Relevant bibliographies by topics / Processus convectifs

Academic literature on the topic 'Processus convectifs'

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Published: 23 February 2024

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Journal articles on the topic "Processus convectifs"

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Coquillat, Sylvain, Véronique Pont, Mickaël Pardé, Michaël Kreitz, Dominique Lambert, Ronan Houel, Didier Ricard, Eric Gonneau, Pierre de Guibert, and Serge Prieur. "Découverte d'une anomalie électrique dans des orages méditerranéens." La Météorologie, no. 120 (2023): 046. http://dx.doi.org/10.37053/lameteorologie-2023-0016.

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L'analyse de 561 jours d'orage sur 6 années de données de l'imageur d'éclair 3D Saetta a permis d'identifier des nuages convectifs en région Corse présentant une structure électrique anormale et apparaissant par flux de sud de poussières désertiques africaines. L'explication physique des processus électriques apporte les bases pour comprendre ce que l'imageur permet de déduire sur la structure électrique des cellules orageuses. Des hypothèses microphysiques et radiatives conduisant à un faible contenu en gouttelettes d'eau surfondue à l'origine de cette électrisation anormale sont explorées en s'appuyant sur l'analyse du contexte en aérosols et des conditions météorologiques environnantes. The analysis of 561 days of thunderstorms over 6 years of data from the 3D lightning imager Saetta has allowed to identify convective clouds in Corsica region with an abnormal electrical structure and appearing by southern flow of African desert dust. The physical explanation of the electrical processes brings the basis to understand what the imager allows to deduce about the electrical structure of thunderstorm cells. Microphysical and radiative hypotheses leading to a low content of supercooled droplets at the origin of this abnormal electrification are explored by relying on the analysis of the aerosol context and the surrounding meteorological conditions.
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Anders, Evan H., Adam S. Jermyn, Daniel Lecoanet, J. R. Fuentes, Lydia Korre, Benjamin P. Brown, and Jeffrey S. Oishi. "Convective Boundary Mixing Processes." Research Notes of the AAS 6, no. 2 (February 28, 2022): 41. http://dx.doi.org/10.3847/2515-5172/ac5892.

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Abstract Convective motions extend beyond the nominal boundaries of a convection zone. These motions mix fluid through multiple mechanisms collectively called “convective boundary mixing.” In this note, we discuss three distinct fluid dynamical processes: convective overshoot, entrainment, and penetrative convection. We describe the structure of a convective boundary that these processes create. To resolve discrepancies between models and observations, the stellar astrophysics community should distinguish between these processes and parameterize each of them separately in 1D evolutionary models.
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Bouffard, Damien, and Alfred Wüest. "Convection in Lakes." Annual Review of Fluid Mechanics 51, no. 1 (January 5, 2019): 189–215. http://dx.doi.org/10.1146/annurev-fluid-010518-040506.

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Lakes and other confined water bodies are not exposed to tides, and their wind forcing is usually much weaker compared to ocean basins and estuaries. Hence, convective processes are often the dominant drivers for shaping mixing and stratification structures in inland waters. Due to the diverse environments of lakes—defined by local morphological, geochemical, and meteorological conditions, among others—a fascinating variety of convective processes can develop with remarkably unique signatures. Whereas the classical cooling-induced and shear-induced convections are well-known phenomena due to their dominant roles in ocean basins, other convective processes are specific to lakes and often overlooked, for example, sidearm, under-ice, and double-diffusive convection or thermobaric instability and bioconvection. Additionally, the peculiar properties of the density function at low salinities/temperatures leave distinctive traces. In this review, we present these various processes and connect observations with theories and model results.
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Zheng, Zhang, Liu, Liu, and Che. "A Study of Vertical Structures and Microphysical Characteristics of Different Convective Cloud–Precipitation Types Using Ka-Band Millimeter Wave Radar Measurements." Remote Sensing 11, no. 15 (August 1, 2019): 1810. http://dx.doi.org/10.3390/rs11151810.

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Millimeter wave cloud radar (MMCR) is one of the primary instruments employed to observe cloud–precipitation. With appropriate data processing, measurements of the Doppler spectra, spectral moments, and retrievals can be used to study the physical processes of cloud–precipitation. This study mainly analyzed the vertical structures and microphysical characteristics of different kinds of convective cloud–precipitation in South China during the pre-flood season using a vertical pointing Ka-band MMCR. Four kinds of convection, namely, multi-cell, isolated-cell, convective–stratiform mixed, and warm-cell convection, are discussed herein. The results show that the multi-cell and convective–stratiform mixed convections had similar vertical structures, and experienced nearly the same microphysical processes in terms of particle phase change, particle size distribution, hydrometeor growth, and breaking. A forward pattern was proposed to specifically characterize the vertical structure and provide radar spectra models reflecting the different microphysical and dynamic features and variations in different parts of the cloud body. Vertical air motion played key roles in the microphysical processes of the isolated- and warm-cell convections, and deeply affected the ground rainfall properties. Stronger, thicker, and slanted updrafts caused heavier showers with stronger rain rates and groups of larger raindrops. The microphysical parameters for the warm-cell cloud–precipitation were retrieved from the radar data and further compared with the ground-measured results from a disdrometer. The comparisons indicated that the radar retrievals were basically reliable; however, the radar signal weakening caused biases to some extent, especially for the particle number concentration. Note that the differences in sensitivity and detectable height of the two instruments also contributed to the compared deviation.
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Tulich, Stefan N., and Brian E. Mapes. "Multiscale Convective Wave Disturbances in the Tropics: Insights from a Two-Dimensional Cloud-Resolving Model." Journal of the Atmospheric Sciences 65, no. 1 (January 1, 2008): 140–55. http://dx.doi.org/10.1175/2007jas2353.1.

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Abstract Multiscale convective wave disturbances with structures broadly resembling observed tropical waves are found to emerge spontaneously in a nonrotating, two-dimensional cloud model forced by uniform cooling. To articulate the dynamics of these waves, model outputs are objectively analyzed in a discrete truncated space consisting of three cloud types (shallow convective, deep convective, and stratiform) and three dynamical vertical wavelength bands. Model experiments confirm that diabatic processes in deep convective and stratiform regions are essential to the formation of multiscale convective wave patterns. Specifically, upper-level heating (together with low-level cooling) serves to preferentially excite discrete horizontally propagating wave packets with roughly a full-wavelength structure in troposphere and “dry” phase speeds cn in the range 16–18 m s−1. These wave packets enhance the triggering of new deep convective cloud systems, via low-level destabilization. The new convection in turn causes additional heating over cooling, through delayed development of high-based deep convective cells with persistent stratiform anvils. This delayed forcing leads to an intensification and then widening of the low-level cold phases of wave packets as they move through convecting regions. Additional widening occurs when slower-moving (∼8 m s−1) “gust front” wave packets excited by cooling just above the boundary layer trigger additional deep convection in the vicinity of earlier convection. Shallow convection, meanwhile, provides positive forcing that reduces convective wave speeds and destroys relatively small-amplitude-sized waves. Experiments with prescribed modal wind damping establish the critical role of short vertical wavelengths in setting the equivalent depth of the waves. However, damping of deep vertical wavelengths prevents the clustering of mesoscale convective wave disturbances into larger-scale envelopes, so these circulations are important as well.
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Deng, Liping, and Xiaoqing Wu. "Effects of Convective Processes on GCM Simulations of the Madden–Julian Oscillation." Journal of Climate 23, no. 2 (January 15, 2010): 352–77. http://dx.doi.org/10.1175/2009jcli3114.1.

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Abstract Weak temporal variability in tropical climates such as the Madden–Julian oscillation (MJO) is one of major deficiencies in general circulation models (GCMs). The uncertainties in the representation of convection and cloud processes are responsible for these deficiencies. With the improvement made to the convection scheme, the Iowa State University (ISU) GCM, which is based on a version of the NCAR Community Climate Model, is able to simulate many features of MJO as revealed by observations. In this study, four 10-yr (1979–88) ISU GCM simulations with observed sea surface temperatures are analyzed and compared to examine the effects of the revised convection closure, convection trigger condition, and convective momentum transport (CMT) on the MJO simulations. The modifications made in the convection scheme improve the simulations of amplitude, spatial distribution, eastward propagation, and horizontal and vertical structures, especially for the coherent feature of eastward-propagating convection and the precursor sign of convective center. The revised convection closure plays a key role in the improvement of the eastward propagation of MJO. The convection trigger helps produce less frequent but more vigorous moist convection and enhance the amplitude of the MJO signal. The inclusion of CMT results in a more coherent structure for the MJO deep convective center and its corresponding atmospheric variances.
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Palotai, Csaba, Shawn Brueshaber, Ramanakumar Sankar, and Kunio Sayanagi. "Moist Convection in the Giant Planet Atmospheres." Remote Sensing 15, no. 1 (December 30, 2022): 219. http://dx.doi.org/10.3390/rs15010219.

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The outer planets of our Solar System display a myriad of interesting cloud features, of different colors and sizes. The differences between the types of observed clouds suggest a complex interplay between the dynamics and chemistry at play in these atmospheres. Particularly, the stark difference between the banded structures of Jupiter and Saturn vs. the sporadic clouds on the ice giants highlights the varieties in dynamic, chemical and thermal processes that shape these atmospheres. Since the early explorations of these planets by spacecrafts, such as Voyager and Voyager 2, there are many outstanding questions about the long-term stability of the observed features. One hypothesis is that the internal heat generated during the formation of these planets is transported to the upper atmosphere through latent heat release from convecting clouds (i.e., moist convection). In this review, we present evidence of moist convective activity in the gas giant atmospheres of our Solar System from remote sensing data, both from ground- and space-based observations. We detail the processes that drive moist convective activity, both in terms of the dynamics as well as the microphysical processes that shape the resulting clouds. Finally, we also discuss the effects of moist convection on shaping the large-scale dynamics (such as jet structures on these planets).
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Hirt, Mirjam, Stephan Rasp, Ulrich Blahak, and George C. Craig. "Stochastic Parameterization of Processes Leading to Convective Initiation in Kilometer-Scale Models." Monthly Weather Review 147, no. 11 (October 11, 2019): 3917–34. http://dx.doi.org/10.1175/mwr-d-19-0060.1.

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Abstract Kilometer-scale models allow for an explicit simulation of deep convective overturning but many subgrid processes that are crucial for convective initiation are still poorly represented. This leads to biases such as insufficient convection triggering and late peak of summertime convection. A physically based stochastic perturbation scheme (PSP) for subgrid processes has been proposed (Kober and Craig) that targets the coupling between subgrid turbulence and resolved convection. The first part of this study presents four modifications to this PSP scheme for subgrid turbulence: an autoregressive, continuously evolving random field; a limitation of the perturbations to the boundary layer that removes artificial convection at night; a mask that turns off perturbations in precipitating columns to retain coherent structures; and nondivergent wind perturbations that drastically increase the effectiveness of the vertical velocity perturbations. In a revised version, PSP2, the combined modifications retain the physically based coupling to the boundary layer scheme of the original scheme while removing undesirable side effects. This has the potential to improve predictions of convective initiation in kilometer-scale models while minimizing other biases. The second part of the study focuses on perturbations to account for convective initiation by subgrid orography. Here the mechanical lifting effect is modeled by introducing vertical and horizontal wind perturbations of an orographically induced gravity wave. The resulting perturbations lead to enhanced convective initiation over mountainous terrain. However, the total benefit of this scheme is unclear and we do not adopt the scheme in our revised configuration.
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Huang, Yipeng, Murong Zhang, Yuchun Zhao, Ben Jong-Dao Jou, Hui Zheng, Changrong Luo, and Dehua Chen. "Inter-Zone Differences of Convective Development in a Convection Outbreak Event over Southeastern Coast of China: An Observational Analysis." Remote Sensing 14, no. 1 (December 29, 2021): 131. http://dx.doi.org/10.3390/rs14010131.

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Among the densely-populated coastal areas of China, the southeastern coast has received less attention in convective development despite having been suffering from significantly increasing thunderstorm activities. The convective complexity under such a region with extremely complex underlying and convective conditions deserves in-depth observational surveys. This present study examined a high-impact convection outbreak event with over 40 hail reports in the southeastern coast of China on 6 May 2020 by focusing on contrasting the convective development (from convective initiation to supercell occurrences) among three adjacent convection-active zones (north (N), middle (M), and south (S)). The areas from N to S featured overall flatter terrain, higher levels of free convection, lower relative humidity, larger convective inhibition, more convective available potential energy, and greater vertical wind shears. With these mesoscale environmental variations, distinct inter-zone differences in the convective development were observed with the region’s surveillance radar network and the Himawari-8 geostationary satellite. Convection initiated in succession from N to S and began with more warm-rain processes in N and M and more ice-phase processes in S. The subsequent convection underwent more vigorous vertical growth from N to S. The extremely deep convection in S was characterized by the considerably strong precipitation above the freezing level, echo tops of up to 18 km, and a great amount of deep (even overshooting) and thick convective clouds with significant cloud-top glaciation. Horizontal anvil expansion in convective clouds was uniquely apparent over S. From N to S, more pronounced mesocyclone and weak-echo region signatures indicated high risks of severe supercell hailstorms. These results demonstrate the strong linkage between the occurrence likelihood of severe convection and associated weather (such as supercells and hailstones) and the early-stage convective development that can be well-captured by high-resolution observations and may facilitate fine-scale convection nowcasting.
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Zakharov N.S., Pokusaev B.G., Vyazmin A.V., Nekrasov D.A., Sulyagina O.A., and Moshin A.A. "Research of heat transfer processes in hydrogels by holographic interferometry and gradient thermometry." Technical Physics Letters 48, no. 5 (2022): 7. http://dx.doi.org/10.21883/tpl.2022.05.53551.19058.

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The study of natural convection in structured optically transparent materials using pure and combined agarose-gelatin gels was carried out by optical holography. The article presents data on visualization of the occurrence and development of convective flows in such gels with non-stationary conductive heating from below. The similarities and differences of the conditions of heat transfer and the occurrence of convection in structured materials and droplet liquids are analyzed. For the first time experimentally obtained data on the effect of two interpenetrating and interacting structured media on the transition from conductive to convective heat transfer. Keywords: natural convection in gels, optical holography, hydrogels, three-dimensional bioprinting.
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Dissertations / Theses on the topic "Processus convectifs"

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Wang, Di. "What controls the 3D distribution of water vapor isotopic composition in East Asia?" Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS567.pdf.

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Contrairement aux carottes de glace polaires, les variations isotopiques dans les carottes de glace tibétaines compliquent l'interprétation des signaux de température. L'une des principales raisons est que dans les régions de mousson aux latitudes basses et moyennes, les isotopes de l'eau sont influencés par des processus convectifs et nuageux. Il est nécessaire de mieux comprendre le comportement des isotopes de l'eau et les contrôles dynamiques impliqués dans la transpiration et la convection de l'humidité. Des observations in situ à grande échelle et des profils verticaux des isotopes de la vapeur pendant la convection seraient utiles, mais ces données sont rares. Le but de cette thèse a été de documenter les variations horizontales, verticales et temporelles de la mousson d'Asie de l'Est. D’abord, afin de documenter les variations horizontales près de la surface et saisonnières de la composition isotopique stable de l’eau en Chine, nous avons effectué des observations in situ des isotopes de la vapeur d'eau sur une vaste région de la Chine (plus de 10 000 km) pendant les saisons de pré-mousson et de mousson, à l'aide d'un système de mesure des isotopes de la vapeur d'eau nouvellement conçu et installé sur un véhicule. Nous avons constaté que les variations spatiales de la vapeur δ18O sont principalement contrôlées par la distillation de Rayleigh le long des trajectoires des masses d'air pendant la saison de pré-mousson, et sont fortement influencées par différentes sources d'humidité, les processus de recyclage continental et la convection le long du transport de l'humidité pendant la saison de la mousson. Ces résultats donnent un aperçu de la distribution spatiale et de la variabilité saisonnière de la composition isotopique de l'eau en Asie de l'Est et de leurs facteurs de contrôle, et soulignent la nécessité d'interpréter les enregistrements proxy dans le contexte du système régional et des sources d'humidité. Ensuite, pour mieux comprendre les processus physiques qui contrôlent la distribution verticale des isotopes de la vapeur et sa variabilité intra-saisonnière et saisonnière, nous avons observé les profils verticaux des isotopes de la vapeur de l'atmosphère jusqu'à la haute troposphère (de la surface du sol à 3856 m jusqu'à 11000 m d'altitude) de juin à octobre dans le sud-est du plateau tibétain à l'aide d'un drone spécialement conçu à cet effet. Pour l’échantillonnage, nous avons utilisé des sacs d’air, mais avons rencontré des problèmes de perméabilité généralement associés à ces sacs. Pour corriger ces problèmes, nous avons développé un modèle de diffusion et en avons calibré les paramètres avec des expériences de laboratoire. Ceci nous a permis de documenter pour la première fois que la distribution verticale des isotopes de la vapeur d'eau atmosphérique pendant toute la période de la mousson jusqu'à la haute troposphère, avec une résolution verticale et une gamme d'altitudes sans précédent. Nous constatons que les profils verticaux de la composition isotopique de la vapeur d'eau reflètent une combinaison de processus à grande échelle, en particulier la convection profonde et le recyclage continental le long des trajectoires, et les processus convectifs locaux, en particulier le détrainement convectif et la sublimation des cristaux de glace. Les variations saisonnières et intra-saisonnières observées sont généralement cohérentes verticalement, en raison du fort mélange convectif vertical et du détrainement convectif local de la vapeur provenant des basses couches, et reflètent les variations de convection profonde le long des trajectoires
Unlike polar ice core records, the isotope variations in Tibetan ice cores challenge the interpretation of temperature signals. One of the main reasons is that in monsoon regions at low and middle latitudes, water isotopes are influenced by convective and cloud processes. A deeper understanding of water isotope behavior and the dynamical controls involved in moisture transpiration and convection is needed. Large-scale in-situ observations and vertical profiles of vapor isotopes during convection would be helpful. However, such data are rare. The aim of this thesis was to document horizontal, vertical, and temporal variations in the isotopic composition of water in East Asian monsoon region. First, to document the horizontal and seasonal variations of water isotopes near the surface across China, we made in-situ observations of near-surface vapor isotopes over a large region (over 10000 km) across China in both pre-monsoon and monsoon seasons, using a newly-designed vehicle-based vapor isotope monitoring system. We found that the observed spatial variations of vapor δ18O are mainly controlled by Rayleigh distillation along air mass trajectories during the pre-monsoon period, but are significantly influenced by different moisture sources, continental recycling processes, and convection along moisture transport during the monsoon period. These results provide an overview of the spatial distribution and seasonal variability of water isotopic composition in East Asia and their controlling factors and emphasize the need to interpret proxy records in the context of the regional system and moisture sources. Second, to better understand the physical processes that control the vertical distribution of vapor isotopes and its intra-seasonal and seasonal variability, we observed the vertical profiles of atmosphere vapor isotopes up to the upper troposphere (from the ground surface at 3856m up to 11000m a.s.l.) from June to October in the southeastern Tibetan Plateau using a specially-designed unmanned-aerial-vehicle (UAV) system. For the sampling, we chose to carry air bags on UAVs as a portable sampling device, but encountered the permeability problem commonly associated with these bags. To corrected for this problem, we developed a diffusion model with diffusion parameters calibrated through laboratory experiments. This allows us to document for the first time the vertical distribution of atmospheric water vapor isotopes across the entire monsoon period up to the upper troposphere, boasting an unprecedented vertical resolution and altitude range. We find that the vertical profiles of water vapor isotopic composition reflect a combination of large-scale processes, in particular deep convection and continental recycling along trajectories, and local convective processes, in particular convective detrainment, and sublimation of ice crystals. The observed seasonal and intra-seasonal variations are generally vertically coherent, due to the strong vertical convective mixing and local convective detrainment of vapor originating from the low levels, and are mainly due to deep convection along trajectories
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CHAUMAT, LAURE. "Etude experimentale des processus de condensation dans les nuages convectifs : elargissement des spectres et distribution spatiale des gouttelettes." Clermont-Ferrand 2, 1999. http://www.theses.fr/1999CLF21118.

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La formation rapide des precipitations dans les cumulus est un phenomene encore mal explique. Plusieurs hypotheses ont ete avancees dont la contribution de noyau ultra geants, une efficacite de collison entre gouttelettes renforcee et l'elargissement des spectres de gouttelettes. Notre etude est consacree plus particulierement a la caracterisation des distributions dimensionnelles de gouttelettes dans les regions de nuage non melangees, a leur elargissement et a l'analyse de la distribution spatiale des gouttelettes a micro-echelle, source potentielle d'elargissement. De recentes mesures in-situ montrent que les spectres de gouttelettes dans les cellules adiabatiques sont plus larges que ceux prevus par la theorie classique de croissance par diffusion de vapeur. Une telle particularite implique que le champ de sursaturation n'est pas uniforme dans les ascendances non melangees. Un grand echantillon d'observations effectuees dans de telles regions est analyse et l'elargissement spectral est represente par la fonction de densite de probabilite de l'integrale de la sursaturation. Il est montre que la dispersion dans cette fonction augmente lineairement avec la valeur moyenne, et une parametrisation simple de l'elargissement des spectres est proposee. Cette variabilite dans l'integrale de la sursaturation peut provenir des heterogeneites dans la distribution spatiale des gouttelettes. Des mesures a tres fine echelle sont analysees pour caracteriser la statistique du comptage des particules. Celle-ci montre que les gouttelettes sont distribuees aleatoirement dans l'espace. Les effets des heterogeneites resultantes sur l'elargissement spectral sont estimes avec un modele conceptuel qui prouve qu'ils ne sont significatifs que pour des valeurs irrealistes du temps de vie des heterogeneites. De recentes simulations numeriques des effets inertiels des gouttelettes dans les structures de micro-echelle de la turbulence sont alors testees. Il est montre que le modele qui produit un elargissement significatif genere des repartitions spatiales de gouttelettes dont les proprietes statistiques sont irrealistes. Nos resultats indiquent que la concentration preferentielle des gouttelettes ne contribue pas a l'elargissement des spectres, du moins tel qu'il est decrit actuellement par les modeles numeriques.
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Burnet, Frédéric. "Validation des mesures aeroportees de la microphysique nuageuse et etude des processus d'entrainement-melange dans les nuages convectifs." Toulouse 3, 1999. http://www.theses.fr/1999TOU30097.

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Le declenchement rapide des precipitations dans les nuages convectifs est encore mal explique. La theorie de la condensation predit en effet des distributions dimensionnelles de gouttelettes etroites alors que la formation des embryons de precipitation necessite des spectres larges avec de grosses gouttelettes. La mesure in situ des distributions dimensionnelles de gouttelettes est essentielle pour mieux comprendre la microphysique nuageuse. La campagne de mesures scms etait ainsi dediee a l'etude de la formation des precipitations dans les petits cumulus chauds (sans phase glace). La premiere partie de ce manuscrit est consacree a la validation des mesures collectees pendant scms, ou de nouveaux instruments etaient utilises. La principale difficulte est qu'il n'existe pas de standard absolu pour etalonner les instruments. Notre methodologie de validation s'appuie sur la comparaison des resultats obtenus dans des conditions variees, afin d'etudier et d'identifier les limites des differents instruments bases sur des principes de mesure differents (compteur de particules, integrateur, capteur a fil chaud). Dans la seconde partie de ce travail, nous utilisons les mesures ainsi validees pour etudier la formation des grosses gouttelettes a partir des processus de melange entre l'air nuageux et son environnement plus sec. Nous developpons une nouvelle methode d'analyse pour caracteriser la nature statistique du melange, homogene ou heterogene. Il est montre que le concept heterogene fournit une description satisfaisante de ses proprietes statistiques. Nous nous appuyons sur ce resultat pour construire un modele simple d'evolution des spectres de gouttelettes dans les cellules melangees, a concentration constante. Les conditions qui favorisent la formation des gouttes suradiabatiques sont identifiees. Les resultats du modele sont ensuite confrontes aux mesures.
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CAILLAULT, KARINE. "Processus physiques impliques dans la dynamique et thermodynamique aux differentes echelles de mouvement des systemes convectifs observes lors de toga-coare." Paris 7, 1998. http://www.theses.fr/1998PA077027.

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La convection profonde joue un role essentiel dans la circulation de l'atmosphere en redistribuant l'energie tropicale excedentaire vers les couches superieures de l'atmosphere et en favorisant les mouvements horizontaux de grande echelle. Une des manifestations de la convection profonde se presente sous la forme des systemes convectifs de mesoechelle (mcs) responsables d'une grande partie des precipitations terrestres. L'objectif de ce travail est l'etude du mcs du 12 decembre 1992 observe durant l'experience toga-coare realisee sur le reservoir d'eaux chaudes du pacifique ouest, zone cle dans la dynamique climatique. Au cours de cette etude, trois echelles de mouvement ont ete distinguees. L'echelle synoptique constitue l'environnement de la perturbation. La part des forcages dynamiques de cette echelle sur le cycle de vie du mcs etudie a ete quantifiee a partir des sorties du modele du cepmmt. La moyenne echelle correspond en general a l'echelle du phenomene (quelques centaines de kilometres carres) et permet d'avoir une vue d'ensemble des processus dynamiques et thermodynamiques gouvernant le systeme convectif et de mettre en evidence les liens existant entre celui-ci et son environnement. Les donnees utilisees pour acceder a cette echelle de mouvement sont issues de radars aeroportes. Elles ont ete cumulees sur des temps assez longs de facon a couvrir une zone d'echantillonnage la plus etendue possible. La comprehension des mecanismes de formation et d'evolution du systeme passe par l'analyse des donnees radar a l'echelle convective. Les domaines de restitution plus petits couvrent des zones distinctes du systeme telles que parties convectives et stratiformes permettant la description precise de la circulation d'echelle convective. Une etude des interactions entre les differentes echelles de mouvement a egalement ete menee ainsi qu'une comparaison des resultats de travaux anterieurs sur les mcs avec ceux issus de cette etude.
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Coutris, Pierre. "Analyse des propriétés dimensionnelles et massiques des cristaux de glace pour l’étude des processus microphysiques dans les systèmes convectifs à méso-échelle." Thesis, Université Clermont Auvergne‎ (2017-2020), 2019. http://www.theses.fr/2019CLFAC007/document.

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L’étude des propriétés et processus microphysiques caractérisant la phase glace permet de mieux définir le rôle des nuages dans le cycle de l’eau et sur bilan radiatif de l’atmosphère. Les modèles atmosphériques et les codes d’inversion des données de télédétection utilisent des paramétrisations établies à partir de mesures in situ. Ces mesures servent également des besoins industriels en lien avec la problématique du givrage en aéronautique. L’étude présentée se base sur les données de deux campagnes aéroportées réalisées dans le cadre de la collaboration internationale HAIC-HIWC, ciblant les zones à fort contenu en glace que l’on peut observe rau sein des systèmes convectifs à méso-échelle (MCS) tropicaux. Sur la question des relations « masse-diamètre » (m - D) d’abord, une nouvelle approche est présentée. Basée sur la résolution d’un problème inverse, elle permet de restituer la masse des cristaux à partir de mesures colocalisées classiques en s’affranchissant de la traditionnelle hypothèse de loi puissance, et montre que cette dernière ne permet pas de représenter correctement les propriétés massiques de populations de cristaux hétérogènes (morphologie et tailles différentes) typiques des MCS. La variabilité horizontale des distributions de tailles permet d’étudier le vieillissement de l’enclume d’un point de vue microphysique et de souligner le rôle essentiel du processus d’agrégation dans l’élimination des petits cristaux apportés dans la haute troposphère par la convection profonde et dans la formation d’agrégats supra-millimétriques, précurseurs glacés des précipitations stratiformes. Les relations m - D restituées permettent d’identifier des régimes microphysiques distincts et ouvre la voie aux développement d’une paramétrisation de la masse volumique des hydrométéores en fonction de critères environnementaux
The detailed characterization of ice cloud microphysics is key to understand their role in theEarth’s hydrological cycle and radiation budget. The developement of atmospheric models and remote sensingalgorithms relies on parametrisations derived from in situ measurements. These measurements are also usedby the aviation industry to handle the problem of ice crystal icing. This PhD work presents an analysis of themass and size properties of ice crystals observed in high ice water content areas embedded in tropical mesoscaleconvective systems (MCS) during two airborne field campaigns of the HAIC-HIWC international project.A new approach is developped to derive mass-size relationships (m - D) from size distributions and icewater contents. The retrieval is formulated as an inverse problem which waives the power law constraint, aclassical assumption that proves to be an oversimplification when applied to heterogeneous populations of iceparticules typical of MCS anvils.The horizontal variability of size distributions and the aging of MCS anvils is described in terms of microphysicalprocesses. The importance of the aggregation growth process is emphasized as it efficiently removessmall ice particles brought into the upper troposphere by deep convection and significantly contributes to theformation of large agregates, precusor of the stratiform precipitations. The analysis of mass properties revealsthat distinctive microphysical regimes may be identified from the m-D relationship retrieved in various conditions.It paves the way toward a statistical model of the effective density of ice particles as a function of environmentalparameters
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Deheuvels, Sébastien. "Apports de la sismologie des étoiles F et G à l'étude des cœurs convectifs." Phd thesis, Observatoire de Paris, 2010. http://tel.archives-ouvertes.fr/tel-00553197.

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La qualité des données sismiques du satellite CoRoT ouvre de nouveaux horizons dans l'étude de la structure interne et de l'évolution des étoiles. Mon travail de thèse a consisté à l'analyse et à l'interprétation des spectres d'oscillations de pulsateurs de type solaire observés au sol et depuis l'espace, en particulier avec le satellite CoRoT. L'objectif de l'analyse d'un spectre d'oscillations est de déterminer les paramètres des modes propres de l'étoile (fréquences propres, amplitudes, durées de vie). Au sein du DAT (groupe en charge de l'analyse des pulsateurs de type solaire observés avec CoRoT), j'ai contribué à adapter aux objets étudiés une méthode utilisée avec succès pour extraire les paramètres des modes du Soleil. J'ai appliqué cette méthode à l'analyse des cinq premiers pulsateurs de type solaire observés avec CoRoT. Un soin particulier a été consacré à l'étude de la significativité des pics détectés, qui a permis de conforter la détection de modes mixtes dans le spectre de l'étoile HD 49385. Dans le cadre de mon travail de modélisation et d'interprétation, j'ai recherché les informations qu'apportent les paramètres sismiques sur la structure du cœur de certaines des étoiles analysées. Ces étoiles possèdent (ou ont possédé) un cœur convectif, dont les caractéristiques dépendent des processus de transport des éléments chimiques (e.g. l'overshooting), aujourd'hui mal décrits par les modèles théoriques. J'ai modélisé trois pulsateurs de type solaire de masses et de stades évolutifs différents, dont les paramètres sismiques permettent de sonder le cœur et donc de contraindre observationnellement les processus de transport. En particulier, la détection dans l'étoile HD 49385 de modes mixtes en croisement évité m'a amené à étudier l'apport de ce type de mode à la compréhension de la structure du cœur.
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Legoix, Léonard. "Étude expérimentale et modélisation de mélangeurs convectifs : agitation de poudres de différentes coulabilités." Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2016. http://www.theses.fr/2016EMAC0020/document.

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Les étapes de mélange sont souvent délicates à appréhender, car il subsiste encore des lacunes sur les lois dynamiques qui régissent ces opérations. De ce fait, la prédiction de l’homogénéité d’un mélange de poudres nécessite encore de nombreux essais. Dans ce travail de thèse, nous nous attachons à développer une méthodologie qui permet de contribuer au développement de modèles prédictifs dans les mélangeurs de poudres tout en mettant en évidence des invariants possibles pour les changements d’échelle sur ces procédés. Ainsi nous avons étudié l’agitation de poudres, avec différentes résistances à l’écoulement, dans un mélangeur convectif planétaire de type Triaxe® d’une contenance de 48 L. Des mesures de propriétés rhéologiques à l’échelle du laboratoire (rhéomètre FT4, voluménomètre) sont effectuées afin de mieux comprendre le comportement des poudres à l’échelle du mélangeur. Un mélangeur convectif prototype a été conçu dans le cadre de cette thèse. Cet appareil polyvalent constitué d’une cuve cylindrique transparente et agité par un mobile constitué de quatre pales, permet de visualiser les régimes et les mécanismes d’écoulement tout en effectuant des mesures rhéologiques. Deux régimes d’écoulement ont été identifiés (roulement, cataracte), ainsi que trois mécanismes (convection, diffusion et avalanche). Ces mécanismes ont permis d’établir un modèle stochastique, dont les paramètres ont été évalués expérimentalement pour une poudre à écoulement libre et pour une poudre cohésive
Mixing systems are usually difficult to understand, because there is a lack of knowledge concerning dynamic laws ruling these operations. Thus, nowadays, several tests are needed to predict properly the homogeneity of a powder mix. Throughout this PhD work, a method is developed to build predictive models for powder mixers and to bring out possible invariants for scale switching on these processes. Thus the stirring of powders is studied using different flow resistances within a 48L capacity Triaxe®, a convective planetary mixer. Rheological properties measurements are done at labscale (FT4 rheometer, volumenometer) for a better understanding of powder behavior at a wider mixer scale. A prototype blender has been built for this work. This polyvalent device, made of four blades and of a transparent vessel, allows to observe flow regimes and mechanisms, and to do rheological measurements. Two flow regimes have been identified (rolling, cataracting) and three flow mechanisms (convection, diffusion and avalanching). These mechanisms allowed to do stochastic modelling, for which parameters have been evaluated with experiments for free-flowing and cohesive powders
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Besson, Lucas. "Processus physiques responsables de l'établissement et de la variabilité de la mousson africaine." Paris 6, 2009. https://tel.archives-ouvertes.fr/tel-00420498.

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La Mousson Africaine est un système complexe, qui présente des variations interannuelles très importantes. Ces variations se traduisent par des fluctuations considérables des précipitations. Avoir une meilleure compréhension du système complexe qu'est la mousson peut permettre de mieux cerner les mécanismes qui influencent la production des précipitations sur le Sahel. La première partie de ce travail consiste en une comparaison entre deux saisons de mousson aux régimes de précipitations différents afin d'extraire les caractéristiques communes et différentes, pour les appliquer à l’étude de la saison de mousson de la campagne AMMA. Cette étude est complétée par une compréhension des processus dynamiques et thermodynamiques qui sont à l'origine du déclenchement de l'Onset de la mousson, et qui permettent l'installation des conditions favorables au développement des précipitations sur le Sahel. Le second volet est basé sur les mécanismes physiques qui entrent en compte dans le cycle de vie des lignes de grains sur le Sahel. Enfin, la dernière partie traite de l'impact des systèmes de méso-échelle sur leur environnement en terme de bilan de chaleur et d'humidité.
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Sánchez, Martín Xavier. "Processos convectius en un sistema aquàtic natural: l'estany de Banyoles." Doctoral thesis, Universitat de Girona, 2008. http://hdl.handle.net/10803/7810.

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En aquesta tesi s'aborda l'estudi de la turbulència convectiva, a partir d'un treball experimental realitzat a l'estany de Banyoles. Més concretament, els objectius s'emmarquen en dues categories diferents. En la primera, es pretén sistematitzar el marc teòric-conceptual de la turbulència i més concretament de la turbulència convectiva, el qual es troba molt dispers a la bibliografia i sovint enfocat des de perspectives prou diverses. Dins aquest primer objectiu també es pretén sistematitzar tot un conjunt d'eines experimentals de tractament de dades que ens permetran obtenir els valors de les velocitats de dissipació de l'energia cinètica turbulenta i de la variància de temperatura de forma automàtica y obtenir els fluxos turbulents. També volem abordar la caracterització del les escales turbulentes, pel que treballarem amb l'escala de Thorpe i utilitzarem l'anàlisi d'ondetes del senyal de microstructura tèrmica. Dins la segona categoria d'objectius, aquests aplicats directament a l'estany de Banyoles, es pretén aplicar els conceptes desenvolupats al primer objectiu en dos sistemes convectius, un de tipus plomall i l'altre del tipus multidifusiu. Dins aquest context, en els dos primers capítols es presenta teòricament com s'obtenen els fluxos turbulents i s'introdueixen els fenòmens convectius, i en el tercer i quart capítols es descriuen tot un conjunt d'eines d'anàlisi experimental que ens serviran per a l'estudi del cas concret de la convecció al fons de l'estany de Banyoles.
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Gouze, Philippe. "Modélisation des transferts de masse liés aux circulations dans les aquifères sédimentaires. Application à l'aquifère du dogger du Bassin de Paris et aux écoulements thermo-convectifs dans les réservoirs gréseux." Paris 6, 1993. http://www.theses.fr/1993PA066105.

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Au cours de la diagenese, les transformations mineralogiques induites par les mouvements du fluide sont susceptibles de modifier les caracteristiques geophysiques des aquiferes et des reservoirs sedimentaires. Cette these a pour but (i) de contribuer a la modelisation mathematique de ces processus et (ii) d'appliquer ces modeles a deux cas d'interet geologique : l'aquifere du dogger du bassin de paris et les reservoirs greseux affectes par des circulations thermo-convectives
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Books on the topic "Processus convectifs"

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Gao, Shouting. Cloud-resolving modeling of convective processes. [Dordrecht]: Springer, 2008.

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Li, Xiaofan, and Shouting Gao. Cloud-Resolving Modeling of Convective Processes. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-26360-1.

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Gao, Shouting, and Xiaofan Li. Cloud-Resolving Modeling of Convective Processes. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-8276-4.

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NATO Advanced Study Institute on Disorder and Mixing (1987 Cargèse, France). Disorder and mixing: Convection, diffusion, and reaction in random materials and processes. Dordrecht: Kluwer Academic Publishers, 1988.

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Leal, L. Gary. Laminar flow and convective transport processes: Scaling principles and asymptotic analysis. Boston: Butterworth-Heinemann, 1992.

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S, Figliola R., Kaviany M, Ebadian M. A, American Society of Mechanical Engineers. Winter Meeting, and American Society of Mechanical Engineers. Heat Transfer Division., eds. Convection heat transfer and transport processes: Presented at the Winter Annual Meeting of the American Society of Mechanical Engineers, San Francisco, California, December 10-15, 1989. New York, N.Y: The Society, 1989.

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Zhang, Yanwu. Spectral feature classification of oceanographic processes using an autonomous underwater vehicle. Cambridge, Mass: Massachusetts Institute of Technology, 2000.

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Meeting, American Society of Mechanical Engineers Winter. Bifurcation phenomena in thermal processes and convection: Presented at the Winter Annual Meeting of the American Society of Mechanical Engineers, Boston, Massachusetts, December 13-20, 1987. New York, N.Y. (345 E. 47th St., New York 10017): ASME, 1987.

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Ruedas, Thomas. Convection and melting processes in a mantle plume under a spreading ridge, with application to the Iceland plume. Berlin: Logos Berlin, 2004.

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S, Kain John, and United States. National Aeronautics and Space Administration., eds. Annual performance report for the period 15 April 1996 - 14 April 1997 for NASA grant no. NAG 5-2927 entitled evaluating and understanding parameterized convective processes and their role in the development of mesoscale precipitation systems. University Park, PA: Pennsylvania State University, Office of Sponsored Programs, 1997.

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Book chapters on the topic "Processus convectifs"

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Luther, Emmanuel E., Seyed M. Shariatipour, Michael C. Dallaston, and Ran Holtzman. "Solute Driven Transient Convection in Layered Porous Media." In Springer Proceedings in Energy, 3–9. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-63916-7_1.

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AbstractCO2 geological sequestration has been proposed as a climate change mitigation strategy that can contribute towards meeting the Paris Agreement. A key process on which successful injection of CO2 into deep saline aquifer relies on is the dissolution of CO2 in brine. CO2 dissolution improves storage security and reduces risk of leakage by (i) removing the CO2 from a highly mobile fluid phase and (ii) triggering gravity-induced convective instability which accelerates the downward migration of dissolved CO2. Our understanding of CO2 density-driven convection in geologic media is limited. Studies on transient convective instability are mostly in homogeneous systems or in systems with heterogeneity in the form of random permeability distribution or dispersed impermeable barriers. However, layering which exist naturally in sedimentary geological formations has not received much research attention on transient convection. Therefore, we investigate the role of layering on the onset time of convective instability and on the flow pattern beyond the onset time during CO2 storage. We find that while layering has no significant effect on the onset time, it has an impact on the CO2 flux. Our findings suggest that detailed reservoir characterisation is required to forecast the ability of a formation to sequester CO2.
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Xu, Liu-Jun, and Ji-Ping Huang. "Theory for Hele-Shaw Convective Cloaks: Bilayer Scheme." In Transformation Thermotics and Extended Theories, 65–86. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-5908-0_6.

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AbstractThermal convection is one of the three basic heat transfer mechanisms, profoundly influencing the natural environment, social production, and daily life. However, the high complexity of governing equation, which describes the coupling of heat and mass transfer, makes it challenging to manipulate thermal convection at will in both theory and experiment. Here, we consider the heat transfer in Hele-Shaw cells, a widely-used model of Stokes flow between two parallel plates with a small gap, and apply the scattering-cancellation technology to construct convective thermal materials with bilayer structures and homogeneous isotropic materials. By tailoring thermal conductivity and viscosity, we demonstrate cloaking devices that can simultaneously hide obstacles from heat and fluid motion and verify their robustness under various thermal-convection environments by numerical simulations. Our results show that about 80% of the temperature and pressure disturbances in the background caused by obstacles can be eliminated by the cloak. The developed approach can be extended to control other convection-diffusion systems or multiphysics processes. The results pave a promising path for designing various metadevices such as concentrators or sensors.
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Tveitereid, Morten, and Hanns Walter Müller. "Rayleigh-Bénard Convection with Weak Shear Flow: Absolute and Convective Instabilities." In Waves and Nonlinear Processes in Hydrodynamics, 303–14. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-0253-4_24.

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Magri, Fabien, Mauro Cacace, Thomas Fischer, Dmitri Naumov, Wenqing Wang, Norihiro Watanabe, Tianyuan Zheng, Xing-Yuan Miao, Thomas Nagel, and Marc Walther. "HT (Convection) Processes." In Terrestrial Environmental Sciences, 157–77. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-68225-9_7.

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Dobran, Flavio. "Mantle Convection and Melt Segregation." In Volcanic Processes, 257–325. Boston, MA: Springer US, 2001. http://dx.doi.org/10.1007/978-1-4615-0647-8_4.

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Johnson, Richard H., and Brian E. Mapes. "Mesoscale Processes and Severe Convective Weather." In Severe Convective Storms, 71–122. Boston, MA: American Meteorological Society, 2001. http://dx.doi.org/10.1007/978-1-935704-06-5_3.

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Doswell, Charles A., and Lance F. Bosart. "Extratropical Synoptic-Scale Processes and Severe Convection." In Severe Convective Storms, 27–69. Boston, MA: American Meteorological Society, 2001. http://dx.doi.org/10.1007/978-1-935704-06-5_2.

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Balachandar, S. "Turbulent Thermal Convection." In Chaotic Processes in the Geological Sciences, 1–10. New York, NY: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4684-0643-6_1.

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Fowler, A. C. "Convection and Chaos." In Chaotic Processes in the Geological Sciences, 43–69. New York, NY: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4684-0643-6_3.

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Li, Xiaofan, and Shouting Gao. "Surface Rainfall Processes." In Cloud-Resolving Modeling of Convective Processes, 57–67. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-26360-1_4.

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Conference papers on the topic "Processus convectifs"

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Di Girolamo, Paolo, Donato Summa, and Dario Stelitano. "Characterization of convection-related parameters by Raman lidar: Selected case studies from the convective and orographically-induced precipitation study." In RADIATION PROCESSES IN THE ATMOSPHERE AND OCEAN (IRS2012): Proceedings of the International Radiation Symposium (IRC/IAMAS). AIP, 2013. http://dx.doi.org/10.1063/1.4804749.

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Bardy, Erik, Merouane Hamdi, Michel Havet, and Olivier Rouaud. "Transient Exergetic Efficiency of a Forced Convection Drying Process With and Without Electrohydrodynamic (EHD) Enhancement." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-38169.

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Electrohydrodynamic (EHD) drying is a novel drying method used to enhance forced convective drying by using a wire-electrode to create an electrostatic field. In this study, it was hypothesized that an EHD enhanced forced convective drying process will not only increase the drying rate, but also the exergetic efficiency over time. A transient exergetic efficiency was defined as the ratio of the exergy use rate in the removing of moisture from the drying product, to the exergy rate of the drying air supplied. In the case of EHD enhanced forced convection, the exergy rate supplied by the wire electrode was also accounted for. Forced convection drying experiments were run on a test specimen simulating a food product (methylcellulose gel) using an air flow channel with and without EHD enhancement with varying air flow velocities. Initial results show that the moisutre loss rate of the methylcellulose gel increased with the application of the electrostatic field. In addition, for low velocities, the exergetic efficiency of EHD enhanced forced convection was higher for the first few hours of drying as compared to conventional forced convection. The exergetic efficiency of both conventional and EHD enhanced forced convection converged at greater air flow velocities.
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Sood, Arun. "Convective SAGD Process." In SPE Canada Heavy Oil Technical Conference. Society of Petroleum Engineers, 2016. http://dx.doi.org/10.2118/180734-ms.

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Krejci, Ludek, Vladimir Dolinek, Ludek Sara, Jiri Vogel, V. Nenicka, and J. Hlina. "CONVECIWE WAVE DRIVEN HEAT TRANSFER PROCESSES IN A TRANSITIONAL PLASMA PLUME." In International Symposium on Transient Convective Heat Transfer. New York: Begellhouse, 1996. http://dx.doi.org/10.1615/ichmt.1996.transientconvheattransf.140.

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Limare, A., E. Surducan, V. Surducan, C. Neamtu, E. di Giuseppe, K. Vilella, C. G. Farnetani, E. Kaminski, and C. Jaupart. "Microwave-based laboratory experiments for internally-heated mantle convection." In PROCESSES IN ISOTOPES AND MOLECULES (PIM 2013). AIP, 2013. http://dx.doi.org/10.1063/1.4833687.

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Verma, Mahendra K., Ambrish Pandey, Pankaj K. Mishra, and Mani Chandra. "Role of bulk flow in turbulent convection." In INTERNATIONAL CONFERENCE ON COMPLEX PROCESSES IN PLASMAS AND NONLINEAR DYNAMICAL SYSTEMS. AIP Publishing LLC, 2014. http://dx.doi.org/10.1063/1.4865360.

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"FLOW VISUALIZATION AND CONVECTIVE HEAT TRANSFER MEASUREMENTS BY MEANS OF INFRARED THERMOGRAPHY." In International Symposium on Imaging in Transport Processes. Connecticut: Begellhouse, 1992. http://dx.doi.org/10.1615/ichmt.1992.intsympimgtranspproc.110.

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Zhilin, A. A. "Acoustic-convective drying of coniferous sawdust." In HIGH-ENERGY PROCESSES IN CONDENSED MATTER (HEPCM 2019): Proceedings of the XXVI Conference on High-Energy Processes in Condensed Matter, dedicated to the 150th anniversary of the birth of S.A. Chaplygin. AIP Publishing, 2019. http://dx.doi.org/10.1063/1.5117467.

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McCreery, Glenn E., Keith G. Condie, Randy C. Clarksean, and Donald M. McEligot. "Convective processes in spent nuclear fuel canisters." In International Heat Transfer Conference 12. Connecticut: Begellhouse, 2002. http://dx.doi.org/10.1615/ihtc12.4380.

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Pang, Liping, and Baomin Sun. "3-D Numerical Simulation on Reheater Fouling in a Utility Boiler." In ASME/JSME 2004 Pressure Vessels and Piping Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/pvp2004-3130.

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A numerical simulation investigation into the furnace and horizontal chimney process in a utility boiler is presented. The work is based on the commercial software FLUENT 6.1. Flow, chemistry, energy, conservation and radiation models are combined with the FLUNENT solver to simulate the process inside the furnace. Radiation and convection models are considered in the horizontal heater. The reheater is processed as a limited thickness heater and the convective heat transfer is considered in this numerical simulation. The temperature and velocity fields are calculated to unveil the process inside and outside the furnace. The result shows that the fouling in reheater is formed because of the temperature and velocity field in the flue gas passage. A limited test is done to validate the numerical simulation.
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Reports on the topic "Processus convectifs"

1

Wyngaard, J. C., Mark Piper, and W. H. Snyder. Fluid-Modeling Studies of Convective Dispersion Processes. Fort Belvoir, VA: Defense Technical Information Center, September 1993. http://dx.doi.org/10.21236/ada351129.

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Whitehead, John A. Convection Processes in the Ocean-Laboratory and Theoretical Studies. Fort Belvoir, VA: Defense Technical Information Center, August 1999. http://dx.doi.org/10.21236/ada366928.

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Whitehead, John A. Convection Processes in the Ocean - Laboratory and Theoretical Studies. Fort Belvoir, VA: Defense Technical Information Center, September 1997. http://dx.doi.org/10.21236/ada628738.

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Denning, Scott. Multi-Scale Land-Atmosphere Interactions: Modeling Convective Processes from Plants to Planet. Office of Scientific and Technical Information (OSTI), February 2021. http://dx.doi.org/10.2172/1766315.

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Smith, David C., and IV. A Process Oriented Study of Shallow Convection in Polar Oceans. Fort Belvoir, VA: Defense Technical Information Center, September 1994. http://dx.doi.org/10.21236/ada299592.

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Parsons, Jeffrey D. Experiments of Particle-Concentration Variability and Transport Associated with Turbulent and Convective Processes. Fort Belvoir, VA: Defense Technical Information Center, September 2004. http://dx.doi.org/10.21236/ada613878.

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Oldenburg, C. M. Comparison of scale analysis and numerical simulation for saturated zone convective mixing processes. Office of Scientific and Technical Information (OSTI), June 1998. http://dx.doi.org/10.2172/663466.

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Parsons, Jeffrey D. Experiments of Particle-Concentration Variability and Transport Associated with Turbulent and Convective Processes. Fort Belvoir, VA: Defense Technical Information Center, September 2003. http://dx.doi.org/10.21236/ada626991.

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9

Thomas, Douglas, and Mellon Michael. Sublimation of terrestrial permafrost and the implications for ice-loss processes on Mars. Engineer Research and Development Center (U.S.), July 2021. http://dx.doi.org/10.21079/11681/41244.

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Sublimation of ice is rate-controlled by vapor transport away from its outer surface and may have generated landforms on Mars. In ice-cemented ground (permafrost), the lag of soil particles remaining after ice loss decreases subsequent sublimation. Varying soil-ice ratios lead to differential lag development. Here we report 52 years of sublimation measurements from a permafrost tunnel near Fairbanks, Alaska, and constrain models of sublimation, diffusion through porous soil, and lag formation. We derive the first long-term in situ effective diffusion coefficient of ice-free loess, a Mars analog soil, of 9.05 × 10⁻⁶ m² s⁻¹, ~5× larger than past theoretical studies. Exposed ice-wedge sublimation proceeds ~4× faster than predicted from analogy to heat loss by buoyant convection, a theory frequently employed in Mars studies. Our results can be used to map near-surface ice-content differences, identify surface processes controlling landform formation and morphology, and identify target landing sites for human exploration of Mars.
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Steenhuis, Tammo S., Israela Ravina, Jean-Yves Parlange, Rony Wallach, and Larry D. Geohring. Improving Preferential Flow Modules by Experimentation. United States Department of Agriculture, September 1994. http://dx.doi.org/10.32747/1994.7570552.bard.

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Preferential flow is the process whereby water and solutes move by preferred pathways. During preferential flow, local wetting fronts propagate to considerable depths in the soil profile, essentially bypassing the matrix pore space. Under such conditions classical methods, such as the convective-dispersive equation, for quantifying flow of water and solutes in uniform soils are not valid. This project set out to develop methods to predict fast and early breakthrough of solutes. To facilitate understanding of these processes, several field drainage studies were conducted in the United States and Israel. In both countries, solutes moved rapidly down and could be found below 1 m depth soon after application. Based on these experiments, we developed and validated a number of modules to predict the solute concentration of the preferentially moving water in the vadose zone. We also successfully simulatd the initial high solute concentration in agriculturel tile lines shortly after the chemical was applied. The understanding gained on fast transport of agri-chemicals is instrumental in developing management practices to reduce the nonpoint sources and to increase the leaching efficiency of salt affected soils.
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