19 climate change exercise part a sea ice

Quiz Instructions

The questions in Part A of the exercise involve examination of time series data for the extent of sea ice in the Arctic and in the Antarctic. The sea ice website (Sea Ice (Links to an external site.)Links to an external site.) provides maps for either the Arctic or Antarctic that illustrate the extent of sea ice for specified time intervals. The aim is to observe the monthly changes, noting the annual cycle and the months of smallest and greatest extent. The goal of exploring these data is to recognize the annual cycle of changes in sea ice and long-term trends in its extent. The buttons on the “Sea Ice Animation Tool” should be set as follows:

• Hemisphere – Northern (subsequently Southern).
• Start Year – 1979; Start Month – January; Image – Sea Ice Extent
• Once these button have been selected it is possible to use play (> button) and faster (twice) to speed up the animation.
• The monthly area of sea ice coverage (in millions of square kilometers) is noted below each map.

In the menu bar below the title line “Sea Ice Index” there are links entitled “Compare Anomalies” and “Compare Trends.” The first of these links enables maps for individual months to be examined side-by-side and the second link provide plots of long-term trends in sea ice that may be helpful for answering the third question in this part of the exercise since it can display trends for the northern hemisphere and then be reset to display trends for the southern hemisphere.

Note: At times the sea ice animation seems to operate better in Chrome and Safari than in Firefox. If you encounter difficulties with the animation please switch browsers.

Questions

Question 1 5 pts

In which months are the highest and lowest values for sea ice extent in the Arctic typically observed, and in which years are the maximum and minimum values observed? Similarly, in which months are the highest and lowest values for sea ice extent in the Antarctic typically observed, and in which years are the maximum and minimum values observed?

A strong answer will identify those months in which Arctic sea ice typically maximizes and minimizes, and also provide similar information for Antarctic sea ice, in both instances citing the specific values for the extent of sea ice and specifying the months when annual highs and lows are typically observed plus the specific years that show the extreme values (high and low) of sea ice measurements.

Question 2 5 pts

Describe the evidence for long-term trends in the extent of sea ice in the Arctic. What predictions can be made based on these trends in terms of future sea ice coverage of the Arctic Ocean at different times of the year?

A strong answer will identify specific areas that are often ice free in specific months later years, and project the annual changes in sea ice extent into the future, including numerical estimates where possible.

Question 3 5 pts

A strong answer will reference the expansion and retreat of sea ice by comparing the characteristics for East and West Antarctica, and comment on the monthly timing of differences in the extent of sea ice for the two regions.

Question 4 5 pts

Based on your observations of Arctic and Antarctic sea ice are there any significant differences in their comparative rate of change over time?

A strong answer will cite explicit values for the extent of sea ice in individual years and comment on the changes in these values over time for both the northern and southern polar regions.