The Second Aerosol Characterization Experiment (ACE-2) data set along with ECMWF reanalysis meteorological fields provided the basis for the single column model (SCM) simulations, performed as part of the PACE (Parameterization of the Aerosol Indirect Climatic Effect) project. Six different SCMs were used to simulate ACE-2 case studies of clean and polluted cloudy boundary layers, with the objective being to identify limitations of the aerosol/cloud/radiation interaction schemes within the range of uncertainty in in situ, reanalysis and satellite retrieved data. The exercise proceeds in three steps. First, SCMs are configured with the same fine vertical resolution as the ACE-2 in situ data base to evaluate the numerical schemes for prediction of aerosol activation, radiative transfer and precipitation formation. Second, the same test is performed at the coarser vertical resolution of GCMs to evaluate its impact on the performance of the parameterizations. Finally, SCMs are run for a 24–48 hr period to examine predictions of boundary layer clouds when initialized with large-scale meteorological fields. Several schemes were tested for the prediction of cloud droplet number concentration (N). Physically based activation schemes using vertical velocity show noticeable discrepancies compared to empirical schemes due to biases in the diagnosed cloud base vertical velocity. Prognostic schemes exhibit a larger variability than the diagnostic ones, due to a coupling between aerosol activation and drizzle scavenging in the calculation of N. When SCMs are initialized at a fine vertical resolution with locally observed vertical profiles of liquid water, predicted optical properties are comparable to observations. Predictions however degrade at coarser vertical resolution and are more sensitive to the mean liquid water path than to its spatial heterogeneity. Predicted precipitation fluxes are severely underestimated and improve when accounting for sub-grid liquid water variability. Results from the 24–48 hr runs suggest that most models have problems in simulating boundary layer cloud morphology, since the large-scale initialization fields do not accurately reproduce observed meteorological conditions. As a result, models significantly overestimate optical properties. Improved cloud morphologies were obtained for models with subgrid inversions and subgrid cloud thickness schemes. This may be a result of representing subgrid scale effects though we do not rule out the possibility that better large-forcing data may also improve cloud morphology predictions.

The thesis comprises two separate journal articles that together form a coherent body of work. In this thesis, the key physical processes responsible for the 23-26 September 2012 UK floods are investigated using a case study approach. The cyclone responsible for the floods developed near the Azores on 20¬-22 September following the interaction between an equatorward-moving potential vorticity (PV) streamer and tropical storm Nadine. Convectively-driven latent heat release associated with the developing cyclone reduced upper-level PV and resulted in the fracture of the PV streamer into a discrete anomaly as the cyclone intensified. In Paper 1, convection-permitting model simulations and diabatic heating rate and PV tendency calculations along trajectories demonstrate that deposition heating strongly reduced upper-level PV in the vicinity of the PV streamer, contributing to its fracture into a discrete anomaly. The cyclone deepened further over the UK on 23-26 September, ahead of a second upper-level PV anomaly. In Paper 2, sensitivity simulations of the storm are presented. PV inversion is used to modify the strength and position of the PV anomaly in the initial conditions and to examine whether the event could have been even more extreme with different upper-level forcing. Results show that quasigeostrophic forcing for ascent ahead of the PV anomaly contributed to the maintenance of the rainfall band over the UK. Counterintuitively however, strengthening the upper-level forcing produced a shallower cyclone with lower rainfall totals. Instead of moving eastward over the UK to interact with the cyclone, the strengthened anomaly rotated cyclonically around a large-scale trough over Iceland, resulting in a fragmented rainfall band. The counterintuitive results suggest that the verifying analysis represents almost the highest-impact scenario possible for this flooding event.

Submitted by Lucienne Costa (lucienneferreira@ufcg.edu.br) on 2018-08-13T17:06:59Z No. of bitstreams: 1 JEFFERSON APARECIDO ARESTIDES DE MELO – DISSERTAÇÃO (PPGMET) 2016.pdf: 4954301 bytes, checksum: 801b98838911a33f335fda02c77f585a (MD5) / Made available in DSpace on 2018-08-13T17:06:59Z (GMT). No. of bitstreams: 1 JEFFERSON APARECIDO ARESTIDES DE MELO – DISSERTAÇÃO (PPGMET) 2016.pdf: 4954301 bytes, checksum: 801b98838911a33f335fda02c77f585a (MD5) Previous issue date: 2016-02-29 / Capes / A linha de instabilidade (LI) Amazônica que atingiu Belém, em 08 de junho de 2008, foi monitorada e analisada por meio de medições de superfície, altitude, satélite e radar. A LI foi identificada, inicialmente, através de imagens do satélite GOES 12. O evento ocorreu durante a campanha de Belém, do Projeto CHUVA, que foi realizada durante o período de 01-30 junho de 2011, durante máxima ocorrência das linhas de instabilidades na região. Através da análise dos dados pluviométricos disponíveis percebe-se que a chuva associada à linha de instabilidade do dia 08 corresponde, aproximadamente, 29% da precipitação acumulada durante todo o experimento. A LI foi monitorada pelo radar meteorológico Banda - XPOL e permitiu a avaliação dinâmica e microfísica do sistema. Esta ultima realizada por meio da classificação de hidrometeoros com as variáveis polarimétricas. As variáveis utilizadas foram: refletividade horizontal (Zh, dBZ), refletividade diferencial (Zdr, dB), fase diferencial específica (Kdp, ° km-1), coeficiente de correlação (ρhv) e, por fim, se realizou a classificação dos hidrometeoros. O sistema apresentou fortes núcleos de refletividade que indicam a região convectiva. Esta parte da LI também é caracterizada por colunas com, relativamente, fortes Zdr e Kdp. A co-localização de colunas de Zh, Zdr e Kdp sugerem que esta é uma zona de elevada concentração de gotas de chuva com um tamanho considerável. A classificação dos hidrometeoros apresentou um resultado bem condizente com o que pode ser observado por outros pesquisadores e com as características microfísicas de outros sistemas convectivos. / A squall line (SL) Amazon, which reached Belém on June 8, 2008, was monitored and analyzed by means of surface measurements, altitude, satellite and radar. The SL was identified initially through the satellite GOES 12 images. The event was during the campaign of Belém, the Chuva Project, which was held during the period 01-30 June 2011, during maximum occurrence of squall line in the region. Through the analysis of available rainfall data we can see that the rain associated with the squall line the day 08 corresponds to approximately 29% of rainfall accumulated during all the experiment. The LI was monitored by weather radar Band - X POL and allowed the dynamic evaluation and microphysics of the system. The latter performed by hydrometeors classification with variables polarimetric. The variables used were: horizontal reflectivity (Zh, dBZ), differential reflectivity (Zdr, dB), specific differential phase (Kdp, ° km -1), correlation coefficient (ρhv) and, finally, was held the classification of hydrometeors. The system showed strong core of reflectivity indicating the convective region. This part of LI is also characterized by columns relatively strong Zdr and Kdp. The co-location columns Zh, Zdr and Kdp suggest that this is an area of high concentration of raindrops with a considerable size. The classification of hydrometeors presented the result well consistent with which can be observed by other researchers and the microphysical characteristics of other convective systems.

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-08-15T19:02:39Z No. of bitstreams: 1 RAFAEL CASTELO GUEDES MARTINS – TESE (PPGMet) 2014.pdf: 3362803 bytes, checksum: 5a99c28e73f6a95fef76f82f96d2edc4 (MD5) / Made available in DSpace on 2018-08-15T19:02:39Z (GMT). No. of bitstreams: 1 RAFAEL CASTELO GUEDES MARTINS – TESE (PPGMet) 2014.pdf: 3362803 bytes, checksum: 5a99c28e73f6a95fef76f82f96d2edc4 (MD5) Previous issue date: 2014-12-12 / Um dos principais desafios atuais da modelagem numérica da atmosfera trata da previsão quantitativa da precipitação e do posicionamento das nuvens de chuva. Este trabalho tem com o principal objetivo avaliar o desempenho das arametrizações de microfísicas na modelagem regional com ênfase no papel da informação de grande escala e sua influência sobre as simulações, e no uso de dados observados de radiossondagens como forma de acrescentar informação à modelagem . Inicialmente, duas reanálises (NCEP2 e ERAI) foram estatisticamente comparadas com dados de PCDs do Estado do Ceará. Verificou - se qu e a ERAI apresentou maior semelhança com as observações, principalmente para as variáveis diretamente ligadas à convecção. Em seguida, a ERAI foi utilizada como forçamento de grande escala em simulações com o modelo WRF. Observou- se que o uso de microfísica detalhada não melhora necessariamente a previsão do modelo, caso não sejam utilizados dados observados no local de estudo. Por último, duas simulações de alta resolução foram realizadas. Uma forçada pela reanálise sem modificação e outra forçada pela reanálise modificada utilizando o método de análise objetiva do WRF, para incluir as séries temporais de radiossondagens coletadas durante campanha experimental do Projeto CHUVA, em Fortaleza- CE. As duas simulações foram comparadas com dados observados pelo radiômetro para o mesmo local e período das radiossondagens . Observou - se que a inclusão das observações de sondagens na modelagem possibilita melhor modelagem de um sistema convectivo ocorrido em abril de 2011, principalmente para as variáveis ligadas à convecção. Este trabalho aponta, utilizando análises comparativas e estatísticas, que a utilização de uma maior densidade de dados observacionais válidos no modelo pode melhorar de forma muito mais eficiente o resultado da modelagem, do que mesmo a utilização do downscaling dinâmico do dado de grande escala ou a utilização de esquemas de microfísica detalhada, que, em algumas situações, pode inclusive inserir mais erros nos sistema s modelados. / The quantitative prediction of precipitation and the positioning of the rain clouds is one of the main challenges of numerical modeling of the atmosphere in present days. This work aims to evaluate the performance of the microphysical parameterizations in regional modeling, with emphasis on the role of large- scale information and its influence on the simulations, and the use of observational data from radiosondes as a way to add information to modeling. Initially, two reanalysis (NCEP2 and ERAI) were statistically compared with data from PCDs from the Ceará State. It was found that the ERAI showed similarity to the observations, especially for variables directly linked to convection. Then, the ERAI is used as large scale forcing in simulations with the WRF model. It was observed that the use of detailed microphysics does not necessarily improve the model performance, if in situ data were not used. Finally, two high resolution simulations were performed. The first f orced by reanalysis without modification and other forced by reanalysis using the modified method of objective analysis of the WRF, to include the time series of radiosonde observations collected during the experimental campaign of the CHUVA Project in Fortaleza- CE. The two simulations were compared with data observed by the radiometer to the same place and period of the radiosonde. It was observed that the inclusion of radiosonde observations in to the model leads to a better simulation of a convective system that occurred in April 2011, mostly for the variables related to convection. Using comparative statistical analysis, t his work points that the use of a higher density of valid observational data in the model can improve much more efficiently the model results than the use of a dynamic downscal ing of large- scale data or the use of schemes with detailed microphysics, which in some circumstances may even introduce more errors into the modeled system s.

The roughness of ice crystals, defined by small-scale surface roughness and large scale complexity, in high-altitude cloud, has been studied due to its important influence on the radiative properties of ice cloud. The Small Ice Detector 3 (SID-3) created at the University of Hertfordshire was used to measure the characteristics of individual ice crystals in situ. These are supplemented by a range of meteorological in situ measurements, including temperature, relative humidity, and wind velocity to investigate the influence of atmospheric conditions on ice crystal roughness/complexity. Since the method of roughness retrieval was novel, for atmospheric ice particles, laboratory experiments were setup to test and improve the characterization techniques. Criteria were set as a result of the laboratory experiments which data was expected to meet for it to be deemed reliable. These criteria and techniques were applied to data collected in situ on research aircraft. A range of degrees of ice crystal roughness were observed over five flights from two campaigns based out of Scotland in 2012 and 2015 (PIKNMIX and CIRCCREX). When all the flights were combined the majority of particles (51%) were categorised as lightly rough; the second most common roughness type was moderately rough (39%). Smooth particles made up 10% of the total particles, and < 0.02% were classed as severely rough. When considering a wave-cloud case separately, a similar range of roughness values were seen, however, smooth particles were only observed at the cloud leading-edge where nucleation was expected to occur during the only straight level run of the aircraft to probe this region. During the same wave-cloud flight smooth particles were more common in supersaturated regions and moderately rough crystals were more common in subsaturated regions, suggesting that crystals are more likely to tend towards rougher values when observed in subsaturated environments (a statistical T-test showed this hypothesis to be statistically significant). It was found that due to limitations associated with instantaneous measurements, it was challenging to observe how ice particle roughness evolved in situ, since the history of the individual crystals was unknown in most cases. Orographic cloud, however, was found to provide a more robust estimation of crystal evolution as a consequence of having sharp-leading edges where nucleation events were expected to occur, and since crystals then follow streamlines, the distance from the sharp-leading edge can act as a proxy for time since nucleation.

Electron transfer processes are investigated through conductance measurements of single molecules. Measurements are performed on metal-molecule-metal junctions using a modified scanning tunneling microscope technique. Through a series of experimental measurements, and accompanying theoretical models, the influence of the molecule on the measured current is explored. These explorations are presented in five separate chapters. In chapter two, the molecular orbitals of sp-hybridized carbon chains are discussed in detail. It is demonstrated that the molecular orbitals can assume an intriguing helical shape. In chapter three, the length-dependent conductance of sp²-hybridized carbon chains is investigated. Experiment and theory demonstrate that the conductance of odd-numbered chains is nearly uniform with length. In chapter four, a new theoretical scheme to calculate quantum interference is developed. Using this scheme, it is demonstrated that quantum interference yields the decay in conductance with length for molecular wires. In chapter five, current-voltage measurements of redox-active molecular clusters are shown to agree with a hopping transport model. In chapter six, a novel experimental setup is presented that can be used to investigate photoconductivity in single-molecule junctions. This thesis provides a broad, yet rigorous, survey of electron transfer processes in single-molecule junctions.

Les conditions à la surface de Vénus sont infernales : température de plus de 400 C, pression atmosphérique 90 fois celle sur Terre dans une atmosphère composée à 96 % de dioxyde de carbone. Une particularité de cette planète est la couche opaque nuageuse de 20 km d'épaisseur qui couvre toute la planète. Les nuages ont un rôle crucial pour le transfert de rayonnement, la dynamique atmosphérique, dans le cycle de certaines espèces chimiques comme le soufre et plus généralement pour le climat de Vénus. Malgré de nombreuses missions spatiales consacrées à cet astre depuis 1961, il y a peu de mesures in-situ. Les couches basses des nuages sont diciles à étudier par satellite, par conséquent il existe encore de nombreuses questions au sujet des nuages : leurs propriétés et leurs impacts radiatifs, dynamiques et chimiques sont mal contraints. Composées majoritairement d'acide sulfurique en solution, les particules sont supposées sphériques et liquides et composent des nuages étalés verticalement entre 50 et 70 km d'altitude environ, entourés par des brumes entre 30 et 50 km et au-dessus de 70 km. Les gouttelettes ont été classées, d'après des observations, en trois modes en fonction de leur taille et de leur composition : les modes 1 et 2 respectivement pour les petites (r = 0.2 μm) et moyennes particules (r = 1.0 μm), et un troisième mode qui contiendrait les plus grandes particules (r = 3.5 μm). Ce dernier mode, qui a été détecté par la sonde Pioneer Venus, demeure de composition et d'existence incertaines, et il n'est pas pris en compte dans notre étude. Afin de compléter et de mieux comprendre les données obtenues par l'observation spatiale, un modèle modal de microphysique, nommé MADMuphy (Modal Aerosol Dynamics with Microphysics), a été développé. L'objectif est d'intégrer MAD-Muphy dans le modèle de climat global vénusien (IPSL-VGCM), il faut donc limiter le nombre de variables que le VGCM doit suivre dans le temps et l'espace (également appelé traceurs). La méthode des moments est déjà utilisée dans les GCM de Titan et de Mars et constitue un bon compromis entre la précision des résultats et le temps de calcul. MAD-Muphy est donc basé sur cette représentation pour une pression et une température dé nies pour une couche de l'atmosphère (ou 0D). La thèse présentée ici détaille le développement des expressions mathématiques des équations de la microphysique avec les moments, présente le nouveau modèle MAD-Muphy ainsi que les hypothèses qui ont été nécessaires pour son développement. Tout d'abord, nous déterminerons le temps caractéristique de chaque processus microphysique et nous étudierons leur comportement en 0D. Ensuite, nos résultats seront comparés avec ceux du modèle sectionné SALSA en 0D. / The conditions on the surface of Venus are infernal: temperature of more than 400 C, 90 times the Earth's atmospheric pressure in an atmosphere composed of 96 % of carbon dioxide. A distinctive characteristic of this planet is the 20 km thick opaque cloud layer, which enshrouds the planet. Clouds have a crucial role in radiative transfer, atmospheric dynamics, in the cycle of some chemical species like sulphur and more generally in the climate of Venus. Despite the numerous space missions devoted to this object since 1961, there are few in-situ measurements. The lower cloud layers are di cult to study by satellite, so there are still many questions about clouds: their properties and their radiative, dynamic and chemical impacts are poorly constrained. Predominantly composed of sulphuric acid solution, the particles are supposed to be spherical and liquid and compose the clouds that are vertically spread between approximately 50 and 70 km of altitude, surrounded by hazes between approximately 30 and 50 km and above 70 km. Based on observations the droplets have been classied into three modes according to their size and composition: modes 1 and 2 respectively for small (r = 0.2 μm) and medium particles (r = 1.0 μm), and a third mode that would contain the largest particles (r = 3.5 μm). The latter mode, which has been detected by the Pioneer Venus probe, remains uncertain in composition and existence, and is not taken into account in our study. To complete and better understand the observational data, a modal microphysical model, called MAD-Muphy (Modal Aerosol Dynamics with Microphysics), has been developed. The goal is to integrate MAD-Muphy into the venusian global climate model (IPSL-VGCM), so we must limit the number of variables that the VGCM must follow in time and space (also called tracers). The moment method is already used in the Titan and Mars GCMs and is a good compromise between the accuracy of the results and the computation time. MAD-Muphy is the refore based on this representation for a pressure and a temperature of one atmospheric layer (or 0D). The thesis presented here details the derivation of the mathematical expressions of the microphysical equations with moments, presents the new MAD-Muphy model as well as the hypotheses that were necessary for its development. We will first determine the characteristic timescale of each microphysical process and we will study their behaviour in 0D. Then, our results will be compared with those of the SALSA sectional model in 0D.

The immaculate control of atoms and molecules with light is the defining trait of modern experiments in ultracold physics. The rich internal degrees of freedom afforded by molecules enrich the toolbox of precision spectroscopy for fundamental physics, and hold great promise for applications in quantum simulation and quantum information science. A vibrational molecular lattice clock with systematic fractional uncertainty at the 14th decimal place is demonstrated for the first time, matching the performance of the earliest optical atomic clocks. Van der Waals dimers of strontium are created at ultracold temperatures and levitated by an optical standing wave, whose wavelength is finely tuned to preserve the delicate molecular vibrational coherence. Guided by quantum chemistry theory refined by highly accurate frequency-comb-assisted laser spectroscopy, record-long Rabi oscillations were demonstrated between vibrational molecular states that span the entire depth of the ground molecular potential. Enabled by the narrow molecular clock linewidth, hertz-level frequency shifts were resolved, facilitating the first characterization of molecular hyperpolarizability in this context. In a parallel effort, deeply bound strontium dimers are coherently created using the technique of stimulated Raman adiabatic passage. Ultracold collisions of alkaline-earth metal molecules in the absolute ground state are studied for the first time, revealing inelastic losses at the universal rate. This thesis reports one of the most accurate measurement of a molecule's vibrational transition frequency to date, which may potentially serve as a secondary representation of the SI unit of time in the terahertz (THz) band where standards are scarce. The prototypical molecular clock lays the important groundwork for future explorations into THz metrology, quantum chemistry, and fundamental interactions at atomic length scales.

For years, frequency standards have been the cornerstone of precision measurement. Among these frequency standards, atomic clocks have set records in both precision and accuracy, and have redefined the second. There is growing interest in more complex molecular systems to complement precision measurements with atoms. The rich internal structure of even the simplest diatomic molecules could provide new avenues for fundamental physics research, including searches for extensions to the Standard Model, dark matter candidates, novel forces or corrections to gravity at short distances, and tests of the variation of fundamental constants. In this thesis, we discuss the fundamental architecture for a precise molecular system based on a strongly forbidden weakly-bound to deeply-bound vibrational transition in 88Sr dimers. We discuss early studies to characterise our system and gain technical and quantum control over the experiment in anticipation of a precise metrological measurement. We, then, demonstrate a record-breaking precision for our 88Sr2 molecular clock ushering in a new era for precision measurement with clocks. Borrowing techniques from previous atomic clock architecture, we measure a ∼32 THz clock transition between two vibrational levels in the electronic ground state, achieving a fractional uncertainty of 4.6 × 10−14 in a new frequency regime. In this current iteration, our molecular clock is fundamentally limited by two-body loss lifetimes of 200 ms and light scattering induced by our high-intensity lattice. Given these limitations, we suggest improvements to combat the effects from both the lattice and two-body collisions in our 1D trap. These include technical improvements to our experiment and strategic choices of particular clock states in our ground electronic potential. We describe in-depth studies of the chemistry and polarizability behaviour of our molecule, which elucidates preferential future directions for a second generation clock system. These empirical results are substantiated by an improved theoretical picture. Ultimately, our molecular system is built in order to probe new physics and as a tool for precision measurement. Leveraging our record-precision clock and our new-found understanding of our molecule, we predict the capacity for our system to place meaningful, competitive constraints on new physics, in particular on Yukawa-type extensions to gravity. These predictions motivate improvements to our current generation clock and set the stage for future measurements with this system.

La présente étude porte sur la simulation numérique de la croissance des cristaux de glace dans le sillage proche d'une aile rectangulaire munie de deux injecteurs qui modélisent les deux moteurs. Dans cette configuration, les phénomènes microphysiques interviennent lors de l'interaction du jet, issu du moteur, et du tourbillon marginal qui se développe à chaque bout d'aile. Cet écoulement, très turbulent, perturbe fortement l'air environnant. Les jets diffusent dans l'atmosphère et s'enroulent autour des deux tourbillons de bout d'aile. Ces jets contiennent de la vapeur d'eau, des suies, des gaz mais également des aérosols et particules chargées. Le modèle microphysique utilisé dans cette étude repose sur l'hypothèse que la vapeur d'eau condense uniquement sur les particules de suie. Les simulations numériques sont effectuées à l’aide du code CEDRE développé à l’ONERA. Les méthodes numériques sont basées sur une approche volume finie pour des maillages non structurés généralisés. La résolution des équations de Navier stokes compressibles pour des fluides multi-espèces se fait selon une approche de type RANS et seul le champ stationnaire, jusqu'à huit envergures en aval de la maquette, est calculé. La turbulence de l'écoulement est modélisée au moyen du système de fermeture à deux équations k-l . Cette approche permet d'obtenir une description spatiale plus réaliste de l'interaction entre le jet et le tourbillon marginal. Le champ aérodynamique du sillage est ainsi comparé aux données expérimentales existantes. Le jet est correctement enroulé autour du tourbillon à huit envergures, et la dilution du panache est bien décrite par les simulations. Le modèle microphysique est ensuite couplé au modèle aérodynamique. Une première simulation porte sur les phénomènes microphysiques intervenant dans le sillage de la maquette dans des conditions particulières, représentatives d'un avion commercial en vol de croisière dans une atmosphère saturée par rapport à la glace. L'influence de la taille initiale des particules de suies émises par les moteurs ainsi que l'humidité relative de l'atmosphère, sur les propriétés de la traînée de condensation, sont ensuite étudiées et discutées. Ce travail, de part la stratégie de calcul mise en place et notamment l'utilisation de maillages non structurés généralisés, permettra d'appréhender le rôle de certains paramètres clés liés à l'avion comme la géométrie des ailes ou bien encore la position des nacelles sur les propriétés microphysiques de la traînée de condensation. / Numerical simulations of ice particles growth, in the near wake of a rectangular wing with two injectors, are presented in this study. In this configuration, microphysical processes occur during the interaction between the engines jets and the marginal vortices developping at each wing tip. This strong turbulent flow disturbs highly the environmental flow. The jets diffuse in the atmosphere and are wrapped around the two wing tip vortices. They contain water vapour, soots, gas, aerosols and charged particles as well. One of the hypothesis of the microphysical modeling, used in this study, is that water vapour condenses on soot particles only. Numerical simulations are performed with the code CEDRE developed at ONERA. The numerical methods are based on a cell-centered finite volume approach for general unstructured grids. A Navier-Stokes solver for turbulent, compressible and multi-species flows with a RANS approach, based on the k-l turbulence model, is used. Only stationary states of the flow, until eight spans downstream the setup, are computed. This approach enables to get a better spatial description of the interaction between the jet and the marginal vortex. The numerical flow field is then compared to existing experimental data. The jet is correctly wrapped around the wing tip vortex at eight spans and the dilution of the effluents is well described by our simulations. The microphysical model is then coupled to the aerodynamics. The microphysical processes occurring in the wake of the setup in specific conditions, representative of a cruising civil aircraft in an ice-saturated atmosphere, are firstly simulated. The role, on the contrail’s properties, of soot particles initial size and of the atmospheric humidity is studied and discussed. This work, through its computational strategy, with the use of unstructured grids, will enable to understand the potential role of some key parameters such as the wings geometry or the engines position on the contrail properties.