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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.
1

Impact of climatic variability on the fire behaviour of different land ecosystems

Viegas de Barros, Ana Lúcia January 2011 (has links)
Wildfires are a natural phenomenon that strongly impacts the environment. Many terrestrial ecosystems depend on fire to maintain their ecological equilibrium and biodiversity, but new destructive fire patterns, often associated with land management practices and rapid climate change, have been degrading soil and water resources, increasing erosion by wind, precipitation and floods, decreasing biodiversity and contributing to desertification. Furthermore, pyrogenic emissions from biomass burning are an important source of atmospheric pollution and they impact the radiative balance of the troposphere, strongly contributing to the greenhouse effect. The objective of this research was to investigate the impact of climate variability on geographic, ecological, seasonal and inter-annual distributions of fires and correspondent pyrogenic emissions, across a variety of ecosystems. With this purpose, 10 years of world, monthly, 1°x1° gridded data, from the Global Fire Emissions Database, were compared with land-cover data, from the Goddard Institute of Space Studies, and with weather data, from the European Centre for Medium Range Weather Forecasting, the Global Precipitation Climatology Centre and the Global Hydrology Resource Centre. Overall, the climate parameters significantly correlated with carbon emissions were air and soil temperature, air and soil humidity, rainfall, wind speed and lightning density during the fire season, and also precipitation and snow cover up to 6 months before the fire season. Good statistical quantitative models of carbon emissions (correlations above 70%, and up to 95%, between estimated and predicted values, with residuals normally distributed) using humidity, temperature or lagged rainfall as predictors, were found almost exclusively in tropical grasslands, shrublands and woodlands, especially in Africa, where fire behaviour was more regular. In boreal and temperate forests and woodlands, where fire patterns were irregular and fire returning periods were larger, there were not enough fires, in 10 years of data, to obtain useful predictive statistical models. The fire models presented here, together with the quantitative statistical relationships found between climate and fire patterns, in different land ecosystems, are apt to be used in predictive climate models, land management, fire risk assessment and mitigation of climate change.
2

Rainmaking, gender and power in Ihanzu, Tanzania, 1885-1995

Sanders, Darrell Todd January 1997 (has links)
This thesis is about rainmaking amongst the Ihanzu (or Isanzu), a 30,000-strong matrilineal, Bantu-speaking agricultural group of north-central Tanzania. By examining rain rituals and their cosmological underpinnings as locally envisaged, I suggest that central to the Ihanzu cultural imagination lies the notion of gender complementarity. In a number of contexts, but particularly in the context of rainmaking, I show how masculine and feminine principles of a gendered universe, when combined, are seen as a site of cosmic and divine powers. To join the genders is to transform, to create, to rejuvenate. Using oral and archival sources, the first section examines the nature of the Ihanzu dual monarchy between 1885 and 1976. In spite of the radical political, economic and social changes that took place throughout this period, the dual leadership-with one male and one female-and people's understandings of royal power and legitimacy remained constant: control over rains is control over reigns. Section two examines annual rainmaking rites as they occur today. The point is to show the extent to which gender complementarity pervades these rites, and the local logic as to why this must be so. An indigenously grounded, gendered model of transformation is developed that applies equally to making children as to making rain. Power, in Ihanzu eyes, comes in gendered pairs. Section three discusses measures taken when annual rain rites fail to bring rain, and how the gendered model of transformation applies to these remedial rites. The penultimate chapter, on rain-witchcraft, suggests that gendered witches are a cosmological inversion of gendered rulers, yet for both duos their powers are based on gender complementarity. In the conclusion it is argued that the notion of gendered complementarity as developed in the thesis might be equally useful in explaining rain rites elsewhere in Africa.
3

Weathering relationships : the intra-action of people with climate in Himalayan India

Jerstad, Heid Maria January 2016 (has links)
Weather – cold, wet, hot and windy – pervades life, material and social. So present and obvious as to provide a challenge for research, material though ephemeral too, weather breaks boundaries and refuses categorisation. While night becomes day, the cold season warms up over weeks and annual patterns are changing on a scale of years, practices in the face of weather transitions are themselves shifting. Based on ten months of fieldwork in the small village of Gau in the Pahari Indian Himalayas this thesis interrogates the saliencies and permeations of weather in people’s lives. It investigates how people intra-act (Barad 2007) with the weather, though practices, infrastructures and relationships with others. My approach argues for the validity of weather as a means by which to learn about socio-material lives. Pahari villagers live and act within the weather that moves around them. They are subject to, but also modify, their thermal environment. Through housing, clothing and tools such as the fire and the fan they affect the impact of the weather as it meets their bodies, but also daily patterns of movement are coloured by weather considerations. This work views weather in relation to health practices (such as refraining from working during the rain so as not to fall ill), for care of others (such as domestic bovines), for house-building and hospitable relationship-building among neighbours, for negotiation of landslide-fraught access roads to elsewhere and for understandings of pollution in the air. This focus on weather is intended to connect dots for people working on climate change, both within and beyond anthropology, and to contribute to discussions in areas including human-animal relations, health and illness and housing.
4

Weather and Climate for Coastal Tourism

Rutty, Michelle January 2014 (has links)
Weather and climate serve as an important travel motivator, influencing destination choice, the timing of travel, travel expenditures and overall trip satisfaction. Climatic resources are a defining factor in destination attractiveness and are a key element of the natural resource base of a destination that can be classified along a spectrum from ideal to unacceptable. A growing literature has sought to measure, evaluate and assess climate resources for tourism, both generally and for specific tourism market segments. A direct impact of climate change on tourism will be the global redistribution of climatic resources. This would change the length and quality of climate-sensitive tourism seasons, affecting both the temporal and spatial distribution of domestic and international tourism flows and spending. Studies have revealed a generally consistent temporal and geographical pattern of climate change impacts on global tourism. As the 21st century progresses, there is anticipated to be a pronounced shift in thermal comfort (and thereby tourism demand) towards higher latitudes and away from sub-tropical and tropical destinations. This would have a substantial impact on the tourism-intensive economy of the Caribbean, as the vast majority of the region’s attractions are based on weather- and climate-dependent 3S (sun, sea, sand) tourism. However, the assertion that major coastal tourism destinations, such as the Caribbean, will become seasonally ‘too hot’ for tourism has been questioned because the literature has not established what tourists to these regions perceive to be thermally unacceptable for coastal tourism activities. In addition, existing climate and tourism assessments do not account for the microclimatic conditions where tourism activities take place. With the inextricable dependency between 3S tourism and favourable weather conditions in the coastal zone, it is important to understand both how tourists perceive and evaluate climatic resources, particularly those conditions that are most preferred or avoided (i.e., trigger behavioural responses), as well as examine the adaptive climatic range tourists’ can experience within a coastal setting. Such information is a prerequisite if accurate projections are to be made about changes in tourism demand as a result of climate variability or future climate change. This dissertation proposes a conceptual framework that integrates the multiple facets known to influence tourists’ evaluation of climatic resources, as well as tourists’ responses to holiday weather conditions. The research advances weather and climate resource assessments for tourism by improving our understanding of the complex relationship between personal and meteorological parameters that influence tourists’ climatic preferences and thresholds for coastal tourism. This was achieved through concurrent meteorological measurements and in situ surveys with 472 beach tourists in the Caribbean islands of Barbados, Saint Lucia and Tobago. The results from this study reveal that tourists’ optimal and unacceptable climatic conditions are dependent on several interpersonal factors, with statistically significant differences (p < 0.05) found based on gender, age, and climatic region of origin. Thermal comfort expectations and perceived thermal control were also found to be key contextual considerations that enable beach tourists’ to not only be exposed to, but to prefer, thermal conditions that elicit strong to very strong heat stress. This indicates that conventional evaluation systems of thermal comfort (e.g., PET, UTCI) cannot be applied to 3S tourists without modification. This research also highlights the importance of microclimatic conditions when evaluating weather and climate for tourism, with thermo-physiological comfort varying up to 4°C within a coastal resort setting. The results from this research can be incorporated into existing climate indices and climate change assessments to allow for more robust projections of tourism demand, as well as used in various decision-making contexts by both tourists (e.g., plan best time/place to travel, plan appropriate accommodation, attire, transportation and activity schedule) and the tourism industry (e.g., marketing strategies, risk assessment, operational decision making, infrastructure planning and development).
5

The weather and climate of Australia at the Last Glacial Maximum

Hope, Pandora January 2005 (has links) (PDF)
The global climate has experienced four glacial cycles in the last 420,000 years, with each cycle characterised by a prolonged period of cooling culminating in maximal glaciation followed by a brief warm period. The most recent period of maximal glaciation is termed the Last Glacial Maximum (LGM) and occurred about 21,000 years ago. We currently live in one of the warm periods. The global climate is changing, and it is becoming more important to understand the extremes of the climate system and how well our modelling capability can capture those extremes. / There has been a modelling intercomparison project established to examine how global general circulation models compare in simulating past climates, including the LGM. Analysis and comparison of these model results has been presented for many parts of the globe, but there has not been a comparison of the different model results over the Australian region. This thesis aims to fill that gap and explore the simulated LGM weather and climate of Australia and its drivers in more detail. Comparison with proxy evidence is also undertaken, and inconsistencies seen in the literature addressed. / The Australian climate at the LGM was believed to be generally cooler, drier and possibly windier from proxy evidence in the literature. In the comparison done here the mean temperature and precipitation fields from most models show cooler and drier conditions, with some seasonal variability, but there are some strong outliers. It was found that the differences were not dependent on model resolution, but that the surface parameterisations were highly important for these fields. / The shifts in the circulation were examined both in the model results and with a study of the non-linear link between the wind, surface moisture and dunes, which are a proxy for past winds. All the models simulate a southward shift in the westerlies in the Australian region. This is strongly driven byte prescribed sea-surface temperatures. Australia's current wind regime is conducive to dune building. However, the binding effect of soil moisture (or vegetation) is strong enough to limit present day movement, whereas in the drier climate at the LGM there was a capacity for sand movement. The analysis of dune orientations did not produce conclusive evidence for how the westerlies might have shifted at the LGM. / An apparent enigma in the proxy evidence at the LGM is the high lake levels in Australia’s south east, while most inland lakes were dry. Previous authors believed that the precipitation was still low, but the high lake levels were driven by lowered potential evaporation. The hydrological cycle was generally depressed in the LGM simulations, but the potential for evaporation remained high. Thus an alternative hypothesis is posed based on increased run off due to a known shift in the vegetation types and a lag in the timing of the run off due to snowmelt. / The analysis here shows that our capacity to simulate climates quite different from the present is still developing, but that model results can help explain apparent inconsistencies in the reconstruction of past climates from proxies.
6

Zum Einfluss von Witterung und Klima auf den Landschaftszustand und die Landschaftsentwicklung im Uvs-Nuur-Becken (NW-Mongolei)

Barsch, Andreas January 2003 (has links)
Im Landschaftszustand und in der Landschaftsentwicklung kommen funktionale Beziehungen zwischen dem naturbedingten Energie-, Wasser- und Stoffhaushalt einerseits und den Auswirkungen der Landnutzung andererseits zum Ausdruck. Gegenwärtig verändert der globale Anstieg der bodennahen Temperaturen vielerorts den landschaftlichen Energie-, Wasser- und Stoffhaushalt, wobei besonders in Trockengebieten zu erwarten ist, dass dieser Trend in Verbindung mit einer unangepassten Landnutzung das Regenerationsvermögen der Vegetation einschränkt und zur Zerstörung der Bodendecke führt.<br /> <br /> Für die Mongolei und für benachbarte Gebiete Asiens sind in Szenarien zur globalen Erwärmung hohe Werte des Temperaturanstiegs prognostiziert worden. Eine globale Einschätzung der anthropogen induzierten Bodendegradation hat diese Region als stark oder extrem stark betroffen eingestuft. Vor diesem Hintergrund wurde im Uvs-Nuur-Becken, das im Nordwesten der Mongolei und damit in einer der trockensten Regionen des Landes gelegen ist, untersucht, wie sich der globale Temperaturanstieg auf der lokalen und regionalen Ebene widerspiegelt und wie der Landschaftshaushalt dabei verändert wird.<br /> <br /> Die Auswirkungen des sommerlichen Witterungsverlaufes auf den Landschaftszustand sind 1997 bis 1999 an einem Transsekt erfasst worden, das sich zwischen dem Kharkhiraa-Gebirge am Westrand des Beckens und dem See Uvs Nuur im Beckeninneren von den Polsterfluren und Matten der alpinen Stufe über die Gebirgswaldsteppe, die Trockensteppe bis zur Halbwüste erstreckt. An neun Messpunkten wurden witterungsklimatische Daten in Verbindung mit Merkmalen der Vegetation, des Bodens und der Bodenfeuchte aufgenommen. Die im Sommer 1998 gewonnenen Messwerte wurden mit Hilfe einer Clusteranalyse gebündelt und verdichtet. Auf dieser Grundlage konnten landschaftliche Zustandsformen inhaltlich gekennzeichnet, zeitlich eingeordnet und durch Zeit-Verhaltens-Modelle (Stacks) abgebildet werden. Aus den Zeit-Verhaltens-Modellen wird ersichtlich, dass man Zustandsformen, in denen die Hitze und die Trockenheit des Sommers 1998 besonders stark zum Ausdruck kommen, an allen Messpunkten beobachten kann, nimmt man die Station auf dem fast 3.000 m hohen Gipfel des Khukh Uul sowie die grundwasserbeeinflusste Station in unmittelbarer Seenähe aus. In ihrer extremen Form sind Trockenperioden jedoch nur im Beckeninneren und am Fuß der Randgebirge, also in der Halbwüste, in der Trockensteppe und in der Wiesensteppe aufgetreten. Im Bergwald sowie im Bereich der alpinen Matten und Polsterfluren fehlen sie.<br /> <br /> Am stärksten sind die grundwasserfreien Bereiche der Halbwüste von der Hitze und Niederschlagsarmut des Sommers 1998 betroffen. An vier Fünfteln der Tage des Beobachtungszeitraumes herrscht an diesem Messpunkt extreme Trockenheit. Es fällt entweder gar kein Niederschlag oder nur so wenig, dass der seit dem Frühjahr erschöpfte Bodenwasservorrat nicht aufgefüllt wird. Das Verhältnis zwischen Niederschlag und potenzieller Verdunstung liegt hier bei 1:12.<br /> <br /> In der Halbwüste zeichnet sich eine fortschreitende Desertifikation ab, zumal hier eine nichtangepasste Weidenutzung dominiert, in der Ziegen eine immer größere Rolle spielen. Dies gilt insbesondere für Bereiche in Siedlungsnähe. Örtlich ist auch der Bestand der Trockensteppe gefährdet, die sich an die Halbwüste zum Beckenrand hin anschließt. Hier ist nicht nur die Viehdichte am höchsten, sondern hier werden auch die meisten unbefestigten Fahrwege wild angelegt und die Bodendecke damit zerstört. Dies kann im Endeffekt zu einem Übergreifen von Prozessen der Desertifikation führen.<br /> <br /> Aus methodischer Sicht zeigt sich, dass die Kennzeichnung landschaftlicher Zustandsformen durch Zeit-Verhaltens-Modelle die Ermittlung der Auswirkungen von Witterung und Klima auf den Landschaftszustand erleichtert, da sie deren Aussage konzentriert. Zur Interpretation der Ergebnisse ist jedoch ein Rückgriff auf die beschreibende Darstellung der Messwerte notwendig. Die im westlichen Uvs-Nuur-Becken und seinen Randgebirgen angewandte Verfahrensweise ermöglicht es, globale Aussagen zur globalen Erwärmung der Kontinente regional oder lokal zu überprüfen und zu untersetzen." / Landscape condition and landscape development express the functional relations between energy balance, water balance and material balance on the one hand and on the other hand they reflect the effects of land use. At present the global increase of near-surface air temperature changes the energy balance, water balance and material balance in many places. Especially in arid regions this trend and an inappropriate land use restrict the regeneration ability of vegetation and lead to the degradation of soil cover.<br /> <br /> Different scenarios for global warming prognosticate high values of increasing air temperature in Mongolia and its adjacent regions in Asia. A global estimation of anthropogenicly induced soil degradation classifies this region as strongly or extremely strong affected. Against this background a research was carried out in the Uvs Nuur Basin, placed in the northwest of Mongolia and therefore in one of the most arid regions of this country. The object of investigation was the reflection of the global increase of air temperature on a local and regional level and the resulting changes of landscape balance.<br /> <br /> From 1997 to 1999 the effects of changes in summer weather on the landscape condition were measured on a transect from the Kharkhiraa mountains at the western margin of the basin up to the lake Uvs at the centre of the basin. The transect included alpine mat, mountain steppe, dry steppe and semi desert. Climatic data was collected at 9 transect stations, in addition with characteristics of vegetation, soil and soil moisture. The data of summer 1998 was bundled and consolidated with a cluster analysis. On this basis forms of landscape condition could be evaluated in content, arranged chronologically and characterised by time performance models (stacks).<br /> <br /> The time performance models prove that forms of landscape condition marking the heat and the drought of summer 1998 can be found at every station of the transect except of the one on the summit of Khukh Uul at almost 3.000 m above sea level and another groundwater-influenced station at the bank of lake Uvs. However, extremely dry periods occur only from the centre of the basin up to the foothills, thus in the semi desert, the dry steppe and the short grass steppe. They do not occur in the mountain forest and in the alpine mat.<br /> <br /> Areas in the semi desert are most affected by drought and lack of precipitation during the summer 1998. Four fifths of the days in the measurement period are extremely droughty days. Either there is no precipitation at all or it is insufficient to fill up the soil water storage exhausted since spring-time. The relation of precipitation and potential evaporation averages out here at 1:12.<br /> <br /> A progressive desertification becomes apparent in the semi desert, particularly determined by an inappropriate land use in conjunction with an increasing goat-rearing in the area around the settlements. Partially this trend even affects the dry steppe in adjacency to the semi desert toward the margin of the basin. These areas are characterised not only by the highest stocking rate but also by the largest number of unofficial dirt roads thus leading to the denudation of the soil cover and finally to the spreading of desertification processes.<br /> <br /> From the methodical point of view it is obvious that the characterisation by time performance models facilitates the determination of weather and climate influence on landscape condition by summarising their information. However, the interpretation of the results has to be accomplished by a describing analysis of the measured data. The procedure applied in the western Uvs Nuur Basin and its adjacent mountains provides the opportunity to examine and substantiate the reports on global warming at regional or local level.
7

Short-term effects of ambient temperature on daily deaths and hospital admissions

Rocklöv, Joacim, January 2010 (has links)
Diss. (sammanfattning) Umeå : Umeå universitet, 2010.

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