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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
541

Reproductive response to elevated CO2 : the roles of vegetative carbon storage, nitrogen and seed traits

Jablonski, Leanne M. January 1997 (has links)
No description available.
542

Investigating the effects of climate change and sea level rise on the coastal processes of the Beaufort Sea, Yukon Territory

Turner, Jennifer, 1979- January 2004 (has links)
No description available.
543

Comparative ecophysiology of temperate and tropical rainforest canopy trees of Australia in relation to climate variables

Cunningham, Shaun Cameron, 1971- January 2001 (has links)
Abstract not available
544

Vegetational and climatic changes during the last 40,000 years at Burraga Swamp, Barrington Tops, NSW

Sweller, Susan, School of Biological Science, UNSW January 2001 (has links)
Burraga Swamp is a small enclosed basin at 985 m altitude in Barrington Tops, in the Eastern Highlands of New South Wales, Australia. It lies in the midst of a Nothofagus moorei cool temperate rainforest, which is at its southern limits here. The swamp is close to the boundaries between temperate rainforest, subtropical rainforest, sclerophyll forest and sub-alpine formations and may be a sensitive recorder of past changes in the vegetation. The palynology and the sediments have been studied to a depth of 6.5 metres and were dated with eleven 14C dates. The base of the sediment is about 40,000 years old. The results showed the following: From 40,000-30,000 years BP, Burraga was a lake with a very slow rate of deposition of fine grained sediments and flourishing aquatic/swamp vegetation. The dryland vegetation was an open or sparsely treed grassland/herbfield. From 30,000-21,000 years BP, the dryland vegetation remained much the same, but the aquatic vegetation disappeared. From 21,000-17,000 years BP, sandy sediments were deposited at an accelerated rate in a relatively shallow lake, culminating in a layer of gravelly sand. The vegetation was a treeless grassland between about 21,000 and 15,000 years BP. After 17,000 years BP, the rate of sediment accumulation slowed and after 15,000 years, some mesic elements appeared. Dicksonia antarctica became prominent between about 13,000 and 12,000 years BP and Nothofagus was consistently present after about 11,500 years BP. Peat deposition started about 6,500 years BP. By 6,000 years BP the cool temperate rainforest was fully developed, remaining on the site until the present. These changes suggest that the climate at 40,000 years BP was drier than the present, becoming drier and reaching maximum aridity about 17,000 years BP, when temperatures were also at their lowest. Subsequently, the temperature increased and around 15,000 years BP the climate became wetter. Maximum moistures and temperatures were reached between about 9,000 and 5,000 years BP. The climate then varied until it reached the present. Burraga extends the record of treeless vegetation over most of southeastern Australia, during the last glacial maximum, to more northerly localities than previously known.
545

Multisite rainfall stochastic downscaling for climate change impact assessment

Mehrotra, Rajeshwar, Civil & Environmental Engineering, Faculty of Engineering, UNSW January 2005 (has links)
This thesis presents the development and application of a downscaling framework for multi site simulation of daily rainfall. The rainfall simulation is achieved in two stages. First, rainfall occurrences at multiple sites are downscaled, which is followed by the generation of daily rainfall amounts at each site identified as wet. A continuous weather state based nonparametric downscaling model conditional on atmospheric predictors and a previous day average rainfall state is developed for simulation of multi site rainfall occurrences. A nonparametric kernel density approach is used for simulation of rainfall amounts at individual sites conditional on atmospheric variables and the previous day rainfall amount. The proposed model maintains spatial correlation of rainfall occurrences by simulating concurrently at all stations and of amounts by using random innovations that are spatially correlated yet serially independent. Temporal dependence is reproduced in the occurrence series by conditioning on previous day average wetness fraction and assuming the weather states to be Markovian, and in the amount series by conditioning on the previous day rainfall amount. The seasonal transition is maintained by simulating rainfall on a day-to-day basis using a moving window formulation. The developed downscaling framework is calibrated using the relevant atmospheric variables and rainfall records of 30 stations around Sydney, Australia. Results indicate a better representation of the spatio-temporal structure of the observed rainfall as compared to existing alternatives. Subsequently, the framework is applied to predict plausible changes in rainfall in warmer conditions using the same set of atmospheric variables for future climate obtained as a General Circulation Model simulation. While the case studies presented are restricted to a specific region, the downscaling model is designed to be useful in any generic catchment modelling and management activity and/or for investigating possible changes that might be experienced by hydrological, agricultural and ecological systems in future climates.
546

Dust storm transport of pathogenic microbes to Viking Scandinavia : a query into possible environmental vectors or disease pathogenesis in a closed biological and ecological system

Boling, David Carter 11 June 2004 (has links)
This thesis is an integrated study that links several disciplines-archaeology, anthropology, geography, atmospheric sciences, and microbiology. It attempts to generate an argument that central to climate change is disequilibrium in human ecologies- in my case, disease ecologies in Iceland during the 15th century. This thesis investigates the environment's effect on human adaptability. The effect of the environment on Icelanders as they moved from settlement to later periods was disquieting. The climate of the world was changing- moving from the Medieval Warm Period to the colder Little Ice Age. I analyze the disease ecology of the 15th century and also conduct an archeological and cultural analysis of the Icelandic people, to show the deficiencies in their adaptation, and submit that certain shortcomings in their physical environment, as well as the inadequate adaptive synthesis to the environment, led to a marginal adaptation. This was augmented by political unrest and problems with outside trade, which left them vulnerable and susceptible to disease pathogenesis. I discuss the climate change during the Little Ice Age, and assert that this event is the crucible that crushed Iceland after 400 years of reasonably good fortune. Hundreds of epidemics, natural disasters, and hardships befall the Icelanders. One of them is the plague, which comes twice in the 15th century. The important observation here is that the epidemiological and archeological evidence does not always match up. The principal problem is that the traditional vector for the disease cannot have survived the climate as it was in the winters during the LIA. I offer an analysis that pontificates this issue and I examine the ongoing debate concerning The Black Death in Europe. I introduce another possible explanation: the introduction of disease through environmental vectors. The creation of disease ecologies through climate change is important, in light of problems that we face today. I discuss the phenomenon of the dust storm and its connection to disease pathogenesis. By showing several key examples of dust from Africa to disease pathogenesis in the Caribbean, I make the connection a good one. In addition to this connection is the atmospheric analysis that shows incontrovertibly that the dust found in Greenland ice cores is only from Asia. Finally, there is the fact that the inveterate loci of the plague bacterium is located in the same areas that Asian Dust Events occur and travel from. I create a methodology for investigating this disease ecology and am able to show that the pathogen can be identified in situ- meaning that it can be found in geological deposits that can be properly dated. My pilot study creates a methodology for the examination of ice cores- the principal reservoir for atmospheric deposits made during the LIA. Finally, I look at the aftermath. I introduce the idea of disease ecology, as opposed to that of a healthy ecology, and suggest by the end of the thesis that within the disease ecology are created many of the platforms for emergent biological changes that translate through evolution over time. Like the bacterium in the ice core, I suggest that evidence for disease states in the history of a people can be found through laboratory techniques. The presence of the CCR5 gene mutation is indicative of such a presence. I believe that the presence of the delta 32 gene mutation found in Icelandic people is the result of being exposed to the plague in the 15th century. This thesis is a platform for future synoptic scale disease studies. / Graduation date: 2005
547

"Walloped" by the weather? Deflections, diversions, and dubious representations of women in climate change discourse

Brinker, Rachel K. 24 May 2012 (has links)
Research shows that women's lives are disproportionately impacted by the effects of climate change. While the topic of women is largely absent from climate discourse overall, the representations of women that occur reveal underlying structures of power rooted in imperialism and colonial dominance. This thesis presents an analysis of the ways in which the category "woman" is constructed in climate change discourse by utilizing data from the micro-blogging site Twitter.com in the 60 days surrounding the 17th UNFCCC Conference of the Parties (COP17) in 2011. The findings of this research are that women are represented through imageries of violence and victimization, while simultaneously constructed as mythical heroines/warriors who will defend and save humanity from this global threat. Using transnational and postcolonial feminist theory, I critique these representations and examine the function and consequences of the narrow representations of women in climate change discourse. Based on the findings, this thesis suggests that a shift towards the discursive feminization of climate change could occur in the future, wherein the ways in which climate change is viewed and responded to may move from the current frame of governability, commodification, and securitization, to a frame that sees climate change as a "women's issue." Feminist intervention into climate change discourse is greatly lacking, and this thesis argues that feminist engagement with the problem of climate change is necessary for gender justice in our climate-altered world. / Graduation date: 2012
548

Tradable permits for greenhouse gas emissions : a primer with particular reference to Europe

11 1900 (has links)
This paper is written as part of a two-year study of climate change policy choices facing Sweden, conducted under the auspices of the Center for Business and Policy Studies in Stockholm. As such, it aims to be a primer on emissions trading as an instrument for limiting greenhouse gas (GHG) emissions under the Kyoto Protocol to the Framework Convention on Climate Change. The first section notes general considerations concerning emissions trading, particularly in relation to climate policy. The second section explains the many forms of emissions trading included in the Kyoto Protocol. The third section provides a brief review of emissions trading proposals that have been advanced in Europe as of mid-2000. The fourth section addresses issues in the design and implementation of a national GHG emissions trading system. The brief conclusion is followed by an appendix, which draws applicable lessons concerning the choice and design of a cap and trade system from the U.S. SO2 emissions trading program. / Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/) / Includes bibliographical references (p. 38-39).
549

Hydrologic implications of 20th century warming and climate variability in the western U.S. /

Hamlet, Alan F. January 2006 (has links)
Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 113-121).
550

Observed decadal variations of the zonal mean hygropause and its relationship to changes in the transport barrier

Roell, Marilee May 24 August 2012 (has links)
This study examines the long-term record of lower stratospheric water vapor focusing on the 20-year data record from the Stratospheric Aerosol and Gas Experiment II (SAGE II). The SAGE II zonal monthly mean water vapor data was enhanced to include the aerosol heavy late 1980s through the use of aerosol extinction filtering of the data. Comparisons between the SAGE II lower stratospheric water vapor and the Limb Infrared Monitor of the Stratosphere (LIMS), the Microwave Limb Sounder (MLS), and HALogen Occultation Experiment (HALOE) are performed. This study further focuses on the minimum lower stratospheric water vapor (i.e., hygropause) and on the dehydration seen in the hygropause with examination of the transport barrier at both the tropical tropopause and the tropopause folding region between the tropics and extra-tropics that would account for this decadal variation. The effects of aerosol contamination on the SAGE II water vapor retrievals from four volcanic eruptions from 1984 to 1992 were examined, leading to a four level filtering of the SAGE II water vapor data to allow retention of good data from early in the data record. With the improved filtered water vapor data, monthly and seasonal time series analyses show a significant decadal variation in the lower stratosphere for all months where the satellite coverage provided data from the late 1980s to the early 2000s. This decadal variation documents a decrease in the water vapor from below approximately 25 km to below the tropopause with this decrease seen in the hygropause from the tropics to the poles. Analysis of the hygropause for all months provided a statistically significant consistent neutral or decreasing value in the long-term water vapor minimum. March was shown to be the seasonal minimum in the hygropause over this 20-year low aerosol record, followed by a discontinuity in the minimum abundance after 2000. Three transport pathways for transport of water vapor from the moist troposphere to the lower stratosphere include the tropical tropopause, isentropic transport at the sub-tropical jet locations, and meridional transport from the tropics to the midlatitudes above the hygropause. The tropical tropopause temperatures were examined using the new Modern Era Retrospective-analysis for Research and Applications (MERRA) data set. Analysis showed a significant decrease in the tropical and sub-tropical tropopause temperatures over the 20-year timeframe for the DJF season preceding the March minimum. The lower temperatures would provide a colder "cold trap" at the tropopause, further "freeze drying" the air seasonally transported from the upper troposphere to the lower stratosphere, providing the long-term dehydration in the hygropause and lower stratosphere. The Ertel's Potential Vorticity (EPV or PV) was examined as a proxy for the sub-tropical jet movement towards the poles over this long-term record. Changes in this pathway location may affect the efficiency of isentropic transport of moist tropospheric air into the lower stratosphere at these higher latitudes. Analysis using the MERRA zonal EPV and maximum zonal Uwind data showed a statistically significant shift in the locations of the contours towards the SH poles over this 20-year timeframe for the DJF, DJFM seasons and the month of December. The meridional winds above the tropopause show an increase over the 20-year record covered by SAGE II water vapor data. These increasing winds are consistent with the increase in the Brewer-Dobson circulation shown in other studies. The colder tropopause temperatures along with the increasing Brewer-Dobson circulation just above the tropopause, are the likely cause for the decreasing water vapor trend as seen in the SAGE II March hygropause over the 20-years from 1986-2005.

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