Information on the Dynamic Activity Index (DAI) based on OMI data from 2004 to 14th, February 2012

For the calculation of the DAI, level 3 total column ozone data (gridded by 0.25 degree latitude x 0.25 degree longitude) of OMI (Ozone Monitoring Instrument) on EOS-AURA are used as they are available from the NASA archive of the Aura validation data center. Due to compatibility reasons the data are re-gridded on a 1.0 x 1.25 degree lat-lon-grid.
Three sinusoidals with given zonal wavelengths (360°, 180°, 120°) are fitted consecutively to all data along one circle of latitude following a least-square approach (harmonic analysis). This analysis is done for each circle of latitude individually if at least 80% of all data points are available. The amplitudes of the sinusoidals are interpreted in terms of the amplitudes of the zonal quasi-stationary planetary waves one, two and three.
The DAI is calculated from the daily amplitudes of the planetary wave with zonal wave number one for the Northern and Southern hemisphere separately: all amplitudes between 0° and 50° are averaged along the corresponding hemisphere requiring 50% of data availability.

Due to data availability problems, the DAI processor will be driven with GOME-2 data in the future. The DAI will be up-to-date again as soon as a consistent transition from OMI to GOME-2 use in made.

Northern Hemisphere

Southern Hemisphere

For further information see Total Column Ozone satellite measurements by OMI.

For further information on the Dynamic Activity Index (DAI) please contact wdc@dlr.de.