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1.
The effect of climatic changes on human comfort levels was investigated through examination and statistical analysis of long-term trends in human discomfort during summer months in the desert city of Beer Sheva, Israel and in the adjacent rural area of Wadi Hatzerim. In an era of global warming, the urban warming effect is likely to be amplified and as a result increase human discomfort, especially during summer.Climate data for the city of Beer Sheva over the last 40 years shows an increase of temperature and air humidity in comparison to the surrounding rural area. Wind velocity data for Wadi Hatzerim show that changes are inconstant and not significant, while in Beer Sheva, wind velocity is significantly reduced. Two indices – the Discomfort Index (DI) and Physiological Equivalent Air temperature (PET) – were used to evaluate the effect of these climatic changes on human discomfort. Although the bio-meteorological indices showed the same tendency of increasing heat stress values and duration, in Beer Sheva they were more pronounced and more significant than in the desert environment. The study concludes that these combined climatic effects negatively impact human comfort and are more noticeable in desert cities at peak daytime hours during summer.  相似文献   

2.
Geografisk Tidsskrift—Danish Journal of Geography 110(2):245–259, 2010

This paper presents results of recent archaeological research at the site of Oakes Bay 1 (HeCg-08), on Dog Island, Labrador, dated from the late 17th to late 18th century. Analyses of faunal remains provide a means of reconstructing the site's subsistence economy. The site's inhabitants practiced a very consistent mode of hunting throughout this time period, depending heavily on adult ringed seals taken on the fast ice in winter and spring. Juvenile ringed seals, taken at the ice edge in the spring were a secondary resource. A lack of evidence for the hunting of harp seals in the fall and of ringed seal pups in late spring suggests that the site had a relatively short season of occupation. The consistent pattern of hunting through time suggests that the impacts of climatic variability on Inuit subsistence in the Nain region were relatively limited, moderated by their capacity for mobility on the sea ice rather than by whole scale changes in hunting practices and species choice. The Oakes Bay 1 site presents an example of a different subsistence economy than that seen at other recently examined sites in Labrador, suggesting that the impacts of the so-called Little Ice Age were not global or uniform.  相似文献   

3.
One significant effect of urbanization is the modification of natural surfaces, local environment, and thermal comfort. Farmland and agricultural land in Klang Valley conurbation, Malaysia have been replaced with engineered surfaces and infrastructures to accommodate the rapid population growth witnessed in the past decades. To understand the current environmental conditions of the conurbation, numerical Weather Research and Forecasting (WRF) model coupled to the Urban Canopy Model (UCM) was used. A model evaluation conducted against a network of observations showed an overall good performance of the model in predicting near-surface meteorological parameters. Also, an examination of spatiotemporal variability of urban parameters revealed a diurnal dependence of human physiological thermal conditions on urbanization level. A maximum urban heat island intensity (UHII) of ∼2.64 °C was observed. In an effort to investigate the effect of urbanization level on the extremities of urban climatic conditions, two different experiments with varying urban/vegetation fractions were further simulated. The latter results indicate that urbanization level has a significant effect on the extremities of urban climatological parameters and spatial extent of the induced impacts. Furthermore, the effect of urbanization level on the mean urban outdoor thermal discomfort (UOTD) level was significant (with an increase of 0.7 °C, 0.64 °C and 0.04 observed) for temperature humidity index (THI), effective temperature index (ETI) and relative strain index (RSI), respectively. However, a non-significant (at 95% level) effect of urbanization level on the extremities of UOTD indices was observed.  相似文献   

4.
云南西庄河流域具有发展粮食和经济作物生产的良好条件。主要粮食作物是小麦、玉米、水稻、杂粮(苦荞、黍),主要经济作物是茶及桑树。由于作物生长具有复杂的生物物理机制和生物化学变化过程,不同作物对气候条件如光、热、水的需求是有差异的。为了监测西庄河流域气候特征,特地在流域中部设立了一个观测站,获得了该流域的主要气象要素特征值,使主要栽培作物的农业气候资源分析成为可能。本文对西庄河流域的农业气候特点及其对主要栽培作物的影响进行了分析,并进一步提出:西庄河流域属于水稻、桑、烟叶分布区;玉米、苦荞、黍分布适宜区;小麦、茶生态分布最适宜区。  相似文献   

5.
Despite the present hyper-aridity, archaeological investigations in South-east Arabia have demonstrated that the region supported extensive human communities throughout the Neolithic and Bronze Age. These early populations utilised the region’s natural environment in a variety of ways, ranging from the exploitation of coastal resources to practicing pastoral and agrarian lifestyles in the interior. Palaeoclimate data suggests the corresponding period was characterised by considerable climatic variability yet, to date, few studies have attempted to investigate the relationship between climate, the environment and early human populations in the region. This paper combines new high-resolution palaeoclimate data from Awafi palaeolake, United Arab Emirates (UAE), with the region’s archaeological record from the Neolithic through to the onset of the Bronze Age. The evidence presented in this paper suggests that the environment of South-east Arabia offered different constraints and opportunities for early human occupation and subsistence. In particular, abrupt phases of aridity are demonstrated to have had a profound impact. Most notable is the change which occurred following the onset of climatic aridity at 5900 cal yr BP, when the region’s semi-nomadic, herder-gatherer populations abandoned much of the landscape and concentrated in selected environmental refugia, such as along the northern Omani coast. Human repopulation during the Bronze Age coincided with a return to more pluvial conditions under which a network of oasis agricultural settlements appeared along the piedmont zone of the northern Hajar Mountains.  相似文献   

6.
风蚀气候侵蚀力研究进展   总被引:1,自引:0,他引:1  
风蚀气候侵蚀力是土壤风蚀方程中的气候因子,计算模型经多次修正后已基本发展成熟,广泛应用于干旱半干旱地区风蚀气候条件评估与响应机理分析及其与风沙地貌、风沙灾害的相关性研究等方面,其中风蚀气候侵蚀力对区域气候变化的响应研究是当下的热点问题。目前,风蚀气候侵蚀力研究仍存在计算模型不完善、研究区域发展不平衡、气候变化响应分析不全面、风沙地貌及风沙灾害相关性争议较多等问题。未来应进一步从构建区域校准性计算模型、计算并分析沿海地区风蚀气候侵蚀力、综合分析风蚀气候侵蚀力对气候变化的响应、建立风沙地貌及风沙灾害相关的综合性风蚀气候评价指标等方面开展风蚀气候侵蚀力的研究。  相似文献   

7.
Subsistence agriculture continues to be the mainstay activity in most tropical regions, and opinions on how it impacts tropical deforestation vary significantly. The sparse literature available on subsistence farm-based models highlights the existing methodological gap in the ability of present-day agent-based models (ABMs) to simulate the impact of subsistence production on frontier tropical deforestation. Though issues concerning agent specification and its variability have been successfully dealt with, gaps exist in the explicit incorporation and articulation of linkages of subsistence production and consumption theories on the one hand and frontier tropical deforestation on the other hand. This demands explicit determination of the decision-making process and the objective functions for subsistence farmers. Once simulated, the trajectories of deforestation and its trigger mechanisms can be understood. Overall, farm-based ABMs have the potential to allow insightful understanding of the small and slow individual homogeneous subsistence practices that have resulted in massive deforestation in the tropics.  相似文献   

8.
能源消费与气候关系的中美比较研究   总被引:3,自引:3,他引:3  
袁顺全  千怀遂 《地理科学》2003,23(5):629-634
应用多项式模型把气候耗能量从能源消费总量中分离出来,用统计分析的方法探讨了中国和美国气候耗能量与气候因子之间的关系及其变化。研究表明:温度是美国近50年来影响气候耗能量的主要气候因子,中国从20世纪50年代到80年代初,旱涝灾害一直是影响中国气候耗能量的主要气候因子,它们之间存在有明显的线性相关关系,自20世纪80年代初以来,随着经济的发展和人民生活水平的提高,旱涝灾害对气候耗能量的影响明显减弱,温度对气候耗能量的影响逐渐增强,如果仅考虑气候耗能量,目前中国的能源消费变化正处于由气象灾害驱动型向温度驱动型的过渡时期。  相似文献   

9.
The computer simulation of a Lake Baikal seismic profile located in the Selenga River Delta area resulted in a lake level record of the last 600 kyr. This curve demonstrates several low-magnitude episodes and both a dramatic 300 m fall and a more than 150 m increase of the lake level relative to present situation. The greatest change in paleo-lake depth at 300 ka corresponds in time with the major glaciation in the Eastern Siberia and is probably the response of the lake to this climatic phenomenon. The results of this study conform with existing hypotheses on the regional tectonic history and climatic events.  相似文献   

10.
With basic information from 8353 archaeological sites, this study describes a holistic spatial-temporal distribution pattern of archaeological sites of the prehistoric culture sequence from 9.5 ka BP (ka BP = thousands of years before 0 BP, where "0 BP" is defined as the year AD 1950) to 2.3 ka BP in the region that extends from the Yanshan Mountains to the Liaohe River Plain(i.e., the Yan-Liao region) in northern China. Based on spatial statistics analysis – including the spatial density of the sites and Geographic Information System nearest-neighbour analysis, combined with a review of environmental and climatic data – this paper analyses cultural evolution, the spatial-temporal features of the archaeological sites and human activities against the backdrop of climatic and environmental changes in this region. The results reveal that prehistoric cultural evolution in the Yan-Liao region is extensively influenced by climatic and environmental changes. The Xinglongwa, Zhaobaogou and Fuhe cultures, which primarily developed during a habitable period from 8.5 ka BP to 6.0 ka BP with strong summer monsoons, have similar maximum density values, spatial patterns and subsistence strategies dominated by hunting-gathering. Significant changes occurred in the Hongshan and Lower Xiajiadian cultures, with a significant increase in numbers and densities of sites and a slump in average nearest-neighbour ratio when the environment began to deteriorate starting in 6.0 ka BP. Additionally, with the onset of a weak summer monsoon and the predominance of primitive agriculture, sites of these two cultures present a different type of concentric circle-shaped pattern in space. As the environment continuously deteriorated with increasing aridity and the spread of steppe, more sites were distributed towards the south, and primitive agriculture was replaced by livestock husbandry in the Upper Xiajiadian culture. The most densely populated areas of the studied cultures are centralized within a limited area. The Laohahe River and Jiaolaihe River basins formed the core area in which most archaeological sites were distributed during the strong summer monsoon period and the first few thousand years of the weak summer monsoon period.  相似文献   

11.
《The Journal of geography》2012,111(8):483-486
Abstract

Although subsistence agriculture may receive little attention in the classroom, it employs the majority of the world's farmers. One way to emphasize the importance of subsistence agriculture in class is to use a simulation game such as the Subsistence Agriculture Game, which allows students to play the role of actual farmers in Central America. The Game represents a new teaching technique available for use and further investigation by geographers.  相似文献   

12.
Analyses of agricultural growth in subsistence economies may be facilitated if agricultural intensity is viewed in terms of the concentration of production or yield per unit area and time. This view of agricultural intensity is implicit in many growth arguments and is consistent with their purpose. Limited production data from various subsistence economies necessitate the use of a surrogate measure of intensity that is based on a variety of input factors.  相似文献   

13.
The Pacific island nation-state of Tuvalu featured significantly at the Copenhagen Conference of Parties (COP) 15 climate change negotiations, where the vulnerability of Tuvalu to sea level rise and emotional outpourings of the Tuvaluan delegation contributed to the nation's prominence. In this paper we discuss the likely impacts for Tuvalu of a 1.5°C versus 2°C global warming target and explore sadness and discomfort surrounding discussion of these targets during COP 15. We highlight tensions between science and emotion, arguing that affective encounters can be significant in climate change decision-making. Weeping by a member of the Tuvalu delegation evoked discomfort in the conference plenary. This discomfort briefly unsettled the apparently stable boundaries of convention and protocol that seek to separate emotion from science and politics. We argue that possibilities for change arise when emotions enter climate change negotiations, even though (or perhaps because) these are arenas that privilege rational exchange. Our conclusion urges that more attention be paid to how climate science and emotion are intertwined in climate change politics.  相似文献   

14.

Analyses of agricultural growth in subsistence economies may be facilitated if agricultural intensity is viewed in terms of the concentration of production or yield per unit area and time. This view of agricultural intensity is implicit in many growth arguments and is consistent with their purpose. Limited production data from various subsistence economies necessitate the use of a surrogate measure of intensity that is based on a variety of input factors.  相似文献   

15.
During most of the early and middle Holocene, Lake Rudolf was 75m deeper than today, flooding the Kibish Lake Plain as much as 60–100km north and northwest of the modern shore, with periodic overflow across the White Nile watershed. The landforms and sediment sequences of this lake plain are mapped or profiled, described, and integrated into a regional geomorphologic framework, controlled by a suite of 14C dates. High lake stands are dated 10,000–7,000, 6500–4000 and about 3250 years ago (uncalibrated), with levels fluctuating around that of the present 7000–6500 and since 2500 years. Environmental changes of such magnitude reflect long-term changes of East African climate, so that the Rudolf Basin provides a well-documented index of regional climatic trends for the last 10 millenia. Since shortly after 10,000 years, prehistoric fishing and hunting settlements dotted the rivers and shorelines, favored by optimal aquatic resources but inhibited by a higher incidence of malaria. Aquatic subsistence patterns survived severe but temporary lake shrinkage 7000 years ago; during the last 5 millennia they have gradually given way to pastoral cultures. The Kibish Lake Plain serves to illustrate that geographic landscape analysis can rarely afford to be ahistorical.  相似文献   

16.
Stream-terrace genesis: implications for soil development   总被引:3,自引:0,他引:3  
Genesis of three distinct types of stream terraces can be understood through application of the concepts of tectonically induced downcutting, base level of erosion, complex response, threshold of critical power, diachronous and synchronous response times, and static and dynamic equilibrium. Climatic and tectonic stream terraces are major terraces below which flights of minor complex-response degradation terraces can form.These three types of terraces can be summarized by describing a downcutting-aggradation-renewed downcutting sequence for streams with gravell bedload. By tectonically induced downcutting, streams degrade to achieve and maintain a dynamic equilibrium longitudinal profile at the base level of erosion. Lateral erosion bevels bedrock beneath active channels to create major straths that are the fundamental tectonic stream-terrace landform. Aggradation events record brief reversals of long-term tectonically induced downcutting because they raise active channels. They may be considered as major (the result of climatic perturbations) or minor (the result of complex-response model types of perturbations). Climatically controlled aggradation followed by degradation leaves an aggradation surface; this type of fill-terrace tread is the fundamental climatic stream-terrace landform. Aggradation surfaces may be buried by subsequent episodes of deposition unless intervening tectonically induced downcutting is sufficient for younger aggradation surfaces to form below older surfaces. Raising of the active channel by either tectonic uplift or by climatically induced aggradation provides the vertical space for degradation terraces to form; first in alluvial fill and then in underlying bedrock along tectonically active streams. These are complex-response terraces because they result from interactions of dependent variables within a given fluvial system. Pauses in degradation to a new base level of erosion, and/or minor episodes of backfilling, lead to formation of complex-response fill-cut and strath, or of fill terraces. Fill-cut terraces are formed in alluvium; they are complex-response terraces because they are higher than the base level of erosion. Good exposures and dating are needed to distinguish static equilibrium complex-response minor strath terraces from dynamic equilibrium tectonic (major) straths. Strath terraces may be regarded as complex-response terraces where degradation rates between times terrace-tread formation exceed the long-term uplift rate for the reach based on ages and positions of tectonic terraces.Late Quaternary global climatic changes control aggradation events and even the times of cutting of major (tectonic) straths, because the base level of erosion can not be attained during times of climatically driven aggradation-degradation events.Most terrace soils form on treads of climatic and complex-response terraces. Aggradation surfaces may provide an ideal flight of terraces on which to study a soils chronosequence. Each aggradation event is recorded by a single relict soil where tectonically induced downcutting is sufficient to provide clear altitudinal separation of the terrace treads. Multiple paleosols are typical of tectonically stable regions where younger aggradation events spread alluvium over treads of older climatic terraces. Pedons on a climatic terrace in a small fluvial system commonly are roughly synchronous - variations of soil properties that can be attributed to temporal differences will be minor compared to altitudinally controlled climatic factors. Climatic terraces of adjacent watersheds also should be roughly synchronous (correlatable) - variations of soil properties that can be attributed to temporal differences will be minor compared to lithologic and climatic factors between different watersheds. Such generalizations may not apply to basins with sufficient relief that geomorphic responses to climatic changes occur at different and overlapping times, and to large rivers whose widely separated reaches are characterized by different response times to climatic perturbations. Soils on climatic terraces of distant watershedswill not be synchronous if their respective aggradation events occur during full-glacial times and interglacial times. Soils on some complex-response terraces may be diachronous within a given fluvial system, and typically are diachronous between watersheds.  相似文献   

17.
Paleolimnological data are presented on trophic development, climatic change and sea level variations in Negra Lagoon, a 142 km2 coastal lagoon in southern Uruguay. Using a sediment core that extended to the early Holocene, analyses of organic matter, carbonate, diatoms and opal phytoliths allowed us to track changes in trophic state and paleosalinity levels, which were closely related to Holocene sea level variation, temperature and humidity. Diatom Association Zones (DAZ) corresponding to transgressive events were dominated by marine/brackish taxa and relatively low organic matter values, while those DAZ corresponding to regressive events showed increases in brackish/freshwater diatoms and organic matter. Opal Phytoliths Association Zones (OPAZ) also were identified, temperature and humidity indices were calculated, and climatic trends were inferred. During the middle Holocene (i.e., ~5000–4000 yr BP), cool–dry climatic conditions were established. After ~4000 yr BP, a transition from cool to warm–humid conditions was observed, but fully warm humid conditions established only after ~1700 yr BP. Such climatic amelioration led to increases in trophic state.  相似文献   

18.
Central Sahara rock shelters offer an early and middle Holocene environmental reconstruction. This paper summarises palynological research carried out within a multidisciplinary archaeological research project on the Wadi Teshuinat area (Tadrart Acacus Mts., in south-western Fezzan, Libya). The sites were occupied by hunter-gatherer and pastoralist cultures. On-site pollen data, treated as a single ‘regional site’, showed that different pollen stratigraphies and flora characterised the past phases. Plant macro-remains also helped to understand local plant exploitation and landscape evolution. Pollen spectra showed the following climate oscillations: wet and cool (approx. 8800–8250 cal. BC), dry and warm (approx. 7920–7520 cal. BC), wet (approx. 7550–7200 cal. BC), dry (approx. 6340–6210 cal. BC—geoarchaeological evidence), wet and warm (approx. 6250–4300 cal. BC, including a wetter and warmer phase at approx. 5500–4600 cal. BC); dry and warm (approx. 4250–2900 cal. BC); drier and warm (approx. 2900–1600 cal. BC, up to the present). Since the early Holocene, both climatic and anthropic factors have played an important and strictly interconnected role in transforming the environment. Thus, while subsistence strategies were adjusting to climatic and environmental changes, the plant landscape was also being slowly and continuously shaped by humans.  相似文献   

19.
The level fluctuations of Lake Ilay, Jura (France) during the last three millennia are reconstructed from sedimentological and malacological analyses of a core that is well-dated by tree-ring, radiocarbon and pollen datings. Changes in sediment facies, in carbonate concretion assemblages and in mollusc assemblages highlight a major lowering phase atc. 1550 BP and minor lowering phases atc. 2800 BP and shortly before AD 1394. Rises in lake level developed during the early Subatlantic and betweenc. 1500 and 1000 BP. These data are in good agreement with other proxy data from higher European and American latitudes. These correlations support the climatic origin of the level fluctuations of the Lake Ilay during the late Holocene. They suggest that the mediaeval climatic optimum is centred rather in the early than the late Middle Age.  相似文献   

20.
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