Artic Sea Ice Volume: A Radar Graph vs. Line Graphs

UPDATE (May 2, 2013): I have removed 2013 from all charts.

I posted an article on my Facebook page the other day asking if this radar graphs about artic sea ice volume works.  The comments were mixed.

I think this radar graph is merely ok.  Radar graphs, in general, are hard to read because relationships and trends are not easily discerned.  Some of the issues I see with this graph include:

• It’s difficult to see the entire pattern over time.  I see the pattern is spiraling in, but does it change year by year.  Ask yourself this: How does 1999 compare with 2004?  It takes a lot of work. 
• It’s very hard to follow the ice volume labels around the chart.  I bet you found this as well in the example above.
• The author only included September.  Why?  The data is available by day.  Get the data here.
• Are there any seasonal patterns?  You can’t answer this question.

I created a couple of different views for your consideration in Tableau.  You can download the workbook here.

In my version, I’ve addressed all of the problems I mentioned above.

• In the upper left graph, you can easily see that the artic sea ice volume is trending down.  
• The upper right chart allows you to see two things:
  1. The seasonal patterns
  2. Comparisons by year:  The comparisons across years can be see because the years get darker as the data gets closer to 2013.  You can see the lines get darker as you look down the graph.
• The Daily Volume graph makes the cyclical patterns much, much clearer.

How would you visualize this data?  Do you agree that these line graphs work better than the radar graph?