Ponencia expuesta online en el 41st annual IGARSS (2021) celebrado en Bruselas del 12-16 de juli

Cardellach, Estel

Casal, Tânia

Hendricks, S.

Huntemann, Marcus

Itkin, Polona

Li, W.

Martín-Neira, Manuel

Nandan, Vishnu

Ribó, Serni

Rius, Antonio

Spreen, Gunnar

Stroeve, Julienne

Tonboe, Rasmus

English

Digital.CSIC

IGARSS 2021                                                                                                                                                                             Brussels/Virtual, July 12-16 2021                                                                                                                                                            Monitoring Arctic Sea Ice During One Year: Linearly Polarized GNSS-Reflectometry at the MOSAiC CampaignE. Cardellach1 2, W. Li1 2, S. Ribó1 2, A. Rius1 2, J. Stroeve3 4, V. Nandan3, P. Itkin5 6, R. Tonboe7, S. Hendricks8, M. Huntemann9, G. Spreen9, T. Casal10, M. Martín-Neira10¹ Institute of Space Studies (ICE, CSIC), Barcelona, Spain ² Institute for Space Studies of Catalonia (IEEC), Barcelona, Spain3 Centre for Earth Observation Science, University of Manitoba, Winnipeg, MB, Canada4 CPOM, University of College London, UK5 UiT The Arctic University of Norway, Tromsø, Norway6 Cooperative Institute for Research in the Atmosphere, Colorado State U., Fort Collins, CO, USA7 Danish Meteorological Institute, Copenhagen, Denmark8 Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany9 Institute of Environmental Physics, University of Bremen, Bremen, Germany10 European Space Agency, ESTEC, Noordwijk, The NetherlandsIGARSS 2021                                                                                                                                                                             Brussels/Virtual, July 12-16 2021                                                                                                                                                             MOSAiC: Multidisciplinary drifting Observatory for the Study of Arctic Climate  RV Polarstern, drifted with the sea ice across the central Arctic for one year (September 2019 - October 2020) Study of key aspects of the coupled Arctic climate system Led by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) Sensors in a distributed network up to ~50km distance from Polarstern Nearby research camps, among others, ICE camp (snow and ice measurements) with a Remote Sensing site MOSAiC Expedition:mosaic-expedition-orgmosaic-expedition-orgIGARSS 2021                                                                                                                                                                             Brussels/Virtual, July 12-16 2021                                                                                                                                                             A system to collect signals emitted by the navigation satellites (GNSS) and reflected off the ice floe structure was deployed at the Remote Sensing site Our GNSS-R system captured, simultaneously, the H- and V-pol components of the direct and reflected L1 and L2 frequency bands signals transmitted by the GPS, Galileo, and GLONASS constellations.GNSS-R on the floe:To which parameters of the air+snow+ice+water system are GNSS-R signals sensitive? Photos: S. Hendricks (AWI)IGARSS 2021                                                                                                                                                                             Brussels/Virtual, July 12-16 2021                                                                                                                                                             Forward scattering in specular direction L-band (~1.5 GHz): penetration into snow and ice The splitted rays suffer coherent scattering These rays interfere with each other and with the direct line-of-sight signals: Observable Interferogram Do interferences depend on snow and ice thickness and permittivities?Scattering process:IGARSS 2021                                                                                                                                                                             Brussels/Virtual, July 12-16 2021                                                                                                                                                             Examples for frequency band L2 (top) and L1-L2 interferograms (bottom) Model & Data:H-pol V-polL2 interferogram, 2020-02-03 (blue)Model (red): 0.1m snow thickness, 1.13 permitt snow, 0.57 m SIT, 3.5 permittivityH-pol V-polL1-L2 interferogram, 2019-11-12 (blue)Model (red): 6cm snow thickness, 1.28 permitt snow, 0.52 m SIT, 3.21 permittivityIGARSS 2021                                                                                                                                                                             Brussels/Virtual, July 12-16 2021                                                                                                                                                             Metrics to quantify mismatch between observables (obs) and parameterized model (mod(parameters)): Misfit evaluated at different parameters: Misfit(snow & ice parameters)  Example: 2019-11-15 H-pol, using L1-L2 together with L2 interferograms as observablesSensitivity:IGARSS 2021                                                                                                                                                                             Brussels/Virtual, July 12-16 2021                                                                                                                                                            Example: 2019-11-15 V-pol, using L1-L2 together with L2 interferograms as observablesSensitivity:IGARSS 2021                                                                                                                                                                             Brussels/Virtual, July 12-16 2021                                                                                                                                                             Overall response of the floe → effective values (e.g., reflectivity of the system rather than each layer) → effective permittivity: Example: effective permittivity assuming different surface roughnessEffective values:IGARSS 2021                                                                                                                                                                             Brussels/Virtual, July 12-16 2021                                                                                                                                                            A GNSS-R equipment with linearly polarized antennas was deployed at the Remote Sensing site, ICE camp, of the MOSAiC expeditionThe collected EM fields present interferograms, compatible with a scattering model of multiple rays reflecting at multiple layers (snow, ice, water).The mismatch or misfit function is defined to analyze the sensitivity of the observables to snow and sea ice parameters– Sensitivity to snow thickness and permittivity– Sensitivity to sea ice thickness and permittivity, but multiple parameter combinations lead to a good match with the data → ancillary information would help breaking possible ambiguities• Response of the overall snow+ice structure → effective valuesDiscussion:

Monitoring Arctic Sea Ice During One Year: Linearly Polarized GNSSReflectometry at the MOSAiC Campaign

https://digital.csic.es/bitstream/10261/270214/1/MOSAiC.pdf

Monitoring Arctic Sea Ice During One Year: Linearly Polarized GNSSReflectometry at the MOSAiC Campaign

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