Abstract. The SLIMCAT three-dimensional chemical transport model (CTM) is used to infer chemical ozone loss from Polar Ozone and Aerosol Measurement (POAM) III observations of stratospheric ozone during the Arctic winter of 2002–2003. Inferring chemical ozone loss from satellite data requires quantifying ozone variations due to dynamical processes. To accomplish this, the SLIMCAT model was run in a "passive" mode from early December until the middle of March. In these runs, ozone is treated as an inert, dynamical tracer. Chemical ozone loss is inferred by subtracting the model passive ozone, evaluated at the time and location of the POAM observations, from the POAM measurements themselves. This "CTM Passive Subtraction" technique relies on accurate initialization of the CTM and a realistic description of vertical/horizontal transport, both of which are explored in this work. The analysis suggests that chemical ozone loss during the 2002–2003 winter began in late December. This loss followed a prolonged period in which many polar stratospheric clouds were detected, and during which vortex air had been transported to sunlit latitudes. A series of stratospheric warming events starting in January hindered chemical ozone loss later in the winter of 2003. Nevertheless, by 15 March, the final date of the analysis, ozone loss maximized at 425 K at a value of about 1.2 ppmv, a moderate amount of loss compared to loss during the unusually cold winters in the late-1990s. SLIMCAT was also run with a detailed stratospheric chemistry scheme to obtain the model-predicted loss. The SLIMCAT model simulation also shows a maximum ozone loss of 1.2 ppmv at 425 K, and the morphology of the loss calculated by SLIMCAT was similar to that inferred from the POAM data. These results from the recently updated version of SLIMCAT therefore give a much better quantitative description of polar chemical ozone loss than older versions of the same model. Both the inferred and modeled loss calculations show the early destruction in late December and the region of maximum loss descending in altitude through the remainder of the winter and early spring.
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IN his Convivio Dante recognizes two kinds of allegory: an 'allegory of poets' and an 'allegory of theologians.' And in the interpretation of his own poems in that work he declares that he intends to follow the allegory of poets, for the reason that the poems were composed after that manner of allegory.One must recall that there is an unfortunate lacuna in the text of the Convivio at just this most interesting point, with the result that those words which denned the literal sense as distinguished from the allegorical are missing. But no one who knows the general argument of the whole work will, I think, make serious objection to the way the editors of the accepted critical text have filled the lacuna.The passage in question, then, patched by them, reads as follows:Dico che, si come nel primo capitolo e narrato, questa sposizione conviene essere litterale e allegorica. E a cio dare a intendere, si vuol sapere che le scritture si possono intendere e deonsi esponere massimamente per quattro sensi. L'uno si chiama litterale [e questo e quello che non si stende phi oltre la lettera de le parole fittizie, si come sono le favole de li poeti. L'altro si chiama allegorico] e questo e quello che si nasconde sotto'l manto di queste favole, ed e una veritade ascosa sotto bella menzogna: si come quando dice Ovidio che Orfeo facea con la cetera mansuete le fiere, e li arbori e le pietre a se muovere; che vuol dire che lo savio uomo con lo strumento de la sua voce f a[r]ia mansuescere e umiliare li crudeli cuori, e fa[r]ia muovere a la sua volontade coloro che non hanno vita di scienza e d'arte: e coloro che non hanno vita ragionevole alcuna sono quasi come pietre. E perche questo nascondimento fosse trovato per li savi, nel penultimo trattato si mosterra. Veramente li teologi questo senso prendono altrimenti che li poeti; ma perd che mia intenzione e qui lo modo de li poeti seguitare, prendo lo senso allegorico secondo che per li poeti e usato. 1
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