Dissertations / Theses on the topic 'Profiler lidar'

The mixing layer (ML) heights inferred from radiosondes, wind profilers, airborne lidar, airborne microwave temperature profiler (MTP), and in-situ aircraft data were compared during the Texas 2000 Air Quality Study in the Houston area. The comparisons and resulting good agreement between the separate instruments allowed for the spatial and temporal evolution of the ML height distribution to be determined across the Houston area on September 1, 2000. A benchmark method was created for determining ML heights from radiosonde data. The ML heights determined using this method were compared to ML heights determined using wind profiler data. The airborne lidar and MTP heights were also compared to the wind profiler heights. This was the first time the MTP was used for estimating ML heights. Because of this, the MTP heights were also compared to the ML heights determined by in-situ aircraft data. There was good agreement between the ML estimates when the instruments were co-located. The comparisons between the benchmark method and the wind profilers were independent of the quality of the profiler heights. The statistics for lidar and the wind profilers were better for the inland profiler comparisons. Even so, the results for coastal profilers were similar to the other comparisons. The results between the MTP and the wind profilers were comparable with the results found between the other instruments, and better, in that the statistics were similar for the both the inland and coastal profilers. The results between the MTP and in-situ aircraft data provided additional support for the use of MTP for determining ML heights. The combination of the inland and coastal wind profilers with the airborne instruments provided adequate information for the spatial and temporal evolution of the ML height to be determined across the Houston area on September 1, 2000. By analyzing the ML height distribution, major features were evident. These features included the shallow ML heights associated with the marine air from Galveston Bay and the Gulf of Mexico, and the sharp gradient of increasing ML heights north of Houston associated with the variation in the inversion depth found on this day.

Thesis (M.S. in Meteorology and Physical Oceanography) Naval Postgraduate School, June 1998.
Thesis advisor(s): Kenneth LaVern Davidson, Carlyle H. Wash. "June 1998." Includes bibliographical references (p. 49-50). Also available online.

Les régimes dynamiques dans les basses couches de l'atmosphère à l'île de la Réunion sont conditionnés par l'action du relief et du rayonnement sur l'écoulement synoptique. L'île est située en permanence dans le flux des alizés de sud-est et son relief élevé, culminant à 3000 m dans le centre de l'île et 2600 m au sud, constitue un obstacle important pour l'écoulement moyen. Le relief, le chauffage différentiel des pentes et le contraste thermique avec l'océan influent sur les échanges locaux entre la couche limite marine et la troposphère libre.L'analyse des phénomènes complexes de l'écoulement atmosphérique au niveau de l'île a pour but initial de caractériser les transferts de polluants émis localement. Cette étude a deux applications : * La première rentre dans le cadre préparatoire à la mise en place, à 2200 m d'altitude sur le Piton Maïdo, de l'observatoire atmosphérique de l'OPAR, à l'horizon 2011. L'objectif est de comprendre les circulations locales induites par le relief et les transports associés afin de discriminer d'éventuelles pollutions par les sources locales sur le signal qui sera mesuré in situ au sommet du Maïdo.* La seconde vise à étudier la diffusion des panaches volcaniques du Piton de la Fournaise. L'éruption majeure d'avril 2007 du volcan réunionnais a montré que des panaches pouvaient générer d'importantes pollutions dans diverses parties de l'île allant jusqu'à poser de réels problèmes environnementaux et de santé publique.Ces applications s'appuient sur une étude par modélisation numérique à haute résolution des écoulements atmosphériques dans les basses couches au niveau de l'île, au moyen du modèle météorologique de recherche MésoNH, permettant de conduire un ensemble de simulations sur cas idéalisés puis sur cas réels avec diffusion de traceurs passifs.

LIDAR is the optical equivalent of RADAR. A LIDAR facility has been established at Rhodes University using a flashlamp-pumped dye laser as the transmitter and a photomultiplier tube at the focus of a searchlight mirror as the receiver. The setting up of the receiver and transmitter as well as the design and construction of the photon counting electronics is described. The LIDAR has been used to measure aerosol scattering ratios and temperature profiles in the stratosphere and these results are presented with the algorithms and software used to reduce the data. Finally some recommendations are made for future work

The methodology to quantify vegetation from airborne laser scanning (or LiDAR - Light Detection And Ranging) is somehow consolidated, but some concerns are still in the checklist of the scientific community. This thesis aims to bring some of those concerns and try to contribute with some results and insights. Four aspects were studied along this thesis. In the first study, the effect of threshold heights (minimum height and height break) in the quality of the set of metrics was investigated aiming the volume estimation of a eucalyptus plantation. The results indicate that higher threshold height may return a better set of metrics. The impact of threshold height was more evident in young stands and for canopy density metrics. In the second study, the stability of the LiDAR metrics between different LiDAR surveys over the same area was analyzed. This study demonstrated how the selection of stable metrics contributed to generate reliable models between different data sets. According to our results, the height metrics provided the greatest stability when used in the models, specifically the higher percentiles (>50%) and the mode. The third study was designed to evaluate the use of machine learning tools to estimate wood volume of eucalyptus plantations from LiDAR metrics. Rather than being limited to a subset of LiDAR metrics in attempting explain as much variability in a dependent variable as possible, artificial intelligence tools explored the complete metrics set when looking for patterns between LiDAR metrics and stand volume. The fourth and last study has focused upon several highly important forest typologies, and shown that it is possible to differentiate the typologies through their vertical profiles as derived from airborne laser surveys. The size of the sampling cell does have an influence on the behavior observed in analyses of spatial dependence. Each typology has its own specific characteristics, which will need to be taken into consideration in projects targeting monitoring, inventory construction, and mapping based upon airborne laser surveys. The determination of a converged vertical profile could be achieved with data representing 10 % of the area for all typologies, while for some typologies 2 % coverage was sufficient.
A metodologia para quantificar vegetação a partir de dados LiDAR (Light Detection And Ranging) está de certa forma consolidada, porém ainda existem pontos a serem esclarecidos que permanecem na lista da comunidade científica. Quatro aspectos foram estudos nesta tese. No primeiro estudo, foi investigado a influência das alturas de referência (altura mínima e altura de quebra) na qualidade do conjunto de métricas extraído visando estimação do volume de um plantio de eucalipto. Os resultados indicaram que valor mais altos de alturas de referência retornaram um conjunto de métricas melhor. O efeito das alturas de referência foi mais evidente em povoamentos jovens e para as métricas de densidade. No segundo estudo, avaliou-se a estabilidade de métricas LiDAR derivadas para uma mesma área sobrevoada com diferentes configurações de equipamentos e voo. Este estudo apresentou como a seleção de métricas estáveis pode contribuir para a geração de modelos compatíveis com diferentes bases de dados LiDAR. De acordo com os resultados, as métricas de altura foram mais estáveis que as métricas de densidade, com destaque para os percentis acima de 50% e a moda. O terceiro estudo avaliou o uso de máquinas de aprendizado para a estimação do volume em nível de povoamento de plantios de eucalipto a partir de métricas LiDAR. Ao invés de estarem limitados a um pequeno subconjunto de métricas na tentativa de explicar a maior parte possível da variabilidade total dos dados, as técnicas de inteligência artificial permitiram explorar todo o conjunto de dados e detectar padrões que estimaram o volume em nível de povoamento a partir do conjunto de métricas. O quarto e último estudo focou em sete áreas de diferentes tipologias florestais brasileiras, estudando os seus perfis verticais de dossel. O estudo mostrou que é possível diferenciar estas tipologias com base no perfil vertical derivado de levantamentos LiDAR. Foi observado também que o tamanho das parcelas possui diferentes níveis de dependência espacial. Cada tipologia possui características específicas que precisam ser levadas em considerações em projetos de monitoramento, inventário e mapeamento baseado em levantamentos LiDAR. O estudo mostrou que é possível determinar o perfil vertical de dossel a partir da cobertura de 10% da área, chegando a algumas tipologias em apenas 2% da área.

O manuseio de grãos durante as operações de carga e descarga geram materiais particulados que são liberados para a atmosfera interferindo na qualidade do ar da região. Essa pesquisa identificou a presença de material particulado proveniente de grãos na cidade de Santos utilizando dados disponibilizados pelos satélites da NASA, índices de qualidade do ar fornecidos pela CETESB e dados obtidos pela técnica LIDAR.
Grain handling during loading and unloading operations generates particulate materials that are released into the atmosphere by interfering with the air quality of the region. This research identified the presence of particulate matter from grain in the city of Santos using data provided by NASA satellites, air quality indexes provided by CETESB and data obtained by the LIDAR technique.

This thesis presents a development to the technique of rotational Raman lidar by, incorporating an imaging spectrometer in conjunction with a clocking CCD detection system. This allowed the rotational Raman spectra of nitrogen and oxygen to be simultaneously recorded as a function of altitude. The rotational Raman spectra were uses to calculate temperature profiles. Recording the complete band envelopes of the rotational Raman spectra removed the need for an external reference, such as a radiosonde. Results are presented from measurements made in Cambridge in chapter 4 and Ny-Alesund in chapter 6. Chapter 7 presents some conventional lidar backscatter measurements made using a PMT in Birmingham during the winter part of the pollution in the Urban Midlands Area (PUMA) campaign. These measurements were used to determine the cloud base and the planetarty boundary layer height. Two automated algorithms were tested at retrieving the PBL height, the inflection point method and the centroid method.

Detecting change in stream channel features over time is important in understanding channel morphology and the effects of both natural and anthropogenic influences. Channel features historically, and now currently, are being measured using a variety of ground survey techniques. These surveys require substantial time commitments and funding to complete. Light Detection and Ranging (LiDAR) is an airborne laser mapping technology that holds promise to provide an alternative to ground-based survey methods. For this study, ground surveys were used to verify the accuracy of data collected using airborne LiDAR. Fifty nine cross-sectional profiles were surveyed in the Little Creek watershed at Cal Poly’s Swanton Pacific Ranch and compared to LiDAR-generated profiles of the same location. LiDAR data were collected in two flights during April and May of 2002. The vertical accuracy of LiDAR elevations was determined to be 0.610 m RSME based on a point-to-point comparison of the elevation of ground survey points in each cross-sectional profile to the corresponding LiDAR elevation. The average ground spacing of the LiDAR survey within the study area was one point every 5.2 square meters. In comparison to ground surveys it was found that with this level of vertical precision and horizontal resolution it would be difficult to detect change in bankfull channel characteristics of a relatively small channel, such as Little Creek. These difficulties are largely attributed to poor point coverage in forested, steep, and mountainous terrain, along with technological limitations of LiDAR that have since improved.

Water, wind, or tillage-induced soil erosion can significantly degrade soil quality and decrease crop yield from farm fields. Traditionally, the research in soil erosion is mostly focused on water or wind erosion. Recent studies over last two decades, however, point to the importance of tillage operations as a source of soil translocation on hilly agricultural land. Tillage disturbs the soil not only vertically but also horizontally by throwing soil in the tillage direction. This study was designed to assess the soil translocation effect in topsoil before and after 5 tillage operations by using three different practices, namely mouldboard ploughing (A), chisel plough (B), and disc harrow (C) in the Chernozems region at the Sardice (South Moravia, the Czech Republic). The influence of different tillage practices on the changes in depth of topsoil was assessed through description of 37 shallow pits - 10 pits was digged out before the tillage operations and then other 27 pits after five tillage operations. The results of the soil survey are based on the evaluation of the stratigraphy of the soil profile where the potential loss of topsoil was determined by a change in transition between the dark Ac horizon and yellow loess Ck horizon and by the type of the transition. Shift of topsoil after five performed operations is in the range of 9-15 cm at the top position of concave-convex slope and 4-14 cm at the top of concave slope. From the results of the experiment are also apparent significant shifts across to each tillage practice (C to A), which are, however, more or less caused by the shape of the slope. By creating and comparing the DEM for the conducted experiment I managed to learn that the largest transport of soil particles was caused by mouldboard plough. Transport of soil particles was larger in the vertical direction than in the horizontal and moved in the range of -5 to +13 cm. When undermining by a chisel plough was a significant horizontal shift of soil particles to the sides in the range of -5 to +5 cm. The method of shallow tillage with a disc harrow showed a change of the relief in the horizontal direction also in the range of -5 to +5 cm.

Les aérosols sont une composante variable de l'atmosphère, ayant un rôle important et complexe sur la qualité de l'air et le climat. La plupart des observations d'aérosols au sol sont limitées à des emplacements fixes, ce qui réduit la connaissance sur leur variabilité spatiale. Afin de compléter cette information, un système mobile d’observation des aérosols (MAMS - Mobile Aerosol Monitoring System) a été mis au point pour explorer la variabilité verticale et spatiale des propriétés optiques et microphysiques des aérosols. MAMS est un « laboratoire » conçu sur un véhicule, se distinguant des autres plateformes transportables par sa capacité à effectuer des mesures au cours du mouvement. Equipé d'instruments de télédétection et in situ, MAMS a exploré la variabilité des aérosols au travers de campagnes mobiles sur routes dans diverses situations. Ce travail présente les études de variabilité et des événements remarquables observés en France et en Chine. L’une des variables aérosols recherchée est leur concentration massique et leur distribution verticale. Ce défi est relevé dans ce travail. Le système mobile offre une grande flexibilité, et un bon rapport coût-efficacité, car il permet de réagir rapidement en cas d’événements aérosols soudains, tels que des épisodes de pollution, poussières, incendies ou éruptions volcaniques, démontrant son utilité pour les réseaux d’observation recherche et opérationnels. Les applications de la plateforme d'exploration mobile pour les activités de validation des missions spatiales d’observation de la Terre et de l’atmosphère, pour l’évaluation des modèles et les campagnes d’intercomparaison d’instruments sont présentées. Des nouvelles perspectives, tant au niveau instrumental que méthodologique, sont introduites, laissant la place à des améliorations dans les observations mobiles des aérosols
Aerosols are a variable component of the atmosphere, having an important and complex role on air quality and climate. Most of the ground-based aerosol observations are limited to fixed locations, narrowing the knowledge on their spatial variability. In order to overcome this issue, a compact Mobile Aerosol Monitoring System (MAMS) has been developed to explore the vertical and spatial variability of aerosol optical and microphysical properties. MAMS is a vehicle-based laboratory, distinguished by other transportable platforms through its ability to perform measurements during the movement. Equipped with remote sensing and in situ instruments, MAMS explored the aerosol variability through mobile on-road campaigns in various situations. This work presents variability studies and remarkable events observed both in France and in China. One of the researched aerosol variables is their mass concentration and vertical distribution. This challenge is taken up in this work. The mobile system presents a great flexibility and is cost-effective, being able to respond quickly in case of sudden aerosol events such as pollution episodes, dust, fire or volcano outbreaks, proving to be a useful platform for aerosol observation and operational networks. Applications of the mobile exploratory platform for validation activities of space missions observing the Earth and the atmosphere, for models’ evaluation and for instrument intercomparison campaigns are presented. New perspectives, both on instrumental and methodology levels are introduced, leaving place for improvements in the mobile aerosol observations

L'objectif de cette thèse est d'étudier la capacité des modèles météorologiques à prévoir des épisodes de cisaillements de vent dans les basses couches de l'atmosphère sur une zone limitée à un aéroport et d'examiner l'apport pour la modélisation d'observations locales à haute fréquence. Nous avons choisi l'aéroport international de Nice, régulièrement soumis à des variations rapides de la direction et de l'intensité du vent selon l'horizontale dans la CLA, appelées aussi renverses. Un pro leur de vent et trois anémomètres sont installés sur les pistes de l'aéroport. Au début de l'année 2009, une campagne de mesures incluant un lidar vent à balayage et un anémomètre sonique s'est déroulée sur l'aéroport fournissant des observations complémentaires. L'ensemble des mesures à haute fréquence temporelle et des simulations numériques obtenues avec le modèle de recherche Méso-NH à 2.5 km de résolution, a fourni une vision de l'enchaînement complexe des écoulements conduisant à des cisaillements de vent d'origine différente. Cette complémentarité a aussi permis d'estimer la capacité du modèle numérique à reproduire les cisaillements de vent. Pour les trois situations étudiées, il reproduit la structure horizontale et verticale de l'écoulement malgré des erreurs de placement spatio-temporel. Bien que les écoulements locaux participent à la mise en place des conditions nécessaires au cisaillement de vent, c'est l'écoulement de méso-échelle (ondes piégées ou talweg d'altitude) qui va déterminer la position du phénomène. Nous avons réalisé des comparaisons avec le modèle opérationnel de Météo-France AROME ainsi que des tests de sensibilité pour étudier l'in uence des conditions de couplage et de la résolution. Nous avons, en particulier, augmenté la résolution horizontale de 2.5 km à 500 m sur un domaine centré sur l'aéroport de Nice sur les situations étudiées. Une résolution de 500 m permet d'améliorer la représentation d'écoulements locaux et de variations locales du vent mais n'améliore pas la position des cisaillements de vent par rapport à une échelle plus grossière. L'extension horizontale limitée du domaine à haute résolution augmente la sensibilité aux conditions aux limites de grande échelle. Pour améliorer les prévisions et contraindre le modèle numérique vers les observations disponibles sur le site d'étude, un système l'assimilation de données basé sur le 'nudging' et permettant de prendre en compte des données à haute fréquence temporelle, le "nudging direct et rétrograde" (BFN pour 'Back and Forth Nudging'), a été mis en place. Nous avons appliqué cet algorithme aux équations de Lorenz pour con rmer le comportement de cette méthode par rapport à des résultats publiés antérieurement avec d'autres méthodes d'assimilation de données. Les résultats encourageants, ont conduit à l'introduction du BFN dans Méso-NH. Nous avons mis en place des simulations avec assimilation de données simulées dans des conditions idéalisées qui ont montré une réponse cohérente du modèle numérique à l'introduction de pro ls verticaux de vent.

With the ever increasing population and economic activities in coastal areas, coastal hazards have become a major concern for coastal management. The fundamental requirement of coastal planning and management is the scientific knowledge about coastal forms and processes. This research aims at developing algorithms for automatically extracting coastal morphological information from LiDAR data. The primary methods developed by this research include automated algorithms for beach profile feature extraction and change analysis, and an object-based approach for spatial pattern analysis of coastal morphologic and volumetric change. Automated algorithms are developed for cross-shore profile feature extraction and change analysis. Important features of the beach profile such as dune crest, dune toe, and beach berm crest are extracted automatically by using a scale-space approach and by incorporating contextual information. The attributes of important feature points and segments are derived to characterize the morphologic properties of each beach profile. Beach profiles from different time periods can be compared for morphologic and volumetric change analysis. An object-oriented approach for volumetric change analysis is developed to identify and delineate individual elevation change patches as discrete objects. A set of two-dimensional and three-dimensional attributes are derived to characterize the objects, which includes planimetric attributes, shape attributes, surface attributes, volumetric attributes, and summary attributes. Both algorithms are implemented as ArcGIS extension modules to perform the feature extraction and attribute derivation for coastal morphological change analysis. To demonstrate the utility and effectiveness of algorithms, the cross-shore profile change analysis method and software tool are applied to a case study area located at southern Monterey Bay, California, and the coastal morphology change analysis method and software tool are applied to a case study area located on Assateague Island, Maryland. The automated algorithms facilitate the efficient beach profile feature analysis over large geographical area and support the analysis of the spatial variations of beach profile changes along the shoreline. The explicit object representation of elevation change patches makes it easy to localize erosion hot spots, to classify the elevation changes caused by various mechanisms, and to analyze spatial pattern of morphologic and volumetric changes.

In der vorliegenden Arbeit wird ein zweistufiger Algorithmus, das sogenannte Retrieval, zur Ableitung von Wasserdampfprofilen aus einer Kombination von Ramanlidar und Mikrowellenradiometer zur operationellen Anwendung vorgestellt. Beide Instrumente kamen während einer groß angelegten Kampagne nahe Jülich im Frühjahr 2013 zum Einsatz (HOPE). Ziel der Arbeit ist es, kontinuierliche Zeitreihen der vertikalen Wasserdampfverteilung abzuleiten. Dies erfordert eine Kalibrierung des Ramanlidars. Im Rahmen dieser Arbeit wurde ein automatisches Kalibrierschema entwickelt, welches auf dem integrierten Wasserdampfgehalt abgeleitet aus Mikrowellenradiometermessungen basiert. Die Methode zeigt eine gute Übereinstimmung mit herkömmlichen Ansätzen, welche auf Radiosondenaufstiegen beruhen. Der Kalibrierfaktor ist sehr stabil mit einer relativen Abweichung von 5 %. Diese Stabilität bietet den Vorteil, das Lidar auch unter bewölkten Bedingungen zu kalibrieren. Hierfür wird der Kalibrierfaktor des letzten wolkenfreien Zeitraums herangezogen. Dies ermöglicht die kontinuierliche Messung von Wasserdampfprofilen bis zu einer möglichen Wolkenbasis. Um verlässliche Wasserdampfinformationen innerhalb und oberhalb einer Wolke zu erhalten, wird ein zweistufiger Algorithmus angewandt. Der erste Schritt ist ein Kalman Filter, der die an der Wolkenbasis abgeschnittenen Wasserdampfprofile vom Ramanlidar mittels eines vorherigen Profils zu einem kompletten Profil (bis zu 10 km) kombiniert. Das komplette Wasserdampfprofil dient dann als Input für die eindimensionale variationelle (1D- VAR) Methode, auch als optimale Schätzung bekannt. Für dieses Profil werden die Helligkeitstemperaturen simuliert, die das Mikrowellenradiometer in der gegebenen Atmosphäre messen würde und anschließend mit den tatsächlich gemessenen verglichen. Das Profil wird dann iterativ entsprechend seiner Fehlerbalken so lange modifiziert, bis die modellierten mit den gemessenen Helligkeitstemperaturen hinreichend übereinstimmen. Die Funktionsweise des Retrievals wird mit Hilfe von Fallstudien unter verschiedenen Bedingungen detailliert beleuchtet. Eine statistische Analyse zeigt, dass die Verfügbarkeit von Ramanlidardaten (nachts) die Genauigkeit der abgeleiteten Profile verbessert. Tagsüber resultiert das Fehlen der Lidarinformationen in größeren Unterschieden zu Referenzradiosonden. Die Datenabdeckung der kompletten Lidarprofile von 17 % während der zweimonatigen Kampagne wird durch Anwendung des Retrievals auf 60 % signifikant erhöht. Da die relative Feuchte oft mals ein nützliches Maß für die Beschreibung von Wolkenbildung und Aerosolwachstum ist, wird die Bestimmung der relativen Feuchte aus den abgeleiteten Profilen unter verschiedenen Temperaturannahmen behandelt. Die Annahme eines Temperaturprofils vom Mikrowellenradiometer resultiert in einem absoluten Bias von 4.7 g/kg . Weiterhin wird in der Arbeit die flexible und vielfältige Anwendung des Retrievals an verschiedenen Messstationen in Jülich, Lindenberg und auf dem Forschungsschiff Polarstern sowie unterschiedlichen Ramanlidargeräten und Mikrowellenradiometern präsentiert. Ein besonders hervorzuhebender positiver Aspekt der Arbeit ist die Implementierung des Retrievals in die Cloudnet-Prozessierung, welche die Untersuchung von Wolken und Niederschlag bereichert. Die gewonnenen Profile werden außerdem für eine Evaluierung des Klima- und Vorhersagemodells ICON verwendet.

The objective of this thesis is to assess the optimal power production and flight trajectories of crosswind, ground-generation or pumping-mode airborne wind energy systems (AWES), subject to realistic onshore and offshore, mesoscale-modeled wind data as well as LiDAR wind resource assessment. The investigation ranges from small scale AWES with an aircraft wing area of 10 m^2 to utility scale systems of 150 m^2. In depth knowledge of the wind resource is the basis for the development and deployment of any wind energy generator. Design and investment choices are made based on this information, which determine instantaneous power, annual energy production and cost of electricity. In the case of AWES, many preliminary and current analyses of AWES rely on oversimplified analytical or coarsely resolved wind models, which can not represent the complex wind regime within the lower-troposphere. Furthermore, commonly used, simplified steady state models do not accurately predict AWES power production, which is intrinsically linked to the aircraft's flight dynamics, as the AWES never reaches a steady state over the course of a power cycle. Therefore, leading to false assumption and unrealistic predictions. In this work, we try to expand our knowledge of the wind resource at altitudes beyond the commonly investigated lowest hundreds of meters. The so derived horizontal wind velocity profiles are then implemented in to an optimal control framework to compute power-optimal, dynamically feasible flight trajectories that satisfy operation constraints and structural system limitations. The so derived trajectories describe an ideal, or at least a local optimum, and not necessarily realistic solution. It is unlikely that such power generation can be reached in practice, given that disturbances, model assumptions, misalignment with the wind direction, control limitations and estimation errors, will reduce actual performance. We first analyze wind light detection and ranging (LiDAR) measurements at a potential onshore AWES deployment site in northern Germany. To complement these measurements we generate and analyze onshore and offshore, mesoscale weather research and forecasting (WRF) simulations. Using observation nudging, we assimilate onshore LiDAR measurements into the WRF model, to improve wind resource assessment. We implement representative onshore and offshore wind velocity profiles into the awebox optimization framework, a Python toolbox for modelling and optimal control of AWES, to derive power-optimal trajectories and estimate AWES power curves. Based on a simplified scaling law, we explore the design space and set mass targets for small to utility-scale, ground-generation, crosswind AWESs.
Graduate

Global and local climate changes affect nature and mankind. Forecasts of these processes on global and local scales rely on a thorough understanding of the underlying physics through accurate data. In this context, the knowledge of the temperature profile of the upper-ocean mixed layer is relevant in oceanography, weather forecasts and climate studies and can be correlated to other parameters, such as concentrations of nutrients, oxygen and CO2. Currently, only in-situ techniques are available, such that a remote sensing application for the measurement of oceanic temperature profiles is highly desirable. Such a system would deliver accurate, cost effective and area wide data, which could be used to improve current models and forecasts within many domains of oceanography and climatology. However, only recent progress in laser and receiver technology made a remote sensing solution feasible. When employing the lidar principle, an airborne compatible system based on the detection of the temperature dependent frequency shift of the Brillouin-scattering becomes feasible. Laser pulses are fired into the ocean and the Brillouin-scattering imprints the temperature information on the backscattered light. An appropriate detector on board an aircraft extracts the temperature and correlates it to the time of flight of the laser pulses. As a result, a three-dimensional temperature profile of the upper-ocean mixed layer is extracted. Measuring the very small frequency shift of the Brillouin-scattering is the main challenge of this project. The shift varies from 6.8~GHz-7.8 GHz for water temperatures between 0°C and 40°C, when injecting laser pulses at a wavelength of 543 nm. The employment of spectrally narrow edge-filters converts the frequency measurement into an intensity measurement. As compact, robust and light weight devices, these filters are in particular suited for an airborne implementation. This work demonstrates that Excited State Faraday Anomalous Dispersion Optical Filters (ESFADOFs) are such high resolution optical edge-filters. They deliver the desired edge-filter characteristics, when operated around the Rubidium 5P3/2 -> 5D5/2 transition (543~nm), and transmission changes of up to 24% within a few GHz were demonstrated. In addition, fundamental investigations of the ESFADOF transmissions are presented. They result in distinct operational limits, due to radiation trapping, energy-pooling and plasma formation. Together with the scalability of these devices, their implementation as the Brillouin-lidar detector is addressed.

Ważną grupę wśród aerozoli atmosferycznych stanowią aerozole absorbujące, których wpływ na klimat Ziemi jest złożony i przez to obarczony dużymi niepewnościami. Ponadto aerozole absorbujące pełnią istotną rolę w procesach fizycznych związanych ze smogiem. Największym problemem w skutecznym szacowaniu ich wpływu na klimat oraz w badaniu warunków smogowych jest bardzo ograniczona baza dostępnych pomiarów, szczególnie w przypadku profili pionowej dystrybucji aerozoli absorbujących. W ramach niniejszej pracy zostało podjęte zagadnienie opracowania i weryfikacji metody pozwalającej na pomiary profilu pionowego współczynnika absorpcji oraz koncentracji aerozoli absorbujących z wykorzystaniem bezzałogowych platform latających - dronów jako platformy do przenoszenia miniaturowych czujników atmosferycznych. Pozyskane w ten sposób dane mogą służyć do modelowania strumieni promieniowania, oceny rozwoju i zaniku warunków smogowych, czy wyznaczania poprawki atmosferycznej dla produktów teledetekcyjnych. W oparciu o synergię pomiarów profili współczynnika absorpcji z pomiarami profili współczynnika ekstynkcji prowadzonych za pomocą systemów lidarowych możliwe jest wyznaczenia profili pionowych albedo pojedynczego rozpraszania. Jako optymalną metodę sondowania wybrano profilowanie z wykorzystaniem wielowirnikowego drona z podwieszonym mikroetalometrem oraz radiosondą meteorologiczną. Metoda ta cechuje się wysoką skutecznością prowadzenia obserwacji (duża powtarzalność, łatwość przygotowania, możliwość osiągnięcia wysokich rozdzielczości czasowych i przestrzennych) przy zachowaniu ograniczonych kosztów. W ramach opracowywania i testowania zaproponowanej metody prowadzone były w latach 2013-2015 eksperymenty terenowe w Strzyżowie, Świdrze i Warszawie pozwalające na sondowanie aerozoli w różnych warunkach oraz wykorzystanie danych z kilku systemów lidarowych, umożliwiających na stosowanie różnych metod inwersji. Uzyskane wyniki obejmujące absorpcyjną aerozolową grubość optyczną oraz albedo pojedynczego rozpraszania były porównywane z danymi dostępnymi w ramach sieci pomiarów fotometrycznych AERONET oraz naziemnymi pomiarami in-situ. Wobec niskiej zgodności danych z bazy AERONET z pozostałymi pomiarami zaproponowane zostały metody szacowania absorpcyjnej aerozolowej grubości optycznej w oparciu o synergię pomiarów prowadzonych z wykorzystaniem drona i lidarów, a także naziemnych pomiarów in-situ. W ramach prowadzonych badań podważono jakość danych AERONET obejmujących absorpcyjne własności optyczne aerozolu w szczególności w warunkach niskiej aerozolowej grubości optycznej. Wpływ zmienności profilu pionowego albedo pojedynczego rozpraszania na bezpośrednie wymuszenie radiacyjne, strumienie krótkofalowego promieniowania rozproszonego docierające do górnej graniczy atmosfery i powierzchni ziemi oraz profile ogrzewania radiacyjnego został oszacowany w oparciu o symulacje prowadzone z wykorzystaniem numerycznego modelu transferu radiacyjnego. Zaobserwowane różnice w strumieniach promieniowania rozproszonego były niskie i nie przekraczały 3% niezależnie od kąta zenitalnego słońca, co przekładało się na zmianę wymuszenia radiacyjnego poniżej 10%. Największe zmiany, sięgające 3K, uzyskano dla grzania radiacyjnego. Wpływ na poprawkę atmosferyczną dla wskaźnika stanu roślinności, w zależności od profilu sięgał 7.7%, przy czym dla albedo śniegu wzrastał do wartości przekraczających 20%.
Absorbing aerosols belong to an important group of atmospheric aerosols. They affect Earth's climate in a complex way, hence their influence is difficult to assess. Moreover, those aerosols play a vital role in physical processes connected with smog emissions. The main difficulty in the analysis of their impact on climate and smog conditions is very limited measurement data, especially as far as profiles of vertical distribution of absorbing aerosols are concerned. The aim of this work is to establish and verify a method that would enable to measure vertical profiles of absorption coefficient and concentration of absorbing aerosols with the usage of unmanned aerial vehicles (drones) as platforms for miniature atmospheric sensors. The data acquired in this way can be used to model radiation streams, assess how smog conditions develop and diminish, or to make atmospheric correction for remote sensing devices. Basing on the synergy of profiles of absorption coefficient with those of extinction coefficient, measured by lidar systems, we can establish vertical profiles of single scattering albedo. It was decided that the optimal method for probing would be profiling with multi-rotor drone, with attached micro-aethalometer and meteorological radiosonde. This method is highly efficient for conducting any observation (high level of repetitiveness, easy preparation, high temporal and spatial resolution) on low budget. In the years 2013-2015, the method was tested during field experiments in Strzyzow, Swider and Warsaw for probing aerosols in various conditions and using data from different lidar systems, which allow to apply multiple inversion methods. The results, scoping absorbing aerosols optical depth and single scattering albedo, were then compared with data from the AERONET photometric network and in-situ measurements on ground level. As the compatibility of AERONET data with other measurement was relatively low, it was proposed to asses absorbing aerosols optical depth on the basis of the synergy of measurements conducted with the use of drones and lidars and on-ground in situ measurements. In the course of the research, it was proved that the quality of AERONET data for optical properties of abrobing aerosols, especially in low aerosol optical depth conditions, is rather questionable. In order to assess how changing vertical profile of single scattering albedo affects direct radiative forcing, streams of short-wave diffused radiation reaching the top of atmosphere and surface of the Earth, and profiles of radiative heating, we conducted simulations on the numeric radiative transfer model. The differences observed in the streams of diffused radiation were low, as they did not exceed 3% ,regardless of the zenith angle of the sun, which changed the radiative forcing to below 10%. The greatest changes, up to 3K, were noted for radiative heating. Depending on the profile, the influence on atmospheric correction for vegetation index reached up to 7.7%, with the ratio exceeding 20% for snow albedo.