April 2007
Lerwick reported a low ozone event of 281 DU on the 10th April 2007. OMI overpass data reported a value of 286 DU, which is within the expected rms range of 2-5% depending on the wavelength pair chosen. This event was part of an extensive dynamic disturbance that reached into Northern Scandinavia.
The origin of this event was traced back to the anti-cyclone located to the west of Ireland at this time. This relatively deep feature caused tropospheric warm advection at its northern flank over Scotland. The tropopause was thus lifted and the pressure anomalously low (Figure B). In this case stratospheric ozone advection from the (relatively low ozone) South seems modest, so that the tropopause lift appears the dominant cause of this event.
Figure B: Operational analysis (GDAS) of tropopause pressure (Pa)
Lerwick reported a low ozone event of 281 DU on the 10th April 2007. OMI overpass data reported a value of 286 DU, which is within the expected rms range of 2-5% depending on the wavelength pair chosen. This event was part of an extensive dynamic disturbance that reached into Northern Scandinavia.
The origin of this event was traced back to the anti-cyclone located to the west of Ireland at this time. This relatively deep feature caused tropospheric warm advection at its northern flank over Scotland. The tropopause was thus lifted and the pressure anomalously low (Figure B). In this case stratospheric ozone advection from the (relatively low ozone) South seems modest, so that the tropopause lift appears the dominant cause of this event.
Figure B: Operational analysis (GDAS) of tropopause pressure (Pa)