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Abstract |
Due to recent climate change conditions, i.e. increasing temperatures and changing precipitation patterns, arctic snow cover dynamics exhibit strong changes in terms of extent and duration. Arctic amplification processes and impacts are well documented expected to strengthen in coming decades. In this context, innovative observation methods are helpful for a better comprehension of the spatial variability of snow properties relevant for climate research and hydrological applications. Microwave remote sensing provides exceptional spatial and temporal performance in terms of all-weather application and target penetration. Time-series of Synthetic Active Radar images (SAR) are becoming more accessible at different frequencies and polarimetry has demonstrated a significant advantage for detecting changes in different media. Concerning arctic snow monitoring, SAR sensors can offer continuous time-series during the polar night and with cloud cover, providing a consequent advantage in regard of optical sensors. The aim of this study is dedicated to the spatial/temporal variability of snow in the Ny-Ålesund area on the Br∅gger peninsula, Svalbard (N 78°55’ / E 11° 55’). The TerraSAR-X satellite (DLR, Germany) operated at X-band (3.1 cm, 9.6 GHz) with dual co-pol mode (HH/VV) at 5-m spatial resolution, and with high incidence angles (36° to 39°) poviding a better snow penetration and reducing topographic constraints. A dataset of 92 images (ascending and descending) is available since 2017, together with a high resolution DEM (NPI 5-m) and consistent in-situ measurements of meteorological data and snow profiles including glaciers sites. Polarimetric processing is based on the Kennaugh matrix decomposition, copolar phase coherence (CCOH) and copolar phase difference (CPD). The Kennaugh matrix elements K0, K3, K4, and K7 are, respectively, the total intensity, phase ratio, intensity ratio, and shift between HH and VV phase center. Their interpretation allows analysing the structure of the snowpack linked to the near real time of in-situ measurements (snow profiles). The X-band signal is strongly influenced by the snow stratigraphy: internal ice layers reduce or block the penetration of the signal into the snow pack. The best R2 correlation performances between estimated and measured snow heights are ranging from 0.50 to 0.70 for dry snow conditions. Therefore, the use of the X-band for regular snow height estimations remains limited under these conditions. Conversely, this study shows the benefit of TerraSAR-X thanks to the Kennaugh matrix elements analysis. A focus is set on the Copolar Phase Difference (CPD, Leinss 2016) between VV and HH polarization: Φ CPD = Φ VV – Φ HH. Our results indicate that the CPD values are related to the snow metamorphism: positive values correspond to dry snow (horizontal structures), negative values indicate recrystallization processes (vertical structures). Backscattering evolution in time offer a good proxy for meteorological events detection, impacting on snow metamorphism. Fresh snowfalls or melting processes can then be retrieved at the regional scale and linked to air temperature or precipitation measurements at local scale. Polarimetric SAR time series is therefore of interest to complement satellite-based precipitation measurements in the Arctic. |
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Author |
TaeOh Kwon, Hideaki Shibata, Sebastian Kepfer-Rojas, Inger K. Schmidt, Klaus S. Larsen, Claus Beier, Björn Berg, Kris Verheyen, Jean-Francois Lamarque, Frank Hagedorn, Nico Eisenhauer, Ika Djukic, TeaComposition Network , TaeOh Kwon, Hideaki Shibata, Sebastian Kepfer-Rojas, Inger Kappel Schmidt, Klaus Steenberg Larsen, Claus Beier, Björn Berg, Kris Verheyen, Jean Francois Lamarque, Frank Hagedorn, Nico Eisenhauer, Ika Djukic, Adriano Caliman, Alain Paquette, Alba Gutiérrez-Girón, Alessandro Petraglia, Algirdas Augustaitis, Amélie Saillard, Ana Carolina Ruiz-Fernández, Ana I. Sousa, Ana I. Lillebø, Anderson da Rocha Gripp, Andrea Lamprecht, Andreas Bohner, André-Jean Francez, Andrey Malyshev, Andrijana Andrić, Angela Stanisci, Anita Zolles, Anna Avila, Anna-Maria Virkkala, Anne Probst, Annie Ouin, Anzar A. Khuroo, Arne Verstraeten, Artur Stefanski, Aurora Gaxiola, Bart Muys, Beatriz Gozalo, Bernd Ahrends, Bo Yang, Brigitta Erschbamer, Carmen Eugenia Rodríguez Ortíz, Casper T. Christiansen, Céline Meredieu, Cendrine Mony, Charles Nock, Chiao-Ping Wang, Christel Baum, Christian Rixen, Christine Delire, Christophe Piscart, Christopher Andrews, Corinna Rebmann, Cristina Branquinho, Dick Jan, Dirk Wundram, Dušanka Vujanović, E. Carol Adair, Eduardo Ordóñez-Regil, Edward R. Crawford, Elena F. Tropina, Elisabeth Hornung, Elli Groner, Eric Lucot, Esperança Gacia, Esther Lévesque, Evanilde Benedito, Evgeny A. Davydov, Fábio Padilha Bolzan, Fernando T. Maestre, Florence Maunoury-Danger, Florian Kitz, Florian Hofhansl, Flurin Sutter, Francisco de Almeida Lobo, Franco Leadro Souza, Franz Zehetner, Fulgence Kouamé Koffi, Georg Wohlfahrt, Giacomo Certini, Gisele Daiane Pinha, Grizelle González, Guylaine Canut, Harald Pauli, Héctor A. Bahamonde, Heike Feldhaar, Heinke Jäger, Helena Cristina Serrano, Hélène Verheyden, Helge Bruelheide, Henning Meesenburg, Hermann Jungkunst, Hervé Jactel, Hiroko Kurokawa, Ian Yesilonis, Inara Melece, Inge van Halder, Inmaculada García Quirós, István Fekete, Ivika Ostonen, Jana Borovská, Javier Roales, Jawad Hasan Shoqeir, Jean-Christophe Lata, Jean-Luc Probst, Jeyanny Vijayanathan, Jiri Dolezal, Joan-Albert Sanchez-Cabeza, Joël Merlet, John Loehr, Jonathan von Oppen, Jörg Löffler, José Luis Benito Alonso, José-Gilberto Cardoso-Mohedano, Josep Peñuelas, Joseph C. Morina, Juan Darío Quinde, Juan J. Jiménez, Juha M. Alatalo, Julia Seeber, Julia Kemppinen, Jutta Stadler, Kaie Kriiska, Karel Van den Meersche, Karibu Fukuzawa, Katalin Szlavecz, Katalin Juhos, Katarína Gerhátová, Kate Lajtha, Katie Jennings, Katja Tielbörger, Kazuhiko Hoshizaki, Ken Green, Klaus Steinbauer, Laryssa Pazianoto, Laura Dienstbach, Laura Yahdjian, Laura J. Williams, Laurel Brigham, Lee Hanna, Liesbeth van den Brink, Lindsey Rustad, Lourdes Morillas, Luciana Silva Carneiro, Luciano Di Martino, Luis Villar, Luísa Alícida Fernandes Tavares, Madison Morley, Manuela Winkler, Marc Lebouvier, Marcello Tomaselli, Marcus Schaub, Maria Glushkova, Maria Guadalupe Almazan Torres, Marie-Anne de Graaff, Marie-Noëlle Pons, Marijn Bauters, Marina Mazón, Mark Frenzel, Markus Wagner, Markus Didion, Maroof Hamid, Marta Lopes, Martha Apple, Martin Weih, Matej Mojses, Matteo Gualmini, Matthew Vadeboncoeur, Michael Bierbaumer, Michael Danger, Michael Scherer-Lorenzen, Michal Růžek, Michel Isabellon, Michele Di Musciano, Michele Carbognani, Miglena Zhiyanski, Mihai Puşcaş, Milan Barna, Mioko Ataka, Miska Luoto, Mohammed H. Alsafaran, Nadia Barsoum, Naoko Tokuchi, Nathalie Korboulewsky, Nicolas Lecomte, Nina Filippova, Norbert Hölzel, Olga Ferlian, Oscar Romero, Osvaldo Pinto-Jr, Pablo Peri, Pavel Dan Turtureanu, Peter Haase, Peter Macreadie, Peter B. Reich, Petr Petřík, Philippe Choler, Pierre Marmonier, Quentin Ponette, Rafael Dettogni Guariento, Rafaella Canessa, Ralf Kiese, Rebecca Hewitt, Robert Weigel, Róbert Kanka, Roberto Cazzolla Gatti, Rodrigo Lemes Martins, Romà Ogaya, Romain Georges, Rosario G. Gavilán, Sally Wittlinger, Sara Puijalon, Satoshi Suzuki, Schädler Martin, Schmidt Anja, Sébastien Gogo, Silvio Schueler, Simon Drollinger, Simone Mereu, Sonja Wipf, Stacey Trevathan-Tackett, Stefan Stoll, Stefan Löfgren, Stefan Trogisch, Steffen Seitz, Stephan Glatzel, Susanna Venn, Sylvie Dousset, Taiki Mori, Takanori Sato, Takuo Hishi, Tatsuro Nakaji, Theurillat Jean-Paul, Thierry Camboulive, Thomas Spiegelberger, Thomas Scholten, Thomas J. Mozdzer, Till Kleinebecker, Tomáš Rusňák, Tshililo Ramaswiela, Tsutom Hiura, Tsutomu Enoki, Tudor-Mihai Ursu, Umberto Morra di Cella, Ute Hamer, Valentin Klaus, Valter Di Cecco, Vanessa Rego, Veronika Fontana, Veronika Piscová, Vincent Bretagnolle, Vincent Maire, Vinicius Farjalla, Vittoz Pascal, Wenjun Zhou, Wentao Luo, William Parker, Yasuhiro Utsumi, Yuji Kominami, Zsolt Kotroczó, Zsolt Tóth |
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