TOMS - Total Calibration Error
The Version 8 algorithm is now used for all TOMS data.
For data beginning in year 2000, the calibration has been stabilized relative to NOAA-16 SBUV/2
in the equatorial zone. Because of continuing changes in the optical properties of the front scan
mirror that are not well understood, we are now seeing a latitude dependent error that cannot be
corrected by a simple calibration correction. The calibration appears to be stable near the equator.
But by 50 degrees latitude, there is now a -2% to -4% error in TOMS, a bit larger in the northern
hemisphere than in the southern hemisphere. Because of this error, data since 2002 should NOT be
used for trend analysis.