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Balloon-borne measurements of CFC-11 (on flights of the DIRAC in situ gas chromatograph and the DESCARTES grab sampler), ClO and O3 were made during the 1999/2000 winter as part of the SOLVE-THESEO 2000 campaign. Here we present the CFC-11 data from nine flights and compare them first with data from other instruments which flew during the campaign and then with the vertical distributions calculated by the SLIMCAT 3-D CTM. We calculate ozone loss inside the Arctic vortex between late January and early March using the relation between CFC-11 and O3 measured on the flights, the peak ozone loss (1200 ppbv) occurs in the 440–470 K region in early March in reasonable agreement with other published empirical estimates. There is also a good agreement between ozone losses derived from three independent balloon tracer data sets used here. The magnitude and vertical distribution of the loss derived from the measurements is in good agreement with the loss calculated from SLIMCAT over Kiruna for the same days.
Balloon-borne measurements of CFC11 (from the DIRAC in situ gas chromatograph and the DESCARTES grab sampler), ClO and O3 were made during the 1999/2000 Arctic winter as part of the SOLVE-THESEO 2000 campaign, based in Kiruna (Sweden). Here we present the CFC11 data from nine flights and compare them first with data from other instruments which flew during the campaign and then with the vertical distributions calculated by the SLIMCAT 3D CTM. We calculate ozone loss inside the Arctic vortex between late January and early March using the relation between CFC11 and O3 measured on the flights. The peak ozone loss (~1200ppbv) occurs in the 440-470K region in early March in reasonable agreement with other published empirical estimates. There is also a good agreement between ozone losses derived from three balloon tracer data sets used here. The magnitude and vertical distribution of the loss derived from the measurements is in good agreement with the loss calculated from SLIMCAT over Kiruna for the same days.
We establish a methodology and present baseline data for a long-term grassy woodland restoration study that commenced in 2007 in two nature reserves (Mulligans Flat, Goorooyarroo (35° 9–13’ S; 149° 9–12’ E)) totalling 1386 ha on the northern boundary of Canberra, in the Australian Capital Territory in south eastern Australia. The experimental infrastructure comprises 96 × 1 ha sites established in Eucalyptus blakelyi / Eucalyptus melliodora dominated woodland. These are being subjected to varying kangaroo grazing pressure and augmentation with logs, while burning treatments are planned. One reserve (Mulligans Flat) has been fenced for feral predator control and contains half the sites, forming a companion experiment to Goorooyarroo. Our baseline floristic study comprised estimates, at the site level, of ground layer biomass, species biomass, ground cover types and soil (0–10 cm) properties. From these data we conclude that the groundlayer vegetation is dominated by Joycea pallida, Austrodanthonia spp., Themeda australis and Aristida ramosa. These grasses varied in abundance according to differences in soil pH, phosphorus and to a lesser extent nitrates. Forb frequencies were highly sensitive to nitrate levels with annual exotic forbs dominating at high nitrate sites. More generally, soil nutrient levels and exotic species in some sites indicated areas of previous pasture improvement activities. Biomass estimates indicated extremely high grazing pressure, sufficient to negatively affect the habitat quality for ground-dependent fauna and some soil processes. These data will provide an important basis for examining rates of ecosystem recovery under different restoration strategies.