Question 68

The Correct Answer is C The terminology used to describe sea ice concentrations is standardized internationally (often by organizations like the World Meteorological Organization - WMO). Ice concentration is measured in tenths, where 10 tenths represents complete ice cover. 1. **Why option C ("4 - 6 tenths") is correct:** The ice concentration range corresponding to **"Open Pack"** ice is defined as 4/10 (four tenths) to 6/10 (six tenths). This range signifies a sea surface that is significantly covered by ice, but with many large openings (leads or polynyas) allowing for relatively easy navigation, particularly for ice-strengthened vessels. 2. **Why the other options are incorrect:** * **A) < 1 tenth:** This concentration range (usually 0/10 to less than 1/10) corresponds to **"Ice Free"** or **"Very Open Water with Ice Floes"** (trace ice). * **B) 1 - 3 tenths:** This concentration range corresponds to **"Very Open Drift"** ice (or sometimes just "Open Water" with scattered ice). Navigation is generally unrestricted. * **D) 7 - 8 tenths:** This concentration range corresponds to **"Close Pack"** ice. In this state, the sea is predominantly ice-covered, and navigation becomes difficult as large openings are rare or nonexistent.