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

No description available.

Encounters with turbulence generated by complex topography, convection, or mechanical forcing present a significant threat to military aircraft operations. Properly forecasting the initiation, duration, and intensity of such encounters is a tremendous challenge to forecasters often resulting in the over-forecasting of turbulence. Over-forecasting the presence or intensity of turbulence can result in unnecessary mission delays, cancellations, and re-routing. The lack of observations and the fact that turbulence is a microscale phenomenon which Numerical Weather Prediction (NWP) models currently can not resolve are what make forecasting turbulence so difficult. Progress has been made in the last several decades in both the observation of turbulence and the resolution of NWP models. A new turbulence forecast approach has been created based on recent developments in observing turbulence and using automated turbulence diagnostics. The development of an in-situ observation platform, using the Eddy Dissipation Rate (EDR), and the Graphical Turbulence Guidance (GTG) model are discussed. A turbulence forecast approach is derived that includes the synoptic patterns which create or allow the turbulent environment to exist, the use of current tools to observe turbulence, and the use of models to help form the turbulence forecast. A turbulence forecasting manual has been created to give the new forecaster improved guidance to effectively forecast turbulence.

The tracks of westward-propagating synoptic disturbances across the Intra-Americas Sea (IAS) and far-eastern Pacific, known as easterly waves or tropical depression (TD) waves, are an important feature of the region's climate. They are associated with heavy rainfall events, seed the majority of tropical cyclones, and contribute to the mean rainfall across the region. This study examines the ability of current climate models (CMIP5) to simulate TD-wave activity and associated environmental factors across the IAS and far-eastern Pacific as compared to reanalysis. Model projections for the future are then compared with the historical model experiment to investigate the southward shift in CMIP5 track density and the environmental factors that may contribute to it. While historical biases in TD-wave track-density patterns are well correlated with model biases in sea surface temperature and midlevel moisture, the projected southward shift of the TD track density by the end of the twenty-first century in CMIP5 models is best correlated with changes in deep wind shear and midlevel moisture. In addition, the genesis potential index is found to be a good indicator of both present and future regions of high TD-wave track density for the models in this region. This last result may be useful for understanding the more complex relationship between tropical cyclones and this index in models found in other studies.

The purpose of the project has been to investigate how synoptic scale climate systems control the frequency of air pollution episodes in the city of Christchurch, New Zealand. The work has been done at the University of Canterbury, New Zealand, and data from the region has been analysed. Air pollution is, during winter time, a growing problem in Christchurch and the project was initiated by the regional environmental legislative body. The first part of the report is on finding relationships on a local-scale between particulate matter concentrations, ground temperature, temperature at 10 meters and wind speed. The data set used in the analysis comes from a monitoring station in St. Albans, situated in the north-east of Christchurch. In the second part, a connection is made thought correlation calculations between the results from the local-scale analysis and the synoptic situation observed over New Zealand during the same period. Two different data sets have been used in the analysis. One data set includes different weather patterns observed over New Zealand and the other data set includes different zonal and meridional circulation indices. A pressure index is also used, the Southern Oscillation Index. On the local-scale, a relationship has been found between the particulate matter concentration and the number of night hours with an inversion present. A correlation also exists between the wind speed and the number of night hours with an inversion present. The connection to the synoptic scale through cluster frequencies and circulation indices was found to be divergent. The cluster frequency analysis indicates on a direct correlation between the Southern Oscillation Index and the air pollution concentration in Christchurch, while the circulation indices analysis indicates on an inverse relationship between the Southern Oscillation Index and the air pollution concentration in Christchurch. / Sammanfattning av ”Kopplingen mellan ENSO och aerosoler mindre än 10 μm i Christchurch” Avsikten med projektet har varit att undersöka om det finns ett samband mellan storskaliga vädersystem (synoptisk skala) och antalet lokalt inträffade händelser med höga halter av luftföroreningar. Arbetet har utförts vid University of Canterbury i Christchurch på Nya Zeeland och mätdata för denna region har analyserats. Luftföroreningar är här ett växande problem, speciellt vintertid, vilket de regionala lagstiftande myndigheterna har identifierat och önskat få utrett. I första delen av rapporten analyseras samband mellan lokala parametrar, så som temperatur vid marknivå och på 10 meters höjd, vindhastighet och koncentrationen av olika luftföroreningar. Data som använts i dessa analyser har uppmätts vid en mätstation placerad i St. Albans, vilken ligger i nordöstra delen av centrala Christchurch. I den andra delen av rapporten beräknas korrelationen mellan resultaten från den lokala analysen och olika synoptiska vädersituationer observerade över Nya Zeeland under motsvarande tidsperioder. Två databaser har använts vid analysen, dels en databas innehållande olika vädersituationer över Nya Zeeland och dels en innehållande olika cirkulationsindex. Dessutom användes också ett lufttrycksindex, ”The Southern Oscillation Index”. Två korrelationer har beräknats i den lokala analysdelen. Dels har ett samband mellan luftföroreningskoncentrationen och antalet timmar med en inversion närvarande nattetid beräknats samt en korrelation mellan vindhastighet och antalet timmar med en inversion närvarande nattetid. Kopplingen till den synoptiska skalan visar på två divergerande resultat. Analys genomförd med olika ”clusters” visar på ett direkt samband mellan ”The Southern Oscillaion Index” och luftföroreningskoncentrationen i Christchurch medan en analys genomförd för circulationsindex visar på ett omvänt samband mellan ”The Southern Oscillation Index” och luftföroreningskoncentrationen i Christchurch.

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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.

Thesis (M.A.)--Columbia International University, 2002. / Abstrakt. Includes bibliographical references (leaves 126-135).

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No description available.