| 1. |
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| 2. |
- Kim, Jae-Young, et al.
(författare)
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Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution
- 2020
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 640
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Tidskriftsartikel (refereegranskat)abstract
- 3C 279 is an archetypal blazar with a prominent radio jet that show broadband flux density variability across the entire electromagnetic spectrum. We use an ultra-high angular resolution technique - global Very Long Baseline Interferometry (VLBI) at 1.3mm (230 GHz) - to resolve the innermost jet of 3C 279 in order to study its fine-scale morphology close to the jet base where highly variable-ray emission is thought to originate, according to various models. The source was observed during four days in April 2017 with the Event Horizon Telescope at 230 GHz, including the phased Atacama Large Millimeter/submillimeter Array, at an angular resolution of ∼20 μas (at a redshift of z = 0:536 this corresponds to ∼0:13 pc ∼ 1700 Schwarzschild radii with a black hole mass MBH = 8 × 108 M⊙). Imaging and model-fitting techniques were applied to the data to parameterize the fine-scale source structure and its variation.We find a multicomponent inner jet morphology with the northernmost component elongated perpendicular to the direction of the jet, as imaged at longer wavelengths. The elongated nuclear structure is consistent on all four observing days and across diffierent imaging methods and model-fitting techniques, and therefore appears robust. Owing to its compactness and brightness, we associate the northern nuclear structure as the VLBI "core". This morphology can be interpreted as either a broad resolved jet base or a spatially bent jet.We also find significant day-to-day variations in the closure phases, which appear most pronounced on the triangles with the longest baselines. Our analysis shows that this variation is related to a systematic change of the source structure. Two inner jet components move non-radially at apparent speeds of ∼15 c and ∼20 c (∼1:3 and ∼1:7 μas day-1, respectively), which more strongly supports the scenario of traveling shocks or instabilities in a bent, possibly rotating jet. The observed apparent speeds are also coincident with the 3C 279 large-scale jet kinematics observed at longer (cm) wavelengths, suggesting no significant jet acceleration between the 1.3mm core and the outer jet. The intrinsic brightness temperature of the jet components are ≤1010 K, a magnitude or more lower than typical values seen at ≥7mm wavelengths. The low brightness temperature and morphological complexity suggest that the core region of 3C 279 becomes optically thin at short (mm) wavelengths.
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| 3. |
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| 4. |
- Walther, Alexander, 1976, et al.
(författare)
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Evaluation of the warm season diurnal cycle of precipitation over Sweden simulated by the Rossby Centre regional climate model RCA3
- 2013
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Ingår i: Atmospheric Research. - : Elsevier BV. - 0169-8095. ; 119, s. 131-139
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Tidskriftsartikel (refereegranskat)abstract
- This study examines the diurnal cycle of precipitation over Sweden for the warm season (April to September) both in hourly observational data and in simulations from the Rossby Centre regional climate model (RCA3). A series of parallel long-term simulations of RCA3 with different horizontal resolutions - 50, 25, 12, and 6 km - were analyzed to investigate the sensitivity of the model's horizontal resolution to the simulated diurnal cycle of precipitation. Overall, a clear distinction between an afternoon peak for inland stations and an early morning peak for stations along the Eastern coast is commonly found both in observation and model results. However, the diurnal cycle estimated from the model simulations show too early afternoon peaks with too large amplitude compared to the observation. Increasing horizontal model resolution tends to reduce this bias both in peak timing and amplitude, but this resolution effect seems not to be monotonic; this is clearly seen only when comparing coarser resolution results with the 6 km resolution result. As the resolution increases, the peak timing and amplitude of the diurnal cycle of resolved large-scale precipitation become more similar to the observed cycle of total precipitation while the contribution of subgrid scale convective precipitation to the total precipitation decreases. An increase in resolution also tends to reduce too much precipitation of relatively light intensity over inland compared to the observation, which may also contribute to the more realistic simulation of the afternoon peak in convective precipitation. (C) 2011 Elsevier B.V. All rights reserved.
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| 5. |
- Walther, Alexander, 1976, et al.
(författare)
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Potential future changes of the diurnal precipitation properties over Sweden
- 2011
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Ingår i: Geophysical Research Abstracts.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this study we investigate potential future changes of the diurnal rainfall cycle over Sweden in the summer season (AMJJAS). Rainfall extremes are one of the most significant natural hazards related to climate. Precipitation characteristics strongly influence crops, soil properties, run-off and erosion, as well as human infrastructure such as the drainage systems in urban areas. The investigation of sub-daily rainfall records makes it possible to get detailed information about the diurnal precipitation cycle. A high-quality 1-hourly precipitation database covering 13 years of observations from 93 stations is available. In previous studies it could be shown that there is a distinct temporal and spatial pattern of the diurnal rainfall cycle. The performance of the Rossby Centre regional climate model (RCA3) in terms of simulating the observed diurnal cycle was investigated and the simulations quite realistically captured the general characteristics of the diurnal cycle. The diurnal cycle can be characterized by the presence of a peak, its timing and its shape. A higher and narrower peak means higher rainfall intensity on a shorter timescale. In contrast, a flatter and wider peak reflects a smaller temporal diurnal variability and lower rainfall intensity.
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| 9. |
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| 10. |
- Brunet, Manola, et al.
(författare)
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Long-term changes in extreme temperatures and precipitation in Spain
- 2007
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Ingår i: Contributions to Science: The International Journal of the Institute for Catalan Studies (IEC). - 1575-6343. ; 3:3, s. 331-342
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The development of the Spanish daily adjusted temperatureseries (SDATS) and the Spanish daily adjusted precipitation series(SDAPS) datasets in the framework of the European Community(EC)-funded project EMULATE (European and North Atlanticdaily to MULtidecadal climATE variability) enabled theassessment of long-term annual changes of extreme temperatureand precipitation indices over peninsular Spain for the period1901–2005. Within this framework, a set of procedureswas developed to generate long-term (1850–2005) daily adjustedtemperature and precipitation series and to use them toassess changes in climatic extremes. The present report describesdetails of the data employed to analyze the behavior ofSpanish climate extremes and discusses the results of investigationsinto the annual changes in selected indices that occurredduring the 20th century: exceedances of upper and lowerpercentiles of daily maximum (Tmax) and minimum (Tmin)temperatures, cold-spell duration index (CSDI), warm-spell durationindex (WSDI), daily rainfall (R) exceeding the 95th and 99thpercentiles, simple daily intensity index (SDII), and greatest 1–and 5-day total precipitation. Upper and lower temperaturepercentiles increased during the 20th century over mainlandSpain, but changes in daytime extreme temperatures werelarger than the changes in night-time extreme temperatures.This pattern, however, shifted slightly in the recent period ofstrong warming, with more similar rates of change among daytimeand night-time extreme temperatures. Changes in extremeprecipitation indices were not as evident as those in extreme-temperature indices, but there was a tendency towardsheavier precipitation.
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| 11. |
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| 12. |
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| 13. |
- Burauskaite-Harju, Agne, et al.
(författare)
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Characterizing and visualizing spatio-temporal patterns in hourly precipitation records
- 2012
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Ingår i: Journal of Theoretical and Applied Climatology. - : Springer. - 0177-798X .- 1434-4483. ; 109:3-4, s. 333-343
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Tidskriftsartikel (refereegranskat)abstract
- We develop new techniques to summarize and visualize spatial patterns of coincidence in weather events such as more or less heavy precipitation at a network of meteorological stations. The cosine similarity measure, which has a simple probabilistic interpretation for vectors of binary data, is generalized to characterize spatial dependencies of events that may reach different stations with a variable time lag. More specifically, we reduce such patterns into three parameters (dominant time lag, maximum cross-similarity, and window-maximum similarity) that can easily be computed for each pair of stations in a network. Furthermore, we visualize such threeparameter summaries by using colour-coded maps of dependencies to a given reference station and distance-decay plots for the entire network. Applications to hourly precipitation data from a network of 93 stations in Sweden illustrate how this method can be used to explore spatial patterns in the temporal synchrony of precipitation events.
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| 14. |
- Chen, Deliang, 1961, et al.
(författare)
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European Trend Atlas of Extreme Temperature and Precipitation Records
- 2015
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This Atlas presents records of climatic variability and change in Europe starting before 1901 and focuses especially on trends of extreme temperatures and precipitation. The authors have used software developed within EMULATE (European and North Atlantic daily to MULtidecadal climATE variability) to obtain the extremes indices and temporal trends. The trend atlas provides an easy way to identify spatial patterns for a given time period, region, season, and index. The Atlas clearly shows that climate in Europe has changed over the last 100 to 150 years, such that the occurrence and intensity of warm temperature extremes have increased. Precipitation extremes have also changed, but with a less clear pattern compared to the temperature extremes.
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| 15. |
- Chen, Deliang, 1961, et al.
(författare)
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Projecting future local precipitation and its extremes for Sweden
- 2015
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Ingår i: Geografiska Annaler. - : Informa UK Limited. - 0435-3676 .- 1468-0459. ; 97:1, s. 25-39
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Tidskriftsartikel (refereegranskat)abstract
- A procedure to obtain future local precipitation characteristics focused on extreme conditions has been developed based on a weather generator. The method involves six major steps: (1) the weather generator was calibrated using observed daily precipitation at 220 Swedish stations during 1961–2004; (2) present and future daily precipitation characteristics for the Swedish stations from two global climate models, namely ECHAM5 and HadCM3, were used to calculate weather generator parameters for the present and future climates at global climate model spatial scales; (3) the ratio of the weather generator parameters for the present climate simulated by the global climate models to those calculated for each station falling into the global climate model grid box were computed for all the stations; (4) these ratios were also assumed to be valid in the future climate, that way the future parameters for each station for the global climate model projected future climate could be calculated; (5) using the estimated future parameters of the weather generator, the future daily precipitation at each station could be simulated by the weather generator; (6) the simulated daily precipitation was used to compute eight indices describing mean and extreme precipitation climates. The future mean and extreme precipitation characteristics at the stations under the Second Report on Emission Scenarios A2 scenario were obtained and presented. An overall increasing trend for frequency and intensity of the indices are identified for the majority of the stations studied. The developed downscaling methodology is relatively simple but useful in deriving local precipitation changes, including changes in the precipitation extremes.
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| 16. |
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| 17. |
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| 18. |
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| 19. |
- Comadran, J., et al.
(författare)
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Natural variation in a homolog of Antirrhinum CENTRORADIALIS contributed to spring growth habit and environmental adaptation in cultivated barley
- 2012
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 44:12, s. 1388-1392
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Tidskriftsartikel (refereegranskat)abstract
- As early farming spread from the Fertile Crescent in the Near East around 10,000 years before the present(1), domesticated crops encountered considerable ecological and environmental change. Spring-sown crops that flowered without the need for an extended period of cold to promote flowering and day length insensitive crops able to exploit the longer, cooler days of higher latitudes emerged and became established. To investigate the genetic consequences of adaptation to these new environments, we identified signatures of divergent selection in the highly differentiated modern-day spring and winter barleys. In one genetically divergent region, we identify a natural variant of the barley homolog of Antirrhinum CENTRORADIALIS(2) (HvCEN) as a contributor to successful environmental adaptation. The distribution of HvCEN alleles in a large collection of wild and landrace accessions indicates that this involved selection and enrichment of preexisting genetic variants rather than the acquisition of mutations after domestication.
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| 20. |
- Franzén, Lars, 1950, et al.
(författare)
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The potential peatland extent and carbon sink in Sweden, as related to the Peatland / Ice Age Hypothesis
- 2012
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Ingår i: Mires and Peat. - 1819-754X. ; 10:artikel nr 08, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- Peatlands cover approximately 65,600 km2 (16 %) of the Swedish land area. The available areas suitable for peatland expansion are far from occupied after ca. 12,000 years of the present interglacial. We estimate the potential extent of peatland in Sweden, based on slope properties of possible areas excluding lakes and glaciofluvial deposits. We assume no human presence or anthropic effects, so the calculation is speculative. It may have been relevant for previous interglacials. We calculate the potential final area of peatlands in three scenarios where they cover all available land with different maximum slope angles (1−3 º) using a Digital Elevation Model (DEM). The three scenarios yield potential peatland areas of 95,663 km2 (21 % of total available area), 168,287 km2 (38 %) and 222,141 km2 (50 %). The relative increases from the present 65,600 km2 are 46, 157 and 239 % respectively. The slope scenarios give CO2 uptake rates of 8.9−10.8, 18.1−22.4 and 24.6−30.5 Mt yr−1. Under global warming conditions with isotherms moved northwards and to higher altitudes, following an increase of raised bog area, the CO2 uptake rates might increase to 12.2−13.8, 24.4−27.7 and 33.5−37.9 Mt yr−1; i.e. up to 4.3−4.9 vpb of atmospheric CO2. If we make the speculative extrapolation from Sweden to all high latitude peatlands, and assume that all suitable areas with slope angle ≤ 3 ° become occupied, the global peatland CO2 sink might approach 3.7 Gt yr−1 (about 2 vpm yr−1) and potentially cause a net radiative cooling approaching 5 W m−2.
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| 21. |
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| 22. |
- Keilwagen, J., et al.
(författare)
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Separating the wheat from the chaff - a strategy to utilize plant genetic resources from ex situ genebanks
- 2014
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- The need for higher yielding and better-adapted crop plants for feeding the world's rapidly growing population has raised the question of how to systematically utilize large genebank collections with their wide range of largely untouched genetic diversity. Phenotypic data that has been recorded for decades during various rounds of seed multiplication provides a rich source of information. Their usefulness has remained limited though, due to various biases induced by conservation management over time or changing environmental conditions. Here, we present a powerful procedure that permits an unbiased trait-based selection of plant samples based on such phenotypic data. Applying this technique to the wheat collection of one of the largest genebanks worldwide, we identified groups of plant samples displaying contrasting phenotypes for selected traits. As a proof of concept for our discovery pipeline, we resequenced the entire major but conserved flowering time locus Ppd-D1 in just a few such selected wheat samples - and nearly doubled the number of hitherto known alleles.
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| 23. |
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| 24. |
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| 25. |
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| 26. |
- Linderholm, Hans W., 1968, et al.
(författare)
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Twentieth-century trends in the thermal growing season in the Greater Baltic Area
- 2008
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Ingår i: Climatic Change. ; 87:3-4, s. 405-419
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Tidskriftsartikel (refereegranskat)abstract
- Phenological data have shown an increase of ca. 10 days in European growing season length in the latter part of the twentieth century. In general, these changes have been associated with global warming. Here we present a study of thermal growing season (GS) trends in the Greater Baltic Area, northern Europe. Yearly dates for the start, end and length of the GS were computed for 49 stations in the studied area, using daily mean temperature measurements. Trends and tendencies of the GS parameters were analysed within the twentieth century. We also examined GS trends in long records (starting before 1850) from the region. The results show a general increase of the length of the GS of ca one week since 1951 in the area, where the most considerable change has occurred in spring (starting ∼6 days earlier). The largest increases were found at stations adjacent to the Baltic Sea and North Sea, where some Danish stations showed significant increasing trends in the length of the GS of more than 20 days. The only tendency for a shorter GS was found in Archangelsk, north western Russia. The three longest records displayed large inter-annual and decadal variability, with tendencies for increased frequencies of longer growing seasons since the 1950s.
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| 27. |
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| 28. |
- Pasam, R. K., et al.
(författare)
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Genetic Diversity and Population Structure in a Legacy Collection of Spring Barley Landraces Adapted to a Wide Range of Climates
- 2014
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 9:12
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Tidskriftsartikel (refereegranskat)abstract
- Global environmental change and increasing human population emphasize the urgent need for higher yielding and better adapted crop plants. One strategy to achieve this aim is to exploit the wealth of so called landraces of crop species, representing diverse traditional domesticated populations of locally adapted genotypes. In this study, we investigated a comprehensive set of 1485 spring barley landraces (LRC1485) adapted to a wide range of climates, which were selected from one of the largest genebanks worldwide. The landraces originated from 5 degrees to 62.5 degrees N and 16 degrees to 71 degrees E. The whole collection was genotyped using 42 SSR markers to assess the genetic diversity and population structure. With an average allelic richness of 5.74 and 372 alleles, LRC1485 harbours considerably more genetic diversity than the most polymorphic current GWAS panel for barley. Ten major clusters defined most of the population structure based on geographical origin, row type of the ear and caryopsis type - and were assigned to specific climate zones. The legacy core reference set LRC648 established in this study will provide a long-lasting resource and a very valuable tool for the scientific community. LRC648 is best suited for multi-environmental field testing to identify candidate genes underlying quantitative traits but also for allele mining approaches.
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| 29. |
- Pourkheirandish, M., et al.
(författare)
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Evolution of the Grain Dispersal System in Barley
- 2015
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Ingår i: Cell. - : Elsevier BV. - 0092-8674. ; 162:3, s. 527-539
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Tidskriftsartikel (refereegranskat)abstract
- About 12,000 years ago in the Near East, humans began the transition from hunter-gathering to agriculture-based societies. Barley was a founder crop in this process, and the most important steps in its domestication were mutations in two adjacent, dominant, and complementary genes, through which grains were retained on the inflorescence at maturity, enabling effective harvesting. Independent recessive mutations in each of these genes caused cell wall thickening in a highly specific grain "disarticulation zone," converting the brittle floral axis (the rachis) of the wild-type into a tough, non-brittle form that promoted grain retention. By tracing the evolutionary history of allelic variation in both genes, we conclude that spatially and temporally independent selections of germplasm with a non-brittle rachis were made during the domestication of barley by farmers in the southern and northern regions of the Levant, actions that made a major contribution to the emergence of early agrarian societies.
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| 30. |
- Shaaf, Salar, et al.
(författare)
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Genetic structure and eco-geographical adaptation of garlic landraces (Allium sativum L.) in Iran
- 2014
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Ingår i: Genetic Resources and Crop Evolution. - : Springer Science and Business Media LLC. - 0925-9864 .- 1573-5109. ; 61:8, s. 1565-1580
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Tidskriftsartikel (refereegranskat)abstract
- In this study we present the genetic analysis of freshly collected garlic landraces (Allium sativum L.) along an eco-geographical transect from northeastern to western Iran covering seven different provinces using ISSR and RAPD markers. A total of 52 polymorphic loci were detected among 31 landrace populations. The percentage of polymorphic bands, the mean effective number of alleles, and the mean gene diversity were 38.82 %, 1.54, and 0.32, respectively. Genetic principal co-ordinate analysis and Structure analysis using 52 polymorphic loci indicated that the germplasm could be divided into two major groups. Principal component analysis (PCA), using geographical and environmental variables suggested the role of both geographical and environmental adaptation in driving and maintaining genetic differentiation between the major groups. In addition, our results showed that the combination of latitude, altitude, and precipitation explains the highest proportion of the variance in the PCA of eco-geographical data. This study shows that geographical and environmental factors together created stronger and more discrete genetic differentiation than isolation by distance alone. These findings emphasize the importance of environmental selection in shaping patterns of genetic structure inferred in Iranian garlic germplasm. We suggest that action should be immediately taken for collecting, protecting and evaluating the genetic diversity of garlic landraces before they disappear in Iran.
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| 31. |
- Song, Y., et al.
(författare)
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Trends of the thermal growing season in China, 1951-2007
- 2010
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Ingår i: International Journal of Climatology. - : Wiley. - 0899-8418 .- 1097-0088. ; 30:1, s. 33-43
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Tidskriftsartikel (refereegranskat)abstract
- Observed 20th century changes in the length of the growing season (GS) across the Northern Hemisphere have been linked to increasing temperatures, associated with global warming. Past studies of GS changes in China have largely been based on phenological observations and satellite data, and little attention has been paid to changes in starting and ending dates of GS. Here we examine changes in the thermal GS over China from 1951 to 2007 based on observed daily surface air temperature. Using five indices, trends of three GS parameters, start, end and length, were determined at 114 high-quality stations over China. Our results show large spatial and temporal differences in the GS parameters in China, where the most prominent changes have occurred in northern China relative to southern China. On average, from 1951 to 2007 the GS has been extended by 2.3 days/decade in northern China where most of these changes is due to an earlier onset of the GS in spring (−1.7 days/decade). In southern China, there is an average increase of GS by 1.3 days/decade with 0.6 days/decade earlier onsets in spring. Furthermore, most stations showing significant trends of GS changes are located in northern China. An extended GS in northern China indicates improved agricultural conditions due to warmer and longer GS. However, this effect may be counteracted by changes in the precipitation pattern. Copyright © 2009 Royal Meteorological Society
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| 32. |
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| 33. |
- Walther, Alexander, 1976
(författare)
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Simulated and observed change of precipitation and temperature in Europe with focus on the Greater Baltic Area
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The regional climate of the Greater Baltic Area is complex and varies at a multitude of scales in space and time. This thesis contributes to increased understanding of climate change and climate variability in this area focusing on four significant research topics. Droughts have a considerable ecological and socio-economic impact. The occurrence of rainfall is strongly controlled by large-scale atmospheric circulation. The observed summer North Atlantic Oscillation (SNAO) was correlated to a gridded dataset of the self-calibrating Palmer Drought Severity Index. A more positive circulation index is strongly linked to dry conditions over large parts of Southern Fennoscandia and northern Central Europe. Less distinct but still significant is the coupling to wetter conditions in the eastern Mediterranean. Using tree-ring based SNAO and precipitation reconstructions over 550 a, the relationship was investigated back in time in a multicentury perspective. Prior to the instrumental period the coupling is generally less pronounced but holds for distinct periods of drought. A database of up to 121 daily more than century-long instrumental records of precipitation and temperature over Europe was analyzed for trends in climate extremes. Over the 20th century a clear increase of warm extremes and a decreasing trend in cold extremes could be detected. Precipitation extremes became slightly more frequent and precipitation amounts increased, especially during winter. The ongoing warming resulted in a significantly extended thermal growing season in the Greater Baltic Area has extended significantly during the last century. An analysis of 48 long-term daily mean temperature records over this area revealed an overall lengthening of about one week between 1951-2000 mostly contributed by an earlier start in spring. The strongest change was observed at stations adjacent to the Baltic Sea in the South and the weakest in the North East. The 100-year records at Danish stations reveal a maximum shift in start (-22.8 d), end (12.6 d) and growing season length (33.5 d). The sub-daily precipitation characteristics in the region are not very well understood yet. By studying hourly observations for 1996-2008 from 93 stations all over Sweden, a distinct summer season diurnal cycle with an afternoon peak mainly contributed by convective activities during summer was identified for inland stations. Along the East coast the influence of the Baltic Sea is evident showing a weaker cycle peaking in the early morning. The observed diurnal cycle was compared to simulations from the Rossby Centre regional climate model (RCA3) run at 50, 25, 12 and 6 km grid resolution. In general the model tends to simulate too frequent convective precipitation events of light intensity. The simulated peak timing is about 2-4 hours too early and the amplitude too high. The model performance varies depending on the spatial resolution. The 6-km simulation most realistically captures the peak timing and the diversity in the spatial pattern. With increasing model resolution the fraction of large-scale (convective) precipitation is increasing (decreasing). The results indicate the need for improvement of the convection parameterization scheme.
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| 34. |
- Westerberg, Ida, et al.
(författare)
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Precipitation data in a mountainous catchment in Honduras: quality assessment and spatiotemporal characteristics
- 2010
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Ingår i: Theoretical and Applied Climatology. - : Springer Nature. - 0177-798X .- 1434-4483. ; 101:3-4, s. 381-396
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Tidskriftsartikel (refereegranskat)abstract
- An accurate description of temporal and spatial precipitation variability in Central America is important for local farming, water supply and flood management. Data quality problems and lack of consistent precipitation data impede hydrometeorological analysis in the 7,500 km2 Choluteca River basin in central Honduras, encompassing the capital Tegucigalpa. We used precipitation data from 60 daily and 13 monthly stations in 1913–2006 from five local authorities and NOAA's Global Historical Climatology Network. Quality control routines were developed to tackle the specific data quality problems. The quality-controlled data were characterised spatially and temporally, and compared with regional and larger-scale studies. Two gapfilling methods for daily data and three interpolation methods for monthly and mean annual precipitation were compared. The coefficient-of-correlation-weighting method provided the best results for gap-filling and the universal kriging method for spatial interpolation. In-homogeneity in the time series was the main quality problem, and 22% of the daily precipitation data were too poor to be used. Spatial autocorrelation for monthly precipitation was low during the dry season, and correlation increased markedly when data were temporally aggregated from a daily time scale to 4–5 days. The analysis manifested the high spatial and temporal variability caused by the diverse precipitationgenerating mechanisms and the need for an improved monitoring network.
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