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Water Surface Research by Radio Methods
Published in N.A. Armand, V.M. Polykov, Radio Propagation and Remote Sensing of the Environment, 2004
The sea ice thickness is estimated by means of indirect data obtained by sidelooking radar (SLR) and SAR. This technique is based on the fact that the scattering properties of sea ice depend on its age. The thickness of the sea ice also depends on its age, which follows from Table 14.3, which characterizes ice types according to the recommendations of the World Meteorological Organization (WMO).114 We can conclude on the basis of the data in this table that some correlation exists between the ice thickness and its properties to scatter microwaves. This correlation has a rather clear physical explanation. As with many simplifications, the surface scattering dominates in the case of first-year (FY) ice. The presence of volumetric scattering is typical for multiyear (MY) ice, which leads to the difference in backscattering coefficient values for both types of ice. FY ice contains a distribution of salt in the form of brine and crystals. The FY ice salinity is especially high at the upper layers, reaching a density near 20%. The approximate value of FY ice permittivity is ε = 3.3+i 0.25.90 This type of ice intensively absorbs microwaves, which at the X-band penetrates into the ice to a depth of only several centimeters (see Equation (2.16)); therefore, volumetric scattering is weak in this case and surface scattering dominates.
Atmospheric Effects
Published in Wayne T. Davis, Joshua S. Fu, Thad Godish, Air Quality, 2021
Wayne T. Davis, Joshua S. Fu, Thad Godish
Decreases in sea ice have been reported in the Arctic. The extent of sea ice in the Arctic spring and summer has decreased on the order of 10%–15% since 1950. This decrease is consistent with an increase in springtime and, to a lesser extent, summer temperatures. The decrease rates of the annual Arctic sea ice extent over the period 1979–2012 were very likely between 3.5% and 4.1% per decade. The average winter sea ice thickness within the Arctic Basin likely decreased between 1.3 and 2.3 m from 1980 to 2008. The average decadal extent of Arctic sea ice has decreased most rapidly in summer and autumn.
Climate Manifestations
Published in Gregory T. Haugan, The New Triple Constraints for Sustainable Projects, Programs, and Portfolios, 2016
Figure 11.13, from the Polar Ice Center, presents recent variations of total Arctic sea ice volume in the context of longer-term variability. Arctic sea ice volume is an important indicator of climate change because it accounts for variations in sea ice thickness as well as sea ice extent. These data are based on observations from satellites, Navy submarines, moorings, and field measurements.
The variability of surface radiation fluxes over landfast sea ice near Zhongshan station, east Antarctica during austral spring
Published in International Journal of Digital Earth, 2019
Lejiang Yu, Qinghua Yang, Mingyu Zhou, Donald H. Lenschow, Xianqiao Wang, Jiechen Zhao, Qizhen Sun, Zhongxiang Tian, Hui Shen, Lin Zhang
The recording interval of the flux data was one minute which was then averaged over a 30-min period. The radiation sensors were checked around 1300 LST (local time) every day. The sensors were seldom covered by snow and/or frost flower during the observation periods. The horizontal level of the sensors was also checked and adjusted, since surface melt on the sensors can cause tilting. The uncertainty of the radiation measurements is ±5%. As the albedo measurements are not reliable for large solar zenith angles (Vihma, Johansson, and Launiainen 2009), the albedo was calculated based on the SW↑ and SW↓ ratio for zenith angles of less than 80°, consistent with Pirazzini (2004) and Järvinen and Leppäranta (2013). Sea ice thickness used in this study was measured with an ice auger every seven days with an accuracy of ±0.5 cm at all three sites, and then averaged. Snow thickness was measured almost every day using a ruler with an accuracy of ±0.2 cm near the the downward-facing pyranometer. The snow/bare ice surface temperature was calculated from the downward/upward long-wave fluxes using a fixed emissivity according to Pirazzini et al. (2006).
The spatiotemporal patterns of sea ice in the Bohai Sea during the winter seasons of 2000–2016
Published in International Journal of Digital Earth, 2019
Lunxi Ouyang, Fengming Hui, Lixian Zhu, Xiao Cheng, Bin Cheng, Mohammed Shokr, Jiechen Zhao, Minghu Ding, Tao Zeng
Sea ice is an important component of the climate system. It can greatly influence the exchange of heat, energy, mass, and momentum between the atmosphere and ocean (Dieckmann and Hellmer 2010). Satellite observations have played a pivotal role in sea ice studies. Sea ice thickness (SIT) is crucial for the quantitative understanding of key physical processes in ice-covered waters. For example, it is important for understanding the heat flux between ocean and atmosphere, the mass balance of sea ice, as well as ocean circulation in Polar Regions. SIT is usually obtained from in situ measurements, ship-based observations, and submarine or moored upward-looking sonar measurement. However, these observations are time consuming and spatially limited.
Copernicus Marine Service Ocean State Report
Published in Journal of Operational Oceanography, 2018
Karina von Schuckmann, Pierre-Yves Le Traon, Neville Smith, Ananda Pascual, Pierre Brasseur, Katja Fennel, Samy Djavidnia, Signe Aaboe, Enrique Alvarez Fanjul, Emmanuelle Autret, Lars Axell, Roland Aznar, Mario Benincasa, Abderahim Bentamy, Fredrik Boberg, Romain Bourdallé-Badie, Bruno Buongiorno Nardelli, Vittorio E. Brando, Clément Bricaud, Lars-Anders Breivik, Robert J.W. Brewin, Arthur Capet, Adrien Ceschin, Stefania Ciliberti, Gianpiero Cossarini, Marta de Alfonso, Alvaro de Pascual Collar, Jos de Kloe, Julie Deshayes, Charles Desportes, Marie Drévillon, Yann Drillet, Riccardo Droghei, Clotilde Dubois, Owen Embury, Hélène Etienne, Claudia Fratianni, Jesús García Lafuente, Marcos Garcia Sotillo, Gilles Garric, Florent Gasparin, Riccardo Gerin, Simon Good, Jérome Gourrion, Marilaure Grégoire, Eric Greiner, Stéphanie Guinehut, Elodie Gutknecht, Fabrice Hernandez, Olga Hernandez, Jacob Høyer, Laura Jackson, Simon Jandt, Simon Josey, Mélanie Juza, John Kennedy, Zoi Kokkini, Gerasimos Korres, Mariliis Kõuts, Priidik Lagemaa, Thomas Lavergne, Bernard le Cann, Jean-François Legeais, Benedicte Lemieux-Dudon, Bruno Levier, Vidar Lien, Ilja Maljutenko, Fernando Manzano, Marta Marcos, Veselka Marinova, Simona Masina, Elena Mauri, Michael Mayer, Angelique Melet, Frédéric Mélin, Benoit Meyssignac, Maeva Monier, Malte Müller, Sandrine Mulet, Cristina Naranjo, Giulio Notarstefano, Aurélien Paulmier, Begoña Pérez Gomez, Irene Pérez Gonzalez, Elisaveta Peneva, Coralie Perruche, K. Andrew Peterson, Nadia Pinardi, Andrea Pisano, Silvia Pardo, Pierre-Marie Poulain, Roshin P. Raj, Urmas Raudsepp, Michaelis Ravdas, Rebecca Reid, Marie-Hélène Rio, Stefano Salon, Annette Samuelsen, Michela Sammartino, Simone Sammartino, Anne Britt Sandø, Rosalia Santoleri, Shubha Sathyendranath, Jun She, Simona Simoncelli, Cosimo Solidoro, Ad Stoffelen, Andrea Storto, Tanguy Szerkely, Susanne Tamm, Steffen Tietsche, Jonathan Tinker, Joaquín Tintore, Ana Trindade, Daphne van Zanten, Luc Vandenbulcke, Anton Verhoef, Nathalie Verbrugge, Lena Viktorsson, Karina von Schuckmann, Sarah L. Wakelin, Anna Zacharioudaki, Hao Zuo
Changes in sea-ice extent and volume (Section 1.4) are important for several aspects of ocean and climate monitoring, as well as for safe marine operation in and close to ice-covered regions. Sea ice is an integrated part of the climate system through its effect on surface albedo and heat and momentum flux between the ocean and the atmosphere. Sea-ice thickness, being a crucial parameter for sea-ice volume, is important for the freshwater content and cycle in the Arctic (Carmack et al. 2016), and also has an impact on the ice drift speed. Sea-ice thickness affects the opening of leads and biological production below the sea ice (Assmy et al. 2017; Horvat et al. 2017).