Refinements in the use of equivalent latitude for assimilating sporadic inhomogeneous stratospheric tracer observations, 2: Precise altitude-resolved information about transport of Pinatubo aerosol to very high latitude P. Good1 and J. Pyle2 1Institute of Environmental Research and Sustainable Development, National Observatory of Athens, Greece 2Centre for Atmospheric Science, Cambridge, UK
Abstract. From high latitude lidar observations, quite precise information
is extracted about the temporal evolution and vertical distribution of volcanic aerosol in the high
latitude lower stratosphere following the eruption
of Mount Pinatubo. Irreversible mixing of lower stratospheric
aerosol, to the arctic pole during early 1992, is demonstrated, as a
function of potential temperature and time. This work
complements previous studies, which either identify vortex intrusions - without demonstrating
irreversible transport, or use lower resolution satellite observations.
The observed transport is associated tentatively with the vortex
disturbance during late January, 1992. A very large number of high
resolution lidar observations of Mount Pinatubo aerosol are analysed,
without any data averaging. Averaging in measurement or analysis can
cause tracer mixing to be overestimated. Averaging in the analysis
can also require assumptions about which quantity has the dominant
error (in this case, the equivalent latitude coordinate or the
measurement), and which part of the data contains real structure. The
method below attempts to avoid such assumptions.
Citation: Good, P. and Pyle, J.: Refinements in the use of equivalent latitude for assimilating sporadic inhomogeneous stratospheric tracer observations, 2: Precise altitude-resolved information about transport of Pinatubo aerosol to very high latitude, Atmos. Chem. Phys., 4, 1837-1848, doi:10.5194/acp-4-1837-2004, 2004.