Résumé : L'étude du couvert nival est essentielle afin de mieux comprendre les processus climatiques et hydrologiques. De plus, avec les changements climatiques observés dans l'hémisphère nord, des événements de dégel-regel ou de pluie hivernale sont de plus en plus courants et produisent des croutes de glace dans le couvert nival affectant les moeurs des communautés arctiques en plus de menacer la survie de la faune arctique. La télédétection micro-ondes passives (MOP) démontre un grand potentiel de caractérisation du couvert nival. Toutefois, a fin de bien comprendre les mesures satellitaires, une modélisation adéquate du signal est nécessaire. L'objectif principal de cette thèse est d'analyser le transfert radiatif (TR) MOP des sols, de la neige et de la glace a fin de mieux caractériser les propriétés géophysiques du couvert nival par télédétection. De plus, un indice de détection des croutes de glace par télédétection MOP a été développé. Pour ce faire, le modèle Microwave Emission Model of Layered Snowpacks (MEMLS) a été étudié et calibré afin de minimiser les erreurs des températures de brillance simulées en présences de croutes de glace. La première amélioration faite à la modélisation du TR MOP de la neige a été la caractérisation de la taille des grains de neige. Deux nouveaux instruments, utilisant la réflectance dans le proche infrarouge, ont été développés afin de mesurer la surface spécifique de la neige (SSA). Il a été démontré que la SSA est un paramètre plus précis et plus objectif pour caractériser la taille des grains de neige. Les deux instruments ont démontré une incertitude de 10% sur la mesure de la SSA. De plus, la SSA a été calibré pour la modélisation MOP a n de minimiser l'erreur sur la modélisation de la température de brillance. Il a été démontré qu'un facteur multiplicatif [phi] = 1.3 appliqué au paramètre de taille des grains de neige dans MEMLS, paramètre dérivé de la SSA, est nécessaire afin de minimiser l'erreur des simulations. La deuxième amélioration apportée à la modélisation du TR MOP a été l'estimation de l'émission du sol. Des mesures radiométriques MOP in-situ ainsi que des profils de températures de sols organiques arctiques gelés ont été acquis et caractérisés a fin de simuler l'émission MOP de ces sols. Des constantes diélectriques effectives à 10.7, 19 et 37 GHz ainsi qu'une rugosité de surface effective des sols ont été déterminés pour simuler l'émission des sols. Une erreur quadratique moyenne (RMSE) de 4.65 K entre les simulations et les mesures MOP a été obtenue. Suite à la calibration du TR MOP du sol et de la neige, un module de TR de la glace a été implémenté dans MEMLS. Avec ce nouveau module, il a été possible de démontré que l'approximation de Born améliorée, déjà implémenté dans MEMLS, pouvait être utilisé pour simuler des croutes de glace pure à condition que la couche de glace soit caractérisée par une densité de 917 kg m[indice supérieur _􀀀3] et une taille des grains de neige de 0 mm. Il a aussi été démontré que, pour des sites caractérisés par des croutes de glace, les températures de brillances simulées des couverts de neige avec des croutes de glace ayant les propriétés mesurées in-situ (RMSE=11.3 K), avaient une erreur similaire aux températures de brillances simulées des couverts de neige pour des sites n'ayant pas de croutes de glace (RMSE=11.5 K). Avec le modèle MEMLS validé pour la simulation du TR MOP du sol, de la neige et de la glace, un indice de détection des croutes de glace par télédétection MOP a été développé. Il a été démontré que le ratio de polarisation (PR) était très affecté par la présence de croutes de glace dans le couvert de neige. Avec des simulations des PR à 10.7, 19 et 37 GHz sur des sites mesurés à Churchill (Manitoba, Canada), il a été possible de déterminer des seuils entre la moyenne hivernale des PR et les valeurs des PR mesurés indiquant la présence de croutes de glace. Ces seuils ont été appliqués sur une série temporelle de PR de 33 hivers d'un pixel du Nunavik (Québec, Canada) où les conditions de sols étaient similaires à ceux observés à Churchill. Plusieurs croutes de glace ont été détectées depuis 1995 et les mêmes événements entre 2002 et 2009 que (Roy, 2014) ont été détectés. Avec une validation in-situ, il serait possible de confirmer ces événements de croutes de glace mais (Roy, 2014) a démontré que ces événements ne pouvaient être expliqués que par la présence de croutes de glace dans le couvert de neige. Ces mêmes seuils sur les PR ont été appliqués sur un pixel de l'Île Banks (Territoires du Nord-Ouest, Canada). L'événement répertorié par (Grenfell et Putkonen, 2008) a été détecté. Plusieurs autres événements de croutes de glace ont été détectés dans les années 1990 et 2000 avec ces seuils. Tous ces événements ont suivi une période où les températures de l'air étaient près ou supérieures au point de congélation et sont rapidement retombées sous le point de congélation. Les températures de l'air peuvent être utilisées pour confirmer la possibilité de présence de croutes de glace mais seul la validation in-situ peut définitivement confirmer la présence de ces croutes. / Abstract : Snow cover studies are essential to better understand climatic and hydrologic processes. With recent climate change observed in the northern hemisphere, more frequent rain-on-snow and meltrefreeze events have been reported, which affect the habits of the northern comunities and the survival of arctique wildlife. Passive microwave remote sensing has proven to be a great tool to characterize the state of snow cover. Nonetheless, proper modeling of the microwave signal is needed in order to understand how the parameters of the snowpack affect the measured signal. The main objective of this study is to analyze the soil, snow and ice radiative transfer in order to better characterize snow cover properties and develop an ice lens detection index with satellite passive microwave brightness temperatures. To do so, the passive microwave radiative transfer modeling of the Microwave Emission Model of Layered Snowpacks (MEMLS) was improved in order to minimize the errors on the brightness temperature simulations in the presence of ice lenses. The first improvement to passive microwave radiative transfer modeling of snow made was the snow grain size parameterization. Two new instruments, based on short wave infrared reflectance to measure the snow specific surface area (SSA) were developed. This parameter was shown to be a more accurate and objective to characterize snow grain size. The instruments showed an uncertainty of 10% to measure the SSA of snow. Also, the SSA of snow was calibrated for passive microwave modeling in order to reduce the errors on the simulated brightness temperatures. It was showed that a correction factor of φ = 1.3 needed to be applied to the grain size parameter of MEMLS, obtain through the SSA measurements, to minimize the simulation error. The second improvement to passive microwave radiative transfer modeling was the estimation of passive microwave soil emission. In-situ microwave measurements and physical temperature profiles of frozen organic arctic soils were acquired and characterized to improve the modeling of the soil emission. Effective permittivities at 10.7, 19 and 37 GHz and effective surface roughness were determined for this type of soil and the soil brightness temperature simulations were obtain with a minimal root mean square error (RMSE) of 4.65K. With the snow grain size and soil contributions to the emitted brightness temperature optimized, it was then possible to implement a passive microwave radiative transfer module of ice into MEMLS. With this module, it was possible to demonstrate that the improved Born approximation already implemented in MEMLS was equivalent to simulating a pure ice lens when the density of the layer was set to 917 kg m−3 and the grain size to 0 mm. This study also showed that by simulating ice lenses within the snow with there measured properties, the RMSE of the simulations (RMSE= 11.3 K) was similar to the RMSE for simulations of snowpacks where no ice lenses were measured (only snow, RMSE= 11.5 K). With the validated MEMLS model for snowpacks with ice lenses, an ice index was created. It is shown here that the polarization ratio (PR) was strongly affected by the presence of ice lenses within the snowpack. With simulations of the PR at 10.7, 19 and 37 GHz from measured snowpack properties in Chucrhill (Manitoba, Canada), thresholds between the measured PR and the mean winter PR were determined to detect the presence of ice within the snowpack. These thresholds were applied to a timeseries of nearly 34 years for a pixel in Nunavik (Quebec, Canada) where the soil surface is similar to that of the Churchill site. Many ice lenses are detected since 1995 with these thresholds and the same events as Roy (2014) were detected. With in-situ validation, it would be possible to confirm the precision of these thresholds but Roy (2014) showed that these events can not be explained by anything else than the presence of an ice layer within the snowpack. The same thresholds were applied to a pixel on Banks island (North-West Territories, Canada). The 2003 event that was reported by Grenfell et Putkonen (2008) was detected by the thresholds. Other events in the years 1990 and 2000’s were detected with these thresholds. These events all follow periods where the air temperature were warm and were followed by a quick drop in air temperature which could be used to validate the presence of ice layer within the snowpack. Nonetheless, without in-situ validation, these events can not be confirmed.

The presence of the sea ice diatom biomarker IP25 in Arctic marine sediments has been used in previous studies as a proxy for past spring sea ice occurrence and as an indicator of wider palaeoenvironmental conditions for different regions of the Arctic over various timescales. The current study describes a number of analytical and palaeoceanographic developments of the IP25 sea ice biomarker. First, IP25 was extracted and purified from Arctic marine sediments. This enabled the structure of IP25 to be confirmed and enabled instrumental (GC-MS) calibrations to be carried out so that quantitative measurements could be performed with greater accuracy. Second, palaeo sea ice reconstructions based on IP25 and other biomarkers were carried out for a suite of sub-Arctic areas within the Greenland, Norwegian and Barents Seas, each of which represent contrasting oceanographic and environmental settings. Further, an evaluation of some combined biomarker approaches (e.g. the PIP25 and DIP25 indices) for quantifying and/or refining definitions of sea ice conditions was carried out. Temporally, particular emphasis was placed on the characterisation of sea ice conditions during the Younger Dryas and the Holocene. Some comparisons with other proxies (e.g. foraminifera, IRD) were also made. A study of a sediment core from Andfjorden (69.16˚N, 16.25˚E), northern Norway, provided unequivocal evidence for the occurrence of seasonal sea ice conditions during the Younger Dryas. The onset (ca. 12.9 cal. kyr BP) and end (ca. 11.5 cal. kyr BP) of this stadial were especially clear in this location, while in a study from the Kveithola Trough (74.52˚N, 16.29˚E), western Barents Sea, these transitions were less apparent. This was attributed to the presence of colder surface waters and the occurrence of seasonal sea ice both before and after this stadial at higher latitudes. Some regional differences regarding the severity of the sea ice conditions were also observed, although an overall general picture was proposed, with more severe sea ice conditions during the early-mid Younger Dryas and less sea ice observed during the late Younger Dryas. A shift in the climate towards ice-free conditions was recorded in northern Norway during the early Holocene (ca. 11.5 – 7.2 cal. kyr BP). Milder conditions were also observed during the Holocene in the western Barents Sea, with three main climate periods observed. During the early Holocene (ca. 11.7 – 9.5 cal. kyr BP), the position of the spring ice edge was close to the study area which resulted in high productivity during summers. During the mid-late Holocene (ca. 9.5 – 1.6 cal. kyr BP), sea ice was mainly absent due to an increased influence of Atlantic waters and northward movement of the Polar Front. During the last ca. 1.6 cal. kyr BP, sea ice conditions were similar to those of the present day. In addition to the outcomes obtained from the Norwegian-Barents Sea region, comparison of biomarker and other proxy data from 3 short cores from Kangerdlugssuaq Trough (Denmark Strait/SE Greenland) with historical climate observations allowed the development of a model of sea ice conditions which was then tested for longer time-scales. It is suggested that the IP25 in sediments from this region is likely derived from drift ice carried from the Arctic Ocean via the East Greenland Current and that two main sea surface scenarios have existed over the last ca. 150 yr. From ca. AD 1850 – 1910, near perennial sea ice conditions resulted in very low primary productivity, while from ca. AD 1910 – 1986, local sea ice conditions were less severe with increased drift ice and enhanced primary productivity. This two-component model was subsequently developed to accommodate different sea surface conditions that existed during the retreat of the Greenland Ice Sheet during the deglaciation (ca. 16.3 – 10.9 cal. kyr BP).

<p>Detta arbete handlar om den tekniska utbildningen i Försvarsmakten, närmare beskrivet hur en kursbeskrivning för systemmekaniker och tornmekaniker genomförs praktiskt och hur den skall genomföras teoretiskt. Uppsatsen kommer inte att behandla hela utbildningen. Den kommer bara behandladen minsta delen av utbildningen - den del som innefattar soldatutbildningen. Syftet med att skriva detta arbete är att komma fram till om den tekniska utbildningen genomförs på ett kvalitativt sätt och kontrollera om en mekaniker kan agera i subarktisk miljö efter sin genomförda utbildning. Denna uppsats är uppbyggd på följande sätt. Först genomförde jag en kvalitativ innehållsanalys för att få en grundstomme i arbetet. Detta följdes av kvalitativa intervjuer för att få veta hur utbildningen genomförs i praktiken. Avslutningsvis diskuterades de frågor jag ställde för att kunna avrunda arbetet ur mina egna synvinklar samt att göra subjektiva bedömningar. Slutsatserna som dragits i denna uppsats är att det finns brister i utbildningen och i kursplaner av tornsystemmekaniker. Bristerna i utbildningen som blev uppenbara är att utbildare inte alltid utbildar på det som skall utbildas som är i detta fall ”kallt väder” utbildning. Detta på grund av att utbildare ser denna del av utbildning som tidstjuv och hellre fokuserar på den tekniska utbildningen. De brister i kursbeskrivningen som kom fram under min rapport är att torn- och systemmekanikerutbildningarna inte är i synk med varandra. Det innebär att utbildningarna inte alltid strävar mot samma mål. Tornmekanikerna genomför enligt kursplan en ”kall väder”-utbildning men inte systemmekanikerna och på grund av detta kan det vara svårt för dessa att samarbeta efter sin genomförda utbildning.</p> / <p>This work is about the technical training of the Armed Forces. It is a closer description how a course description for system mechanics and turret mechanics are implemented in practice and how it should be done theoretically. The essay will not treat the full training, it will only deal with the smaller part of the training, the soldier training. The purpose of writing this work is to show how the technical training is conducted in a qualitative way and check whether a mechanic can operate in a subarctic environment after the training is completed. This paper will be structured as follows. First, I conduct a qualitative content analysis to provide a foundation, this will be followed by qualitative interviews to discover how training is conducted in practice. Finally, I will discuss the issues I have set out, from my own points of view. The conclusions which have been drawn from this paper are that there are gaps in training and in curricula of turret-system mechanics. The shortcomings of the education that became obvious are that educators do not always deliver, "cold weather". This is because the trainer views this part of the training as taking away time, and would rather focus on the technical training. The shortcomings in the course description that developed from my report are that the turret and system mechanic training are not in sync with each other, it means that courses are not always pursuing the same objectives. Turret mechanics implement curriculum as a "cold weather" training, but not the system mechanics and for this reason it may be difficult for them to cooperate after their education is complete.</p>

Detta arbete handlar om den tekniska utbildningen i Försvarsmakten, närmare beskrivet hur en kursbeskrivning för systemmekaniker och tornmekaniker genomförs praktiskt och hur den skall genomföras teoretiskt. Uppsatsen kommer inte att behandla hela utbildningen. Den kommer bara behandladen minsta delen av utbildningen - den del som innefattar soldatutbildningen. Syftet med att skriva detta arbete är att komma fram till om den tekniska utbildningen genomförs på ett kvalitativt sätt och kontrollera om en mekaniker kan agera i subarktisk miljö efter sin genomförda utbildning. Denna uppsats är uppbyggd på följande sätt. Först genomförde jag en kvalitativ innehållsanalys för att få en grundstomme i arbetet. Detta följdes av kvalitativa intervjuer för att få veta hur utbildningen genomförs i praktiken. Avslutningsvis diskuterades de frågor jag ställde för att kunna avrunda arbetet ur mina egna synvinklar samt att göra subjektiva bedömningar. Slutsatserna som dragits i denna uppsats är att det finns brister i utbildningen och i kursplaner av tornsystemmekaniker. Bristerna i utbildningen som blev uppenbara är att utbildare inte alltid utbildar på det som skall utbildas som är i detta fall ”kallt väder” utbildning. Detta på grund av att utbildare ser denna del av utbildning som tidstjuv och hellre fokuserar på den tekniska utbildningen. De brister i kursbeskrivningen som kom fram under min rapport är att torn- och systemmekanikerutbildningarna inte är i synk med varandra. Det innebär att utbildningarna inte alltid strävar mot samma mål. Tornmekanikerna genomför enligt kursplan en ”kall väder”-utbildning men inte systemmekanikerna och på grund av detta kan det vara svårt för dessa att samarbeta efter sin genomförda utbildning. / This work is about the technical training of the Armed Forces. It is a closer description how a course description for system mechanics and turret mechanics are implemented in practice and how it should be done theoretically. The essay will not treat the full training, it will only deal with the smaller part of the training, the soldier training. The purpose of writing this work is to show how the technical training is conducted in a qualitative way and check whether a mechanic can operate in a subarctic environment after the training is completed. This paper will be structured as follows. First, I conduct a qualitative content analysis to provide a foundation, this will be followed by qualitative interviews to discover how training is conducted in practice. Finally, I will discuss the issues I have set out, from my own points of view. The conclusions which have been drawn from this paper are that there are gaps in training and in curricula of turret-system mechanics. The shortcomings of the education that became obvious are that educators do not always deliver, "cold weather". This is because the trainer views this part of the training as taking away time, and would rather focus on the technical training. The shortcomings in the course description that developed from my report are that the turret and system mechanic training are not in sync with each other, it means that courses are not always pursuing the same objectives. Turret mechanics implement curriculum as a "cold weather" training, but not the system mechanics and for this reason it may be difficult for them to cooperate after their education is complete.

During the 1740’s, Hudson Bay went from an obscure backwater of the British Empire to a locus of colonial ambition. Arthur Dobbs revitalized Northwest Passage exploration, generating new information about the region’s environment and indigenous peoples. This study explores evolving English and British representations of Hudson Bay’s climate and landscape in travel and natural history writing, and probes British anxieties about foreign environments. I demonstrate how Dobbs’ ideology of improvement optimistically re-imagined the North, opening a new discursive space wherein the Subarctic could be favourably described and colonized. I examine how Hudson Bay explorers’ responses to difficulties in the Arctic and Subarctic were seen to embody, even amplify, central principles and features of eighteenth-century British culture and identity. Finally, I investigate how latitude served as a benchmark for civilization and savagery, subjugating the Lowland Cree and Inuit to British visions of settlement and improvement in their home territories.