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   

Oxygen ion escape at Mars in a hybrid model: High energy and low energy ions     

Esa Kallio  Kaijun Liu  Valter Pohjola 《Icarus》2010,206(1):152-163

We have studied the escape and energization of several O⁺ populations and an population at Mars by using a hybrid model. The quasi-neutral hybrid model, HYB-Mars model, included five oxygen ion populations making it possible to distinguish photoions from oxygen ions originating from charge exchange processes and from the ionosphere.We have identified two high-energy ion components and one low-energy ion component of oxygen. They have different spatial and energy distributions near Mars. The two high-energy oxygen ion components, consisting of a high-energy “beam” and a high-energy “halo”, have different origins. (1) The high-energy (>∼100 eV) “beam” of O⁺ and ions are originating from the ionosphere. These ions form a highly asymmetric spatial distribution of escaping oxygen ions with respect to the direction of the convective electric field in the solar wind. (2) The high-energy (>∼100 eV) “halo” component contains O⁺ ions which are formed from the oxygen neutral exosphere by extreme ultraviolet radiation (EUV) and by charge exchange processes. These energetic halo ions can be found all around Mars. (3) The low energy O⁺ and ions (<∼100 eV) form a relatively symmetric spatial distribution around the Mars-Sun line. They originate from the ionosphere and from charge exchange processes between protons and exospheric oxygen atoms.The existence of the low- and the high-energy oxygen components is in agreement with recent in situ plasma measurements made by the ASPERA-3 instrument on the Mars Express mission. The analysis of the escaping oxygen ions suggests that the global energization of escaping planetary ions in the martian tail is controlled by the convective electric field.  相似文献   

Biomarker responses as indication of contaminant effects in blue mussel (Mytilus edulis) and female eelpout (Zoarces viviparus) from the southwestern Baltic Sea   总被引：1，自引：0，他引：1  

Schiedek D  Broeg K  Barsiene J  Lehtonen KK  Gercken J  Pfeifer S  Vuontisjärvi H  Vuorinen PJ  Dedonyte V  Koehler A  Balk L  Schneider R 《Marine pollution bulletin》2006,53(8-9):387-405

During a field study performed in spring and autumn 2001 and 2002, blue mussels (Mytilus edulis) and female eelpout (Zoarces viviparus) were collected at three locations in the Wismar Bay (Baltic Sea), and several biomarkers of contaminant effects were analysed. Besides seasonal and inter-annual variations, biomarker signals were most pronounced at the location closest to Wismar Harbour (Wendorf) in both species. Lysosomal membrane stability (LMS) was lowest and acetylcholinesterase activity (AChE) was significantly reduced. Frequency of micronuclei (MN) was significantly higher (in blue mussels), indicating mutagenic effects. In eelpout elevated levels of DNA adducts, EROD induction and PAH-metabolites were measured. Metallothionein (MT), biomarker for trace metal exposure, showed a gradient only in spring. Organochlorine contaminant analyses (PCBs, DDTs) corresponded to the observed biomarker levels. The results obtained clearly demonstrate pollution effects in the southwestern Baltic Sea. Moreover, they show that a multibiomarker approach is also applicable in a brackish water environment.  相似文献   

Location of the bow shock and ion composition boundaries at Venus—initial determinations from Venus Express ASPERA-4     

C. Martinecz  M. Fränz  N. Krupp  E. Dubinin  S. Barabash  M. Holmström  M. Yamauchi  Y. Futaana  H. Gunell  J.D. Winningham  J. Scherrer  D.R. Linder  E. Kallio  W. Schmidt  H.E.J. Koskinen  J. Luhmann  E.C. Roelof  C.C. Curtis  B.R. Sandel  J.-A. Sauvaud  J.-J. Thocaven  S. McKenna-Lawler  R. Cerulli-Irelli  A. Mura  P. Wurz  P. Bochsler  K. Szego  T.L. Zhang 《Planetary and Space Science》2008,56(6):780-784

For the first time since 1992 when the Pioneer Venus Orbiter (PVO) ceased to operate, there is again a plasma instrument in orbit around Venus, namely the ASPERA-4 flown on Venus Express (inserted into an elliptical polar orbit about the planet on April 11, 2006). In this paper we report on measurements made by the ion and electron sensors of ASPERA-4 during their first five months of operation and, thereby, determine the locations of both the Venus bow shock (BS) and the ion composition boundary (ICB) under solar minimum conditions. In contrast to previous studies based on PVO data, we employ a 3-parameter fit to achieve a realistic shape for the BS. We use a different technique to fit the ICB because this latter boundary cannot be represented by a conic section. Additionally we investigate the dependence of the location of the BS on solar wind ram pressure (based on ASPERA-4 solar wind data) and solar EUV flux (using a proxy from Earth).  相似文献   

Magnetized Mars: Transformation of Earth-like magnetosphere to Venus-like induced magnetosphere     

E. Kallio  S. Barabash  R. Jarvinen 《Planetary and Space Science》2008,56(6):823-827

Using a global numerical model, we have studied how the present Martian magnetosphere may have looked in the past when the planet had a global intrinsic magnetic field. A Mars version (HYB-Mars) of the self-consistent quasi-neutral hybrid model was used which treats the ions as particles and the electrons as a massless charge-neutralizing fluid. We compare four cases where an intrinsic dipole magnetic field was 0 nT (the present situation), 10, 30, and 60 nT at the surface of Mars along the magnetic equator. We find that the 10 nT dipolar magnetic field already results in a magnetosphere which in many respects is more Earth-like than, a non-magnetized, “induced” magnetosphere. However, the 10 nT dipole magnetosphere is still relatively strongly connected to the interplanetary magnetic field, while the 30 nT dipole case, and especially the 60 nT dipole case, results in a magnetosphere whose morphology is determined predominantly by the Martian intrinsic magnetic field. A change of the magnetosphere due to a decreasing dipole magnetic field strength from 60 to 0 nT could have happened during the history of Mars when a globally magnetized Mars turned into the present, globally non-magnetized, planet.  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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Depositional history of peatland pines (Pinus sylvestris L.) in NW Enontekiö, Finnish Lapland: implications for Middle Holocene drought and temperature fluctuations     

Samuli Helama  Hannu Herva  Joonas Uusitalo  Andy Moir  Kari Mielikäinen  Pekka Nöjd  Markku Oinonen  Raimo Sutinen 《Boreas: An International Journal of Quaternary Research》2023,52(3):427-439

High altitude and latitude findings of subfossil peatland pine trees were unearthed from the region of NW Finnish Lapland and dated by ¹⁴C and tree-ring methods. The depositional history of the trees illustrated two distinct peatland pine phases dated to Middle Holocene intervals 4900–4400 and 4100–3400 cal. a BC. It seems evident that both thermal and hydroclimatic fluctuations have played roles of varying importance in the establishment of this pine population and its demise. The presence of these pines, from a site ~60 km north of the coniferous timberline and conditions ~1 °C and 100 degree-days colder than those at the present-day timberline, concurs with previous studies demonstrating the association between the high-latitude summer-temperature cooling and circumpolar timberline retreat since the Middle Holocene due to Milankovitch forcing. On the other hand, the peatland pine recruitment was made possible by drier than present surface conditions during the previously reconstructed Middle Holocene drought anomaly (Hyvärinen-Alhonen event). Our data suggest this event was not continuous but reached its two-phase climax during the peatland pine phases, with an interruption of several centuries with moister surface conditions between 4400 and 4100 cal. a BC. The findings highlight the sensitivity of well-dated peatland tree assemblages in terms of recording past climatic evolution and events and the need for new collections from north and south Fennoscandia and the Baltic region, for more detailed analyses over extended time intervals and regions.  相似文献   

Energetic Neutral Atoms (ENA) at Mars: Properties of the hydrogen atoms produced upstream of the martian bow shock and implications for ENA sounding technique around non-magnetized planets     

E. Kallio  S. Barabash  H. Gunell  Y. Futaana  T. Säles  P. Riihelä  H. Andersson  A. Grigoriev  R.A. Frahm  J.R. Scherrer  D.R. Linder  J. Kozyra  E. Roelof  S. Livi  C.C. Curtis  B.R. Sandel  M. Carter  A. Fedorov  S. McKenna-Lawler  R. Cerulli-Irelli  P. Wurz  N. Krupp  M. Fränz  C. Dierker 《Icarus》2006,182(2):448-463

We have studied the interaction of fast solar wind hydrogen atoms with the martian atmosphere by a three-dimensional Monte Carlo simulation. These energetic neutral hydrogen atoms, H-ENAs, are formed upstream of the martian bow shock. Both H-ENAs scattered and non-scattered from the martian atmosphere/exosphere were studied. The colliding H-ENAs were found to scatter both to the dayside and nightside. On the dayside they contribute to the so-called H-ENA albedo. On the nightside the heated and scattered hydrogen atoms were found also in the martian wake. The density, the energy distribution function and the direction of the velocity of H-ENAs on the nightside are presented. The present study describes a novel “ENA sounding” technique in which energetic neutral atoms are used to derive information of the properties of planetary exosphere and atmosphere in a similar manner as the solar wind photons are used to derive atmospheric densities by measuring the scattered UV light. A detailed study of the direction and energy of the scattered and non-scattered H-ENAs suggest that the ENA sounding is a method to study the interaction between the planetary atmosphere and the solar wind and to monitor the density, and likely also the magnetization, of the planetary upper atmosphere. Already present-day ENA instrument should be capable to detect the analyzed particle fluxes.  相似文献