infer variable compositions of the surface. Passive radar return intensity will be used to characterize the surface type, whether snow, firn, ice, or water. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Characterization of Antarctic Firn by Multi-Frequency Passive Remote Sensing from Space

1844793

2021-06-25

Aksoy, Mustafa

In-Situ Density, Temperature, Grain Size, and Layer Thickness data for the Antarctic Ice Sheet	USAP-DC
Antarctic Firn Brightness Temperatures Measured by AMSR2 and SSMIS (Concordia, Vostok, and the Entire Ice Sheet))	USAP-DC

This project will test the hypothesis that physical and thermal properties of Antarctic firn--partially compacted granular snow in an intermediate stage between snow and glacier ice--can be remotely measured from space. Although these properties, such as internal temperature, density, grain size, and layer thickness, are highly relevant to studies of Antarctic climate, ice-sheet dynamics, and mass balance, their measurement currently relies on sparse in-situ surveys under challenging weather conditions. Sensors on polar-orbiting satellites can observe the entire Antarctic every few days during their years-long lifetime. Consequently, the approaches developed in this study, when coupled with the advancing technologies of small and low-cost CubeSats, aim to contribute to Antarctic science and lead to cost-effective, convenient, and accurate long-term analyses of the Antarctic system while reducing the human footprint on the continent. Moreover, the project will be solely based on publicly-available datasets; thus, while contributing to interdisciplinary undergraduate and graduate research and education at the grantee's institution, the project will also encourage engagement of citizen scientists through its website. The overarching goal of this project is to characterize Antarctic firn layers in terms of their thickness, physical temperature, density, and grain size through multi-frequency microwave radiometer measurements from space. Electromagnetic penetration depth changes with frequency in ice; thus, multi-frequency radiometers are able to profile firn layer properties versus depth. To achieve its objective, the project will utilize the Global Precipitation Measurement (GPM) satellite constellation as a single multi-frequency microwave radiometer system with 11 frequency channels observing the Antarctic Ice Sheet. Archived in-situ measurements of Antarctic firn density, grain size, temperature, and layer thickness will be collected and separated into training and test datasets. Microwave emissions simulated using the training data will be compared to GPM constellation measurements to evaluate and improve state-of-the-art forward microwave emission models. Based on these models, the project will develop numerical retrieval algorithms for the thermal and physical properties of Antarctic firn. Results of retrievals will be validated using the test dataset, and uncertainty and error analyses will be conducted. Lastly, changes in the thermal and physical characteristics of Antarctic firn will be examined through long-term retrieval studies exploiting GPM constellation measurements. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

USAP-DC