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1
Caruso, Steven J. "Synoptic climatology of subtropical cyclogenesis." Thesis, University of Hawaii at Manoa, 2003. http://hdl.handle.net/10125/7024.
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During the Hawaiian cool season (October - April), upper-level lows sometimes become cut off from the polar westerlies south of 30°N latitude in central Pacific. Seventy such lows formed during the years 1980-2002. There is strong inter-annual variability in their frequency, with an average of ~3 lows per season. The number of lows decreased during the 3 strongest EI Nino seasons and increased during the 3 strongest La Nina seasons, with statistically significant excursions. Low formation is greatest during October and November, when storm genesis is concentrated to the west-northwest of the Hawaiian Islands. Low genesis shifts eastward through the cool season, favoring the area to the east-northeast of Hawaii during February and March, consistent with the shift in the climatological position of trough aloft during the cool season. Out of a total of 70 upper-level lows, 43 were accompanied by surface cyclogenesis and were classified as kona lows. Kona-Iow formation is concentrated to the west-northwest of Hawaii, whereas lows without surface development are concentrated in the area to the east-northeast of Hawaii. Analysis reveals several distinctions between the kona lows and the lows without surface development. Surface deepening correlates strongly with positive vorticity advection by the thermal wind. Surface deepening also correlates with potential vorticity on the 340-K isentropic surface and the maximum v-component of the wind aloft. Static stability and advection of low level moisture are less strongly correlated to surface deepening. These results confirm that kona-Iow formation, to first order, is driven be upper-level forcing that originates in the midlatitudes, and that convection and latent heat release playa secondary role.vii 49 leaves
2
Laternser, Martin Christian. "Snow and avalanche climatology of Switzerland /." [S.l.] : [s.n.], 2002. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=14493.
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Fischer, Alexandre P. "A synoptic climatology of Montreal precipitation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0022/MQ50767.pdf.
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Rigby, Matthew. "Air Pollution Climatology Using Meteorogical Reanalysis." Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498958.
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5
Turek, Allon G. "Smart climatology applications for undersea warfare." Thesis, Monterey, Calif. : Naval Postgraduate School, 2008. http://edocs.nps.edu/npspubs/scholarly/theses/2008/Sept/08Sep%5FTurek.pdf.
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Thesis (M.S. in Meteorology and Physical Oceanography)--Naval Postgraduate School, September 2008.Thesis Advisor(s): Murphree, Tom. "September 2008." Description based on title screen as viewed on November 5, 2008. Includes bibliographical references (p. 91-93). Also available in print.
6
Shahgedanova, Maria. "Climatology of air pollution in Moscow." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320808.
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Appelhans, Tim. "A climatology of particulate pollution in Christchurch." Thesis, University of Canterbury. Geography, 2010. http://hdl.handle.net/10092/4014.
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The research presented in this thesis provides a quantitative analysis of atmospheric influences on particulate matter pollution in Christchurch across a wide range of spatial and temporal scales. A complex interaction of low level flow characteristics that form in response to local and regional features of complex terrain, together with an urban setting that is characterised by low density housing, mostly comprised of single storey dwellings that are poorly insulated, regularly leads to nocturnal smog events during winter in Christchurch. Provided synoptic flow is weak, the above mentioned flow interaction promotes flow stagnation over the city, when nocturnal katabatic drainage flows and day-time north-easterly on-shore winds converge over the city. Additionally, undercutting of the density currents promotes highly stable atmospheric stratification close to the surface, so that, in combination, both horizontal and vertical air movement is suppressed. As particulate emission release from solid fuel burning for home heating coincides with this poor atmospheric dispersion potential, particle concentrations can increase substantially so that national air quality guidelines are regularly exceeded during winter in Christchurch.
At the core of this thesis is a classification based approach that examines the day-to-day probabilities of breaches of the national air quality guideline for PM over the last decade at a single location in Christchurch as a result of variations in meteorological conditions alone. It is shown that, based on variations in temperature and wind speed, up to 85% of exceedence occurrence can be explained. From this, concentration trends over time, when meteorological variability is kept to a minimum, are assessed and evidence is found that recent regulatory measures to enhance air quality are beginning to show positive effects. Atmospheric processes that control pollution dispersion on the mesoscale are investigated through means of atmospheric numerical modelling in a novel approach that assimilates observational climatic wind field averages to drive low level flow for two idealised case studies. It is shown that this approach is able to reproduce the observed diurnal concentration patterns very well and that much of these patterns can be attributed to mesoscale circulation characteristics and associated atmospheric dispersion potential, namely flow stagnation and recirculation of contaminants. When timing of stagnation and subsequent recirculation is such that it occurs within a few hours after peak emission release, concentration increase is enhanced and dilution is delayed, thus severely exacerbating the problem. Links between exceedence probabilities and synoptic situations that favour the degradation of air quality are established and various synoptic transition scenarios are examined with regard to local air quality. The progression of anticyclones across the country is identified to be the dominant synoptic control mechanism and it is shown that latitudinal variation in the progression path determines the extent of expected exceedence probability. On interdecadal hemispheric scales, it is found that a particular combination of local and synoptic atmospheric conditions that favours air quality degradation, shows a re-occurring pattern of frequency maxima (and minima) with a periodicity of approximately 14 - 16 years. For the synoptic part of this interdecadal variability, a close relationship to Southern Hemispheric pressure anomalies in high latitudes is revealed. Finally, for verification of the combined findings and to assess their prediction capability, a validation case study is given which shows that the applied methodology is able to capture day-to-day variations in pollution levels with acceptable (statistically significant) accuracy.
8
Plante, Mathieu. "Extratropical cyclone climatology for eastern Canadian cities." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121563.
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In this study, a Lagrangian tracking algorithm is applied to the 850-hPa relative vorticity field to characterize extratropical cyclone tracks across eastern Canada. Seasonal cycles are examined in terms of overall cyclone frequency, intensity, regions of development and decay. We found that cyclones tend to develop over the Rockies, the Great Lakes or the Western Atlantic. They are most intense over Newfoundland and North Atlantic, and decay over Greenland. Cyclones tracking across Toronto, Montreal, Halifax and St-John's are further analyzed, with typical cyclone tracks, origin, frequency, mean local growth rate, and mean intensity. Among others, we found that cyclone activities at east coast cities (Halifax, St-John's) are dominated by Atlantic cyclones, more frequent in winter, while Montreal's and Toronto's cyclones travel primarily from the Great Lakes, frequent and intense in spring and autumn. Cyclones from the Gulf of Mexico are not frequent, but extreme. The relationship between winter cyclone tracks and modes of atmospheric variability are also examined with an emphasis on the El Niño - Southern Oscillation (ENSO), North Atlantic Oscillation (NAO) and Pacific North American pattern (PNA). An ENSO and PNA-related oscillation between continental and coastal cyclones is confirmed. The inter-annual variability of winter cyclones cross eastern Canadian cities are quantified. Cyclone activities in Toronto and Montreal shown to be modulated by ENSO and PNA, while NAO dominates the cyclone variability in Halifax and St-John's. The local cyclone variability is found to be small in terms of overall cyclone statistics, but important in terms of changes in the origins of the local cyclones.Un algorithme est appliqué sur le tourbillon relatif à 850-hPa afin de calculer la trajectoire des cyclones affectant l'Est du Canada. Les variations saisonnières de ces trajectoires sont approfondies par l'étude de plusieurs paramètres, tels que la fréquence, l'intensité, l'origine, le taux de développement et le taux de dissipation des cyclones. L'étude démontre que les cyclones se développent principalement au dessus des Rocheuse, des Grands Lacs et de la côte Est des États-Unis, et se dissipent près des côtes Est et Ouest du Groendland. Les plus intenses se trouvent à Terre Neuve et au Nord de l'Atlantique. Ces statistiques de cyclones sont ensuite évaluées plus spécifiquement pour les cyclones atteignant Toronto, Montréal, Halifax et St-John's. Entre autre, il est démontré que les villes côtières sont pricipalement affectées par les cyclones en provenance de la côte Est Américaine, fréquents en hiver, tandis que Toronto et Montréal sont principalement affectés par les cyclones en provenance des Grands Lacs, plutôt fréquents au printemps et à l'automne. Les cyclones en provenance du Golf du Mexique sont moins fréquents, mais constituent une grande partie des extrêmes. La variation inter-annuelle de l'activité cyclonique est ensuite évaluée selon différents régimes de variabilité climatiques, tels qu'ENSO (El Nino-Southern Oscillation), le NAO (North Atlantic Oscillation) et le PNA (Pacific-North America). Les résultats consolident la présence d'une oscillation entre cyclones continentaux et cyclones côtiers pendant ENSO. L'étude démontre que la variabilité cyclonique inter-annuelle à Toronto et Montréal est dominée par ENSO et le PNA, tandis que le NAO a un plus grand impact à Halifax et à St-John's.
9
Herron, Joshua P. "Mesospheric Temperature Climatology Above Utah State University." DigitalCommons@USU, 2004. https://digitalcommons.usu.edu/etd/6877.
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A Rayleigh-scatter lidar has been in operation at Utah State University (41. 7° N, 111.8 ° W) starting in September 1993 until the present (October 2003). The return profiles from the atmosphere have been analyzed to provide temperature measurements of the middle atmosphere from 45 to 90 km. Various methods of averaging were used to construct a temperature climatology of the region based on these observations. The data analysis algorithm has been critically analyzed to find possible sources of error, and has been compared to an independently derived technique. The resulting temperatures have been compared to other mid-latitude lidars with good agreement. Comparisons were made with temperatures from other ground-based instruments at Bear Lake Observatory. Additional comparisons were carried out with two satellite-based instruments, WINDII and SABER The comparison of individual nights with the SABER instrument produced surprisingly good agreement considering the difference in the two methods. With the basic analysis of the temperature climatology completed in this work, an outline is given for future research and upgrades to the facility.
10
Dacre, Helen Frances. "Climatology and development mechanisims of frontal waves." Thesis, University of Reading, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417338.
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11
Lawrence, Bryan N. "The Southern Hemisphere middle atmosphere: climatology and waves." Thesis, University of Canterbury. Physics, 1990. http://hdl.handle.net/10092/7978.
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Data from a number of sources are used to examine the climatology of the southern hemisphere middle atmosphere. The stratospheric data used are winds and higher order quantities derived from stratospheric analyses provided by the U.S. National Meterological Center and the British Meteorological Office. Mesospheric winds are used from a number of years of continuous partial reflection radar observations at four southern hemisphere sites.
A comparison of the stratospheric analyses is used to highlight the regions of inadequacy in the data, and to assess its reliability.
A three year zonal mean climatology of the stratosphere is provided, and compared on an individual monthly basis with a time mean mesospheric climatology. This comparison highlights the importance of interannual variability in both the stratosphere and mesosphere, and emphasizes the mesospheric dependance on the stratospheric state below.
Wave motions are traced propagating through the stratosphere and tentatively identified in the mesospheric winds. One particular wave, the four day wave is examined in detail, and shown to exist on occasion in both the stratosphere and mesosphere.
Some suggestions for further work are presented, with respect to both data comparisons and stratosphere-mesosphere interactions.
12
Trigo, Isabel Franco. "A climatology of cyclones in the Mediterranean region." Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327284.
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13
Betts, Nicholas Leonard. "A synoptic climatology of precipitation in Northern Ireland." Thesis, Queen's University Belfast, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335059.
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14
Rheinwalt, Aljoscha. "Spatial analyses of precipitation climatology using Climate Networks." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17449.
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Im folgenden wird ein Verfahren dargestellt welches die Möglichkeit bietet komplexe räumliche Zusammenhänge zwischen Niederschlagsereignissen quantitativ in Klimanetzwerke zu fassen und diese auf vielfältige Arten und Weisen zu analysieren. In dem Maße wie synchronisiert Niederschlagsereignisse zwischen Raumpunkten auftreten, in dem Maße sind diese Raumpunkte in Event Synchronization Klimanetzwerken verbunden. Zum einen wird das bestehende Ähnlichkeitsmaß der Ereignissynchronisation verbessert und erweitert, und zum anderen werden verschiedene, zum Teil neue, statistische Methoden zur Netzwerkanalyse vorgestellt und erläutert. Klimanetzwerke sind räumlich eingebettete Netzwerke und die statistisch zu zeigende Abhängigkeit der Ähnlichkeit vom räumlichen Abstand führt zu einer vom Raum nicht unabängigen Netzwerkstruktur. Dies ist in einer Vielzahl von Fällen ein ungewünschter Effekt und es wird eine Methodik entwickelt wie dieser statistisch quantifiziert werden kann. Des weiteren werden zwei weitere neue Netzwerkstatistiken vorgestellt. Einerseits das neue Netzwerkmaß Directionality und andererseits eine Netzwerkreduktion welche Klimanetzwerke auf Klimanetzwerke mit weitreichenden Verbindungen reduziert. Dieser neue Ansatz steht gewissermaßen im Gegensatz zur klassischen Klimanetzwerkkonstruktion die vor allem zu kurzreichweitigen Verbindungen führt. Das neue Netzwerkmaß Directionality gibt für jeden Raumpunkt des Netzwerks eine dominante Raumrichtung der Netzwerkverbindungen an und kann dadurch z.B. für bestimmte Event Synchronization Klimanetzwerke Isochronen abbilden.In the following an approach to the analysis of spatial structures of precipitation event synchronizations is presented. By estimating the synchronicity of precipitation events between points in space, a spatial similarity network is constructed. These Climate Networks can be analyzed statistically in various ways. However, the similarity measure Event Synchronization that will be presented, as well as the concept of Climate Networks, is more general. Climate Network precipitation analyses are done in the applications part in order to present improvements to existing methodologies, as well as novel ones. On one hand, the existing similarity measure Event Synchronization will be refined and extended to a weighted and continuous version, and on the other hand, new methods for statistical analyses of Climate Networks will be presented. Climate Networks are spatially embedded networks and the probability of a link between two nodes decreases with the distance between these nodes. In other words, Climate Network topologies depend on the spatial embedding. Often this effect is distracting and should be considered as a bias in Climate Network statistics. This thesis provides a methodology to estimate this bias and to correct network measures for it. Furthermore, two novel graph statistics are introduced. First, the novel network measure Directionality, and second, a network coarse-graining approach that reduces Climate Networks to Climate Networks of teleconnections, i.e., long-ranged interrelations. This new approach is in contrast to existing Climate Network construction schemes, since commonly most links are short. The novel network measure Directionality provides a dominant direction of links in the embedding space. For undirected Event Synchronization networks this measure is applied for the estimation of Isochrones, i.e., lines of synchronous event occurrences.
15
Hawksworth, Kevin. "The synoptic climatology of daily precipitation in Wales." Thesis, University of Wales Trinity Saint David, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.683158.
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16
Cossuth, Joshua Howard. "Climatology of Dvorak classifications for operational probabilistic genesis forecasts." Tallahassee, Fla. : Florida State University, 2010. http://purl.fcla.edu/fsu/lib/digcoll/undergraduate/honors-theses/2181932.
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Henderson, Gina R. "European snowcover extent variability a climatology from 1967--2002 /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 3.81 Mb., 114 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1435922.
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Kozak, Steven Alexander. "Lightning strikes in Alberta thunderstorms, climatology and case studies." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0006/MQ34385.pdf.
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Catto, Jennifer. "Extratropical cyclones in HiGEM : Climatology, structure and future predictions." Thesis, University of Reading, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529970.
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20
Linder, Christopher Anthony. "A climatology of the Middle Atlantic Bight shelfbreak front." Thesis, Monterey, California. Naval Postgraduate School, 1996. http://hdl.handle.net/10945/8093.
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Description of the shelfbreak front in the Middle Atlantic Bight is hampered by the extreme variability of the front. In order to gain more insight into the mean frontal structure and associated baroclinic jet, historical data is used to produce two dimensional climatological fields of temperature and salinity for the region south of Nantucket shoals. Associated cross-shelf fields of density, geostrophic velocity, relative vorticity, and shallow water potential vorticity have also been computed. Historical data from a quality- controlled database (HydroBase) in the region 69-72 deg W, 39.5-41 deg N is included. Cross-shelf sections are obtained by averaging the data in nine depth bins with an average cross-shelf spacing of 10 km but an increased resolution of 4 km near the shelfbreak. The vertical averaging interval was 10 m over the shelf and upper slope waters, increasing to 50 m in the deep slope waters. The data were averaged in bimonthly periods to study seasonal trends. For inter- regional comparison, similar analyses were performed for the south flank of Georges Bank and the shelf off New Jersey. The climatological temperature and salinity are consistent with previous descriptions of the frontal hydrography. Most importantly, features such as the cold pool, the upper slope pycnostad, and the frontal boundary are well resolved when compared with synoptic sections. The temperature contrast across the front varies seasonally between 2-6 deg C near the surface and at depths of 45-65 m. The salinity contrast is 1.5-2 PSS, with little seasonal variation. The resulting cross-frontal near surface density gradients are strongest during the winter and weakest during the summer, when the seasonal thermocline is established
21
Round, Robert D. "Climatology and analysis of the Monterey Bay sea breeze." Thesis, Monterey, California. Naval Postgraduate School, 1993. http://hdl.handle.net/10945/39991.
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Sea breeze events on the Monterey Bay are examined from a single station at the mouth of the Salinas Valley. Data analyzed are continuous, two- minute meteorological samples of windspeed, wind direction, temperature, dew point, incoming shortwave irradiance, and incoming longwave irradiance. A speed index is defined using the average hourly maximum and minimum windspeeds oriented in the cross-shore direction thereby reflecting the thermally induced diurnal windspeed enhancement. Large-scale effects on this mesoscale circulation are presented through evaluation of changes in boundary layer depth with changes in speed index. Changes in boundary layer depth as reflected in trends of inland stratus penetration and offshore flow provide insight for anticipating sea breeze intensity.
22
Linder, Christopher A. (Christopher Anthony) 1972. "A climatology of the Middle Atlantic Bight shelfbreak front." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/41009.
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Hinneburg, Detlef. "The calculation of a wind climatology of the Erzgebirge." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-212336.
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Ausgangspunkt für die Berechnung klimatologisch gemittelter Windgeschwindigkeiten ist die mesoskalige Simulation atmosphärischer Strömungsereignisse, die von der geostrophischen Windgeschwindigkeit gesteuert werden. Der geostrophische Wind wird in 8 Richtungssektoren und Betragsklassen zu je 5m/s eingeteilt, so daß für jeden Sektor bis zu 7 Simulationen auszuführen waren. Die Simulationen wurden mit dem nicht-hydrostatischen Modell GESIMA für eine adiabatisch geschichtete Atmosphäre durchgeführt. Die statistische Mittelung der berechneten Werte erfolgte mit Hilfe einer 10-jährigen Häufigkeitsverteilung des 850hPa-Windes der Radiosondenmessungen von Prag. Ein Vergleich mit den Beobachtungswerten einiger Bodenstationen ergibt Abweichungen bis zu lm/s über höheren BergenStarting from the classification of the geostrophic wind into 8 sectors each of them splitted up into 7 classes by 5m/s, simulations with the non-hydrostatic mesoscale atmospheric model GESIMA were performed assuming adiabatic stratification of the atmosphere for each class. The climatologically averaged wind velocities are obtained by the folding with a ten-years frequency distribution of the geostrophic wind measured by the radio sonde station of Prague. Wind velocities observed at some surface stations indicate, that the simulated values can deviate from them by up to lm/s on high mountains
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Hinneburg, Detlef. "The calculation of a wind climatology of the Erzgebirge." Universität Leipzig, 1995. https://ul.qucosa.de/id/qucosa%3A15017.
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Ausgangspunkt für die Berechnung klimatologisch gemittelter Windgeschwindigkeiten ist die mesoskalige Simulation atmosphärischer Strömungsereignisse, die von der geostrophischen Windgeschwindigkeit gesteuert werden. Der geostrophische Wind wird in 8 Richtungssektoren und Betragsklassen zu je 5m/s eingeteilt, so daß für jeden Sektor bis zu 7 Simulationen auszuführen waren. Die Simulationen wurden mit dem nicht-hydrostatischen Modell GESIMA für eine adiabatisch geschichtete Atmosphäre durchgeführt. Die statistische
Mittelung der berechneten Werte erfolgte mit Hilfe einer 10-jährigen Häufigkeitsverteilung des 850hPa-Windes der Radiosondenmessungen von Prag. Ein Vergleich mit den Beobachtungswerten einiger Bodenstationen ergibt Abweichungen bis zu lm/s über höheren Bergen.Starting from the classification of the geostrophic wind into 8 sectors each of them splitted up into 7 classes by 5m/s, simulations with the non-hydrostatic mesoscale atmospheric model GESIMA were performed assuming adiabatic stratification of the atmosphere for each class. The climatologically averaged wind velocities are obtained by the folding with a ten-years frequency distribution of the geostrophic wind measured by the radio sonde station of Prague. Wind velocities observed at some surface stations indicate, that the simulated values can deviate from them by up to lm/s on high mountains.
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Edwards, Jennifer L. "Post-Disaster Climatology for Hurricanes and Tornadoes in the United States: 2000-2009." Kent State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=kent1366415657.
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Rust, Henning. "Detection of long-range dependence : applications in climatology and hydrology." Phd thesis, Universität Potsdam, 2007. http://opus.kobv.de/ubp/volltexte/2007/1334/.
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It is desirable to reduce the potential threats that result from the
variability of nature, such as droughts or heat waves that lead to
food shortage, or the other extreme, floods that lead to severe
damage. To prevent such catastrophic events, it is necessary to
understand, and to be capable of characterising, nature's variability.
Typically one aims to describe the underlying dynamics of geophysical
records with differential equations. There are, however, situations
where this does not support the objectives, or is not feasible, e.g.,
when little is known about the system, or it is too complex for the
model parameters to be identified. In such situations it is beneficial
to regard certain influences as random, and describe them with
stochastic processes. In this thesis I focus on such a description
with linear stochastic processes of the FARIMA type and concentrate on
the detection of long-range dependence. Long-range dependent processes
show an algebraic (i.e. slow) decay of the autocorrelation
function. Detection of the latter is important with respect to,
e.g. trend tests and uncertainty analysis.
Aiming to provide a reliable and powerful strategy for the detection
of long-range dependence, I suggest a way of addressing the problem
which is somewhat different from standard approaches. Commonly used
methods are based either on investigating the asymptotic behaviour
(e.g., log-periodogram regression), or on finding a suitable
potentially long-range dependent model (e.g., FARIMA[p,d,q]) and test
the fractional difference parameter d for compatibility with
zero. Here, I suggest to rephrase the problem as a model selection
task, i.e.comparing the most suitable long-range dependent and the
most suitable short-range dependent model. Approaching the task this
way requires a) a suitable class of long-range and short-range
dependent models along with suitable means for parameter estimation
and b) a reliable model selection strategy, capable of discriminating
also non-nested models. With the flexible FARIMA model class together
with the Whittle estimator the first requirement is
fulfilled. Standard model selection strategies, e.g., the
likelihood-ratio test, is for a comparison of non-nested models
frequently not powerful enough. Thus, I suggest to extend this
strategy with a simulation based model selection approach suitable for
such a direct comparison. The approach follows the procedure of
a statistical test, with the likelihood-ratio as the test
statistic. Its distribution is obtained via simulations using the two
models under consideration. For two simple models and different
parameter values, I investigate the reliability of p-value and power
estimates obtained from the simulated distributions. The result turned
out to be dependent on the model parameters. However, in many cases
the estimates allow an adequate model selection to be established.
An important feature of this approach is that it immediately reveals
the ability or inability to discriminate between the two models under
consideration.
Two applications, a trend detection problem in temperature records and
an uncertainty analysis for flood return level estimation, accentuate the
importance of having reliable methods at hand for the detection of
long-range dependence. In the case of trend detection, falsely
concluding long-range dependence implies an underestimation of a trend
and possibly leads to a delay of measures needed to take in order to
counteract the trend. Ignoring long-range dependence, although
present, leads to an underestimation of confidence intervals and thus
to an unjustified belief in safety, as it is the case for the
return level uncertainty analysis. A reliable detection of long-range
dependence is thus highly relevant in practical applications.
Examples related to extreme value analysis are not limited to
hydrological applications. The increased uncertainty of return level
estimates is a potentially problem for all records from autocorrelated
processes, an interesting examples in this respect is the assessment
of the maximum strength of wind gusts, which is important for
designing wind turbines. The detection of long-range dependence is
also a relevant problem in the exploration of financial market
volatility. With rephrasing the detection problem as a model
selection task and suggesting refined methods for model comparison,
this thesis contributes to the discussion on and development of
methods for the detection of long-range dependence.Die potentiellen Gefahren und Auswirkungen der natürlicher Klimavariabilitäten zu reduzieren ist ein wünschenswertes Ziel. Solche Gefahren sind etwa Dürren und Hitzewellen, die zu Wasserknappheit führen oder, das andere Extrem, Überflutungen, die einen erheblichen Schaden an der Infrastruktur nach sich ziehen können. Um solche katastrophalen Ereignisse zu vermeiden, ist es notwendig die Dynamik der Natur zu verstehen und beschreiben zu können. Typischerweise wird versucht die Dynamik geophysikalischer Datenreihen mit Differentialgleichungssystemen zu beschreiben. Es gibt allerdings Situationen in denen dieses Vorgehen nicht zielführend oder technisch nicht möglich ist. Dieses sind Situationen in denen wenig Wissen über das System vorliegt oder es zu komplex ist um die Modellparameter zu identifizieren. Hier ist es sinnvoll einige Einflüsse als zufällig zu betrachten und mit Hilfe stochastischer Prozesse zu modellieren. In dieser Arbeit wird eine solche Beschreibung mit linearen stochastischen Prozessen der FARIMA-Klasse angestrebt. Besonderer Fokus liegt auf der Detektion von langreichweitigen Korrelationen. Langreichweitig korrelierte Prozesse sind solche mit einer algebraisch, d.h. langsam, abfallenden Autokorrelationsfunktion. Eine verläßliche Erkennung dieser Prozesse ist relevant für Trenddetektion und Unsicherheitsanalysen. Um eine verläßliche Strategie für die Detektion langreichweitig korrelierter Prozesse zur Verfügung zu stellen, wird in der Arbeit ein anderer als der Standardweg vorgeschlagen. Gewöhnlich werden Methoden eingesetzt, die das asymptotische Verhalten untersuchen, z.B. Regression im Periodogramm. Oder aber es wird versucht ein passendes potentiell langreichweitig korreliertes Modell zu finden, z.B. aus der FARIMA Klasse, und den geschätzten fraktionalen Differenzierungsparameter d auf Verträglichkeit mit dem trivialen Wert Null zu testen. In der Arbeit wird vorgeschlagen das Problem der Detektion langreichweitiger Korrelationen als Modellselektionsproblem umzuformulieren, d.h. das beste kurzreichweitig und das beste langreichweitig korrelierte Modell zu vergleichen. Diese Herangehensweise erfordert a) eine geeignete Klasse von lang- und kurzreichweitig korrelierten Prozessen und b) eine verläßliche Modellselektionsstrategie, auch für nichtgenestete Modelle. Mit der flexiblen FARIMA-Klasse und dem Whittleschen Ansatz zur Parameterschätzung ist die erste Voraussetzung erfüllt. Hingegen sind standard Ansätze zur Modellselektion, wie z.B. der Likelihood-Ratio-Test, für nichtgenestete Modelle oft nicht trennscharf genug. Es wird daher vorgeschlagen diese Strategie mit einem simulationsbasierten Ansatz zu ergänzen, der insbesondere für die direkte Diskriminierung nichtgenesteter Modelle geeignet ist. Der Ansatz folgt einem statistischen Test mit dem Quotienten der Likelihood als Teststatistik. Ihre Verteilung wird über Simulationen mit den beiden zu unterscheidenden Modellen ermittelt. Für zwei einfache Modelle und verschiedene Parameterwerte wird die Verläßlichkeit der Schätzungen für p-Wert und Power untersucht. Das Ergebnis hängt von den Modellparametern ab. Es konnte jedoch in vielen Fällen eine adäquate Modellselektion etabliert werden. Ein wichtige Eigenschaft dieser Strategie ist, dass unmittelbar offengelegt wird, wie gut sich die betrachteten Modelle unterscheiden lassen. Zwei Anwendungen, die Trenddetektion in Temperaturzeitreihen und die Unsicherheitsanalyse für Bemessungshochwasser, betonen den Bedarf an verläßlichen Methoden für die Detektion langreichweitiger Korrelationen. Im Falle der Trenddetektion führt ein fälschlicherweise gezogener Schluß auf langreichweitige Korrelationen zu einer Unterschätzung eines Trends, was wiederum zu einer möglicherweise verzögerten Einleitung von Maßnahmen führt, die diesem entgegenwirken sollen. Im Fall von Abflußzeitreihen führt die Nichtbeachtung von vorliegenden langreichweitigen Korrelationen zu einer Unterschätzung der Unsicherheit von Bemessungsgrößen. Eine verläßliche Detektion von langreichweitig Korrelierten Prozesse ist somit von hoher Bedeutung in der praktischen Zeitreihenanalyse. Beispiele mit Bezug zu extremem Ereignissen beschränken sich nicht nur auf die Hochwasseranalyse. Eine erhöhte Unsicherheit in der Bestimmung von extremen Ereignissen ist ein potentielles Problem von allen autokorrelierten Prozessen. Ein weiteres interessantes Beispiel ist hier die Abschätzung von maximalen Windstärken in Böen, welche bei der Konstruktion von Windrädern eine Rolle spielt. Mit der Umformulierung des Detektionsproblems als Modellselektionsfrage und mit der Bereitstellung geeigneter Modellselektionsstrategie trägt diese Arbeit zur Diskussion und Entwicklung von Methoden im Bereich der Detektion von langreichweitigen Korrelationen bei.
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Stephens, Kate 1968. "A synoptic climatology of ground-level ozone for Montreal, Quebec." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22811.
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A mean sea level (MSL) and 500 hPa height field synoptic climatology of ozone is developed for the Montreal region over the period 1980-1992 using the Kirchhofer computer-assisted map-pattern technique. Synoptic class air quality signatures are examined on an annual, seasonal and interannual basis. Residual cumulative dose analysis confirms that the "Back of the High" synoptic types are responsible for above average ozone concentrations in the summer months. In contrast, during the winter, the stable conditions and cold temperatures associated with these same synoptic types promote ozone scavenging and below average ozone concentrations. Above average winter ozone levels are associated with cyclonic synoptic types, possibly as a result of stratospheric ozone intrusion. Synoptic sequencing confirms the importance in stability in upper level features (particularly an upper level trough to the northeast of Montreal) and stagnation of surface features (primarily the "Back of the High") for the development of elevated ozone concentrations in Montreal. Finally, a declimatizing technique is evaluated as a means of removing the synoptic signal from the ozone time series. Results of this study are in broad agreement with similar investigations elsewhere in northeastern North America.
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Perry, Lester Baker Konrad Charles Edward. "Synoptic climatology of northwest flow snowfall in the southern Appalachians." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2006. http://dc.lib.unc.edu/u?/etd,165.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2006.Title from electronic title page (viewed Oct. 10, 2007). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Geography (Climatology)." Discipline: Geography; Department/School: Geography.
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Reynolds, D. J. "Severe local storms in the United Kingdom : climatology and forecasting." Thesis, Swansea University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638649.
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This thesis investigates severe local storms in the United Kingdom, specifically tornadoes, waterspouts and severe hailstorms. Reference is also made to the United Kingdom's place in the tornado climatology of Europe and some comparisons are made with the United States. Outline forecast guidance is then considered. A major part of this thesis was the development of computerised tornado, waterspout and severe hailstorm data for the United Kingdom, followed by the validation and verification of as much of the component information as was reasonably possible. A European tornado and waterspout data base was developed likewise. Events that have been reported during the research period have been added to ensure that the data bases are up-to-date. Tornado, waterspout and severe hailstorm climatologies for the United Kingdom are presented. The place of the United Kingdom in the tornado climatology of Europe is discussed and comparisons are made with the tornado climatology of the United States. From the climatologies and several case studies, the possibilities of prediction, detection and warning are considered in outline. It is very much hoped and intended that this research will perpetuate further and more detailed research, as well as development and education. To this end, the thesis concludes with an internet web site on severe weather in general, which has been developed in parallel with this research. The site, of the Tornado and Storm Research Organisation, includes questionnaires developed by the writer which have already proven very useful in attracting numerous new reports of severe weather and also in greater detail than before. The site also serves to increase the awareness of severe weather in the United Kingdom and Europe, as well as to educate visitors about it. The web site in particular lends itself to on-going development.
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Clapp, Lynette Joan. "An analysis of the oxidant climatology in the United Kingdom." Thesis, University of London, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556562.
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Ozone (03) and nitrogen dioxide (N02) are two of a series of air pollutants targeted in the UK Air Quality Strategy, by virtue of their adverse effects on human health and the natural environment. Because 03 and N02 are rapidly chemically inter-converted in the atmosphere, their behaviour is coupled and they can be collectively referred to as 'oxidant' (OX). Sources and trends of OX in the UK have been examined through a combination of dedicated field measurements of 03, N02 and nitric oxide (NO), over three years (January 2005 - December 2007) at the Silwood Park Atmospheric Research Station (SPARS) near Ascot; and through analysis of data for the same species at 31 sites across the UK, which are part of the UK Automatic Urban and Rural Network (AURN). SPARS measurements have contributed to data available from the London Air Quality Network (LAQN), the site being referred to as "Windsor and Maidenhead - Ascot" (MW3). Total Oxidant [OXh can be interpreted in terms of: (i) a Global hemispheric baseline, [OX]H, representing the baseline air transported into the UK; (ii) a Regional modification, [OX]R, which has contributions from production via regional-scale photochemical processing of emitted volatile organic compounds (VOC) and nitrogen oxides (NOx), and loss via deposition; and (iii) a Local enhancement, [OX]L, from direct emissions of N02 (e.g., road vehicle exhaust). Separation of these components involved an air mass screening methodology, using back-trajectories calculated with meteorological models. [OX]H makes the major contribution to [OXh at rural and polluted urban centre sites, although either of the other components can dominate during episodes. [OX]R is typically enhanced during the period from April to September when meteorological conditions are favourable and photochemical processes operate efficiently. [OX]L is largest at polluted urban sites close to emission sources, and maximises in the winter months when dispersion is least efficient. Abstract Annual mean data since the 1990s show an increasing trend for [OX]H (a consequence of increasing emissions of methane and NOx), while [OX]R and [OX]L show decreasing trends because of emissions control strategies within the EU and UK. Seasonal and spatial variations in [OX]H and [OX]R are valuable for forecasting and modelling 03. [OX]H is important for policy when baseline 03 concentrations exceed international air quality standards. 11.
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Lamakin, Mikhail. "Synoptic climatology of aerosol optical depth in the Eurasian Arctic." Thesis, University of Reading, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414600.
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McGuffie, K. "Radiation and cloud over cryospheric surfaces : climatology and climate sensitivity." Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332180.
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Bowers, Carrie. "The Diablo Winds of Northern California| Climatology and Numerical Simulations." Thesis, San Jose State University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13424229.
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Extreme fire behavior in the San Francisco Bay Area (SFBA) has historically been associated with strong offshore wind events referred to locally as Diablo winds. A 17 year surface-based climatological analysis was performed to establish a definition of Diablo winds and to identify their frequency and spatial distribution. Synoptic composites of events were constructed using North American Regional Reanalysis, and high resolution Weather Research and Forecasting (WRF) model simulations were used to investigate the mesoscale dynamics of three significant Diablo wind events. Diablo winds were defined as dry northeasterly, downslope winds that occur in the SFBA with minimum sustained wind speeds of 6 m s –1. Climatological analysis results illustrate that Diablo winds most frequently impact the Coast Ranges nearest the Sacramento Valley and occur, on average, 2.5 times annually. The highest monthly frequency occurs in October when live fuel moisture is at its driest, creating the most severe fire danger for the SFBA during that time. Numerical simulations of significant Diablo events revealed that Diablo winds have complex character with contributions from small-scale downslope winds, as well as large-scale mountain waves interacting with terrain.
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Surprenant, Jeremy Lee. "A Synoptic Climatology of Wildfires in the Midwestern United States." OpenSIUC, 2009. https://opensiuc.lib.siu.edu/theses/467.
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Predicting wildfire activity has been a major concern for fire weather forecasters and fire managers in recent decades. Identifying mid-tropospheric circulation patterns that are conducive to higher rates of spread has been widely employed as a predictive tool. This study classifies circulation patterns at the 500 mb level for 3865 fire days from 1970 through 2004 in the central hardwood region of the Midwestern United States. Several circulation patterns were identified that are associated with enhanced fire activity relative to other patterns. All patterns with elevated fire activity were associated with either flow from dry air source regions, or patterns that placed the region on the periphery of a high pressure system. Weather variables associated with each type of circulation pattern were also analyzed and were found to vary among patterns. Circulation patterns with greater fire activity were identified as being drier than patterns with lesser activity. The findings of this study provide crucial information to fire managers and forecasters, which can help them achieve their ultimate goal of minimizing loss of life and property.
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Emmert, John T. "Climatology of Upper Thermospheric Daytime Neutral Winds from Satellite Observations." DigitalCommons@USU, 2001. https://digitalcommons.usu.edu/etd/6807.
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We studied the global climatology of mid- and low-latitude F region daytime neutral winds using extensive measurements by the Wind Imaging Interferometer (WINDII) instrument on board the Upper Atmosphere Research Satellite (UARS). Quiet-time winds are mostly poleward and westward during the day, and are generally 5-20 m/s smaller in the longitudinal sector closest to the magnetic pole, compared to longitudinally averaged winds. The pre-noon zonal winds are less westward with increasing solar flux, while the post-noon meridional winds are less poleward . Our quiet-time results are in good agreement with the NCAR ThermosphereIonosphere- Electrodynamics General Circulation Model (TIEGCM).
We computed residual winds by subtracting quiet-time values calculated along the satellite orbit, which effectively removes average measurement bias. Using these residuals, we studied the average change in the winds under disturbed conditions. The zonal disturbance winds are mostly westward, increase with latitude, and have largest values in the late afternoon sector. In general, the meridional perturbation winds are equatorward, increase linearly with latitude, and decrease from morning to afternoon hours. The zonal and meridional perturbations increase roughly linearly with Kp. We developed empirical analytical models for the disturbance winds from 60° to the equator; these model winds are in poor agreement with results from the empirical Horizontal Wind Model. There are also important discrepancies between the average perturbations winds from WINDII and TIEGCM.
We studied the average time-dependent development of disturbance winds during geomagnetic storms. The onset of a storm is characterized by equatorward surges, mostly in the morning sector, that reach the equator in about 2 h. These surges lessen 5-6 h after the onset of a storm, but subsequently increase, reaching their largest values about 15 h after the start of the storm before leveling off or diminishing. Following the end of typical storms, the disturbance winds decrease quickly but oscillate for at least one 8-9 h cycle. We developed time-dependent analytical models of the disturbance winds as a function of the polar cap index at key storm time lags. Our results are consistent with predictions from theoretical models. (146 pages)
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Pugmire, Jonathan Rich. "Mesospheric Gravity Wave Climatology and Variances Over the Andes Mountains." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7387.
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Look up! Travelling over your head in the air are waves. They are present all the time in the atmosphere all over the Earth. Now imagine throwing a small rock in a pond and watching the ripples spread out around it. The same thing happens in the atmosphere except the rock is a thunderstorm, the wind blowing over a mountain, or another disturbance. As the wave (known as a gravity wave) travels upwards the thinning air allows the wave to grow larger and larger. Eventually the gravity wave gets too large – and like waves on the beach – it crashes causing whitewater or turbulence. If you are in the shallow water when the ocean wave crashes or breaks, you would feel the energy and momentum from the wave as it pushes or even knocks you over. In the atmosphere, when waves break they transfer their energy and momentum to the background wind changing its speed and even direction. This affects the circulation of the atmosphere.
These atmospheric waves are not generally visible to the naked eye but by using special instruments we can observe their effects on the wind, temperature, density, and pressure of the atmosphere. This dissertation discusses the use of a specialized camera to study gravity waves as they travel through layers of the atmosphere 50 miles above the Andes Mountains and change the temperature. First, we introduce the layers of the atmosphere, the techniques used for observing these waves, and the mathematical theory and properties of these gravity waves. We then discuss the camera, its properties, and its unique feature of acquiring temperatures in the middle layer of the atmosphere. We introduce the observatory high in the Andes Mountains and why it was selected. We will look at the nightly fluctuations (or willy-nillyness) and long-term trends from August 2009 until December 2017. We compare measurements from the camera with similar measurements obtained from a satellite taken at the same altitude and measurements from the same camera when it was used at a different location, over Hawaii. Next, we measure the amount of change in the temperature and compare it to a nearby location on the other side of the Andes Mountains. Finally, we look for a specific type of gravity wave caused by wind blowing over the mountains called a mountain wave and perform statistics of those observed events over a period of six years.
By understanding the changes in atmospheric properties caused by gravity waves we can learn more about their possible sources. By knowing their sources, we can better understand how much energy is being transported in the atmosphere, which in turn helps with better weather and climate models.
Even now –all of this is going on over your head!
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Heydenrych, Clive Malcolm. "A climatology of the coastal low in the SW Cape." Master's thesis, University of Cape Town, 1987. http://hdl.handle.net/11427/14293.
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Bibliography: leaves 103-109.The Coastal Low is a shallow cyclonic mesoscale weather 'disturbance' which migrates around the southern African subcontinent on a fairly regular basis. It is generated and maintained by the synoptic scale circulations. The movement and surface characteristics have been well documented by a number of authors but few detailed studies have been undertaken on its vertical structure in southern Africa. In addition to this, most of the previous work has been of a meteorological nature. This study has concentrated on a more climatic approach in its investigation of the vertical and· surface features of the Coastal Low as it migrates through the South Western (SW) Cape. The SW Cape is a 'transition region' for the migration of the Coastal Low; situated between the west and south coasts with a distinct local climate due to the complex topography of the region. This fact tends to alter the characteristic features of the Coastal Low system but appears not to prevent the Coastal Low from migrating through the region. The Coastal Low is regarded as being an internal trapped Kelvin wave and corrected surface pressure values best indicate its migration characteristics. However upper air analysis indicates that temperature values (between 950- 900mb) at the level of the inversion, produce one of the best signatures of the Coastal Low's passage. This is related to the strong subsidence from above the 850mb level in the pre-Low period. This strong divergence dynamically compresses the lower layers into low level wind speed maxima on either side of the centre of the system. The Coastal Low appears to have a very complex structure, and two results from this study in the. SW Cape bear particular mention. Firstly the offshore flow at the escarpment level is weakly defined. Secondly also, the longshore spatial extent of the Coastal Low system has been estimated to have an 'inner' diameter of 150-200km and an 'outer' diameter of approximately 1000km.
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Krautmann, Alek J. "Midwest Urban Heat Wave Climatology: What Constitutes the Worst Events?" Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1338578478.
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Panturat, Suwanna. "Optimal sampling to provide user-specific climate information /." Full-text version available from OU Domain via ProQuest Digital Dissertations, 1987.
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Rémillard, Jasmine. "Cloud climatology and microphysics at Eureka using synergetic radar/lidar measurements." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32392.
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Despite their importance in Earth's radiation budget and atmospheric models, Arctic clouds remain poorly documented and understood. The deployment of a cloud radar and a high spectral resolution lidar at Eureka (80°N) in August 2005 offers a unique data set for the study of Arctic clouds. In this project, synergetic retrievals were developed and applied to two years of data in order to provide a first climatology of the clouds and their microphysics at this remote location. Results show an annual cycle in cloud coverage. They are mostly detected in the low levels or in single-layer, especially in winter due to a temperature inversion and cloud top radiative cooling. An analysis of the winds also demonstrated that different wind directions relate to different cloudiness conditions, while a strong channelling from the topography is present in the low levels. Moreover, liquid phase particles were detected all year round, with a minimum occurrence in winter due to colder temperatures. Turbulence and high relative humidity seem to maintain supercooled liquid, especially when ice crystals were also present. Precipitation was mostly identified during summer months, often in the form of virga, although falling snow might have been missed due to the difficulty to distinguish it from glaciated clouds. Finally, results show that satellite validation is possible using Eureka's data, but only under homogeneous conditions and when the instruments characteristics (like the sampling and sensitivity) are taken into account.Malgré leur importance dans le budget radiatif terrestre et les modèles atmosphériques, les nuages arctiques restent mal documentés et incompris. Le déploiement d'un radar millimétrique et d'un lidar à haute résolution spectrale à Eureka (80°N) en août 2005 offre un ensemble unique de données pour l'étude des nuages arctiques. Dans ce projet, des algorithmes synergétiques furent développés et appliqués à deux ans de données pour fournir une première climatologie des nuages et de leur microphysique à cet emplacement éloigné. Les résultats montrent un cycle annuel dans l'étendue des nuages. Ils sont surtout détectés dans les bas niveaux ou en une couche, particulièrement en hiver à cause de l'inversion thermique et du refroidissement radiatif du haut des nuages. Une analyse des vents a démontré que différentes directions sont reliées à différentes conditions nuageuses, alors qu'une forte canalisation des vents due à la topographie est présente dans les bas niveaux. De plus, la phase liquide fut détectée à l'année longue, avec une occurrence minimale en hiver causée par des températures plus froides. De la turbulence et un haut taux d'humidité semblent maintenir les particules liquides surfondues, particulièrement quand des cristaux de glace sont aussi présents. Les précipitations furent principalement identifiées durant l'été, surtout sous forme de virga, bien que la difficulté à distinguer la neige des nuages glacés a pu influencer les résultats. Finalement, la validation d'un satellite est possible grâce aux données d'Eureka, mais seulement sous des conditions homogènes et si les caractéristiques instrumentales
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Comer, Neil Thomas. "A climatology and mesoscale model intercomparison of summertime Lake Ontario breezes /." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61058.
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The lake breeze is shown to develop on 30% of all summer days in the Toronto region, similar to other findings in the Great Lakes area. Simulations with the Colorado State University (CSU) model show that under northwest to north gradient flow the lake breeze is characterized by a broad band of westerlies over the lake, while southwesterly gradient flow produces a broad band of easterlies. A nocturnal mesoscale cyclonic eddy is predicted over western Lake Ontario under west and northwest gradient flow conditions.A statistical model intercomparison of the CSU and Ontario Ministry of Environment models over a 19600 km$ sp2$ domain centred on Pickering, ON revealed the CSU model generally more accurately predicts the temporal and spatial lake breeze characteristics. This is attributed to improved model parameterizations and larger domain size enabling the model to resolve the full-lake scale circulations which develop.
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O'Hara, Brian F. "A synoptic climatology of heavy snowfall in the Sierra Nevada, USA." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1446431.
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Souders, Matthew B. "The Climatology of Rossby Wave Packets Using Object-based Tracking Techniques." Thesis, State University of New York at Stony Brook, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1586114.
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This research produces an objective, track-based climatology of Rossby wave packets (RWPs) and tests the sensitivity of the results to changes in the methods used in filtering the raw data and in tracking. NCEP/NCAR Reanalysis wind and geopotential height data at 300 hPa every 6 hours were spectrally filtered using a Hilbert transform technique under the assumption that RWPs propagate along a waveguide defined by the 14-day running average of the 300 hPa wind. After some spatial smoothing, the local maxima in RWP envelope amplitude (WPA) were tracked using two objective techniques: a point-based cost optimization routine and a hybrid of point identification and object-based tracking following rules similar to those used in the tracking of tropical convective clusters. The total energy flux term of the eddy kinetic energy equation was used as a cross-check for the purpose of hand-verifying RWP tracks in order to compare the performance of each tracking method. Track data and object-based descriptive statistics (including area, average intensity, intensity volume, intensity-weighted centroid position and velocity) were gathered to describe the inter-annual, annual, seasonal, and regime-based climatology of RWPs.
When tracking methods are verified over two winter seasons and compared, the hybrid technique statistically outperforms point-based tracking, particularly when estimating track duration and propagation. When long lived RWPs are verified, there is strong evidence that some RWPs can last over 30 days and circumnavigate the Northern (Southern) Hemisphere up to two (three) times. RWPs are found to exhibit a much more pronounced seasonal cycle in the Northern Hemisphere, where they are nearly non-existent in the summer months (JJA), as compared to nearly continuous RWP activity downwind of South Africa during Austral Summer (DJF). Interannual variability in packet frequency and intensity in the Northern Hemisphere is found to be strongly connected with the large scale flow regime, with oscillatory patterns like ENSO and the AO playing significant roles. Enhanced WPA is also found to coherently propagate in composites of regime change events (e.g. a reversal of the AO). No significant long-term changes in RWP frequency or intensity are found; however, the North Pacific storm track appears to have shifted northward in the last thirty years.
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Mulder, Kelsey. "Tornadoes in the British Isles : climatology, formation environments, and storm dynamics." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/tornadoes-in-the-british-isles-climatology-formation-environments-and-storm-dynamics(151a1743-b10c-474f-9eda-c7e47ebdc2f7).html.
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This thesis was funded by a scholarship from the Faculty of Engineering and Physical Sciences, University of Manchester and is presented in an alternative thesis format. The thesis consists of three separate journal articles which form a coherent research project. Paper 1 is a climatology of tornadoes in the British Isles from 1980-2012. The climatology included interannual variability, seasonality, diurnal cycle, intensity, location of occurrence, sounding-derived environmental parameters, and parent storm types of tornadoes. One finding from Paper 1 was that the most common parent storm type in the British Isles was linear storms, for example, storms forming along cold fronts. This finding motivated Papers 2 and 3, which studied vortexgenesis in a tornadic narrow cold-frontal rainband (NCFR), a storm type common to the British Isles, which occurred 29 November 2011. This NCFR caused seven tornadoes across Wales and England. Paper 2 compares the differ- ences in WRF simulation runs of the NCFR based on initialization time, planetary boundary layer scheme, microphysics scheme, and land surface scheme. Out of 96 simulations, the most realistic (most similar to observed radar reflectivity) run was chosen for a case study in Paper 3. Paper 3 analyzes vortices along the NCFR to determine mechanisms dominating their formation and maturation.
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Rettig, Andrew J. "An Open Geospatial Consortium Standards-based Arctic Climatology Sensor Network Prototype." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1282932649.
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Sando, Thomas Roy. "A climatology of air pollution in the Kansas City metropolitan area." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/11987.
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Master of ArtsDepartment of Geography
Douglas G. Goodin
My thesis characterizes the temporal and spatial behavior of ozone and fine particulate matter in the Kansas City metropolitan area. I also investigate the capability of a synoptic weather typing scheme, the Spatial Synoptic Classification, to characterize and explain the behavior of ozone and fine particulate matter in the Kansas City area. Daily maximum ozone concentrations from nine active ozone monitoring stations and daily average particulate concentrations six active PM2.5 monitoring stations were compared to daily SSC weather type records from 2004-2010. Analysis of Variance (ANOVA) tests were conducted on the ozone and PM2.5 data to analyze temporal and spatial behavior. A non-parametric recursive partitioning technique was used to create a conditional inference tree-based regression model to analyze the association between the different SSC weather types and the selected pollutants. The ANOVA results showed significant seasonal trends with both pollutants. In general, ozone concentrations are typically lower in the spring and autumn months and higher during the summer months. PM2.5 concentrations were not as dependent on the season, however, they did tend to be higher in the late summer months and lower in the autumn months. The results also showed significant differences for both pollutants in average concentration depending on location. The ozone concentrations generally tended to be higher in the areas that are located downwind of Kansas City and lowest at the station located in the middle of the urban area. Fine particulates also seemed to be highest in the downwind portion of the urban area and lowest in the region upwind of the city. The conditional inference tree showed that higher concentrations of both pollutants are associated with tropical air masses and lower concentrations are associated with polar air masses.
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Adams, Aaron M. "Climatology and Variability of Aerosol over Africa, the Atlantic, and the Americas." Scholarly Repository, 2011. http://scholarlyrepository.miami.edu/oa_theses/273.
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Using Vertical Feature Mask (VFM) data from Cloud - Aerosol Lidar Infrared Pathfinder Satellite Observations (CALIPSO), I have documented 3-dimensional (3D) structures in occurrence probabilities of aerosol over a broad region of Africa, the Atlantic, Europe, and Americas. The 3D structures illustrate the seasonal means and seasonal cycle in the zonal and meridional variability of the vertical profiles of mineral dust, biomass burning smoke, and polluted dust (external mixture of dust and smoke), and their emissions sources and transport pathways. Emission sources vary by geographical location. The persistent Saharan dust source is evident throughout the year and observed and recorded by CALIPSO 70-80% of the time over Africa. Horizontal and vertical occurrence of dust is variable in time with maximum heights and westward transport occurring in boreal summer and minimum heights and transport occurring in boreal winter. The southern African biomass burning source is also evident throughout the year, through westward transport over the Atlantic is only evident in boreal summer and fall; mixing with dust over the continent limits westward transport of pure smoke to the continent in winter and spring. Other smaller smoke and dust sources are discussed. The role of the Inter-Tropical Convergence Zone (ITCZ) in limiting the southward transport of dust and northward transport of smoke over Africa is demonstrated. Surprisingly, the highest probability of polluted dust is found in the ITCZ, even though the probabilities of dust and smoke are low. Wind trajectories reveal smoke of southern African origin is transported northward at the lower levels, but rarely penetrating through ITCZ rainband while Saharan dust is transported southward at higher levels, crossing the ITCZ frequently. This quasi-circulation of aerosol is shown to be the mixing mechanism of dust and smoke into polluted dust in the area of the ITCZ.
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Small, David. "Beaufort coast wind climatology and case study of a high wind event." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66951.
Full textAbstract:
Tuktoyaktuk, a community along the Beaufort coast in the western Canadian Arctic, experiences serious coastal erosion during periods of strong and persistent northwesterly winds during the late summer season when the sea ice coverage reaches its annual minimum. The prevalence of strong northwesterly winds along the Beaufort coast has often been linked to the passage of powerful storms. In this study, a climatology of late summer winds at Tuktoyaktuk is compiled that links the observed wind regime to the orography of the Brooks Range. The climatology and a detailed case study of an extreme wind event indicate that an anticyclone over the Chukchi or western Beaufort Seas is conducive for cold air damming events north of the Brooks Range that alter the pressure gradient in a direction favorable for strong northwesterly geostrophic winds over Tuktoyaktuk to be mixed to the surface in a neutrally stratified atmosphere.Tuktoyaktuk, une communauté sur la côte de Beaufort à l'ouest de l'arctique canadien, est aux prises à de graves épisodes d'érosion côtière à la fin de l'été, lorsque la couverture glacière est à son minimum et que soufflent de persistants et forts vents du nord-ouest. La prévalence de forts vents du nord-ouest le long de la côte de Beaufort a souvent été lié au passage de puissantes tempêtes. Dans cette étude, une climatologie des épisodes de vent de fin d'été est établie et mise en lien avec avec l'orographie de la chaîne de montagnes Brooks. La climatologie ainsi qu'une étude de cas détaillée d'un épisode de vents de force extrême indiquent qu'un anticyclone au dessus de la mer de Chukchi ou la mer de Beaufort conduit à un blocage d'air froid au nord de la chaîne Brooks qui modifie le gradient de pression dans une direction favorable à un mélange des forts vents géostrophiques nord-ouest au dessus de Tuktoyaktuk jusqu'à la surface dans une atmosphère stratifiée à stabilité neutre.
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Fernandes, Katia de Avila. "The Amazon hydrometeorology climatology, variability and links to changes in weather patterns /." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31846.
Full textAbstract:
Thesis (Ph.D)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2010.Committee Chair: Rong Fu; Committee Member: Marc Stieglitz; Committee Member: Peter Webster; Committee Member: Robert E. Dickinson; Committee Member: Robert X. Black. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Shih, Nengwei Tom. "Formation and Development of Diabatic Rossby Vortices in a 10-Year Climatology." Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/7415.
Full textAbstract:
A diabatic Rossby vortex (DRV) is a short-scale, diabatically dominated, moist baroclinic disturbance that forms and grows in the absence of discernible upper tropospheric forcing. The overarching goal of this work is to expand on the limited amount of DRV research by examining the general characteristics of real-world DRVs that have been identified in an automated 10-year DRV climatology. The identified 314 DRVs form preferentially over warm ocean currents. All DRVs track to the east northeast. While more DRVs form during the warm season, a larger fraction of storms that explosively deepen occur during the cold season. Composite analyses bear strong resemblance to DRV structural plots in the published literature, confirming that moisture, baroclinicity and the diabatic generation of eddy available potential energy are essential to DRV formation and development. Upon inspection of the interaction between DRVs and the dynamic tropopause (DT), nine (30%) of the 31 explosively deepened DRVs are subjectively determined (based on how the DRVs interacted with DT to bomb) to be of type A development (as defined by Petterssen and Smebye [1971], so-called bottom-up development). The remaining 22 (70%) are subjectively identified as type C development (mutual interaction of pre-existing upper and lower tropospheric disturbances, as defined by Deveson et al. [2002]).