Rate of loss of Arctic Sea Ice Area per day of year

For the period covered by the satellite 2002 to 2010 the change in extent on a particular day of the year is plotted as a linear trend.
It is interesting that just before the summer melt (May) the area increases by 5000sqkm over the 9 years.
There is then a sharp fall to 20,000 sqkm loss per year in october.
The area change over the remaining year seems to be about 5000sqkm/year

Is the rise from April to may due to delayed melt? or is it spreading of melting ice?