| 41. |
- Kjellström, Erik, et al.
(författare)
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Simulated climate conditions in Fennoscandia during a MIS 3 stadial
- 2010
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Ingår i: Boreas. - : Wiley. - 0300-9483 .- 1502-3885. ; 39:2, s. 436-456
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Tidskriftsartikel (refereegranskat)abstract
- State-of-the-art climate models were used to simulate climate conditions in Europe during Greenland Stadial (GS) 12 at 44 ka BP. The models employed for these simulations were: (i) a fully coupled atmosphere–ocean global climate model (AOGCM), and (ii) a regional atmospheric climate model (RCM) to dynamically downscale results from the global model for a more detailed investigation of European climate conditions. The vegetation was simulated off-line by a dynamic vegetation model forced by the climate from the RCM. The resulting vegetation was then compared with the a priori vegetation used in the first simulation. In a subsequent step, the RCM was rerun to yield a new climate more consistent with the simulated vegetation. Forcing conditions included orbital forcing, land–sea distribution, ice-sheet configuration, and atmospheric greenhouse gas concentrations representative for 44 ka BP. The results show a cold climate on the global scale, with global annual mean surface temperatures 5 °C colder than the modern climate. This is still significantly warmer than temperatures derived from the same model system for the Last Glacial Maximum (LGM). Regional, northern European climate is much colder than today, but still significantly warmer than during the LGM. Comparisons between the simulated climate and proxy-based sea-surface temperature reconstructions show that the results are in broad agreement, albeit with a possible cold bias in parts of the North Atlantic in summer. Given a prescribed restricted Marine Isotope Stage 3 ice-sheet configuration, with large ice-free regions in Sweden and Finland, the AOGCM and RCM model simulations produce a cold and dry climate in line with the restricted ice-sheet configuration during GS 12. The simulated temperature climate, with prescribed ice-free conditions in south-central Fennoscandia, is favourable for the development of permafrost, but does not allow local ice-sheet formation as all snow melts during summer.
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| 42. |
- Kjellström, Sofia, 1970-, et al.
(författare)
-
A developmental questionnaire on knowing and learning
- 2014
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Konferensbidrag (refereegranskat)abstract
- Are students and teachers up to the developmental challenge of teaching and learning the exceptional capabilities needed to address the complex issues of our time? Issues such as moving towards a sustainable development of society are typically quite complex and ill-structured. In order for higher education to provide opportunities for intellectual growth and development among students, a key issue besides complex thinking is to acknowledge the different epistemological beliefs of teachers and students, such as conceptions of teaching and learning, that may influence the teaching and learning experience and so the quality of the learning outcome. We will present a newly constructed epistemological beliefs questionnaire, concerning views on knowledge and learning. The questionnaire consists of 6 domains (a good study book, discussions, application of knowledge, responsibility for learning, understanding, good teaching), with 6 items in each domain, which are rated and ranked. The questionnaire is based on adult developmental theory (e.g. van Rossum & Hamer, 2010), where the developmental trajectory goes from a view of knowledge as being true or false and provided by the teacher as authority, to a view that emphasizes the constructed and contextual nature of knowledge – allowing teachers to adapt the teaching to the context and the student’s developmental level. In the spring of 2014, this questionnaire and a previously developed value system questionnaire will be sent to all teachers at Jönköping University (JU). The epistemological beliefs questionnaire is to be analysed with multivariate methods such as a multivariate pattern recognition method and factor analysis. Previous analyses of the value system questionnaire, using corresponding methods, have resulted in an identification of several developmental stages of values, and the epistemological beliefs questionnaire is expected to yield a similar result. Results from the two questionnaires will be compared in order to investigate the relationship between values and epistemological assumptions.
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| 43. |
- Kjellström, Sofia, et al.
(författare)
-
Psychometric properties of the Epistemological Development in Teaching Learning Questionnaire (EDTLQ) : An inventory to measure higher order epistemological development
- 2016
-
Ingår i: Frontline Learning Research. - : EARLI. - 2295-3159. ; 4:5, s. 22-54
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Tidskriftsartikel (refereegranskat)abstract
- Qualitative research supports a developmental dimension in views on teaching and learning, but there are currently no quantitative tools to measure the full range of this development. To address this, we developed the Epistemological Development in Teaching and Learning Questionnaire (EDTLQ). In the current study the psychometric properties of the EDTLQ were examined using a sample (N= 232) of teachers from a Swedish University. A confirmatory factor and Rasch analysis showed that the items of the EDTLQ form a unidimensional scale, implying a single latent variable (eg epistemological development). Item and person separation reliability showed satisfactory levels of fit indicating that the response alternatives differentiate appropriately. Endorsement of the statements reflected the preferred constructivist learning-teaching environment of the response group. The EDTLQ is innovative since is the first quantitative survey to measure unidimensional epistemological development and it has a potential to be used as an apt tool for teachers to monitor the development of students as well as to offer professional development opportunities to the teachers.
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| 44. |
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| 45. |
- Lagergren, Fredrik, et al.
(författare)
-
Kilometre-scale simulations over Fennoscandia reveal a large loss of tundra due to climate warming
- 2024
-
Ingår i: Biogeosciences. - 1726-4170 .- 1726-4189. ; 21:5, s. 1093-1116
-
Tidskriftsartikel (refereegranskat)abstract
- The Fennoscandian boreal and mountain regions harbour a wide range of vegetation types, from boreal forest to high alpine tundra and barren soils. The area is facing a rise in air temperature above the global average and changes in temperature and precipitation patterns. This is expected to alter the Fennoscandian vegetation composition and change the conditions for areal land use such as forestry, tourism and reindeer husbandry. In this study we used a unique high-resolution (3 km) climate scenario with considerable warming resulting from strongly increasing carbon dioxide emissions to investigate how climate change can alter the vegetation composition, biodiversity and availability of suitable reindeer forage. Using a dynamical vegetation model, including a new implementation of potential reindeer grazing, resulted in simulated vegetation maps of unprecedented high resolution for such a long time period and spatial extent. The results were evaluated at the local scale using vegetation inventories and for the whole area against satellite-based vegetation maps. A deeper analysis of vegetation shifts related to statistics of threatened species was performed in six “hotspot” areas containing records of rare and threatened species. In this high-emission scenario, the simulations show dramatic shifts in the vegetation composition, accelerating at the end of the century. Alarmingly, the results suggest the southern mountain alpine region in Sweden will be completely covered by forests at the end of the 21st century, making preservation of many rare and threatened species impossible. In the northern alpine regions, most vegetation types will persist but shift to higher elevations with reduced areal extent, endangering vulnerable species. Simulated potential for reindeer grazing indicates latitudinal differences, with higher potential in the south in the current climate. In the future these differences will diminish, as the potentials will increase in the north, especially for the summer grazing grounds. These combined results suggest significant shifts in vegetation composition over the present century for this scenario, with large implications for nature conservation, reindeer husbandry and forestry.
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| 46. |
- Leijonhufvud, Gustaf, 1977-, et al.
(författare)
-
Uncertainties in damage assessments of future indoor climates
- 2013
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Ingår i: Climate for Collections - Standards and Uncertainties. - Munich. - 9781909492004 ; , s. 405-418
-
Konferensbidrag (refereegranskat)abstract
- A significant amount of uncertainty is generated in the processof combining projections of future climate, building simulationsand damage functions to produce risk maps for historic buildings.The objective of this paper is to identify and qualitatively describethe main uncertainties in the production of such maps. The mainsources of uncertainty for each modeling step are identified. It isconcluded that the level of uncertainty in risk maps is so high thatdeterministic approaches have severe limitations, and that furtherresearch is needed to assess the levels of uncertainty introducedby each modeling step.
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| 47. |
- Lin, Changgui, 1985, et al.
(författare)
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Present and future European heat wave magnitudes: climatologies, trends, and their associated uncertainties in GCM-RCM model chains
- 2022
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Ingår i: Earth System Dynamics. - : Copernicus GmbH. - 2190-4979 .- 2190-4987. ; 13:3, s. 1197-1214
-
Tidskriftsartikel (refereegranskat)abstract
- This study investigates present and future European heat wave magnitudes, represented by the Heat Wave Magnitude Index-daily (HWMId), for regional climate models (RCMs) and the driving global climate models (GCMs) over Europe. A subset of the large EURO-CORDEX ensemble is employed to study sources of uncertainties related to the choice of GCMs, RCMs, and their combinations. We initially compare the evaluation runs of the RCMs driven by ERA-interim reanalysis to E-OBS (observation-based estimates), finding that the RCMs can capture most of the observed spatial and temporal features of HWMId. With their higher resolution compared to GCMs, RCMs can reveal spatial features of HWMId associated with small-scale processes (e.g., orographic effects); moreover, RCMs represent large-scale features of HWMId satisfactorily (e.g., by reproducing the general pattern revealed by E-OBS with high values at western coastal regions and low values at the eastern part). Our results indicate a clear added value of the RCMs compared to the driving GCMs. Forced with the emission scenario RCP8.5, all the GCM and RCM simulations consistently project a rise in HWMId at an exponential rate. However, the climate change signals projected by the GCMs are generally attenuated when downscaled by the RCMs, with the spatial pattern also altered. The uncertainty in a simulated future change of heat wave magnitudes following global warming can be attributed almost equally to the difference in model physics (as represented by different RCMs) and to the driving data associated with different GCMs. Regarding the uncertainty associated with RCM choice, a major factor is the different representation of the orographic effects. No consistent spatial pattern in the ensemble spread associated with different GCMs is observed between the RCMs, suggesting GCM uncertainties are transformed by RCMs in a complex manner due to the nonlinear nature of model dynamics and physics. In summary, our results support the use of dynamical downscaling for deriving regional climate realization regarding heat wave magnitudes. © Author(s) 2022.
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| 48. |
- Lind, Petter, 1979-, et al.
(författare)
-
Benefits and added value of convection-permitting climate modeling over Fenno-Scandinavia
- 2020
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Ingår i: Climate Dynamics. - : Springer Science and Business Media LLC. - 0930-7575 .- 1432-0894. ; 55:7-8, s. 1893-1912
-
Tidskriftsartikel (refereegranskat)abstract
- Convection-permitting climate models have shown superior performance in simulating important aspects of the precipitation climate including extremes and also to give partly different climate change signals compared to coarser-scale models. Here, we present the first long-term (1998–2018) simulation with a regional convection-permitting climate model for Fenno-Scandinavia. We use the HARMONIE-Climate (HCLIM) model on two nested grids; one covering Europe at 12 km resolution (HCLIM12) using parameterized convection, and one covering Fenno-Scandinavia with 3 km resolution (HCLIM3) with explicit deep convection. HCLIM12 uses lateral boundaries from ERA-Interim reanalysis. Model results are evaluated against reanalysis and various observational data sets, some at high resolutions. HCLIM3 strongly improves the representation of precipitation compared to HCLIM12, most evident through reduced “drizzle” and increased occurrence of higher intensity events as well as improved timing and amplitude of the diurnal cycle. This is the case even though the model exhibits a cold bias in near-surface temperature, particularly for daily maximum temperatures in summer. Simulated winter precipitation is biased high, primarily over complex terrain. Considerable undercatchment in observations may partly explain the wet bias. Examining instead the relative occurrence of snowfall versus rain, which is sensitive to variance in topographic heights it is shown that HCLIM3 provides added value compared to HCLIM12 also for winter precipitation. These results, indicating clear benefits of convection-permitting models, are encouraging motivating further exploration of added value in this region, and provide a valuable basis for impact studies.
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| 49. |
- Lind, Petter, 1979-, et al.
(författare)
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Climate change information over Fenno-Scandinavia produced with a convection-permitting climate model
- 2022
-
Ingår i: Climate Dynamics. - : Springer Science and Business Media LLC. - 0930-7575 .- 1432-0894. ; 61:1-2, s. 519-541
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents results from high-resolution climate change simulations that permit convection and resolve mesoscale orography at 3-km grid spacing over Fenno-Scandinavia using the HARMONIE-Climate (HCLIM) model. Two global climate models (GCMs) have been dynamically down-scaled for the RCP4.5 and RCP8.5 emission scenarios and for both near and far future periods in the 21st century. The warmer and moister climate conditions simulated in the GCMs lead to changes in precipitation characteristics. Higher precipitation amounts are simulated in fall, winter and spring, while in summer, precipitation increases in northern Fenno-Scandinavia and decreases in the southern parts of the domain. Both daily and sub-daily intense precipitation over Fenno-Scandinavia become more frequent at the expense of low-intensity events, with most pronounced shifts in summer. In the Scandinavian mountains, pronounced changes occur in the snow climate with a shift in precipitation falling as snow to rain, reduced snow cover and less days with a significant snow depth. HCLIM at 3-km grid spacing exhibits systematically different change responses in several aspects, e.g. a smaller shift from snow to rain in the western part of the Scandinavian mountains and a more consistent decrease in the urban heat island effect by the end of the 21st century. Most importantly, the high-resolution HCLIM shows a significantly stronger increase in summer hourly precipitation extremes compared to HCLIM at the intermediate 12-km grid spacing. In addition, an analysis of the statistical significance of precipitation changes indicates that simulated time periods of at least a couple of decades is recommended to achieve statistically robust results, a matter of important concern when running such high-resolution climate model experiments. The results presented here emphasizes the importance of using “convection-permitting” models to produce reliable climate change information over the Fenno-Scandinavian region.
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| 50. |
- Lind, Petter, 1979-, et al.
(författare)
-
Spatial and temporal characteristics of summer precipitation over Central Europe in a suite of high-resolution climate models
- 2016
-
Ingår i: Journal of Climate. - 0894-8755 .- 1520-0442. ; 29:10, s. 3501-3518
-
Tidskriftsartikel (refereegranskat)abstract
- High-impact, localized intense rainfall episodes represent a major socio-economic problem for societies worldwide, and at the same time these events are notoriously difficult to simulate properly in climate models. Here, the authors investigate how horizontal resolution and model formulation influence this issue by applying the HARMONIE regional climate model (HCLIM) with three different setups; two using convection parameterization at 15 and 6.25 km horizontal resolution (the latter within the “grey-zone” scale), with lateral boundary conditions provided by ERA-Interim reanalysis and integrated over a pan-European domain, and one with explicit convection at 2 km resolution (HCLIM2) over the Alpine region driven by the 15 km model. Seven summer seasons were sampled and validated against two high-resolution observational data sets. All HCLIM versions underestimate the number of dry days and hours by 20-40%, and overestimate precipitation over the Alpine ridge. Also, only modest added value were found of “grey-zone” resolution. However, the single most important outcome is the substantial added value in HCLIM2 compared to the coarser model versions at sub-daily time scales. It better captures the local-to-regional spatial patterns of precipitation reflecting a more realistic representation of the local and meso-scale dynamics. Further, the duration and spatial frequency of precipitation events, as well as extremes, are closer to observations. These characteristics are key ingredients in heavy rainfall events and associated flash floods, and the outstanding results using HCLIM in convection-permitting setting are convincing and encourage further use of the model to study changes in such events in changing climates.
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