The cryosphere has been shown to be particularly adept as a proxy for climate change by various studies. Accordingly, historical records from the field of ice phenology have been harvested by climate scientists for the express purpose of studying the temporal variation of ice phenomena, namely freeze-up and ice-out. Ice-out records from 20 lakes in Maine, U.S.A. were collected and clustered by z-score for this thesis. Rather than attempt to relate ice-out to spring air temperature or global teleconnections/oscillations, the Spatial Synoptic Classification (SSC) method was used to encapsulate several meteorological variables that could have a bearing on ice-out variation. The balance between occurrence of relatively cool Moist Polar (MP) and relatively warm Dry Moderate (DM) weather-types during the winter-spring "superseason" was found to be a synoptic barometer of whether ice-out would occur seasonably early or late. The significance of this is predicated upon the finding that quantity of DM days has steadily risen at the expense of MP days during the latter-half of the twentieth-century, in accordance with observed climatic warming during the same period. The remaining SSC weather-types, most notably omnipresent Dry Polar (DP), remained generally stable during the historical record in Maine, further undergirding the significance of the DM-MP relationship. / Master of Science

ABSTRACT The relationships between high ozone events and synoptic weather patterns were investigated based on the meteorological and air-quality data at four monitoring stations in Kaohsiung city during 1997 to 2004 in this study. The PCA (principal component analysis) and correlation studies show that ozone concentration exhibit positive correlations with the ambient temperature and sunshine duration, while negative correlation with the cloud cover. The frequency of high ozone events was highest under the weather patterns of northeast seasonal wind (B1 type), high-pressure system with recirculation (B3 type), high-pressure system with offshore type (B2 type), and in the warm core of approaching front (B4 type), most frequently in autumn, winter, and spring, and least frequently in summer. The above four weather patterns are primarily dominated by the high-pressure system from Mainland China, with relatively cold and dry weather and little rain in Taiwan. Since the high-pressure center is usually located north or northeast of Taiwan during autumn, winter, and spring such that the leeside areas of Central Mountain Ranges in the western coast of Taiwan are prone to high pollution events, particularly when the wind speed is low (< 4m/s) and duration of sunshine is long (> 5.5 hr). Or sometimes the meso-scale wind system, for example, the sea-land breeze or the combined flow caused by the detouring flow from the Henchun Peninsula and northeast wind tends to raise the pollutant concentrations. Keywords¡GHigh ozone event, Synoptic weather pattern, Principal component analysis.

Landslides present a geomorphological hazard in alpine regions, threatening life, infrastructure and property. Presented in this thesis is the development of a new Regional Landslide Inventory (RI) for the European Alps. The new inventory is used to investigate links between landslide size and frequency in the European Alps and weather and climatic controls. Temperatures in the European Alps have risen by 2 C since the end of the Little Ice Age (LIA); a trend which is set to continue. Previous research has shown that past landslide clusters are centred around periods of signi ficant climate change, thus understanding how this translates to the current warming trend is important both for communities living in the European Alps and for the insurance industry. The RI compiled here, provides a substantial temporal and spatial picture of landsliding in the Alps; with particular focus on the Swiss and French Alps. The temporal distribution and estimates of completeness were tested through the use of segmented models, scaling relationships and area-frequency distributions; the post-1970 portion of the database is considered most complete, although underestimating the frequency of medium-sized landslides. Analysis of the RI in the context of synoptic weather types demonstrates that high precipitation over the European Alps is consistent with higher landslide frequencies. Whilst analysis with climate data show that annual landslide frequencies are correlated with changes in precipitation and temperature across the European Alps; accounting for up to 35% of the seasonal variation in landslide frequency.

Bering Sea storms regularly bring adverse environmental conditions, including large waves and storm surges of up to 4 m, to the west coast of Alaska. These conditions can cause flooding, erosion and other damage that affects marine subsistence activities and infrastructure in the low-lying coastal communities. Storm impacts also include interactions with sea ice in various states: large floes, shore-fast ice, the acceleration of sea-ice formation in frazil or slush state, and the formation of slush-ice berms. Slush-ice berms are accumulations of slush ice that develop under the right wind, water level, water and air temperature, and snow conditions. During a strong wind event, large amounts of slush may be formed and pushed onto the shore, where the slush can accumulate, solidify and protect communities from flooding and erosion. Slush ice berms can also be problematic, restricting access to the coast and presenting other hazards. Residents of Shishmaref and Shaktoolik, communities on the west coast of Alaska, observed the formation of slush-ice berms during storms that occurred in 2007, 2009 and 2011. These formations are important to the communities, and it would be useful to develop the capacity to predict their occurrence. However, scientific work has not been conducted on this phenomenon, with the result that a physical conceptual model describing the formation of slush-ice berms does not exist. In recognition of this need, a project thesis was designed, and had as its main objective to identify and document the environmental and synoptic weather conditions that lead to these types of events, and to develop a descriptive physical conceptual model of slush-ice berm formation. A key to this work was the engagement of traditional knowledge holders and local observers to gather data and information about slush ice and slush-ice berm formation, along with the specific dates when these events took place. This dissertation is organized around three major elements: development of a conceptual model of slush-ice berm formation; presenting the traditional knowledge gathered that led to the development of this model; and documenting the methods and tools used to engage traditional knowledge holders and local observers in this process. In this dissertation, the knowledge from traditional knowledge holders on slush ice formation is presented in the context of feeding into a physical scientific process – specifically, developing a descriptive physical conceptual model of slush-ice berm formation. It is expected that this type of research will contribute to slush-ice berm forecasting which would aid communities’ safety by improving assessment of environmental risk. / Graduate

Previous studies, such as van der Veen (2012) and White et al. (2017), have demonstrated the potential of using measurement-based cloud data to improve Numerical Weather Prediction (NWP) based cloud forecasts. This can be done through cloud initialization; a process of injecting cloud data after the regular data assimilation in an NWP model. The purpose of this study was to use cloud data from the Mesoscale Analysis system MESAN to investigate cloud initialization in the HARMONIE-AROME model system for improving short-range cloud forecasts. The cloud initialization method that was used was similar to a method used by van der Veen (2012), where specific humidities, temperatures, and hydrometeor concentrations were altered using information on cloud fractions, cloud base heights and cloud top heights. MESAN input data analyses as well as cloud initialization investigations were carried out. MESAN input data analyses revealed significant differences in cloud fractions between MESAN and the background model field in MESAN. Overestimations of cloud fractions in MESAN over sea were caused by satellite data, particularly due to the inclusion of the fractional cloud category. Underestimations of cloud fractions over land were caused by limitations of the synoptic weather (SYNOP) stations in measuring clouds. Furthermore, larger differences between MESAN and SYNOP were found over Sweden and Finland compared to Norway, which may be tied to Norway having mostly manual SYNOP stations, and Sweden and Finland having mostly automatic stations. Shortcomings were found in the investigated cloud initialization method. Such shortcomings involved a limit check on the specific humidity change, the cloud initialization being repeated for an unnecessarily large amount of iterations, and the use of a sub-optimal profile of critical relative humidity. Using a one-dimensional vertical column version of HARMONIE-AROME, named MUSC, to integrate forward in time revealed a large sensitivity to the use of forcing profiles and forcing time scales in MUSC. Alterations made through cloud initialization were found to last over 12 h, with varying effects depending on the investigated height. A reasonably good agreement between MUSC results and results from the three-dimensional version of HARMONIE-AROME was found. Findings in this thesis point at potential to further enhance the HARMONIE-AROME cloud initialization technique. These enhancements concern a revised MESAN cloud product and taking care of some flaws in the cloud initialization method. / I en operationell vädermodell inkluderas olika mätdata, såsom temperatur och atmosfärstryck, i ett regelbundet intervall. Molnighet är inte vanligtvis en del av dessa cykler; istället bildas molnen av modellen utifrån balanser i de andra fysikaliska fälten. Detta projekt gick ut på att direkt införa molnmätningar från väderanalyssystemet MESAN i vädermodellsystemet HARMONIE-AROME genom en metod som kallas molninitialisering. Specifikt förbättringar för korttidsprognoser var av i ntresse. MESAN är ett system vars produkter är en sammanslagning av ett bakgrundsfält från en vädermodellkörning med olika mätdata. I MESAN kommer molndata från tre källor: bakgrundsfältet, satellitdata och synoptisk väderstationsdata (SYNOP-data). Undersökningar av indata till MESAN samt molninitialiseringsmetoden har utförts. Analyser av indata till MESAN visade på överskattningar av moln i satellitdata över hav och underskattningar av moln i SYNOP-data över land. För satellitdatat berodde detta på medtagande av moln på liten skala eller väldigt tunna moln, medan det för SYNOP berodde på begränsningar i mätmetoderna. Det fanns även en skillnad i kvalitet i SYNOP-data i Sverige och Finland gentemot Norge, vilket kan bero på att de flesta mätstationer i Norge är manuella medan de flesta i Sverige och Finland är automatiska. Molninitialiseringsmetoden bestod i att extrahera data om molnbashöjd och molntopphöjd från MESAN, och sedan modifiera fuktighet, temperatur och hydrometeorer (såsom molndroppar och iskristaller) i HARMONIE-AROME utifrån molnens position. Brister i metoden hittades. Initialiseringsprocessen upprepades ett suboptimalt antal gånger. En begränsning i hur mycket fuktigheten tillåts modifieras förändras under initialiseringsprocessen och fungerade inte som avsett. Dessutom, jämförese med radiosonddata pekar på att relativa fuktighetsgränserna för villket moln bildas inledningsvis inte ansattes korrekt. Effekterna av metoden kunde vara i över 12 timmar, men denna studie pekar på ytterligare troliga förbättringsmöjligheter i HARMONIE-AROME genom införande av reviderad version av metoden samt förbättrade satellitprodukter.

Ground-level ozone (O3) is a familiar pollutant because it is associated with summer haze and smog alerts. The 2000-2008 weekday-weekend variations of ozone concentration were examined in relation to the Toronto weather conditions. The goal of this work is twofold: (1) To determine whether extreme ozone events were associated with specific weather conditions, (2) To determine whether the weekday-weekend effect of extreme ozone events could be detectable during the nine-year study period. The results show that in the study period, there were totally 313 days having extreme ground-level ozone events with ozone concentration ≥ 80 ppb, which is the current Ontario Ambient Air Quality Criterion for ozone concentration, in the four selected Toronto sites. Additionally, the weather condition mainly associated with these 313 days was the Dry Tropical one. This study also shows the phenomenon of the weekday-weekend effect of extreme ozone events in the past nine years in Toronto.

Ground-level ozone (O3) is a familiar pollutant because it is associated with summer haze and smog alerts. The 2000-2008 weekday-weekend variations of ozone concentration were examined in relation to the Toronto weather conditions. The goal of this work is twofold: (1) To determine whether extreme ozone events were associated with specific weather conditions, (2) To determine whether the weekday-weekend effect of extreme ozone events could be detectable during the nine-year study period. The results show that in the study period, there were totally 313 days having extreme ground-level ozone events with ozone concentration ≥ 80 ppb, which is the current Ontario Ambient Air Quality Criterion for ozone concentration, in the four selected Toronto sites. Additionally, the weather condition mainly associated with these 313 days was the Dry Tropical one. This study also shows the phenomenon of the weekday-weekend effect of extreme ozone events in the past nine years in Toronto.

This dissertation investigates the impact of 2000-2050 climate change on fine particulate matter \((PM_{2.5})\) air quality. We first applied a multiple linear regression model to study the correlations of total \(PM_{2.5}\) and its components with meteorological variables using the past decadal \(PM_{2.5}\) observations over the contiguous US. We find that daily variation in meteorology can explain up to 50% of \(PM_{2.5}\) variability. Temperature is positively correlated with sulfate and organic carbon (OC) almost everywhere. The correlation of nitrate with temperature is negative in the Southeast but positive in California and the Great Plains. Relative humidity (RH) is positively correlated with sulfate and nitrate, but negatively with OC. Precipitation is strongly negatively correlated with all \(PM_{2.5}\) components. We then compared the observed correlations of \(PM_{2.5}\) with meteorological variables with results from the GEOS-Chem chemical transport model. The results indicate that most of the correlations of \(PM_{2.5}\) with temperature and RH do not arise from direct dependence but from covariation with synoptic transport. We applied principal component analysis and regression to identify the dominant meteorological modes controlling \(PM_{2.5}\) variability, and showed that 20-40% of the observed \(PM_{2.5}\) daily variability can be explained by a single dominant meteorological mode: cold frontal passages in the eastern US and maritime inflow in the West. From 1999-2010 observations we further showed that interannual variability of annual mean \(PM_{2.5}\) in most of the US is strongly correlated with the synoptic period T of the dominant meteorological mode as diagnosed from a spectral-autoregressive analysis. We then used the observed local \(PM_{2.5}\)-to-period sensitivity to project \(PM_{2.5}\) changes from the 2000-2050 changes in T simulated by fifteen IPCC AR4 GCMs following the SRES A1B scenario. We project a likely increase of \(\sim 0.1 \mu g m^{-3}\) in annual mean \(PM_{2.5}\) in the eastern US arising from less frequent frontal ventilation, and a likely decrease of \(\sim 0.3 \mu g m^{-3}\) in the northwestern US due to more frequent maritime inflows. These circulation-driven changes are relatively small, representing only a minor climate penalty or benefit for \(PM_{2.5}\) regulatory purpose. / Engineering and Applied Sciences

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this Dissertation were identified events of influence of the Antarctic ozone hole over the South of Brazil that occurred in the period between 1979 and 2011. For this, we analyzed the daily average data of total ozone column obtained through the Brewer Spectrophotometers MKIV #081 model during the period 1992-2000, MKII model #056 of 2000-2002 and MKIII #167 model from 2002 to the present day, installed in the Southern Space Observatory- OES/CRS/INPE MCTI (29,4 °S; 53,8°O; 488,7m) and by satellite instruments Total Ozone Mapping Spectrometer (TOMS) and Ozone Monitoring Instrument (OMI) to the same latitude of the southern Space Observatory in the absence of surface equipment data, searching for days of falls in ozone content. For these days, isentrópicas analyses were conducted of potential vorticity using Reanalysis data provided by the National Centers for Environmental PredictionAtmospheric Research (NCEPNCAR), in order to verify the origin of ozone-poor air mass. Confirmation of the origin of polar air masses took place through the analysis of the trajectories retroactive made through the Hysplit model of NOAA. In addition, it was also conducted a complementary analysis through the pictures of the ozone content of TOMS and OMI, the ozone hole in the Antarctic region and its connection to the South of Brazil. The methodology used was effective in the identification of 66 events of the Influence of Antarctic Ozone Hole over south of Brazil, which showed an average drop of 8.66 ± 3.13 in the ozone content. The identification of the stratospheric circulation pattern through the medium of the vorticity field potential for the occurrence of the phenomenon was performed. In addition, were shown an analysis of synoptic weather troposphere during the occurrence of two events, noting that in both cases, the events occurred in a situation front post on the South of Brazil, coupled with the passage of the input region polar polar or subtropical jet stream, characterized by the occurrence of the event of the tropopause folding where stratospheric air intrusion occurs in the troposphere, and advancement of a high-pressure front post system that prevents the formation of significant cloud cover. Leveraging the operating environment of the Atmospheric Modeling Group (GRUMA) at the Federal University of Santa Maria (UFSM), using data from the output of numerical weather forecasting model Global Forecast System (GFS) in making maps of potential vorticity, can carry out effectively the clue of the forecast arrival of stratospheric air masses of polar origin on the southern Brazil during the spring of the year of 2012 with at least four days in advance, coinciding with the events of transport these side effects of the Antarctic ozone hole over the South of Brazil identified in the current year. / Na presente Dissertação foram identificados os eventos de Efeito Secundário do Buraco de Ozônio Antártico ocorridos sobre o Sul do Brasil no período entre 1979 e 2011. Para isso, foram analisados os dados médios diários da coluna total de ozônio obtidos através dos Espectrofotômetros Brewer modelo MKIV #081 durante o período de 1992 2000, modelo MKII #056 de 2000 2002 e modelo MKIII #167 de 2002 até os dias atuais, instalados no Observatório Espacial do Sul OES/CRS/INPE MCTI (29,4 °S; 53,8°O; 488,7m) e pelos instrumentos de satélite Total Ozone Mapping Spectrometer (TOMS) e Ozone Monitoring Instrument (OMI) para a mesma latitude do Observatório Espacial do Sul na falta de dados do equipamento de superfície, buscando dias de quedas no conteúdo de ozônio. Para estes dias, foram realizadas análises isentrópicas de vorticidade potencial utilizando dados de reanálise fornecidos pelo National Centers for Environmental Prediction/Atmospheric Research (NCEP/NCAR), a fim de verificar a origem da massa de ar pobre em ozônio. A confirmação da origem polar das massas de ar deu-se através da análise das trajetórias retroativas confeccionadas através do modelo Hysplit da NOAA. Além disso, foi também realizada uma análise complementar através das imagens do conteúdo de ozônio dos satélites TOMS e OMI, verificando-se a atuação do Buraco de Ozônio na região Antártica e sua conexão com o Sul do Brasil. A metodologia empregada mostrou-se eficaz na identificação de 66 eventos de Efeito Secundário do Buraco de Ozônio Antártico sobre o Sul do Brasil, os quais apresentaram uma queda média de 8,66 ± 3,13 % no conteúdo de ozônio. Foi realizada a identificação do padrão de circulação estratosférica através da confecção do campo médio da vorticidade potencial para os dias de ocorrência do fenômeno. Além disso, foram mostradas as analises das condições sinótica troposférica durante a ocorrência de dois eventos, observando-se que em ambos os casos, os eventos ocorreram em uma situação pós frontal sobre o Sul do Brasil, associada à passagem da região de entrada polar da corrente de jato subtropical ou polar, caracterizada pela ocorrência de evento de quebra da tropopausa onde ocorre intrusão de ar estratosférico para dentro da troposfera, e avanço de um sistema de alta pressão pós frontal que impede a formação de nebulosidade significativa. Aproveitando o ambiente operacional do Grupo de Modelagem Atmosférica (GRUMA) da Universidade Federal de Santa Maria (UFSM), utilizando dados da saída do modelo de previsão numérica de tempo Global Forecast System (GFS) na confecção de mapas de vorticidade potencial, pode-se realizar eficazmente a previsão do indício da chegada de massas de ar estratosféricas de origem polar sobre o Sul do Brasil durante o período da primavera do ano de 2012, com pelo menos quatro dias de antecedência, coincidindo estes transportes com os eventos de Efeito Secundário do Buraco de Ozônio Antártico sobre o Sul do Brasil identificados no corrente ano.