# Satellite-Based Sea Ice Navigation for Prydz Bay, East Antarctica
## 5 Discussion
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline \hline  & & \multicolumn{3}{c}{**Fast Ice \({}^{\bullet}\)**} & \multicolumn{3}{c}{**Speed in Pack Ice (Knots)**} & \multicolumn{3}{c}{**Speed in Fast Ice (Knots)**} & \multicolumn{3}{c}{**Navigation Duration (Houns)**} & \multicolumn{3}{c}{**Deviation from Planned Route \({}^{\bullet}\)**} \\ \cline{3-14}
**Epeelition** & **Mobile Ice Synoptic** & \multicolumn{3}{c}{**Thickness**} & \multicolumn{3}{c}{**Eetent**} & \multicolumn{3}{c}{**Automated**} & \multicolumn{3}{c}{**Deviation (Sloke)**} & \multicolumn{3}{c}{**Average**} & \multicolumn{3}{c}{**Side:**} & \multicolumn{3}{c}{**Pack Ice**} & \multicolumn{3}{c}{**Fast Ice**} & \multicolumn{3}{c}{**Total \({}^{\bullet}\)**} & \multicolumn{3}{c}{**Range**} & \multicolumn{3}{c}{**Stokes:**} \\ \hline  & & & & & & & & & & & & & & & & \\
2011 & Concentration \textgreater{} 90\% in most & & & & & & & & & & & & & & & \\ areas, with region of 70\% and a & 1-2-1.61 & 28 & 9.9 & 3.3 & 3.5 & 1.7 & 15 & 43 & 69 & 165 m-25.3 km & 6.1 & 6.1 & 65 m-6.9 km & 2.8 & \\  & limited open water area & & & & & & & & & & & & & \\ \hline  & Concentration \textless{} 70\% in most & & & & & & & & & & & & & \\ parts, lower concentration in area & 1.23-1.55 & 20 & 10.2 & 1.9 & 3.7 & 1.7 & 23 & 33 & 125 & - & - \\  & of merged polynynas & & & & & & & & & & & & \\ \hline  & Concentration \textgreater{} 90\%, barely any & & & & & & & & & & & & & \\ lead visible, quiescent wind & 1.22-1.58 & 21 & 5.7 & 3.6 & 2.6 & 1.6 & 48 & 69 & 130 & 245 m-11.0 km & 3 & \\ conditions, no significant change & & & & & & & & & & & & & \\ in ice conditions & & & & & & & & & & & & \\ \hline \hline \end{tabular}  
* The land-fast ice information was measured by scientists in Zhonghan Station prior to the CHINARE expedition in late October and early November. \({}^{\star}\) The total navigation duration included the navigation time in Dryde Bay Polynya. \({}^{\star}\) In 2011, the first group data is calculated by 20 waypoints, and the second group data is from 18 waypoints (exclusion of the waypoints I7 and [8]). In 2013, the first group data is calculated from 13 waypoints in SAR data, and the second group data is from 12 waypoints in MODIS data.  
\end{table} 
Table 2: Summary of ice navigation for CHINARE2011, CHINARE2012 and CHINARE2013. As explained before, analysis in SatSINS starts with examination of coarse-resolution SIC daily maps. This is performed in conjunction with the analysis of a medium-resolution imagery data (MODIS data) to develop a synoptic description of the ice conditions (concentration, types, floe size, etc.) particularly in areas of high ice concentrations. This first-cut information is used to: (1) provide the expected location of the ice edge; (2) identify the synoptic ice conditions that will be encountered; (3) support a decision on whether there is a need for better timely and finer-resolution SAR images to develop a route through hazardous ice cover. The system continues with examining meteorological data to estimate possible deformation of the ice cover, and fine-resolution remote sensing data to assess the deformation and the ice types in ice-risk areas. Five scientific questions related to geophysical forces that impede navigation, along with their relevant navigation variables, are addressed in the rest of this section. _Question 1: What are the priority ice parameters that should be evaluated to the benefit of the ship navigation in ice-covered water?_  
As presented in Section 1, the four parameters needed to plan for a safe nautical route are (in a descending order of priority): SIT, SIC, SIE and ice surface deformation (which may be manifested as a local increase in ice thickness). SIC is useful in providing a synoptic-scale description of the ice regime.