Another trend chart...this one compares the annual amount of melt for SIA and SIE. There are a couple of not very enlightening observations, a third that simply supports an argument for which Crandles has already provided more than enough support and a 4th observation that raises some interesting questions.
1. SIE and SIA seasonal melt has been increasing from 1979 to 2015.
2. There is a strong correlation between SIE and SIA annual melt trends. Of the 38 years charted, the SIE and SIA seasonal melt quantity trend line moved in opposition only four times (1988, 1999, 2001, 2005).
3. There is a shift upwards in seasonal melt which occurs in 2007. Crandles has, in my mind, clearly shown that it was the devastation of volume and thick MYI in 2007 which has driven this. We have a new, smaller MYI floor which serves to limit how low SIA and SIE can go.
4. In general SIA seasonal melt amounts are greater than SIE seasonal melt although this difference seems to have shrunk, beginning around 2004. From 1979 to 2003, there are only 2 years where SIE melt exceeded SIA melt (1985 9.613 to 9.602) (1990 10.141 to 10.059). Of the remaining 23 years, SIA melt exceeded SIE melt, on average, by 477 Sq Km. In the last 11 years from 2004 to 2015, SIE melt exceeded SIA melt 4 times (2005, 2007, 2011, 2012). Of the remaining 8 years where SIA melt did exceed SIE, the average was by only 186K Sq Km.
Many of these graphs clearly show a transition that occurred in or around 2007. Some of the graphs suggest additional transition points in 1988 and, if you have as vivid imagination as I have, 1998 as well. Finally, these are only trend charts of specific ways of measuring what is going on in the Arctic. What I am most interested in is what these changing trend lines suggest is actually going on with the ice. Things are changing. What is driving these changes in trend lines? Is it weather changes, characteristics of the ice, SST increases?
As always, I haven't a clue.