We present particle optical properties of stratospheric smoke layers observed with multiwavelength polarization Raman lidar over Punta Arenas (53.2∘ S, 70.9∘ W), Chile, at the southernmost tip of ...South America in January 2020. The smoke originated from the record-breaking bushfires in Australia. The stratospheric aerosol optical thickness reached values up to 0.85 at 532 nm in mid-January 2020. The main goal of this rapid communication letter is to provide first stratospheric measurements of smoke extinction-to-backscatter ratios (lidar ratios) and particle linear depolarization ratios at 355 and 532 nm wavelengths. These aerosol parameters are important input parameters in the analysis of spaceborne CALIPSO and Aeolus lidar observations of the Australian smoke spreading over large parts of the Southern Hemisphere in January and February 2020 up to heights of around 30 km. Lidar and depolarization ratios, simultaneously measured at 355 and 532 nm, are of key importance regarding the homogenization of the overall Aeolus (355 nm wavelength) and CALIPSO (532 nm wavelength) lidar data sets documenting the spread of the smoke and the decay of the stratospheric perturbation, which will be observable over the entire year of 2020. We found typical values and spectral dependencies of the lidar ratio and linear depolarization ratio for aged stratospheric smoke. At 355 nm, the lidar ratio and depolarization ratio ranged from 53 to 97 sr (mean 71 sr) and 0.2 to 0.26 (mean 0.23), respectively. At 532 nm, the lidar ratios were higher (75–112 sr, mean 97 sr) and the depolarization ratios were lower with values of 0.14–0.22 (mean 0.18). The determined depolarization ratios for aged Australian smoke are in very good agreement with respective ones for aged Canadian smoke, observed with lidar in stratospheric smoke layers over central Europe in the summer of 2017. The much higher 532 nm lidar ratios, however, indicate stronger absorption by the Australian smoke particles.
In this study we present an approach that uses the polarimetric variable SLDR (slanted linear depolarization ratio) from a scanning polarimetric cloud radar MIRA-35 in the SLDR configuration, to ...derive the vertical distribution of particle shape (VDPS) between the top and base of mixed-phase cloud systems. The polarimetric parameter SLDR was selected for this study due to its strong sensitivity to shape and low sensitivity to the wobbling effect of particles at different antenna elevation angles. For the VDPS method, elevation scans from 90 to 30∘ elevation angle were deployed to estimate the vertical profile of the particle shape by means of the polarizability ratio, which is a measure of the density-weighted axis ratio. Results were obtained by retrieving the best fit between observed SLDR from 90 to 30∘ elevation angle and respective values simulated with a spheroidal scattering model. The applicability of the new method is demonstrated by means of three case studies of isometric, columnar, and plate-like hydrometeor shapes, respectively, which were obtained from measurements at the Mediterranean site of Limassol, Cyprus. The identified hydrometeor shapes are demonstrated to fit well to the cloud and thermodynamic conditions which prevailed at the time of observation. A fourth case study demonstrates a scenario where ice particle shapes tend to evolve from a pristine state at the cloud top toward a more isometric shape or less dense particles at the cloud base. Either aggregation or riming processes contribute to this vertical change of microphysical properties. The new height-resolved identification of hydrometeor shape and the potential of the VDPS method to derive its vertical distribution are helpful tools to understand complex processes such as riming or aggregation, which occur particularly in mixed-phase clouds.
Cloud and precipitation processes are still a main source of
uncertainties in numerical weather prediction and climate change
projections. The Priority Programme “Polarimetric Radar Observations meet
...Atmospheric Modelling (PROM)”, funded by the German Research Foundation
(Deutsche Forschungsgemeinschaft, DFG), is guided by the hypothesis that
many uncertainties relate to the lack of observations suitable to challenge
the representation of cloud and precipitation processes in atmospheric
models. Such observations can, however, at present be provided by the
recently installed dual-polarization C-band weather radar network of the
German national meteorological service in synergy with cloud radars and
other instruments at German supersites and similar national networks
increasingly available worldwide. While polarimetric radars potentially
provide valuable in-cloud information on hydrometeor type, quantity,
and microphysical cloud and precipitation processes, and atmospheric models
employ increasingly complex microphysical modules, considerable knowledge
gaps still exist in the interpretation of the observations and in the
optimal microphysics model process formulations. PROM is a coordinated
interdisciplinary effort to increase the use of polarimetric radar
observations in data assimilation, which requires a thorough evaluation and
improvement of parameterizations of moist processes in atmospheric models.
As an overview article of the inter-journal special issue “Fusion of radar
polarimetry and numerical atmospheric modelling towards an improved
understanding of cloud and precipitation processes”, this article outlines
the knowledge achieved in PROM during the past 2 years and gives
perspectives for the next 4 years.
De nombreuses recherches empiriques montrent que la façon dont les locuteurs et locutrices parlent peut varier en fonction du contexte, des dispositions mentales des locuteurs·trices, du type de la ...relation interpersonnelle (horizontale ou verticale) qu’entretiennent interlocuteurs·trices, de l’environnement culturel, etc. Mais en continuant d’exposer le grand public à des données incomplètes s’appuyant sur des stéréotypes de genres, les médias continuent d’entretenir l’idée, que les hommes et les femmes parlent différemment ; il y a donc une discordance entre la réalité des pratiques langagières et la représentation que les individus s’en font (Freed 2014). Notre étude du masculin et du féminin dans quatre séries de BDs de science-fiction franco-belges a pour but de vérifier si les héros et héroïnes de ces quatre séries sont représenté·e·s selon des stéréotypes de genre. Concernant le physique, comment héroïnes et héros sont-ils représentés ? Y a-t-il une frontière nette entre représentation de la féminité et de la masculinité ? Et, concernant la requête du type demande de faire, les héroïnes et héros formulent-ils différemment leurs requêtes ? Ces trois questions nous permettent de savoir si le lectorat des quatre séries de BDs analysées est exposé aux stéréotypes de genre. Les seuls stéréotypes de genre exposés s’appliquent aux corps et au vêtements (sauf dans une série). Pour le reste, attitudes, comportements, façons de parler, les stéréotypes sont globalement évacués. Il en ressort que la féminité et la masculinité s’inscrivent sur un continuum du genre. Pour ce qui est de la requête, dans deux séries les héroïnes se distinguent de leurs partenaires masculins du point de vue du fond de la requête (c.-à-d. de son objet), mais pas du point de vue de la forme et ce schéma est un corrélat de l’absence de leadership des partenaires masculins et révèle l’état mental de ces derniers ou la crainte de la prise de risque. Nous parlons alors de schémas de requêtes différenciées (et non genrées). Dans la troisième BD, le schéma des requêtes est genré dans la forme (et non dans le fond) dans la mesure où l’héroïne emploie davantage de requêtes indirectes que le héros, mais ce schéma n’est aucunement corrélé au manque de pouvoir de l’héroïne, qui, bien au contraire, jouit d’un grand pouvoir symbolique (probablement raison pour laquelle, le fond de ses requêtes est identique à celui du héros). Dans la quatrième série, celle où la représentation corporelle des hommes et des femmes est globalement similaire, on ne trouve ni schéma de requête genré ni schéma de requête différencié. La variation stylistique qui caractérise la nature directe ou indirecte des requêtes des personnages fictifs étudiés est fonction de l’urgence de la situation (contextuel), de leur expertise ou pouvoir (relation verticale) ou de leur état mental. Ils et elles privilégient la sauvegarde des faces à mesure que le caractère anxiogène du contexte de l’énonciation s’éloigne ou s’ils·elles entretiennent une relation interpersonnelle horizontale avec leur(s) allocutaire(s). Nos résultats sur la requête sont ainsi conformes avec les recherches empiriques : dans un cas ils illustrent la manifestation d’un des aspects du style langagier féminin et dans les trois autres, ils invalident l’existence de stéréotypes langagiers féminins dans le sens ou ces derniers sont dépassés par le contexte situationnel ou la relation interpersonnelle.
A significant number of case studies have shown that the way individuals speak, be they men or women, varies according to variables as the kind of relationship (vertical or horizontal) existing between interlocutors, mental state of speakers, context, culture and so forth. However, as Freed (2014) states, the mass media keep exposing their large audience to incomplete or erroneous data and stereotypes concerning the way men and women speak. Thus, individuals keep thinking that there is such a thing as «women and men speak differently». To put it in a nutshell, the way men and women speak is at odds with what occurs in reality. Our study about masculinity and femininity within four series of Franco-Belgian science-fictional comics aims at verifying how masculinity and femininity are represented in the four heroines and their male counterpart or partner(s). On the ground of non-linguistics representation, how are the female and male characters represented ? And does a clear line delineate masculinity and femininity ? Second, on the ground of linguistics, do the heroines phrase their requests differently than do the hero or male partner(s) ? In other words, are female characters more enclined than male characters to formulate indirect requests ? These three questions lead us to determine if the lectorate is exposed to gendered stereotypes. Our results show that stereotypes are only confined into the bodies (and at a certain point, the clothing). Other than that, attitudes and the way the characters speak are not bound to gendered stereotypes. Concerning the analysis of the requests, in two of our series, there is a difference between the requests made by the heroine and the ones made by the male in terms of the content of the requests. Therefore, we say that their request schema is not gendered but differentiated. That is to say, the content of the requests made by the males is correlated to their lack of power and reveal either their mental states or their being concerned with risk taking. In the third comic, we observe indeed a gendered schema of requests between the heroine and her male counterpart, the latter phrasing more direct requests. Conversely to the two previously mentioned comics, here, the stylish gendered request schema is not correlated with the heroine lack of power, that’s probably why both characters’ content of requests is the same. In the fourth series, which is the one where men and women are almost physically alike, we neither observe differentiated pattern of request nor gendered pattern of requests. Globally, in the four series, male and female characters articulate direct requests according to the emergency (contextual), their expertise or power (vertical relationship with interlocutor) or their mental state ; moreover, they indulge themselves into face-saving speech strategies as the emergency diminishes or disappears or if they have an horizontal type of relationship with their interlocutors. Thus, the variation is either stylistic or due to interpersonal relationship. Our results are not at odds with the empirical data : in one case, they illustrate the display of one aspect of the feminine language stereotype, and in the three other ones they invalidate the existence of stereotyped language styles in the sense that the stereotypes are overcome by the context or the interpersonal relationship.
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