Vortex-averaged Arctic ozone depletion in the winter 2002/2003 (original) (raw)
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Ozone depletion in and below the Arctic vortex for 1997 (1998)
The winter 1996/97 was quite unusual with late vortex formation and polar stratospheric cloud (PSC) development and subsequent record low temperatures in March. Ozone depletion in the Arctic vortex is determined using ozonesondes. The diabatic cooling is calculated with PV-theta mapped ozone mixing ratios and the large ozone depletions, especially at the center of the vortex where most PSC existence was predicted, enhances the diabatic cooling by up to 80%. The average vortex chemical ozone depletion from January 6 to April 6 is 33, 46, 46, 43, 35. 33. 32 and 21% in air masses ending at 375,400, 425, 450, 475. 500, 525, and 550 K (about 14 -22 km). This depletion is corrected for transport of ozone across the vortex edge calculated with reverse domain-filling trajectories. 375 K is in fact below the vortex, but the calculation method is applicable at this level with small changes. The column integrated chemical ozone depletion amounts to about 92 DU (21%), which is comparable to the depletions observed during the previous four winters.
Ozone depletion in and below the Arctic vortex for 1997
Geophysical Research Letters, 1998
The winter 1996/97 was quite unusual with late vortex formation and polar stratospheric cloud (PSC) development and subsequent record low temperatures in March. Ozone depletion in the Arctic vortex is determined using ozonesondes. The diabatic cooling is calculated with PV-theta mapped ozone mixing ratios and the large ozone depletions, especially at the center of the vortex where most PSC existence was predicted, enhances the diabatic cooling by up to 80%. The average vortex chemical ozone depletion from January 6 to April 6 is 33, 46, 46, 43, 35. 33. 32 and 21% in air masses ending at 375,400, 425, 450, 475. 500, 525, and 550 K (about 14 -22 km). This depletion is corrected for transport of ozone across the vortex edge calculated with reverse domain-filling trajectories. 375 K is in fact below the vortex, but the calculation method is applicable at this level with small changes. The column integrated chemical ozone depletion amounts to about 92 DU (21%), which is comparable to the depletions observed during the previous four winters.
Atmospheric Chemistry and Physics Discussions Vortex-averaged Arctic ozone depletion in
2013
A total ozone depletion of 68 Dobson units from 10 December 2002 to 10 March 2003 is derived by the vortex-average method taking into account both diabatic descent of the air masses and transport of air into the vortex. When the vortex is divided into three equal-area regions, the results are 85 DU for the collar region (closest to the edge), 52 DU for the vortex centre and 68 DU for the middle region in between centre and collar.
Temporal development of ozone within the Arctic vortex during the winter of 1991/92
Geophysical Research Letters, 1994
In this study we address the question of temporal ozone trends on isentropic surfaces within the Arctic polar vortex during EASOE. We have combined ozone sonde data from twelve campaign stations distributed throughout the European sector of the Arctic. The development of ozone at the 425,475, 550 and 700 K levels is presented, using analysed fields of isentropic potential vorticity and isentropic back-trajectories to separate inner vortex air from air staying outside the vortex.
Geophysical Research Letters, 2001
Lower stratospheric in situ observations are used to quantify both the accumulated ozone loss and the ozone chemical loss rates in the Arctic polar vortex during the 1999-2000 winter. Multiple long-lived trace gas correlations are used to identify parcels in the inner Arctic vortex whose chemical loss rates are unaffected by extra-vortex intrusions. Ozone-tracer correlations are then used to calculate ozone chemical loss rates. During the late winter the ozone chemical loss rate is found to be-46 q-6 (1•) ppbv/day. By mid-March 2000, the accumulated ozone chemical loss is 58 q-4 % in the lower stratosphere near 450 K potential temperature (-19 km altitude).
ILAS observations of chemical ozone loss in the Arctic vortex during early spring 1997
Geophysical Research Letters, 2000
Chemical ozone loss rates were estimated for the Arctic stratospheric vortex by using ozone profile data (Version 3.10) obtained with the Improved Limb Atmospheric Spectrometer (ILAS) for the spring of 1997. The analysis method is similar to the Match technique, in which an air parcel that the ILAS sounded twice at different locations and at different times was searched from the ILAS data set, and an ozone change rate was calculated from the two profiles. A statistical analysis indicates that the maximum ozone loss rate was found on the 450 K potential temperature surface in February, amounting to 84 ppbv/day.
Quarterly Journal of the Royal Meteorological Society, 2008
In this paper we investigate the evolution of the northern polar vortex during the winter 2002-2003 in the lower stratosphere by using assimilated fields of ozone (O 3) and nitrous oxide (N 2 O). Both O 3 and N 2 O used in this study are obtained from the Sub-Millimetre Radiometer (SMR) aboard the Odin satellite and are assimilated into the global three-dimensional chemistry transport model of Météo-France, MOCAGE. O 3 is assimilated into the 'full' model including both advection and chemistry whereas N 2 O is only assimilated with advection since it is characterized by good chemical stability in the lower stratosphere. We show the ability of the assimilated N 2 O field to localize the edge of the polar vortex. The results are compared to the use of the maximum gradient of modified potential vorticity as a vortex edge criterion. The O 3 assimilated field serves to evaluate the ozone evolution and to deduce the ozone depletion inside the vortex. The chemical ozone loss is estimated using the vortex-average technique. The N 2 O assimilated field is also used to substract out the effect of subsidence in order to extract the actual chemical ozone loss. Results show that the chemical ozone loss is 1.1 ± 0.3 ppmv on the 25 ppbv N 2 O level between mid-November and mid-January, and 0.9 ± 0.2 ppmv on the 50 ppbv N 2 O level between mid-November and the end of January. A linear fit over the same periods gives a chemical ozone loss rate of ∼18 ppbv day −1 and ∼9.3 ppbv day −1 on the 25 ppbv and 50 ppbv N 2 O levels, respectively. The vortex-averaged ozone loss profile from the O 3 assimilated field shows a maximum of 0.98 ppmv at 475 K. Comparisons to other results reported by different authors using different techniques and different observations give satisfactory results.
POAM III observations of arctic ozone loss for the 1999/2000 winter
Journal of Geophysical Research, 2002
During the Stratospheric Aerosol and Gas Experiment (SAGE) III Ozone Loss and Validation Experiment (SOLVE)/Third European Stratospheric Experiment on Ozone (THESEO) campaign, Polar Ozone and Aerosol Measurement (POAM) III sampled in the vortex core, on the vortex edge, and outside the vortex on a near-daily basis from December 1999 through mid-March 2000. During this period, POAM observed a substantial amount of ozone decline. For example, ozone mixing ratios in the core of the vortex dropped from about 3.5 ppmv in mid-January to about 2 ppmv by mid-March at 500 K. The ozone chemical loss indicated by these measurements is assessed using two methodologies. First, the POAM data is used to construct vortex-averaged ozone profiles, which are advected downward using vortex average descent rates. The maximum ozone loss (1 January to 15 March) is found to be about 1.8 ppmv. In a second approach, the REPROBUS 3-D CTM is used to specify the passive ozone distribution throughout the winter. The chemical loss in the vortex is estimated by performing a point-by-point subtraction of the POAM measurements inside the vortex from the model passive ozone evaluated at the time and location of the POAM measurements. Both ozone loss estimates are in general agreement and they agree well with published loss estimates from ER2 and ozonesonde measurements.
Early unusual ozone loss during the Arctic winter 2002/2003 compared to other winters
Atmospheric Chemistry and Physics, 2005
Ozone loss during the winter 2002/2003 has been evaluated from comparisons between total ozone reported by the SAOZ network and simulated in passive mode by both REPROBUS and SLIMCAT. Despite the fact that the two models have a different approach to calculate the descent inside vortex, both evaluations provide similar results 18±4% using REPROBUS and 20±4% using SLIMCAT and show that the loss started around mid-December, at least ten to twenty days earlier than during any of the previous eleven winters, except 1993/1994. This unusual behaviour is consistent with the low temperatures reported in the stratosphere as well to the signature of early chlorine activation indicated by ground-based, balloon and satellite observations. A significant ozone loss is also simulated by the current versions of two models, but of lesser amplitude compared to SAOZ, 13±2% for REPROBUS and 16±2% for SLIMCAT, the underestimation being already observed by mid-January. The early ozone depletion captured by both model show that chemical depletion did indeed take place in December, predominantly at the illuminated edge of the distorted vortex, but the reason for the underestimation compared to the observations and the differences among the models have still to be investigated.