The impact of mixing across the polar vortex edge on Match ozone loss estimates

The Match method for quantification of polar chemical ozone loss is investigated mainly with respect to the impact of mixing across the vortex edge onto this estimate. We show for the winter 2002/03 that significant mixing across the vortex edge occurred and was accurately modeled by the Chemical Lagrangian Model of the Stratosphere. Observations of inert tracers and ozone in-situ from HAGAR on the Geophysica aircraft and sondes and also remote from MIPAS on ENVISAT were reproduced well. The model even reproduced a small vortex remnant that was isolated until June 2003 and was observed in-situ by a balloon-borne whole air sampler. We use this CLaMS simulation to quantify the impact of cross vortex edge mixing on the results of the Match method. It is shown that a time integration of the determined vortex average ozone loss rates as performed in Match results in larger ozone loss than the polar vortex average ozone loss in CLaMS. Also, the determination of the Match ozone loss rates can be influenced by mixing. This is especially important below 430 K, where ozone outside the vortex is lower than inside and the vortex boundary is not a strong transport barrier. This effect and further sampling effects cause an offset between vortex average ozone loss rates derived from Match and deduced from CLaMS with an even sampling for the entire vortex. Both, the time-integration of ozone loss and the determination of ozone loss rates for Match are evaluated using the winter 2002/03 CLaMS simulation. These impacts can explain the differences between CLaMS and Match column ozone loss. While the investigated effects somewhat reduce the apparent discrepancy in January ozone loss rates, a discrepancy between simulations and Match remains. However, its contribution to the accumulated ozone loss over the winter is not large

Educational profession-oriented propaedeutic Russian language course as a basis of coming of international students of pre-university training stage into the educational medium of the higher medical institution

Цель статьи - рассмотреть некоторые способы и методы (фреймовый подход) формирования лингвокультурологической медицинской компетенции иностранных учащихся предвузовского этапа на занятиях по русскому языку общелитературного стиля в соответствии со спецификой их будущего обучения в русскоязычной среде медицинского вуза. Актуальность исследования заключается в том, что учебный пропедевтический курс русского языка, ориентированный на изучение иностранными учащимися языка медицинской науки, является важнейшим и необходимым условием для их обучения в медицинском университете. Преподавание основывается на использовании общедидактических и методических принципов начального обучения русскому языку будущих студентов- медиков, которые способствуют дальнейшему усвоению и совершенствованию учебно- профессиональных знаний в условиях русской языковой среды медицинского вуза. В процессе исследования были использованы следующие методы: теоретический и практический анализ научной литературы по методике преподавания иностранного языка и русского как иностранного, аудиовизуальное наблюдение, беседы с иностранными студентами, пробное обучение. Результаты. В процессе изучения русского языка иностранные учащиеся приобретают новые знания, расширяется их эрудиция, кругозор. Иностранные учащиеся предвузовского этапа входят в мир языка медицинской науки, знакомясь с элементами её лингвистической, коммуникативной и культурологической базы. Выводы: пропедевтический курс русского языка закладывает основы знаний о специфике изучения медицины на русском языке, которые помогут иностранным учащимся предвузовского этапа подготовки спустя год войти в образовательную среду медицинского университета.The aim of the research is to consider some ways and methods (frame approach) of forming lingual- cultural medical competence of international students of pre-University training stage at the Russian Language classes in accordance with the specifics of their future learning in Russian-speaking medium of higher medical institution. Relevance of the study lies in the fact that educational propaedeutic course of the Russian Language, focused on training foreign students the language of medical science, is the most important and necessary condition for their studying in the medical university. Training is based on the usage of general didactic and methodical principles of elementary level of teaching Russian the future medical students, which promoting further learning and mastering the educational-professional knowledge in the conditions of Russian speaking environment of higher medical institution. The author has used the following methods: theoretical and practical analysis of scientific literature on methods of teaching foreign language and Russian as a foreign language, audio-visual monitoring, interviews with foreign students, experimental teaching. Results. When learning Russian the international students get knowledge, enlarge their erudition, the outlook. International students of pre-University training stage come into the world of the Language of medical science, becoming acquainted with the elements of its linguistic, communicative and cultural base. Conclusion. The propaedeutic course of Russian lays foundations of knowledge of specifics of learning medicine in Russian, which will help international students of pre-university training stage to be admitted to the educational environment of medical University after the first year of studying

Mixing and chemical ozone loss during and after the Antarctic polar vortex major warming in September 2002

The 3D version of the Chemical Lagrangian Model of the Stratosphere (CLAMS) is used to study the transport of CH4 and 03 in the Antarctic stratosphere between I September and 30 November 2002, that is, over the time period when unprecedented major stratospheric warming in late September split the polar vortex into two parts. The isentropic and cross-isentropic velocities in CLAMS are derived from ECMWF winds and heating/cooling rates calculated with a radiation module. The irreversible part of transport, that is, mixing, is driven by the local horizontal strain and vertical shear rates with mixing parameters deduced from in situ observations.The CH4 distribution after the vortex split shows a completely different behavior above and below 600 K. Above this potential temperature level, until the beginning of November, a significant part of vortex air is transported into the midlatitudes up to 40 degrees S. The lifetime of the vortex remnants formed after the vortex split decreases with the altitude with values of about 3 and 6 weeks at 900 and 700 K, respectively.Despite this enormous dynamical disturbance of the vortex, the intact part between 400 and 600 K that "survived" the major warming was strongly isolated from the extravortex air until the end of November. According to CLAMS simulations, the air masses within this part of the vortex did not experience any significant dilution with the midlatitude air.By transporting ozone in CLAMS as a passive tracer, the chemical ozone loss was estimated from the difference between the observed [Polar Ozone and Aerosol Measurement III (POAM 111) and Halogen Occultation Experiment (HALOE)] and simulated ozone profiles. Starting from I September, up to 2.0 ppmv O-3 around 480 K and about 70 Dobson units between 450 and 550 K were destroyed until the vortex was split. After the major warming, no additional ozone loss can be derived, but in the intact vortex part between 450 and 550 K, the accumulated ozone loss was "frozen in" until the end of November

Mixing and Ozone Loss in the 1999-2000 Arctic Vortex: Simulations with the 3-dimensional Chemical Lagrangian Model of the Stratosphere (CLaMS)

[1] The three-dimensional (3-D) formulation of the Chemical Lagrangian Model of the Stratosphere (CLaMS-3d) is presented that extends the isentropic version of CLaMS to cross-isentropic transport. The cross-isentropic velocities of the Lagrangian air parcels are calculated with a radiation module and by taking into account profiles of ozone and water vapor derived from a HALOE climatology. The 3-D extension of mixing maintains the most important feature of the 2-D version as mixing is mainly controlled by the horizontal deformations of the wind fields. In the 3-D version, mixing is additionally driven by the vertical shear in the flow. The impact of the intensity of mixing in the 3-D model formulation on simulated tracer distributions is elucidated by comparing observations of CH4, Halon-1211, and ozone from satellite, balloon, and ER-2 aircraft during the SOLVE/ THESEO-2000 campaign. CLaMS-3d simulations span the time period from early December 1999 to the middle of March 2000, with air parcels extending over the Northern Hemisphere in the vertical range between 350 and 1400 K. The adjustment of the CLaMS-3d mixing parameters to optimize agreement with observations was obtained for strongly inhomogeneous, deformation-induced mixing that affects only about 10% of the air parcels per day. The optimal choice of the aspect ratio a defining the ratio of the mean horizontal and vertical separation between the air parcels was determined to be 250 for model configuration with a horizontal resolution r(0) = 100 km. By transporting ozone in CLaMS-3d as a passive tracer, the chemical ozone loss was inferred as the difference between the observed and simulated ozone profiles. The results show, in agreement with previous studies, a substantial ozone loss between 380 and 520 K with a maximum loss at 460 K of about 1.9 ppmv, i.e., of over 60% locally, from December to the middle of March 2000. During this period, the impact of isentropic mixing across the vortex edge outweighs the effect of the spatially inhomogeneous ( differential) descent on the tracer/ ozone correlations in the vortex. Mixing into the vortex shifts the early winter reference tracer/ ozone correlation to higher values, which may lead to an underestimate of chemical ozone loss, on average by 0.4 and 0.1 ppmv in the entire vortex and the vortex core, respectively