scholarly journals Parameter Identification for Salinity in a Quasilinear Thermodynamic System of Sea Ice

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Wei Lv ◽  
Xiaojiao Li ◽  
Enmin Feng
Keyword(s):  
Sea Ice ◽  
Parameter Identification ◽  
Optimal Solution ◽  
Thermodynamic System ◽  
Polar Night ◽  
Night Time ◽  
Zhongshan Station ◽  
Estimated Parameters ◽  
Salinity Data ◽  
Antarctic Research

This study is intended to provide a parameter identification method to determine salinity of sea ice by temperature and salinity observations. A quasilinear thermodynamic system of sea ice with unknown salinity is described and its property is proved. Then, a parameter identification model is established and the existence of its optimal solution is discussed. The salinity profile is calculated by the temperature and salinity data, which were measured at Nella Fjord around Zhongshan Station, Antarctica, during the polar night time by the 22nd Chinese Antarctic Research Expedition. Another simulation for temperature profiles during different measurement periods is operated. Results show that better simulations of the salinity and temperature distribution are possible with the estimated parameters than Eicken’s (Eicken 1992) and THESCI’s (Lv et al. 2009). This method will help people understand the salinity evolution of sea ice more thoroughly.

Xuelong Navigation in Fast Ice Near the Zhongshan Station, Antarctica

2014 ◽  
Vol 48 (1) ◽  
pp. 84-91 ◽  
Author(s):  
Xianwei Wang ◽  
Xiao Cheng ◽  
Fengming Hui ◽  
Cheng Cheng ◽  
H.S. Fok ◽  
...  
Keyword(s):  
Sea Ice ◽  
Expert Witness ◽  
Effective Means ◽  
Time Saving ◽  
Major Barrier ◽  
Zhongshan Station ◽  
Ice Conditions ◽  
Fast Ice ◽  
Antarctic Research ◽  
Sar Imagery

AbstractNavigation in polar sea regions requires special attention to the sea ice condition because it is a major barrier for an icebreaker to break the drift ice or fast ice, allowing the vessel to keep moving forward. The advancement of remote sensing imagery provides an effective means to classify and identify various features, including different types of sea ice. Hence, it permits fuel and time saving for the entire voyage, especially when drift ice or fast ice becomes a barrier for the icebreaker. In this study, we exploit the potential usage of high-resolution synthetic aperture radar (SAR) imageries from Radarsat-2 to identify sea ice conditions for precise navigation of China’s icebreaker vessel (Xuelong) during the 29th Chinese Antarctic Research Expedition in December 2012. Different features on the fast ice were identified from horizontal-transmit and horizontal-receive polarized imagery. The potential usage of SAR imagery for precise navigation was confirmed by an expert witness on the Xuelong vessel at that time. The final voyage route has validated our analysis of fast ice and navigation of the Xuelong vessel. The predicted regions for unloading locations were also found to be matching well with the actual vessel unloading locations after the final voyage route.

Parameter identification for volumetric heat capacity and thermal conductivity in a quasi-linear thermodynamic system of sea ice

2016 ◽  
Vol 09 (03) ◽  
pp. 1650044
Author(s):  
Wei Lv
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Sea Ice ◽  
Parameter Identification ◽  
Control Variable ◽  
Thermodynamic System ◽  
Physical Parameters ◽  
Volumetric Heat Capacity ◽  
Identification Model ◽  
Linear Thermodynamic

This paper is intended to determine physical parameters describing volumetric heat capacity and thermal conductivity of sea ice in a quasi-linear thermodynamic system using field observations. The quasi-linear thermodynamic system of sea ice with unknown physical parameters is described, and the existence and uniqueness of its solution is proved. Then the physical parameters are taken as control variable, temperature deviations as objective function, and a parameter identification model is established. The existence of its optimal solution is discussed. To solve the identification model, a new algorithm containing genetic algorithm, Hooke–Jeeves algorithm and semi-implicit finite difference scheme is constructed. The physical parameters are calculated using the observations measured at Nella Fjord around Zhongshan Station, Antarctic in CHINARE 2006. For comparability and consistency with other works, a new international standard named TEOS-10 is used. To examine the validity of the identified results, another simulation for temperature profiles in different measurement period is operated. Numerical results show that better simulations of temperature distribution are possible with the identified parameters than EC1993. Therefore not only the identified parameters can be applied in sea ice modeling, but also this study can enrich and supplement observations of sea ice.

scholarly journals Spectral albedo of coastal landfast sea ice in Prydz Bay, Antarctica

2020 ◽  
pp. 1-11
Author(s):  
Guanghua Hao ◽  
Roberta Pirazzini ◽  
Qinghua Yang ◽  
Zhongxiang Tian ◽  
Changwei Liu
Keyword(s):  
Sea Ice ◽  
Near Infrared ◽  
Elevation Angle ◽  
Early Summer ◽  
Prydz Bay ◽  
Katabatic Wind ◽  
Surface Conditions ◽  
Zhongshan Station ◽  
Landfast Sea Ice ◽  
Two Phases

Abstract The surface spectral albedo was measured over coastal landfast sea ice in Prydz Bay (off Zhongshan Station), East Antarctica from 5 October to 26 November of 2016. The mean albedo decreased from late-spring to early-summer, mainly responding to the change in surface conditions from dry (phase I) to wet (phase II). The evolution of the albedo was strongly influenced by the surface conditions, with alternation of frequent snowfall events and katabatic wind that induce snow blowing at the surface. The two phases and day-to-day albedo variability were more pronounced in the near-infrared albedo wavelengths than in the visible ones, as the near-infrared photons are more sensitive to snow metamorphism, and to changes in the uppermost millimeters and water content of the surface. The albedo diurnal cycle during clear sky conditions was asymmetric with respect to noon, decreasing from morning to evening over full and patchy snow cover, and decreasing more rapidly in the morning over bare ice. We conclude that snow and ice metamorphism and surface melting dominated over the solar elevation angle dependency in shaping the albedo evolution. However, we realize that more detailed surface observations are needed to clarify and quantify the role of the various surface processes.

scholarly journals Response of the sea‐ice diatom Fragilariopsis cylindrus to simulated polar night darkness and return to light

2019 ◽  
Vol 65 (5) ◽  
pp. 1041-1060 ◽  
Author(s):  
Philippe‐Israël Morin ◽  
Thomas Lacour ◽  
Pierre‐Luc Grondin ◽  
Flavienne Bruyant ◽  
Joannie Ferland ◽  
...  
Keyword(s):  
Sea Ice ◽  
Polar Night ◽  
Fragilariopsis Cylindrus
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