Timescales of storage and recycling of crystal mush at Krafla Volcano,Iceland     

Kari M. Cooper  Kenneth W. W. Sims  John M. Eiler  Neil Banerjee 《Contributions to Mineralogy and Petrology》2016,171(6):54

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Gardening at the edge: Documenting the limits of tropical Polynesian kumara horticulture in southern New Zealand     

Kari N. Bassett  Hamish W. Gordon  David C. Nobes  Chris Jacomb 《Geoarchaeology》2004,19(3):185-218

An Erratum has been published for this article in Geoarchaeology 19(6) 2004, 613. Kumara (Ipomoea batatus), a major food source for Maori, was brought to New Zealand from tropical Eastern Polynesia ∼700 years ago. Maori successfully adapted their cultivation techniques to grow kumara in New Zealand's cooler, seasonal climate, although most kumara cultivation was limited to the warmer North Island, with cultivation becoming more marginal southward. Banks Peninsula area is considered to be the southernmost limit for kumara gardening. The Okuora Farm archeological site on the southern side of Banks Peninsula has five pits that appear to be of the raised‐rim type used for over winter storage of kumara tubers. We conducted a preliminary investigation into the nature of the pits and surrounding 1 km² area using nondestructive techniques in accordance with Maori designation of food storage sites as tapu. Ground penetrating radar (GPR) investigation of two of the pits revealed subsurface disturbances consistent with postholes and drains, typical of raised rim kumara storage pits. Soil modification typical of kumara gardening was identified on a 1 ha area on a warm north‐northwest facing hillside. Several large borrow pits were identified as the likely source of the gravel added to the modified soil, possibly to retain heat and moisture. A plant phytolith study of soil samples identified several that appear to be from kumara. The combination of results strongly suggests this site was one of the southernmost Maori kumara gardening sites yet identified in New Zealand. © 2004 Wiley Periodicals, Inc.  相似文献   

Geografi i videregående skole i Fagfornyelsen: Forslag til et rammeverk for feltarbeid som fremmer dybdelæring     

Kari Beate Remmen 《Norsk geografisk tidsskrift. Norwegian journal of geography》2020,74(2):105-110

ABSTRAKT

Feltarbeid har en lang tradisjon i geografiundervisningen, men er fremdeles utfordrende å gjennomføre i skolefaget geografi. Denne artikkelen tar utgangspunkt i et kompetansemål i den nye læreplanen i geografi for videregående skole, utviklet gjennom Fagfornyelsen 2020. I kompetansemålet heter det at elevene skal kunne «gjennomføre eit feltarbeid for å undersøkje og presentere geografiske forhold». Dybdelæring er et viktig begrep i Fagfornyelsen, som blant annet innebærer å utvikle forståelse av begreper og sammenhenger i faget. Dette er ambisiøst for elever som får undervisning i geografi to timer per uke i ett år i videregående skole. I artikkelen undersøkes elementer som kan være viktige å ta hensyn til i undervisning av det overnevnte kompetansemålet. Gjennom drøfting av teori og empiriske eksempler identifiseres elementer som kan fremme dybdelæring: gi et oppdrag om å løse en arealsak og åpne for at elevene kan trekke inn egne etno-geografiske erfaringer, forbered elevene på feltarbeidet gjennom å øve på ferdigheter, gjennomfør feltarbeidet i nærmiljøet, diskuter data i lys av teori og etno-geografiske erfaringer, og reflekter over egne beslutninger i arealsaken. Disse elementene kan til sammen fungere som et rammeverk for lærere og forskere som skal designe feltarbeid i geografiundervisning som fremmer dybdelæring.  相似文献   

Spatial inference with an interchangeable rule format     

Raimo Nikkilä  Edward Nash  Jens Wiebensohn  Ilkka Seilonen  Kari Koskinen 《International journal of geographical information science》2013,27(6):1210-1226

Rule interchange between information systems is expanding as new interoperable rule formats are emerging from research. However, existing spatial inference systems generally operate on locally stored data with an internal rule format. Consequently, their design offers little support or facilities for rule interchange. This article presents the requirements, components and design for a spatial inference system with rule interchange. Computational efficiency and overall functionality of the design are considered separately, with the latter demonstrated using encoded agricultural legislation and data. A spatial inference system with rule interchange is based on three primary components: rule representation, spatial functionality and data integration. Of these, the interoperable rule representation and data integration distinctly differ from existing spatial inference systems. The presented inference system combines a spatial superset of the W3C Rule Interchange Format (RIF) with full Open Geospatial Consortium simple feature access (OGC SFA) functionality and on-demand data integration utilising Resource Deception Framework (RDF). The design was found to be effective with a computational efficiency depending predominantly on the spatial operations. This design could be further adapted to implement spatial extensions for existing inference systems. Considerable benefits were also discovered when RIF was used as the native language for the inference engine, thereby removing the need for rule transformations and facilitating on-demand data integration with the GML.  相似文献   

Lithostratigraphy and Optically Stimulated Luminescence age determinations of pre‐Late Weichselian deposits in the Suupohja area,western Finland     

Reijo Pitkäranta  Juha‐Pekka Lunkka  Kari O. Eskola 《Boreas: An International Journal of Quaternary Research》2014,43(1):193-207

The lithostratigraphy of pre‐Late Weichselian sediments and OSL‐dating results from four localities in the Suupohja area of western Finland, adjacent to the centre of the former Scandinavian glaciations, are presented. The studied sections expose glacifluvial, quiet‐water, littoral and aeolian deposits overlain by Middle and/or Late Weichselian tills. Litho‐ and biostratigraphical results together with seven OSL age determinations on buried glacifluvial sediment at Rävåsen (94±15 ka) and on till‐covered littoral and aeolian sediments at Risåsen, Rävåsen, Jätinmäki and Kiviharju (79±10 to 54±8 ka), accompanied by previous datings and interpretations, suggest that the glacifluvial sediments at Risåsen were deposited at the end of the Saalian Stage (MIS 6) and those at Risåsen were deposited possibly in the Early Weichselian Substage (MIS 5d?). Palaeosol horizons and ice‐wedge casts together with the dated littoral and aeolian sediments between the Harrinkangas Formation (Saalian) and the overlying till(s) indicate that western Finland was ice‐free during most of the Weichselian time. Littoral deposits, dated to the Middle Weichselian (MIS 4–3), occur at altitudes of 50–90 m a.s.l., which indicates significant glacio‐isostatic depression. The depression resulted from expansion of the ice sheet in the west of Finland at that time.  相似文献   

Evaluation of snow products over the Tibetan Plateau          下载免费PDF全文

Juntao Yang  Lingmei Jiang  Cécile B. Ménard  Kari Luojus  Juha Lemmetyinen  Jouni Pulliainen 《水文研究》2015,29(15):3247-3260

Four satellite‐based snow products are evaluated over the Tibetan Plateau for the 2007–2010 snow seasons. The Moderate Resolution Imaging Spectroradiometer (MODIS) Terra and Aqua snow cover daily L3 Global 500‐m grid products (MOD10A1 and MYD10A1), the National Oceanic and Atmospheric Administration Interactive Multisensor Snow and Ice Mapping System (IMS) daily Northern Hemisphere snow cover product and the Advanced Microwave Scanning Radiometer – Earth Observing System Daily Snow Water Equivalent were validated against Thematic Mapper (TM) snow cover maps of Landsat‐5 and meteorological station snow depth observations. The overall accuracy of MOD10A1, MYD10A1 and IMS is higher than 91% against stations observations and than 79% against Landsat TM images. In general, the daily MODIS snow cover products show better performance than the multisensor IMS product. However, the IMS snow cover product is suitable for larger scale (~4km) analysis and applications, with the advantage over MODIS to allow for mitigation for cloud cover. The accuracy of the three products decreases with decreasing snow depth. Overestimation errors are most common over forested regions; the IMS and Advanced Microwave Scanning Radiometer – Earth Observing System Snow Water Equivalent products also show poorer performance that the MODIS products over grassland. By identifying weaknesses in the satellite products, this study provides a focus for the improvement of snow products over the Tibetan plateau. The quantitative evaluation of the products proposed here can also be used to assess their relative weight in data assimilation, against other data sources, such as modelling and in situ measurement networks. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Return to Black Mountain: palaeomagnetic reassessment of the Chatsworth and Ninmaroo formations, western Queensland, Australia   总被引：1，自引：0，他引：1  

Kari L. Anderson  Mark A. Lackie  David A. Clark  Phil W. Schmidt 《Geophysical Journal International》2004,157(1):87-104

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Early and Middle Valdaian glaciations, ice-dammed lakes and periglacial interstadials in northwest Russia: new evidence from the Pyoza River area     

Michael Houmark-Nielsen  Igor Demidov  Svend Funder  Kari Grsfjeld  Kurt H. Kjr  Eiliv Larsen  Nadya Lavrova  Astrid Lys  Jan K. Nielsen 《Global and Planetary Change》2001,31(1-4)

The Pyoza River area in the Arkhangelsk district exposes sedimentary sequences suitable for study of the interaction between consecutive Valdaian ice sheets in Northern Russia. Lithostratigraphic investigations combined with luminescence dating have revealed new evidence on the Late Pleistocene history of the area. Overlying glacigenic deposits of the Moscowian (Saalian) glaciation marine deposits previously confined to three separate transgression phases have all been connected to the Mikulinian (Eemian) interglacial. Early Valdaian (E. Weichselian) proglacial, lacustrine and fluvial deposits indicate glaciation to the east or north and consequently glacier damming and meltwater run-off in the Pyoza area around 90–110 ka BP. Interstadial conditions with forest-steppe tundra vegetation and lacustrine and fluvial deposition prevailed at the end of the Early Valdaian around 75–95 ka BP. A terrestrial-based glaciation from easterly uplands reached the Pyoza area at the Early to Middle Valdaian transition around 65–75 ka BP and deposited glaciofluvial strata and subglacial till (Yolkino Till). During deglaciation, laterally extensive glaciolacustrine sediments were deposited in ice-dammed lakes in the early Middle Valdaian around 55–75 ka BP. The Barents–Kara Sea ice sheet deposited the Viryuga Till on the lower Pyoza from northerly directions. The ice sheet formed the Pyoza marginal moraines, which can be correlated with the Markhida moraines further east, and proglacial lacustrine deposition persisted in the area during the first part of the Middle Valdaian. Glacio-isostatic uplift caused erosion followed by pedogenesis and the formation of a deflation horizon in the Middle Valdaian. Widely dispersed periglacial river plains were formed during the Late Valdaian around 10–20 ka BP. Thus, the evidence of a terrestrial-based ice sheet from easterly uplands in the Pyoza area suggests that local piedmont glaciers situated in highlands such as the Timan Ridge or the Urals could have developed into larger, regionally confined ice sheets. Two phases of ice damming and development of proglacial lakes occurred during the Early and Middle Valdaian. The region did not experience glaciation during the Late Valdaian.  相似文献   

Some photometric properties of the Martian south polar cap region during the 1971 apparition     

Kari Lumme  Philip B. James 《Icarus》1984,58(3):363-376

High-quality Earth-based photographs from the Lowell Observatory Planetary Research Center collection have been analyzed to derive some photometric parameters for the Martian south polar cap region during the 1971 apparition. The optical thickness of the atmosphere above the cap varied with wavelength from 0.35 ± 0.05 in red light to 0.58 ± 0.06 inuv light. The effective geometric albedo is calculated from the 30° phase data assuming isotropic scattering; it varies from 0.85 ± 0.04 (in red light) to 0.63 ± 0.05 (in uv light).  相似文献   

Quaternary foraminifera and sediments in the Norwegian Channel     

Jenö Nagy  Kari Ofstad 《Boreas: An International Journal of Quaternary Research》1980,9(1):39-52

The foraminiferal fauna and lithology of 17 short sediment cores from two profiles in the Norwegian Channel have been investigated. Three ecostratigraphical zones are distinguished and their depositional environment, age and correlation with adjacent areas are discussed. The zones form a climatically conditioned succession (from below): the Cassidulina-Nonion zone contains an arctic fauna affected by meltwater influx, and its deposition was in progress in Late Weichselian; the Uvigerina-Cassidulina zone with a mixed fauna of arctic and boreal species is referred to the Early Flandrian; the Uvigerina-Bulimina zone contains a boreal fauna and was deposited under influence of Atlantic water; its age is regarded as Middle and Late Flandrian. Transport and deposition of sediments in the channel is discussed on the basis of recent current conditions and distribution of the zones.  相似文献