Ozone Measurement

1 Dobson Unit (DU) is defined to be 0.01 mm thickness at STP (standard temperature and pressure). Ozone layer thickness is expressed in terms of Dobson units, which measure what its physical thickness would be if compressed in the Earth's atmosphere.

NASA decided to change the EP/TOMS operational processing configuration in order to apply a correction for the cross-track bias errors that have grown large over the past year or so. These data are being made available at the TOMS web site on an operational basis. Data starting August 1, 2001 will be reprocessed with this configuration and made available as well to provide a consistent data set over the 2001 ozone hole season. The data previous to August are the old data, so a discontinuity will be seen at the July 31 / August 1, 2001 boundary. The reprocessed ozone images will also use the new color scale. The cross-track bias correction will remove almost all of the cross-track bias, but will not remove residual long-term changes in ozone due to related instrument degradation. The current EP/TOMS data should not be used for studies of long-term changes in ozone beyond the summer of 2000.

The white area on the images is where data cannot be retrieved in the earth's shadow or polar night regions by the satellite.

Oct 1 2004

Oct 2 2004

Oct 3 2004

Oct 4 2004

Oct 5 2004

Oct 6 2004

Oct 7 2004

Oct 8 2004

Oct 9 2004

Oct 10 2004

Oct 11 2004

Oct 12 2004

Oct 13 2004

Oct 14 2004

Oct 15 2004

Oct 16 2004

Oct 17 2004

Oct 18 2004

Oct 19 2004

Oct 20 2004

Oct 21 2004

Oct 22 2004

Oct 23 2004

Oct 24 2004

Oct 25 2004

Oct 26 2004

Oct 27 2004

Oct 28 2004

Oct 29 2004

Oct 30 2004

Oct 31 2004