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Joni Tuomas Vainikka 《GeoJournal》2016,81(1):5-22
Scale is a debatable term in the humanities and social sciences. Conceptualized in human geography as spatial categories of thought, as the arenas where social processes occur, as bounded political-economic frames or as unhelpful binaries privileging either the local or the global, scale intersects a significant body of geographical research. The unfolding and intermeshing of topological connections that help to share moments and experiences are important sources for the differentiation, renewal and recalibration of individual identities, but they often work as co-components to scalar identifications. Engaging with the recent discussion on scale and the upsurge of emotional geographies, I seek to understand how people contextualize space through situated scalar perspectives and how they realign and recognize their identities through embodied emotions. The analysis of the empirical material, that comprises 23 focus groups with locally and universally-orientated civic organizations in Finland and England, focuses on the ways people use landscapes and communities as emotional signposts in their scalar identification. I argue that scale is a situated category, whose spectrum individuals negotiate through the performance of social discourses and cultural practices. In such negotiation, people scale their identity narratives to overcome or emphasize the distinctions between ‘us’ and ‘others’. 相似文献
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An AMS radiocarbon-dated pollen record from a peat deposit on Mitkof Island, southeastern Alaska provides a vegetation history spanning ∼12,900 cal yr BP to the present. Late Wisconsin glaciers covered the entire island; deglaciation occurred > 15,400 cal yr BP. The earliest known vegetation to develop on the island (∼12,900 cal yr BP) was pine woodland (Pinus contorta) with alder (Alnus), sedges (Cyperaceae) and ferns (Polypodiaceae type). By ∼12,240 cal yr BP, Sitka spruce (Picea sitchensis) began to colonize the island while pine woodland declined. By ∼11,200 cal yr BP, mountain hemlock (Tsuga mertensiana) began to spread across the island. Sitka spruce-mountain hemlock forests dominated the lowland landscapes of the island until ∼10,180 cal yr BP, when western hemlock (Tsuga heterophylla) began to colonize, and soon became the dominant tree species. Rising percentages of pine, sedge, and sphagnum after ∼7100 cal yr BP may reflect an expansion of peat bog habitats as regional climate began to shift to cooler, wetter conditions. A decline in alders at that time suggests that coastal forests had spread into the island's uplands, replacing large areas of alder thickets. Cedars (Chamaecyparis nootkatensis, Thuja plicata) appeared on Mitkof Island during the late Holocene. 相似文献
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Joni Downs Mark Horner Rebecca Loraamm James Anderson Hyun Kim Dave Onorato 《Transactions in GIS》2014,18(1):46-65
Crossing structures are an effective method for mitigating habitat fragmentation and reducing wildlife‐vehicle collisions, although high construction costs limit the number that can be implemented in practice. Therefore, optimizing the placement of crossing structures in road networks is suggested as a strategic conservation planning method. This research explores two approaches for using the maximal covering location problem (MCLP) to determine optimal sites to install new wildlife crossing structures. The first approach is based on records of traffic mortality, while the second uses animal tracking data for the species of interest. The objective of the first is to cover the maximum number of collision sites, given a specified number of proposed structures to build, while the second covers as many animal tracking locations as possible under a similar scenario. These two approaches were used to locate potential wildlife crossing structures for endangered Florida panthers (Puma concolor coryi) in Collier, Lee, and Hendry Counties, Florida, a population whose survival is threatened by excessive traffic mortality. Historical traffic mortality records and an extensive radio‐tracking dataset were used in the analyses. Although the two approaches largely select different sites for crossing structures, both models highlight key locations in the landscape where these structures can remedy traffic mortality and habitat fragmentation. These applications demonstrate how the MCLP can serve as a useful conservation planning tool when traffic mortality or animal tracking data are available to researchers. 相似文献
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Although large numbers of imageries over planetary surfaces have been aquired by notable space missions over the past twenty years, the versatile technical remote sensing achievements, which have found their long-term and successful applications within the fields of different geosciences, have not been employed in planetology. High resolution imageries allow small-scale surface features to be observed, various filters allow different wavelength bands and surface units of different colour or spectral reflectance to be recorded. Also long-term missions transmit information about multitemporal changes, but such diversified multitemporal surface mapping, as possible by Landsat MSS data, to say nothing of the potential of the Landsat TM and SPOT equipment, are mostly unexecuted.This paper contains an example of the aquatic environment research by computer-assited remote sensing using Landsat MSS data. The western parts of Lake Yli-Kitka, northeastern Finland were studied and mapped according to spectrally identified classes which were improved after field work by associated reclassification.The Landsat classification of open water areas depends on the water quality and depth, or shore distance relations. The recognition of aquatic vegetation complexes is based on the main life-form (helophytic, nymphaeid, isoetid etc.) and the amount of recorded radiation reflected from the chlorophyll (or from other shallow bottom coverage) in respect to the open water surface radiation absorbance within near infrared wavelengths.Aquatic areas are quite featureless in respect to their reflectance, especially in northeastern Finland area studied. The use of wide-channel multispectral satellite data has demonstrated to be valid under quite difficult circumstances. Similar or preferably more up-to-date planetary imagery data could be of high utility value in mapping various surface units of the terrestrial planets and large moons. 相似文献
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H. Jantunen 《Earth, Moon, and Planets》1983,29(3):225-228
Two bright spots shown by Voyager 2 images on Saturn's north temperate belt are discussed in terms of a simple photometric model in which the brightness differences are caused by obscuring matter above the main cloud layer. In the ultraviolet light, in which scattering by small particles is very effective, the spots are invisible. In the violet light they seem to be holes in the dark matter and therefore the brighter layer below it becomes visible. Also they could be rises in the bright matter. In the green light the spots are more complicated since this wavelength interval contains very strong emission spectra lines of ammonia. 相似文献
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Spatially distributed tracer‐aided modelling to explore water and isotope transport,storage and mixing in a pristine,humid tropical catchment 
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下载免费PDF全文 Joni Dehaspe Christian Birkel Doerthe Tetzlaff Ricardo Sánchez‐Murillo Ana María Durán‐Quesada Chris Soulsby 《水文研究》2018,32(21):3206-3224
Rapidly transforming headwater catchments in the humid tropics provide important resources for drinking water, irrigation, hydropower, and ecosystem connectivity. However, such resources for downstream use remain unstudied. To improve understanding of the behaviour and influence of pristine rainforests on water and tracer fluxes, we adapted the relatively parsimonious, spatially distributed tracer‐aided rainfall–runoff (STARR) model using event‐based stable isotope data for the 3.2‐km2 San Lorencito catchment in Costa Rica. STARR was used to simulate rainforest interception of water and stable isotopes, which showed a significant isotopic enrichment in throughfall compared with gross rainfall. Acceptable concurrent simulations of discharge (Kling–Gupta efficiency [KGE] ~0.8) and stable isotopes in stream water (KGE ~0.6) at high spatial (10 m) and temporal (hourly) resolution indicated a rapidly responding system. Around 90% of average annual streamflow (2,099 mm) was composed of quick, near‐surface runoff components, whereas only ~10% originated from groundwater in deeper layers. Simulated actual evapotranspiration (ET) from interception and soil storage were low (~420 mm/year) due to high relative humidity (average 96%) and cloud cover limiting radiation inputs. Modelling suggested a highly variable groundwater storage (~10 to 500 mm) in this steep, fractured volcanic catchment that sustains dry season baseflows. This groundwater is concentrated in riparian areas as an alluvial–colluvial aquifer connected to the stream. This was supported by rainfall–runoff isotope simulations, showing a “flashy” stream response to rainfall with only a moderate damping effect and a constant isotope signature from deeper groundwater (~400‐mm additional mixing volume) during baseflow. The work serves as a first attempt to apply a spatially distributed tracer‐aided model to a tropical rainforest environment exploring the hydrological functioning of a steep, fractured‐volcanic catchment. We also highlight limitations and propose a roadmap for future data collection and spatially distributed tracer‐aided model development in tropical headwater catchments. 相似文献
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Rio Raharja Endra Gunawan Irwan Meilano Hasanuddin Z. Abidin Joni Efendi 《地震科学（英文版）》2016,29(5):291-298
The Java earthquake occurred on July 17,2006 with magnitude 7.8 associated to the subduction process of Indo-Australian plate and Sundaland block off southwestern coast of Java. We present postseismic deformation parameters of the 2006 Java earthquake analyzed using campaign GPS observation from 2006 to 2008 and continuous observation from 2007 to 2014. We use an analytical approach of logarithmic and exponential functions to model these GPS data. We find that the decay time in the order of hundreds of days after the mainshock as observed by 8 years' data after the mainshock for magnitude 7 earthquake is longer than a general megathrust earthquake event. Our findings suggest that the 2006 Java earthquake which is considered as ‘‘tsunami earthquake' most probably occurred in the region that has low rigidity and tends to continuously slip for long time periods. 相似文献
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Elina Ahokangas Joni Mäkinen 《Boreas: An International Journal of Quaternary Research》2014,43(1):90-106
We provide evidence for the subglacial to ice‐marginal successive deposition of the Lohtaja?Kivijärvi ice lobe margin esker influenced by the changes in the meltwater delivery and proglacial water depth within the Finnish Lake District lobe trunk during the last deglaciation in Finland. The study is mostly based on the sedimentological data from the 100 km long esker chain with 15 logged sites. The long breaks in the lobe margin esker and the re‐emerged deposition along the stable position of the subglacial meltwater route were related to the discontinuities and reappearances of the neighbouring eskers. This considerable variability in the meltwater discharge and debris transport under the described deglacial conditions cannot be explained by markedly decreased meltwater production due to palaeoclimatic factors or lack of debris within the trunk region. The primary control on the changes in meltwater availability and related esker deposition was thus due to the spatial and temporal changes in ice mass properties and shifting of the meltwater flow paths within the trunk. These changes were initiated by the topographically higher and partly supra‐aquatic Suomenselkä watershed area with subsequent deepening of the proglacial water during the deglaciation. The understanding of the long‐lived esker deposition along the former ice‐stream trunk margin adds to the evaluation of palaeoglaciological reconstructions and geomorphologically based spatial models for ice‐stream landscapes. 相似文献
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