Tesis sobre el tema "Cloud aerosol"
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Grandey, Benjamin Stephen. "Investigating aerosol-cloud interactions". Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:8b48c02b-3d43-4b04-ae55-d9885960103d.
Texto completoGryspeerdt, Edward. "Aerosol-cloud-precipitation interactions". Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:3d1210b0-2ada-403c-8fdf-2bef1724fcd8.
Texto completoDuong, Hanh To. "Studies of Organic Aerosol and Aerosol-Cloud Interactions". Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/311585.
Texto completoHsieh, Wei-Chun. "Representing droplet size distribution and cloud processes in aerosol-cloud-climate interaction studies". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29619.
Texto completoCommittee Chair: Athanasios Nenes; Committee Member: Andrew G. Stack; Committee Member: Irina N. Sokolik; Committee Member: Judith A. Curry; Committee Member: Mike Bergin; Committee Member: Rodney J. Weber. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Barahona, Donifan. "On the representation of aerosol-cloud interactions in atmospheric models". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/41169.
Texto completoRosenfeld, Daniel, Meinrat O. Andreae, Ari Asmi, Mian Chin, Leeuw Gerrit de, David P. Donovan, Ralph Kahn et al. "Global observations of aerosol-cloud-precipitation-climate interactions: Global observations of aerosol-cloud-precipitation-climateinteractions". American Geophysical Union (AGU), 2014. https://ul.qucosa.de/id/qucosa%3A13459.
Texto completoPringle, Kirsty Jane. "Aerosol - cloud interactions in a global model of aerosol microphysics". Thesis, University of Leeds, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431991.
Texto completoPartridge, Daniel. "Inverse Modeling of Cloud – Aerosol Interactions". Doctoral thesis, Stockholms universitet, Institutionen för tillämpad miljövetenskap (ITM), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-60454.
Texto completoAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 4: Manuscript.
Zhong, Weiguo. "Characteristics of the Pinatubo aerosol cloud". Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/290573.
Texto completoDeaconu, Lucia-Timea. "Study on multi-layer "aerosol" situations and of "aerosol-cloud" interactions". Thesis, Lille 1, 2017. http://www.theses.fr/2017LIL10165.
Texto completoOne of the main objectives of this study is to analyze the consistency between the aerosol above clouds (AAC) retrievals from passive and active satellite measurements. We consider the method based on the passive polarization measurements provided by the POLDER instrument, the operational method developed for the space borne lidar CALIOP, and the CALIOP-based depolarization ratio method (DRM), for which we also propose a calibrated version. We perform a regional analysis and a global multi-annual analysis to provide robust statistics results. Our findings show good agreement between DRM and POLDER AOT retrievals (R2=0.68 at global scale). This result gives confidence in our ability to measure the properties of AAC. Differences occur when the aerosol and cloud layers are in contact. CALIOP operational method is largely underestimating the above cloud AOT, compared to the other two methods.The second objective is to study the impact of aerosols on the cloud properties and their radiative forcing, over the South Atlantic Ocean. We perform a synergy between CALIOP vertical profiles and POLDER retrievals, with collocated meteorological parameters. We performed radiative transfer calculations in the short- and longwave domains, and analyzed the effect of aerosol loading on the cloud properties and meteorology. We found that aerosols and water vapor effects could impact the cloud convection. Our results show that under large loads of AACs, clouds become optically thicker, with an increase in liquid water path of 20 g.m-2 and their cloud top altitudes are lower by 200 m, which may indicate a potential semi-direct effect of aerosols above clouds
Merk, Daniel. "Uncertainties in the Quantification of Aerosol-Cloud Interactions". Doctoral thesis, Universitätsbibliothek Leipzig, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-225523.
Texto completoPaunova, Irena T. "Explicit numerical study of aerosol-cloud interactions in boundary layer clouds". Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100670.
Texto completoThree summertime cases have been evaluated: a marine stratus and a cold frontal system over the Bay of Fundy near Nova Scotia, formed on 1 Sep 1995 and extensively sampled as a part of the Radiation, Aerosol, and Cloud Experiment (RACE); and a continental stratocumulus, formed over the southern coast of Lake Erie on 11 July 2001. The marine stratus and the frontal system have been examined for the effects of aerosol on cloud properties and thoroughly evaluated against the available observations. The frontal system and the continental stratocumulus have been evaluated for the effects of cloud processing on the aerosol spectrum.
The marine stratus simulations suggest a significant impact of the aerosol on cloud properties. A simulation with mechanistic activation and a uni-modal aerosol showed the best agreement with observations in regards to cloud-base and cloud-top height, droplet concentration, and liquid water content. A simulation with a simple activation parameterization failed to simulate essential bulk cloud properties: droplet concentration was significantly underpredicted and the vertical structure of the cloud was inconsistent with the observations. A simulation with a mechanistic parameterization and a bi-modal aerosol, including a coarse mode observed in particle spectra below cloud, showed high sensitivity of droplet concentration to the inclusion of the coarse mode. There was a significant reduction in droplet number relative to the simulation without the coarse mode. A similar change occurred in the precipitating system preceding the stratus formation, resulting in an enhancement of precipitation in the weaker (upstream) part of the system while the precipitation in the more vigorous (downstream) part of the system remained almost unaffected.
Aerosol processing via collision-coalescence and aqueous chemistry in the non-drizzling stratocumulus case suggests that impact of the two mechanisms is of similar magnitude and can be as large as a 3-5 % increase in particle mean radius. A more detailed analysis reveals that the impact of chemical processing is oxidant-limited; beyond times when the oxidant (H 2O2) is depleted (∼ 40 minutes), the extent of processing is determined by supply of fresh oxidant from large-scale advection (fresh gaseous emissions are not considered). Aerosol processing via drop collision-coalescence alone suggests, as expected, sensitivity to the strength of the collection process in clouds. Larger particle growth, up to 5-10 %, is observed in the case of the frontal clouds, which exhibit stronger drop collection compared to that in the stratocumulus case. The processed aerosol exerted a measurable impact on droplet concentrations and precipitation production in the frontal clouds. For the case modeled here, contrary to expectations, the processed spectrum (via physical processing) produced higher droplet concentration than the unprocessed spectrum. The reasons explaining this phenomenon and the resulting impact on precipitation production are discussed.
The current work illustrates the complexity of the coupled system at the cloud system scales, revealed earlier at much smaller large eddy scales. If future parameterizations of the regional effect of aerosols on clouds are to be developed, careful consideration is required of the many of feedbacks in the boundary layer.
Quaas, Johannes, Bjorn Stevens, Philip Stier y Ulrike Lohmann. "Interpreting the cloud cover". Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-186087.
Texto completoMenon, Surabo, Jean-Louis Brenguier, Olivier Boucher, Paul Davison, Genio Anthony D. Del, Johann Feichter, Steven Ghan et al. "Evaluating aerosol/cloud/radiation process parameterizations with single-column models and Second Aerosol Characterization Experiment (ACE-2) cloudy column observations: Evaluating aerosol/cloud/radiation process parameterizations withsingle-column models and Second Aerosol Characterization Experiment (ACE-2) cloudy column observations". Wiley, 2003. https://ul.qucosa.de/id/qucosa%3A13455.
Texto completoBulgin, Claire Elizabeth. "Improved understanding of aerosol processes using satellite observations of aerosol optical properties". Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4906.
Texto completoCostantino, Lorenzo. "Analysis of aerosol-cloud interaction from space". Versailles-St Quentin en Yvelines, 2012. http://www.theses.fr/2012VERS0004.
Texto completoThe aim of this work is to provide a comprehensive analysis of cloud and aerosol interaction over South-East Atlantic, to quantify the overall aerosol impact on the regional radiation budget. We used data from MODIS, PARASOL and CALIPSO satellites, that fly in close proximity on the same sun-synchronous orbit and allow for complementary observations of the same portion of the atmosphere, within a few minutes. The main idea is to use CALIPSO vertical information to define whether or not aerosol and cloud layers observed by MODIS and PARASOL are mixed and interacting. We found evidences that, in case of interaction, cloud properties are strongly influenced by aerosol presence (first indirect effect). In particular, there is a decrease in cloud droplet effective radius and liquid water path with aerosol enhancement. On the other hand, we could not evidence any significant impact on the cloud reflectance. We also analyzed the aerosol impact on precipitation (second indirect effect). In polluted low clouds over the ocean, we found evidence of precipitation suppression and cloud cover increase with increasing aerosol concentration. On the other hand, cloud fraction is shown to be affected by aerosol presence, even if pollution particles are located above cloud top, without physical interaction. This observation is interpreted as a consequence of the aerosol radiative effect. Aerosol shortwave direct (DRF) and indirect (IRF) radiative forcing at TOA has been quantified, with the use of a radiative transfer model constrained by satellite observations. For the direct effect, there is a competition between cooling (negative, due to light scattering by the aerosols) and warming (positive, due to the absorption by the same particles). The six year (2005-2010) mean estimate is equal to -0. 07 (DRF) and -0. 05 (IRF) W/m². The resulting total aerosol forcing is negative (cooling) and equal to -0. 12 W/m²
Menon, Surabo, Jean-Louis Brenguier, Olivier Boucher, Paul Davison, Genio Anthony D. Del, Johann Feichter, Steven Ghan et al. "Evaluating aerosol/cloud/radiation process parameterizations with single-column models and Second Aerosol Characterization Experiment (ACE-2) cloudy column observations". Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-177303.
Texto completoFarrington, Robert. "Testing mixed phase cloud parametrizations through confronting models with in-situ observations". Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/testing-mixed-phase-cloud-parametrizations-through-confronting-models-with-insitu-observations(e2b7e31b-fa4a-4501-9f30-2ca2452c58fa).html.
Texto completoLathem, Terry Lee. "On the water uptake of atmospheric aerosol particles". Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/50112.
Texto completoRosenfeld, Daniel, Meinrat O. Andreae, Ari Asmi, Mian Chin, Leeuw Gerrit de, David P. Donovan, Ralph Kahn et al. "Global observations of aerosol-cloud-precipitation-climate interactions". Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-177356.
Texto completoRothenberg, Daniel (Daniel Alexander). "Fundamental aerosol-cloud interactions and their influence on the aerosol indirect effect on climate". Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/108963.
Texto completoCataloged from PDF version of thesis.
Includes bibliographical references (pages 173-189).
The influence of anthropogenic aerosol emissions on the optical properties of clouds and the radiative forcing arising from these interactions, known as the aerosol indirect effect on climate, constitutes a fundamental uncertainty in our understanding of 2 0 th century climate change. In this dissertation, we investigate the role of a keystone physical process, droplet activation, in contributing to this uncertainty. The first half of the ensuing work focuses on the parameterization of this process in global model, assessing both existing schemes and developing a novel one. The second half then quantifies the influence of activation by using a suite of aerosol-climate models which include a complete description of the physics which give rise to the indirect effect. Parameterizations of droplet activation perform well for idealized single-mode aerosol populations, but show systematic biases in high-pollution, weak-updraft regimes. These are exacerbated when the aerosol in question is a complex mixture. We show that estimates of droplet nucleation are highly sensitive to changes in the accumulation mode size and number concentration; this mode is itself sensitive to anthropogenic aerosol emissions, which potentially further biases modeled cloud droplet number. Using a model emulation technique, we develop a framework for building efficient metamodels of activation, which greatly reduce the mean error in droplet number predicted across regimes. The biases in these parameterizations raise questions the influence of activation on the indirect effect. Using different schemes, we calculate a spread of 1 W m- 2 in the indirect effect, which we show is equal to the spread computed from an independent suite of global models with different aerosol and physics modules. The estimated indirect effect scales more strongly with the baseline cloud droplet number concentration simulated by each model than by its change from pre-industrial to present day, indicating a strong saturation effect. While present-day estimates of aerosol-cloud interactions derived from satellite-based instruments are inadequate at constraining the pre-industrial cloud droplet burden, we show that process-based measurements could overcome this problem.
by Daniel Alexander Rothenberg.
Ph. D. in Atmospheric Science
Morales, Betancourt Ricardo. "On the representation of sub-grid scale phenomena and its impact on clouds properties and climate". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50373.
Texto completoLance, Sara. "Quantifying compositional impacts of ambient aerosol on cloud formation". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/26700.
Texto completoCommittee Chair: Nenes, Athanasios; Committee Co-Chair: Smith, Jim; Committee Member: Bergin, Mike; Committee Member: Huey, Greg; Committee Member: Weber, Rodney. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Karlsson, Karl-Göran. "The use of a satellite-derived cloud climatology for studying cloud-aerosol processes and the performance of regional cloud climate simulations". Doctoral thesis, Stockholm University, Department of Meteorology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1364.
Texto completoThe entry of satellite-derived decadal cloud datasets with homogeneous coverage in time and space enables studies not possible before. This thesis presents two such applications. The first study deals with cloud-aerosol processes and the second with an evaluation of cloud simulations from a regional climate model.
The first part of the thesis describes the used satellite-derived dataset based on imagery from the Advanced Very High Resolution Radiometer (AVHRR) on the polar orbiting NOAA satellites. A method for cloud retrieval and the compilation of a 1991-2000 Scandinavian cloud climatology are described.
The second part reveals an intriguing anti-correlation between monthly mean satellite-derived cloudiness and the concentration of the cosmogenetic isotope Beryllium-7 in near-surface aerosol samples for three measurement sites in Sweden. Large-scale transport processes are suggested as the most likely physical mechanism for this behaviour but more complex relations to cloud microphysical processes are not ruled out.
The final part presents a thorough evaluation of cloud simulations of the SMHI Rossby Centre regional atmospheric model (RCA3). Several model-to-satellite adaptations are applied to avoid artificial biases of results. The study stresses the necessity to account for initial differences between observed and modelled clouds caused by satellite cloud detection limitations. Results show good agreement of modelled and observed cloud amounts while the vertical distribution of clouds appears largely different. RCA3 underestimates medium-level clouds while overestimating low- and high-level clouds. Also, the current use of the Maximum cloud overlap approach in the radiation scheme and an indicated excess of cloud condensate in modelled clouds appear to create excessive cloud optical thicknesses with serious implications for the surface radiation budget.
Future applications are outlined based on greatly enhanced satellite-derived cloud and radiation budget datasets.
Liu, Qingfu. "Modeling of the aerosol-cloud interactions in marine stratocumulus /". Full-text version available from OU Domain via ProQuest Digital Dissertations, 1997.
Buscar texto completoSlater, Daniel. "Predicting the impacts of cloud processing on aerosol properties /". Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/10175.
Texto completoGunturu, Udaya Bhaskar. "Aerosol-Cloud interactions : a new perspective in precipitation enhancement". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/58462.
Texto completoCataloged from PDF version of thesis.
Includes bibliographical references (p. 171-184).
Increased industrialization and human activity modified the atmospheric aerosol composition and size-distribution during the last several decades. This has affected the structure and evolution of clouds, and precipitation from them. The processes and mechanisms by which clouds and precipitation are modified by changes in aerosol composition and size-distribution are very intricate. The objective of this thesis is to improve the understanding of the processes and mechanisms through which the changes in aerosol concentrations impact the evolution of deep convective clouds and precipitation formation. We develop a new coupled model in which a very detailed model of aerosol activation is coupled to a three-dimensional cloud resolving model. This coupled model can accurately represent different kinds of aerosol populations. This coupled model is used to investigate the impact of changing aerosol concentrations on the dynamics, microphysical evolution and precipitation formation in deep convective clouds. We examine the theories of aerosol activation, and the representation of aerosol activation in cloud models. The limitations of the extant methods of representation of aerosol activation in cloud models are evaluated. Then we descibe the components of the coupled model - Modified Eulerian and Lagrangian Aerosol Model (MELAM) and the Cloud Resolving Model (CRM). The features of these two component models with respect to aersol activation and cloud formation are discussed. The evaluation of the coupled model by simulation of a deep convertive event observed during the INDian Ocean EXperiment (INDOEX) by statistcal comparison of observed and simulated cloud fields shows that the coupled model can simulate deep convective events reasonably well. We present a study of the senstivity of the model to initial thermodynamic conditions (CAPE). Different initial thermodynamic conditons sampled during the INDOEX are used to initialize the coupled model and, the structure and evolution of the deep convective event are discussed. The study sheds new light on the respone of deep convection to CAPE. It is found that when the atmosphere has moderate CAPE, the precipitation forming processes are very active and when the CAPE is (cont.) low or high, they are comparatively less efficient.
As the most important part of our study, we examine the response of deep convection to changing initial aerosol concentration. Different aerosol concentrations from those representing pristine to polluted atmospheres are considered. We look at the buoyancy of the cloud and the microphysical evolution. It is found that the dynamics and microphysics are tightly coupled and we infer that to understand aerosol-cloud interactions in deep convective clouds, both - dynamics and microphysics - and their interaction have to be taken into consideration. Our results show that the response of a deep convective cloud to changing aerosol concentration is very different from the much well understood reponse of shallow clouds or small cumulus clouds. In general, increase in aerosol concentratin is seen to invigorate convection and lead to greater condensate. Although the cloud droplet size decreases, collision-coalescence is not completely inefficient. The precipitation in high aerosol regime is seen to occure in short spells of intense rain. A very interesting anomalous response of deep convection to initial aerosol concentration is observed at intermediate aerosol concentrations. The cloud lifetime, and precipitation are seen to increase in this regime. A possible mechanism to explain this anomalous behavior is proposed and the available circumstantial support for the mechanism from extant observations is presented. It is proposed that the efficient collection of rain and cloud droplets by ice and graupel particles in the middle troposphere is primarily responsible for this increased cloud lifetime and precipitation.
by Udaya Bhaskar Gunturu.
Ph.D.
Gryspeerdt, Edward, Tom Goren y Tristan W. P. Smith. "Observing the timescales of aerosol–cloud interactions in snapshot satellite images". Copernicus Publications, 2021. https://ul.qucosa.de/id/qucosa%3A74863.
Texto completoNichman, Leonid. "Optical measurements of the microphysical properties of aerosol and small cloud particles in the CLOUD project". Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/optical-measurements-of-the-microphysical-properties-of-aerosol-and-small-cloud-particles-in-the-cloud-project(ad792d0c-90d1-4704-b666-b75d284b40fe).html.
Texto completoSteele, Henry Donnan 1974. "Investigations of cloud altering effects of atmospheric aerosols using a new mixed Eulerian-Lagrangian aerosol model". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/58445.
Texto completoIncludes bibliographical references (p. 275-315).
Industry, urban development, and other anthropogenic influences have substantially altered the composition and size-distribution of atmospheric aerosol particles over the last century. This, in turn, has altered cloud albedo, lifetime, and patterns which together are thought to exert a negative radiative forcing on the climate; these are the indirect effects of atmospheric aerosols. The specifics of the process by which aerosol particles seed cloud particles are complex and highly uncertain. The goal of this thesis is to refine understanding of the role of various aerosol types in determining cloud properties. We approach this goal by constructing a new highly detailed aerosol-cloud process model that is designed to simulate condensation upon complex aerosol populations. We use this model to investigate the microphysics of aerosol-cloud interactions, specifically considering the role of cloud dynamics and of the ubiquitous mixed soot / sulfate aerosols. We describe the Mixed Eulerian-Lagrangian Aerosol Model (MELAM). This new computer model of aerosol microphysics is specifically tailored to simulate condensation and activation as accurately as possible. It specifically calculates aerosol thermodynamics, condensation, coagulation, gas and aqueous phase chemistry, and dissolution. The model is able to consider inorganic aerosols and aerosols with both inorganics and insoluble cores; the specific chemical system to be considered is specified by the user in text input files. Aerosol particles may be represented using "sectional distributions" or using a "representative sample" distribution which tracks individual particles.
(cont.) We also develop a constant updraft speed, adiabatic parcel model and a variable updraft speed, episodically entraining parcel model to provide boundary conditions to MELAM and allow simulations of aerosol activation in cloud updrafts. Using MELAM and the parcel models, we demonstrate that aerosol activation depends on the composition and size distribution of the sub-cloud aerosol population, on the updraft speed through a parcel's lifting condensation level, on the vertical profile of the updraft speed, and on entrainment. We use a convective parameterization that was developed for use in global or regional models to drive the episodically entraining, variable updraft speed parcel model. Ultimately, reducing the uncertainty of the global impact of the indirect effects of aerosols will depend on successfully linking cloud parameterizations to models of aerosol activation; our work represents a step in that direction. We also consider the activation of mixed soot / sulfate particles in cloud updrafts. We constrain for the first time a model of condensation onto these mixed particles that incorporates the contact angle of the soot / solution interface and the size of the soot core. We find that as soot ages and its contact angle with water decreases, mixed soot / sulfate aerosols activate more readily than the equivalent sulfate aerosols that do not have soot inclusions. We use data from the Aerosol Characterization Experiments (ACE) 1 and 2, and from the Indian Ocean Experiment (INDOEX) to define representative aerosol distributions for clean, polluted, and very polluted marine environments. Using these distributions, we argue that the trace levels of soot observed in clean marine environments do not substantially impact aerosol activation, while the presence of soot significantly increases the number of aerosol that activate in polluted areas.
by Henry Donnan Steele.
Ph.D.
Cravigan, Luke. "The role of marine biota on the composition and concentration of potential cloud condensation nuclei". Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/132173/1/Luke_Cravigan_Thesis.pdf.
Texto completoMegahed, Khaled. "The impact of mineral dust aerosol particles on cloud formation". [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=984083375.
Texto completoJunior, Theotonio Mendes Pauliquevis. "\"Os efeitos de aerossóis emitidos por queimadas na formação de gotas de nuvens e na composição da precipitação na Amazônia\"". Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-27082007-101307/.
Texto completoThe main objective of this study was to investigate the relationship between anthropogenic emissions in the Amazon basin and the indirect aerosol effect on climate. A detailed study of physical and chemical properties of natural and biomass burning aerosols was conducted, in order to understand how these completely different aerosols behave as Cloud Condensation Nuclei (CCN). It was also investigated the influence of biomass burning aerosols in chemical composition of precipitation, and transport of nutrients. The measurements were carried out in completely different regions respect to the impact of anthropogenic activities, especially biomass burning emissions. The analysis of aerosols and rainwater chemistry showed that anthropogenic emissions have a significant influence in the composition of precipitation. Factor analysis was applied to perform source identification, and the conclusion is that at remote and free of anthropogenic emission areas, the most important contribution was from biogenic emissions, with a small contribution of soil dust and marine aerosols advection. It was quite different at regions under influence of anthropogenic activities, where measurements showed a clear anthropogenic influence even during wet season both in aerosols and precipitation chemistry. In the study of hygroscopic properties of aerosol particles, the main conclusion was that size distribution of particles is the most important parameter to determine the ability of aerosols to act as CCN, because most of biomass burning emission are particles bigger than the activation diameter. Chemical composition was an important factor only if supersaturation is below 0.2%, because in this supersaturation range the activation diameter is extremely sensible to small changes in supersaturation. Transport of nutrients due to largescale transport of biomass burning aerosols was specially critical concerning phosphorus exportation, estimated as 7 times the apportionment through wet deposition. Continuous exportation of phosphorus can be a long term limitation to the forest ecosystem, if biomass burning activity maintain its present levels.
Wang, Zhen y Zhen Wang. "Interactions Between Atmospheric Aerosols and Marine Boundary Layer Clouds on Regional and Global Scales". Diss., The University of Arizona, 2018. http://hdl.handle.net/10150/626640.
Texto completoKarlsson, Karl-Göran. "The use of a satellite-derived cloud climatology for studying cloud-aerosol processes and the performance of regional cloud climate simulations /". Stockholm : Department of Meteorology, Stockholm University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1364.
Texto completoRuppe, Karen M. "A maritime and continental aerosol-cloud interaction study from ASTEX '92". Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23949.
Texto completoJahani, Babak. "Cloud-aerosol transition zone radiative effects from modeling and observational perspectives". Doctoral thesis, Universitat de Girona, 2021. http://hdl.handle.net/10803/673743.
Texto completoEls aerosols i els núvols, com a dos casos particulars d’un mateix fenomen (és a dir, una suspensió de partícules a l’aire), són components importants del sistema climàtic. Tenen un paper crucial en la determinació del balanç energètic de la Terra, ja que afecten fortament l’equilibri entre la radiació solar, d’ona curta, que absorbeixen l’atmosfera i la superfície de la Terra i la radiació tèrmica, d’ona llarga, emesa des de la Terra. Tot i que els aerosols i els núvols interactuen entre ells, modificant uns les característiques dels altres, les seves propietats i efectes radiatius se solen tractar per separat en estudis i models climàtics, meteorològics i de predicció del temps. Per tant, sovint es requereix una discriminació entre el cel serè i el cel ennuvolat. Tradicionalment, els algoritmes utilitzats per realitzar aquesta discriminació suposen que l’estat del cel és o bé ennuvolat o bé serè (sense núvols però que conté una certa càrrega d’aerosol), sense deixar espai per a una fase intermèdia. No obstant això, el canvi de l'estat del cel d’ennuvolat a serè (o viceversa) es produeix gradualment i comprèn una fase addicional anomenada "zona de transició" (o "twilight zone"), que pot representar una varietat de processos atmosfèrics: hidratació / deshidratació d’aerosols, fragments de núvols que sorgeixen dels núvols adjacents, núvols incipients o a punt de desaparèixer, etc. Com a resultat d’aquest supòsit simplificat sobre l’estat del cel, l’àrea corresponent a la zona de transició sovint s’etiqueta com una àrea que conté capes òpticament primes de núvol o aerosol, tot i que s’espera que les característiques microfísiques i radiatives de la zona de transició es trobin al límit entre les que corresponen a un núvol i les que corresponen a un aerosol atmosfèric. En altres paraules, les propietats òptiques i radiatives corresponents a cel serè (no nuvolós) o ennuvolat s’utilitzen de manera no del tot adequada per caracteritzar les condicions de zones de transició. En la present tesi contribuïm al coneixement disponible sobre la zona de transició des d’una perspectiva de balanç energètic
Programa de Doctorat en Medi Ambient
Mallet, Marc D. "Water uptake and composition of natural Australian cloud condensation nuclei". Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/104437/1/Marc_Mallet_Thesis.pdf.
Texto completoDoutriaux-Boucher, Marie y Johannes Quaas. "Evaluation of cloud thermodynamic phase parametrizations in the LMDZ GCM by using POLDER satellite data". Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-189683.
Texto completoKniffka, Anke y Thomas Trautmann. "Verwendung von mikrophysikalischen Messungen zur Charakterisierung von Aerosol und Wolken für Strahlungsübertragungsrechnungen". Universitätsbibliothek Leipzig, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-218078.
Texto completoIn this article some methods to reconstruct an artificial three-dimensional atmosphere from flight measurement data are described. The artificial atmosphere shall accurately represent the scattering properties of the real atmosphere, that are necessary to perform radiative transfer simulations. The method is applied to conduct a preliminary analysis of several atmospheric situations corresponding to different sets of radiative properties. The analyzed measurement data was collected during the first measurement campaign within the INSPECTRO project. In the case of an atmosphere containing a stratiform cloud layer, the measurements and simulation results are in very good agreement. A more accurate calculation of the extinction of radiation within the clouds by way of accounting for measured droplet spectra does momentarily not lead to an improvement in comparison with the simple parameterization method. In the case of a broken cloud field the significant local discrepancies between the measurement data and simulation results are to be noted. Nevertheless it can be shown that the statistical properties of the measured and calculated actinic flux fields resemble each other very closely
Boström, Patrik. "Revisiting Observed Changes in Cloud Properties over Europe". Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-179997.
Texto completoJordens atmosfär är ett känsligt system som lätt förändras av mikro- samt makrofysikaliska variationer. Stora minskningar i föroreningsnivåer av svaveldioxid över centrala Europa från 1980 till 2000-talet ledde till minskade masskoncentrationer av fasta och flytande atmosfäriska partiklar. Detta ger en möjlighet att undersöka hur dessa partiklar påverkar atmosfären. Nyligen utvecklad klimatologisk satellitdata användes för att analysera statistik av molnegenskaper under fyra år i en högt förorenad atmosfär (1985-88) och fyra år i en mindre förorenad atmosfär (2004-07). De två perioderna undersöktes i samarbete med Enheten för atmosfärisk fjärranalys av forskningsavdelningen till Sveriges meteorologiska och hydrologiska institut (SMHI). Molntopptemperaturen för moln i vätskefas över förorenande områden under den tidigare perioden var mer än 2 K kallare och mer än 5 K kallare för endast optiskt tunna moln i vätskefas. Förändringarna i masskoncentrationer för atmosfäriska partiklar och droppar med svaveldioxidusläpp som ursprung visas vara högst möjliga att ligga bakom de observerade molnförändringarna.
Chang, Dong Yeong [Verfasser]. "Aerosol-cloud interactions studied with a chemistry-climate model / Dong Yeong Chang". Mainz : Universitätsbibliothek Mainz, 2015. http://d-nb.info/1065634471/34.
Texto completoSweat, Perry C. "Verification of aerosol optical depth retrievals from cloud shadows using satellite imagery". Thesis, Monterey, Calif. : Naval Postgraduate School, 2008. http://bosun.nps.edu/uhtbin/hyperion-image.exe/08Mar%5FSweat.pdf.
Texto completoThesis Advisor(s): Durkee, Philip A. "March 2008." Description based on title screen as viewed on May 13, 2008. Includes bibliographical references (p. 65-67). Also available in print.
LeBlanc, Samuel Elie. "Spectral signatures in shortwave radiation measurements to derive cloud and aerosol properties". Thesis, University of Colorado at Boulder, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3624806.
Texto completoThe amplitude and spectral shape of shortwave radiation are used to retrieve aerosol and cloud properties from airborne and ground based measurements. By interacting with clouds and aerosols in the Earth's atmosphere, the wavelength-dependent radiation emitted by the sun is modified. This thesis presents the change in radiation due to absorption and scattering by clouds and aerosols, which result in distinct spectral signatures in shortwave radiation spectra.
The spectral signature in shortwave radiation due to aerosols is quantified by airborne measurements of irradiance above and below aerosol layers. This radiative effect is quantified by the relative forcing efficiency, which is used to compare the impact of aerosols from different air masses, locations, and time of day. The relative forcing efficiency is the net irradiance change due to the presence of aerosols normalized by aerosol optical thickness and incident irradiance. It is shown to vary by less than 20% per unit of midvisible aerosol optical thickness for aerosols sampled during 4 different experiments, except for highly absorbing aerosols near Mexico City. The similarity in relative forcing efficiency for these experiments, not expected a priori, suggests that this quantity is constrained for various types of aerosols with differing scattering and absorption characteristics even when surface albedo differs. To estimate the radiative effect of aerosols sampled in the Los Angeles basin during one of the experiments, where no concurrent measurements of optical thickness with spectral irradiance were available, a new iterative technique was devised to use aerosol optical thickness measurements from another airborne platform.
Cloud-transmitted zenith radiance spectra were measured from the ground in Boulder, Colorado. In these measurements, spectral signatures of cloud optical and microphysical properties were uncovered. The spectral signatures are the result of radiation that is transmitted through clouds, where ice or liquid water cloud particles modulate the radiation by absorbing and scattering incident light in a wavelength-dependent manner. Typically, the magnitudes of radiance at 2 wavelengths have been used to retrieve cloud properties, but by using wavelength-dependent features more sensitivity to cloud microphysical properties is obtained. This thesis presents a method to analyze wavelength-dependent signal, where spectral features such as slopes, curvatures, and shifts in locations of maxima and minima are parameterized. These spectral features found in normalized radiance are quantified by introducing 15 parameters. These 15 parameters form the basis of a new generalized retrieval obtaining cloud optical thickness (τ), effective radius (re), and thermodynamic phase (&phis;). When applied to a liquid water cloud case, this retrieval matched a measured transmittance spectrum with a smaller root mean square difference over the entire spectrum (3.1%) than two other methods (up to 6.4%). To quantify the retrieval over all possible combinations of τ, re, and &phis;, simulated measurements were used in conjunction with realistic measurement and model error characteristics. By combining these error characteristics within the GEneralized Nonlinear Retrieval Analysis (GENRA) a solution probability distributions can be built. The information of cloud properties contained within cloud-transmitted radiance is greater on average for liquid water clouds than for ice clouds. For all possible combinations of cloud properties, radiance transmitted through clouds with τ<20 contain the most information on cloud properties, indicating that the 15 parameters have greatest sensitivity to cloud properties of optically thin clouds (τ<20). Of the 15 parameters, only 10 are required to retrieve accurately τ, re, and &phis; for any cloud except for ice clouds with τ>25 and re>30 μm. Using this retrieval, the correct thermodynamic phase is determined from transmittance with a probability greater than 99.4% for horizontally homogeneous clouds that contain either ice or liquid water cloud particles.
Kipling, Zak. "Cloud cycling, scavenging and aerosol vertical profiles : process sensitivity and observational constraints". Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:16f442be-dac6-40d2-b1fa-4c5a2ff69e9c.
Texto completoCosta, Maria João Tavares da. "Aerosol and cloud satellite remote sensing: monitoring and modelling using passive radiometers". Doctoral thesis, Universidade de Évora, 2004. http://hdl.handle.net/10174/11498.
Texto completoMoore, Richard Herbert. "Using measurements of CCN activity to characterize the mixing state, chemical composition, and droplet growth kinetics of atmospheric aerosols to constrain the aerosol indirect effect". Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45945.
Texto completoAlroe, Joel. "Emission sources, cloud-relevant properties and variability of aerosol over the Southern and Pacific Oceans". Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/209152/1/Joel_Alroe_Thesis.pdf.
Texto completoDoutriaux-Boucher, Marie y Johannes Quaas. "Evaluation of cloud thermodynamic phase parametrizations in the LMDZ GCM by using POLDER satellite data: Evaluation of cloud thermodynamic phase parametrizations in theLMDZ GCM by using POLDER satellite data". Wiley, 2004. https://ul.qucosa.de/id/qucosa%3A13984.
Texto completoPainemal, David. "Investigation of the Cloud Microphysics and Albedo Susceptibility of the Southeast Pacific Stratocumulus Cloud Deck". Scholarly Repository, 2011. http://scholarlyrepository.miami.edu/oa_dissertations/581.
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