TEMIS -- UV index & UV dose based on GOME -- archive

UV index & UV dose based on GOME	UV radiation monitoring
Overview of the data product archive

Monthly averages versus monthly climatology
The archive of the GOME-based UV index and UV dose presents the data also in the form of monthly averages and a monthly climatology. A monthly average is an average over all days of a single month of a given year, e.g. all days in January 2000. A monthly climatology is an average over all days of a single month over all years, e.g. all days in January 1996 to 2003. Comparing the individual monthly means with the monthly climatology gives an idea of possible trends in the data.
The following graphs show the comparison for the ozone column at local solar noon (the input for the UV index and UV dose calculations) and the erythemal UV index. The graphs on the left present the monthly averages (in red) over the GOME-period August 1995 to May 2003, and for each month the monthly climatology (in blue). The graphs on the right show for each month the difference between the monthly average and the monthly climatology.
From these graphs there is no clear trend visible in the ozone or the UV index over the given period. But then again the period is quite short: just under 8 years. It has been estimated that a trend in the UV index should show up over a period of 11 to 15 years.


Monthly ozone column at local solar noon for De Bilt over the period August 1995 to May 2003 in Dobson Units (DU). On the left the monthly averages of the individual months (red), compared with the monthly climatology (blue). On the right the difference between these two.

Monthly erythemal UV index local solar noon for De Bilt over the period August 1995 to May 2003. On the left the monthly averages of the individual months (red), compared with the monthly climatology (blue). On the right the difference between these two.