| 1. |
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| 2. |
- Arndt, D. S., et al.
(författare)
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STATE OF THE CLIMATE IN 2017
- 2018
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Ingår i: Bulletin of The American Meteorological Society - (BAMS). - : American Meteorological Society. - 0003-0007 .- 1520-0477. ; 99:8, s. S1-S310
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Forskningsöversikt (refereegranskat)
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| 3. |
- Arndt, D. S., et al.
(författare)
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State of the Climate in 2016
- 2017
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Ingår i: Bulletin of The American Meteorological Society - (BAMS). - 0003-0007 .- 1520-0477. ; 98:8, s. S1-S280
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Tidskriftsartikel (refereegranskat)abstract
- In 2016, the dominant greenhouse gases released into Earth's atmosphere-carbon dioxide, methane, and nitrous oxide-continued to increase and reach new record highs. The 3.5 +/- 0.1 ppm rise in global annual mean carbon dioxide from 2015 to 2016 was the largest annual increase observed in the 58-year measurement record. The annual global average carbon dioxide concentration at Earth's surface surpassed 400 ppm (402.9 +/- 0.1 ppm) for the first time in the modern atmospheric measurement record and in ice core records dating back as far as 800000 years. One of the strongest El Nino events since at least 1950 dissipated in spring, and a weak La Nina evolved later in the year. Owing at least in part to the combination of El Nino conditions early in the year and a long-term upward trend, Earth's surface observed record warmth for a third consecutive year, albeit by a much slimmer margin than by which that record was set in 2015. Above Earth's surface, the annual lower troposphere temperature was record high according to all datasets analyzed, while the lower stratospheric temperature was record low according to most of the in situ and satellite datasets. Several countries, including Mexico and India, reported record high annual temperatures while many others observed near-record highs. A week-long heat wave at the end of April over the northern and eastern Indian peninsula, with temperatures surpassing 44 degrees C, contributed to a water crisis for 330 million people and to 300 fatalities. In the Arctic the 2016 land surface temperature was 2.0 degrees C above the 1981-2010 average, breaking the previous record of 2007, 2011, and 2015 by 0.8 degrees C, representing a 3.5 degrees C increase since the record began in 1900. The increasing temperatures have led to decreasing Arctic sea ice extent and thickness. On 24 March, the sea ice extent at the end of the growth season saw its lowest maximum in the 37-year satellite record, tying with 2015 at 7.2% below the 1981-2010 average. The September 2016 Arctic sea ice minimum extent tied with 2007 for the second lowest value on record, 33% lower than the 1981-2010 average. Arctic sea ice cover remains relatively young and thin, making it vulnerable to continued extensive melt. The mass of the Greenland Ice Sheet, which has the capacity to contribute similar to 7 m to sea level rise, reached a record low value. The onset of its surface melt was the second earliest, after 2012, in the 37-year satellite record. Sea surface temperature was record high at the global scale, surpassing the previous record of 2015 by about 0.01 degrees C. The global sea surface temperature trend for the 21st century-to-date of +0.162 degrees C decade(-1) is much higher than the longer term 1950-2016 trend of +0.100 degrees C decade(-1). Global annual mean sea level also reached a new record high, marking the sixth consecutive year of increase. Global annual ocean heat content saw a slight drop compared to the record high in 2015. Alpine glacier retreat continued around the globe, and preliminary data indicate that 2016 is the 37th consecutive year of negative annual mass balance. Across the Northern Hemisphere, snow cover for each month from February to June was among its four least extensive in the 47-year satellite record. Continuing a pattern below the surface, record high temperatures at 20-m depth were measured at all permafrost observatories on the North Slope of Alaska and at the Canadian observatory on northernmost Ellesmere Island. In the Antarctic, record low monthly surface pressures were broken at many stations, with the southern annular mode setting record high index values in March and June. Monthly high surface pressure records for August and November were set at several stations. During this period, record low daily and monthly sea ice extents were observed, with the November mean sea ice extent more than 5 standard deviations below the 1981-2010 average. These record low sea ice values contrast sharply with the record high values observed during 2012-14. Over the region, springtime Antarctic stratospheric ozone depletion was less severe relative to the 1991-2006 average, but ozone levels were still low compared to pre-1990 levels. Closer to the equator, 93 named tropical storms were observed during 2016, above the 1981-2010 average of 82, but fewer than the 101 storms recorded in 2015. Three basins-the North Atlantic, and eastern and western North Pacific-experienced above-normal activity in 2016. The Australian basin recorded its least active season since the beginning of the satellite era in 1970. Overall, four tropical cyclones reached the Saffir-Simpson category 5 intensity level. The strong El Nino at the beginning of the year that transitioned to a weak La Nina contributed to enhanced precipitation variability around the world. Wet conditions were observed throughout the year across southern South America, causing repeated heavy flooding in Argentina, Paraguay, and Uruguay. Wetter-than-usual conditions were also observed for eastern Europe and central Asia, alleviating the drought conditions of 2014 and 2015 in southern Russia. In the United States, California had its first wetter-than-average year since 2012, after being plagued by drought for several years. Even so, the area covered by drought in 2016 at the global scale was among the largest in the post-1950 record. For each month, at least 12% of land surfaces experienced severe drought conditions or worse, the longest such stretch in the record. In northeastern Brazil, drought conditions were observed for the fifth consecutive year, making this the longest drought on record in the region. Dry conditions were also observed in western Bolivia and Peru; it was Bolivia's worst drought in the past 25 years. In May, with abnormally warm and dry conditions already prevailing over western Canada for about a year, the human-induced Fort McMurray wildfire burned nearly 590000 hectares and became the costliest disaster in Canadian history, with $3 billion (U.S. dollars) in insured losses.
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| 4. |
- Dunn, R. J. H., et al.
(författare)
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GLOBAL CLIMATE : State of the Climate in 2020
- 2021
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Ingår i: Bulletin of the American Meteorological Society. - : American Meteorological Society. - 0003-0007 .- 1520-0477. ; 102:8
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Tidskriftsartikel (refereegranskat)
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| 5. |
- Ades, M., et al.
(författare)
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Global Climate : in State of the climate in 2019
- 2020
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Ingår i: Bulletin of The American Meteorological Society - (BAMS). - : American Meteorological Society. - 0003-0007 .- 1520-0477. ; 101:8, s. S17-S127
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Tidskriftsartikel (refereegranskat)
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| 6. |
- Ades, M., et al.
(författare)
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GLOBAL CLIMATE
- 2020
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Ingår i: BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY. - 0003-0007 .- 1520-0477. ; 101:8
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Tidskriftsartikel (refereegranskat)
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| 7. |
- Fowler, D., et al.
(författare)
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Atmospheric composition change : Ecosystems-Atmosphere interactions
- 2009
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 43:33, s. 5193-5267
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Forskningsöversikt (refereegranskat)abstract
- Ecosystems and the atmosphere: This review describes the state of understanding the processes involved in the exchange of trace gases and aerosols between the earth's surface and the atmosphere. The gases covered include NO, NO2, HONO, HNO3, NH3, SO2, DMS, Biogenic VOC, O-3, CH4, N2O and particles in the size range 1 nm-10 mu m including organic and inorganic chemical species. The main focus of the review is on the exchange between terrestrial ecosystems, both managed and natural and the atmosphere, although some new developments in ocean-atmosphere exchange are included. The material presented is biased towards the last decade, but includes earlier work, where more recent developments are limited or absent. New methodologies and instrumentation have enabled, if not driven technical advances in measurement. These developments have advanced the process understanding and upscaling of fluxes, especially for particles, VOC and NH3. Examples of these applications include mass spectrometric methods, such as Aerosol Mass Spectrometry (AMS) adapted for field measurement of atmosphere-surface fluxes using micrometeorological methods for chemically resolved aerosols. Also briefly described are some advances in theory and techniques in micrometeorology. For some of the compounds there have been paradigm shifts in approach and application of both techniques and assessment. These include flux measurements over marine surfaces and urban areas using micrometeorological methods and the up-scaling of flux measurements using aircraft and satellite remote sensing. The application of a flux-based approach in assessment of O-3 effects on vegetation at regional scales is an important policy linked development secured through improved quantification of fluxes. The coupling of monitoring, modelling and intensive flux measurement at a continental scale within the NitroEurope network represents a quantum development in the application of research teams to address the underpinning science of reactive nitrogen in the cycling between ecosystems and the atmosphere in Europe. Some important developments of the science have been applied to assist in addressing policy questions, which have been the main driver of the research agenda, while other developments in understanding have not been applied to their wider field especially in chemistry-transport models through deficiencies in obtaining appropriate data to enable application or inertia within the modelling community. The paper identifies applications, gaps and research questions that have remained intractable at least since 2000 within the specialized sections of the paper, and where possible these have been focussed on research questions for the coming decade.
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| 8. |
- Laj, P., et al.
(författare)
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Measuring Atmospheric Composition Change
- 2009
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1873-2844 .- 1352-2310. ; 43:33, s. 5351-5414
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Tidskriftsartikel (refereegranskat)abstract
- Scientific findings from the last decades have clearly highlighted the need for a more comprehensive approach to atmospheric change processes. In fact, observation of atmospheric composition variables has been an important activity of atmospheric research that has developed instrumental tools (advanced analytical techniques) and platforms (instrumented passenger aircrafts, ground-based in-situ and remote sensing stations, earth observation satellite instruments) providing essential information on the composition of the atmosphere. The variability of the atmospheric system and the extreme complexity of the atmospheric cycles for short-lived gaseous and aerosol species have led to the development of complex models to interpret observations, test our theoretical understanding of atmospheric chemistry and predict future atmospheric composition. The validation of numerical models requires accurate information concerning the variability of atmospheric composition for targeted species via comparison with observations and measurements. In this paper, we provide an overview of recent advances in instrumentation and methodologies for measuring atmospheric composition changes from space, aircraft and the surface as well as recent improvements in laboratory techniques that permitted scientific advance in the field of atmospheric chemistry. Emphasis is given to the most promising and innovative technologies that will become operational in the near future to improve knowledge of atmospheric composition. Our current observation capacity, however, is not satisfactory to understand and predict future atmospheric composition changes, in relation to predicted climate warming. Based on the limitation of the current European observing system, we address the major gaps in a second part of the paper to explain why further developments in current observation strategies are still needed to strengthen and optimise an observing system not only capable of responding to the requirements of atmospheric services but also to newly open scientific questions.
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| 9. |
- Monks, P. S., et al.
(författare)
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Atmospheric composition change : global and regional air quality
- 2009
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 43:33, s. 5268-5350
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Forskningsöversikt (refereegranskat)abstract
- Air quality transcends all scales with in the atmosphere from the local to the global with handovers and feedbacks at each scale interaction. Air quality has manifold effects on health, ecosystems heritage and, climate. In this review the state of scientific understanding in relation to global and regional air quality is outlined. The review discusses air quality, in terms of emissions, processing and transport of trace gases and aerosols. New insights into the characterization of both natural and anthropogenic emissions are reviewed looking at both natural (e.g. dust and lightning) as well as plant emissions. Trends in anthropogenic emissions both by region and globally are discussed as well as biomass burning emissions. In terms of chemical processing the major air quality elements of ozone, non-methane hydrocarbons, nitrogen oxides and aerosols are covered. A number of topics are presented as a way of integrating the process view into the atmospheric context; these include the atmospheric oxidation efficiency, halogen and HOx chemistry, nighttime chemistry, tropical chemistry, heat waves, megacities, biomass burning and the regional hot spot of the Mediterranean. New findings with respect to the transport of pollutants across the scales are discussed, in particular the move to quantify the impact of long-range transport on regional air quality. Gaps and research questions that remain intractable are identified. The review concludes with a focus of research and policy questions for the coming decade. In particular, the policy challenges for concerted air quality and climate change policy (co-benefit) are discussed.
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| 10. |
- Young, William J., et al.
(författare)
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Genetic analyses of the electrocardiographic QT interval and its components identify additional loci and pathways
- 2022
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- The QT interval is a heritable electrocardiographic measure associated with arrhythmia risk when prolonged. Here, the authors used a series of genetic analyses to identify genetic loci, pathways, therapeutic targets, and relationships with cardiovascular disease. The QT interval is an electrocardiographic measure representing the sum of ventricular depolarization and repolarization, estimated by QRS duration and JT interval, respectively. QT interval abnormalities are associated with potentially fatal ventricular arrhythmia. Using genome-wide multi-ancestry analyses (>250,000 individuals) we identify 177, 156 and 121 independent loci for QT, JT and QRS, respectively, including a male-specific X-chromosome locus. Using gene-based rare-variant methods, we identify associations with Mendelian disease genes. Enrichments are observed in established pathways for QT and JT, and previously unreported genes indicated in insulin-receptor signalling and cardiac energy metabolism. In contrast for QRS, connective tissue components and processes for cell growth and extracellular matrix interactions are significantly enriched. We demonstrate polygenic risk score associations with atrial fibrillation, conduction disease and sudden cardiac death. Prioritization of druggable genes highlight potential therapeutic targets for arrhythmia. Together, these results substantially advance our understanding of the genetic architecture of ventricular depolarization and repolarization.
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| 11. |
- Bollerslev, J., et al.
(författare)
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Medical observation, compared with parathyroidectomy, for asymptomatic primary hyperparathyroidism: a prospective, randomized trial
- 2007
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Ingår i: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 92:5, s. 1687-92
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: The clinical presentation of primary hyperparathyroidism (pHPT) has changed during the last half century, and the diagnosis is now more often made by chance in patients with no specific symptoms. OBJECTIVE: The present study is a randomized, controlled trial that investigates the effects of parathyroidectomy or medical observation in mild asymptomatic pHPT on morbidity and quality of life (QoL). DESIGN/SETTING/PATIENTS: A total of 191 patients (26 men) with asymptomatic pHPT [mean age 64.2 +/- 7.4 (sd) yr] were recruited in the study and randomized to medical observation (serum calcium level 2.69 +/- 0.08 mmol/liter) or surgery (2.70 +/- 0.08 mmol/liter). We here report baseline and 1 (n = 119) and 2 yr data (n = 99) on those who had completed the follow-up visits by the end of the inclusion period. RESULTS: At baseline, the patients had significantly lower QoL (SF-36) and more psychological symptoms, compared with age- and sex-matched healthy subjects. The two groups were similar at baseline, and no clinically significant changes in these parameters were seen during the observation time. Calcium and PTH normalized after surgery. The areal bone mineral density increased in the group randomized to operation, whereas the bone mineral density remained stable in the medical observation group. No change in kidney function (creatinine) or blood pressure was observed longitudinally or between the groups. CONCLUSIONS: Asymptomatic patients with mild pHPT have decreased QoL and more psychological symptoms than normal controls. No benefit of operative treatment, compared with medical observation, was found on these measures so far.
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| 12. |
- Halbritter, Aud H., et al.
(författare)
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Plant trait and vegetation data along a 1314 m elevation gradient with fire history in Puna grasslands, Perú
- 2024
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Ingår i: SCIENTIFIC DATA. - 2052-4463. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Alpine grassland vegetation supports globally important biodiversity and ecosystems that are increasingly threatened by climate warming and other environmental changes. Trait-based approaches can support understanding of vegetation responses to global change drivers and consequences for ecosystem functioning. In six sites along a 1314 m elevational gradient in Puna grasslands in the Peruvian Andes, we collected datasets on vascular plant composition, plant functional traits, biomass, ecosystem fluxes, and climate data over three years. The data were collected in the wet and dry season and from plots with different fire histories. We selected traits associated with plant resource use, growth, and life history strategies (leaf area, leaf dry/wet mass, leaf thickness, specific leaf area, leaf dry matter content, leaf C, N, P content, C and N isotopes). The trait dataset contains 3,665 plant records from 145 taxa, 54,036 trait measurements (increasing the trait data coverage of the regional flora by 420%) covering 14 traits and 121 plant taxa (ca. 40% of which have no previous publicly available trait data) across 33 families.
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| 13. |
- Young, WJ, et al.
(författare)
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Genetic architecture of spatial electrical biomarkers for cardiac arrhythmia and relationship with cardiovascular disease
- 2023
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 14:1, s. 1411-
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Tidskriftsartikel (refereegranskat)abstract
- The 3-dimensional spatial and 2-dimensional frontal QRS-T angles are measures derived from the vectorcardiogram. They are independent risk predictors for arrhythmia, but the underlying biology is unknown. Using multi-ancestry genome-wide association studies we identify 61 (58 previously unreported) loci for the spatial QRS-T angle (N = 118,780) and 11 for the frontal QRS-T angle (N = 159,715). Seven out of the 61 spatial QRS-T angle loci have not been reported for other electrocardiographic measures. Enrichments are observed in pathways related to cardiac and vascular development, muscle contraction, and hypertrophy. Pairwise genome-wide association studies with classical ECG traits identify shared genetic influences with PR interval and QRS duration. Phenome-wide scanning indicate associations with atrial fibrillation, atrioventricular block and arterial embolism and genetically determined QRS-T angle measures are associated with fascicular and bundle branch block (and also atrioventricular block for the frontal QRS-T angle). We identify potential biology involved in the QRS-T angle and their genetic relationships with cardiovascular traits and diseases, may inform future research and risk prediction.
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| 14. |
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| 15. |
- Anisimov, O., et al.
(författare)
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Permafrost
- 2009
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Ingår i: Melting snow and ice: a call for action.. - 9788276662641 ; , s. 64-71
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 16. |
- Bjørnarå, Helga Birgit, et al.
(författare)
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The impact of weather conditions on everyday cycling with different bike types in parents of young children participating in the CARTOBIKE randomized controlled trial
- 2023
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Ingår i: International Journal of Sustainable Transportation. - : Taylor & Francis Group. - 1556-8318 .- 1556-8334. ; 17:2, s. 128-135
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge about how weather conditions affect travel behavior in different user groups and contexts is relevant for planners and policymakers to facilitate sustainable transportation systems. We aimed to assess the influence of day-to-day weather on cycling for transportation among parents of young children with access to different bike types (e-bike vs non e-bike) in a natural study setting over nine months. We hypothesized less impact of weather variability on cycling when using an e-bike compared with a non e-bike. A randomized, controlled trial was conducted in Southern Norway. The intervention group (n = 18) was in random order equipped with an e-bike with trailer for child transportation (n = 6), a cargo (longtail) bike (n = 6) and a traditional bike with trailer (n = 6), each for three months. These 18 participants reported cycling on 832 out of 3276 person-days (25%). We used dynamic structural equation modeling for intensive longitudinal data to examine the relations between daily weather conditions, bike type (e-bike vs traditional bike), and cycling (dichotomized daily at yes or no). Air temperature (positively) and wind speed (negatively) were both credible predictors of cycling, whereas the other predictors (precipitation in the morning (yes or no) and presence of snow (yes or no) were not. We added interaction terms between bike type and weather conditions, but none of the interaction terms had a credible effect on cycling. Thus, the relations between weather conditions and cycling were not moderated by bike type among parents of young children.
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| 17. |
- Bryn, V., et al.
(författare)
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Brain derived neurotrophic factor (BDNF) and autism spectrum disorders (ASD) in childhood
- 2015
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Ingår i: European Journal of Paediatric Neurology. - : Elsevier BV. - 1090-3798. ; 19:4, s. 411-414
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Tidskriftsartikel (refereegranskat)abstract
- Background: Neurotrophic factors are essential regulators of neuronal maturation including synaptic synthesis. Among those, Brain derived neurotrophic factor (BDNF) has been in particular focus in the understanding of autism spectrum disorders (ASD). Purpose: The aim of our study was to investigate whether BNDF could be used as diagnostic/biological marker for ASD. For this purpose we examined the plasma levels of BDNF and the precursors pro- BDNF in patients with ASD and compared it with non-autistic controls; determined whether there was a correlation between the BDNF and proBDNF levels and clinical severity. We also investigated the coding region of BDNF identify for well-variations which could be associated to ASD. Methods: The 65 ASD patients (51 boys) were enrolled from a recent completed epidemiological survey covering two counties (Oppland and Hedmark) in Norway. The mean age of the total number of children who participated in this study was 11,7 years. 30 non-autistic children were included as controls, 14 boys and 16 girls. The mean age was 11.3 years. Exclusion criteria for control group were individuals suffering from either neurological, endocrine, or immune insuffiency. Results and conclusions: Patients with ASD were characterized by moderately but significantly elevated plasma levels of BDNF compared to matched controls. No differences were observed in the proBDNF level between patients and controls. Within the ASD group, children with intellectual disability demonstrated increased BDNF, but not proBDNF levels, while the presence of ADHD had no impact on circulating proBDNF or BDNF. No further associations between plasma proBDNF or BDNF and other clinical demographics were observed. (C) 2015 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.
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| 18. |
- Bryn, V., et al.
(författare)
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Cytokine Profile in Autism Spectrum Disorders in Children
- 2017
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Ingår i: Journal of Molecular Neuroscience. - : Springer Science and Business Media LLC. - 0895-8696 .- 1559-1166. ; 61:1, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- The pathogenesis of autism spectrum disorders (ASD) is not completely understood, but there is evidence of associations with altered immune responses. The aim of this study was to determine the serum levels of various cytokines in children with ASD and in healthy controls, in order to determine their role in ASD and its diagnostic subgroups. Sixty-five ASD patients were enrolled from an epidemiological survey in Norway, of which 30 were diagnosed with childhood autism, 16 with Asperger syndrome, 12 with atypical autism, 1 with Rett syndrome, and 6 with another ASD diagnosis. The serum levels of 12 cytokines were measured in all of the patients and in 30 healthy children. The cytokine levels did not differ significantly between the ASD group and the healthy controls. However, the interleukin-8 (IL-8) level was significantly higher (6.82 vs 4.58 pg/ml, p = 0.017) while that of IL-10 was significantly lower (2.24 vs 6.49 pg/ml, p = 0.009) in patients with childhood autism than in controls. Furthermore, the IL-8 level was significantly higher in childhood autism than in Asperger syndrome (6.82 vs 4.05 pg/ml, p = 0.013). Our study shows that the cytokine profile of children diagnosed with ASD, regardless of the subdiagnosis, does not differ from healthy controls. However, differentiation into different diagnostic subgroups reveals significantly different levels of IL-8 and IL-10. This indicates that different mechanisms may underlie the different ASD subdiagnoses. Future research into the pathophysiological mechanisms of ASD should pay more attention to the different subdiagnoses of ASD.
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| 19. |
- Christiansen, H. H., et al.
(författare)
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The Thermal State of Permafrost in the Nordic Area during the International Polar Year 2007-2009
- 2010
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Ingår i: Permafrost and Periglacial Processes. - : Wiley. - 1099-1530 .- 1045-6740. ; 21:2, s. 156-181
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides a snapshot of the permafrost thermal state in the Nordic area obtained during the International Polar Year (IPY) 2007-2009. Several intensive research campaigns were undertaken within a variety of projects in the Nordic countries to obtain this snapshot. We demonstrate for Scandinavia that both lowland permafrost in palsas and peat plateaus, and large areas of permafrost in the mountains are at temperatures close to 0 degrees C, which makes them sensitive to climatic changes. In Svalbard and northeast Greenland, and also in the highest parts of the mountains in the rest of the Nordic area, the permafrost is somewhat colder, but still only a few degrees below the freezing point. The observations presented from the network of boreholes, more than half of which were established during the IPY, provide an important baseline to assess how future predicted climatic changes may affect the permafrost thermal state in the Nordic area. Time series of active-layer thickness and permafrost temperature conditions in the Nordic area, which are generally only 10 years in length, show generally increasing active-layer depths and risings permafrost temperatures. Copyright (C) 2010 John Wiley & Sons, Ltd.
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| 20. |
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| 21. |
- Megner, Linda, et al.
(författare)
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Linearity aspects of the ensemble of data assimilations technique
- 2015
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Ingår i: Quarterly Journal of the Royal Meteorological Society. - : Wiley. - 0035-9009 .- 1477-870X. ; 141:687, s. 426-432
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Tidskriftsartikel (refereegranskat)abstract
- We examine the linearity of the Ensemble of Data Assimilations (EDA) technique with respect to the amplitude of the applied observation perturbations. We provide explicit examples to assess the linear relationship between such modifications of the observing system and the resulting changes in the EDA ensemble spread. The results demonstrate that, for a state-of-the-art numerical weather prediction (NWP) system, such linearity between the applied observation perturbations and the EDA ensemble spread holds well for temporal and spatial regimes relevant to global medium-range weather prediction: specifically, for forecast lead-times of up to approximately 5 days, in the vertical throughout the troposphere up to the lower and middle stratosphere and for broad horizontal scales.
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| 22. |
- Ormstad, H., et al.
(författare)
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Serum Tryptophan, Tryptophan Catabolites and Brain-derived Neurotrophic Factor in Subgroups of Youngsters with Autism Spectrum Disorders
- 2018
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Ingår i: Cns & Neurological Disorders-Drug Targets. - : Bentham Science Publishers Ltd.. - 1871-5273. ; 17:8, s. 626-639
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Tidskriftsartikel (refereegranskat)abstract
- Background: There is evidence that changes in neuro-immune responses coupled with dysfunctions in serotonin metabolism underpin the pathophysiology of autism spectrum disorders (ASD). Objective: This study aimed to delineate whether ASD subgroups or characteristics show aberrations in tryptophan and brain-derived neurotrophic factor (BDNF) metabolism. Methods: 65 individuals with ASD (diagnosed according to ICD criteria) and 30 healthy control patients were included. Measured were serum levels of tryptophan, kynurenine (KYN), kynurenic acid (KA), quinolinic acid (QA), BDNF and PRO-BDNF and total blood 5-HT and 5-OH-tryptophan (5-HTP). Results: Elevated BDNF levels and lower tryptophan and KA levels were characteristics of both childhood autism and intellectual disability disorder, whilst elevated tryptophan and lower 5-HT synthesis were hallmarks of Asperger syndrome. A pathological MRI was associated with elevated tryptophan and lowered KA. Abnormal EEG results and dysmorphology were both associated with an elevated BDNF/ PRO-BDNF ratio. Any brain pathology and gastro-intestinal symptoms were accompanied by lowered KA. Conclusions: Increased BDNF production and changes in the metabolism of tryptophan are associated with many ASD characteristics, showing particularly strong associations with childhood autism and Intellectual and Developmental Disabilities. Peripheral BDNF and tryptophan metabolism appear to take part in the pathophysiology of autism spectrum disorders and their phenotypes.
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| 23. |
- Renette, Cas, et al.
(författare)
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Simulating the effect of subsurface drainage on the thermal regime and ground ice in blocky terrain in Norway
- 2023
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Ingår i: Earth Surface Dynamics. - : Copernicus GmbH. - 2196-6311 .- 2196-632X. ; 11:1, s. 33-50
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Tidskriftsartikel (refereegranskat)abstract
- Ground temperatures in coarse, blocky deposits such as mountain blockfields and rock glaciers have long been observed to be lower in comparison with other (sub)surface material. One of the reasons for this negative temperature anomaly is the lower soil moisture content in blocky terrain, which decreases the duration of the zero curtain in autumn. Here we used the CryoGrid community model to simulate the effect of drainage on the ground thermal regime and ground ice in blocky terrain permafrost at two sites in Norway. The model set-up is based on a one-dimensional model domain and features a surface energy balance, heat conduction and advection, as well as a bucket water scheme with adjustable lateral drainage. We used three idealized subsurface stratigraphies, blocks only, blocks with sediment and sediment only, which can be either drained (i.e. with strong lateral subsurface drainage) or undrained (i.e. without drainage), resulting in six scenarios. The main difference between the three stratigraphies is their ability to retain water against drainage: while the blocks only stratigraphy can only hold small amounts of water, much more water is retained within the sediment phase of the two other stratigraphies, which critically modifies the freeze-thaw behaviour. The simulation results show markedly lower ground temperatures in the blocks only, drained scenario compared to other scenarios, with a negative thermal anomaly of up to 2.2 degrees C. For this scenario, the model can in particular simulate the time evolution of ground ice, with build-up during and after snowmelt and spring and gradual lowering of the ice table in the course of the summer season. The thermal anomaly increases with larger amounts of snowfall, showing that well-drained blocky deposits are less sensitive to insulation by snow than other soils. We simulate stable permafrost conditions at the location of a rock glacier in northern Norway with a mean annual ground surface temperature of 2.0-2.5 degrees C in the blocks only, drained simulations. Finally, transient simulations since 1951 at the rock glacier site (starting with permafrost conditions for all stratigraphies) showed a complete loss of perennial ground ice in the upper 5 m of the ground in the blocks with sediment, drained run; a 1.6 m lowering of the ground ice table in the sediment only, drained run; and only 0.1 m lowering in the blocks only, drained run. The interplay between the subsurface water-ice balance and ground freezing/thawing driven by heat conduction can at least partly explain the occurrence of permafrost in coarse blocky terrain below the elevational limit of permafrost in non-blocky sediments. It is thus important to consider the subsurface water-ice balance in blocky terrain in future efforts in permafrost distribution mapping in mountainous areas. Furthermore, an accurate prediction of the evolution of the ground ice table in a future climate can have implications for slope stability, as well as water resources in arid environments.
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- von Hobe, M, et al.
(författare)
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Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions (RECONCILE): activities and results
- 2013
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 13:18, s. 9233-9268
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Tidskriftsartikel (refereegranskat)abstract
- The international research project RECONCILE has addressed central questions regarding polar ozone depletion, with the objective to quantify some of the most relevant yet still uncertain physical and chemical processes and thereby improve prognostic modelling capabilities to realistically predict the response of the ozone layer to climate change. This overview paper outlines the scope and the general approach of RECONCILE, and it provides a summary of observations and modelling in 2010 and 2011 that have generated an in many respects unprecedented dataset to study processes in the Arctic winter stratosphere. Principally, it summarises important outcomes of RECONCILE including (i) better constraints and enhanced consistency on the set of parameters governing catalytic ozone destruction cycles, (ii) a better understanding of the role of cold binary aerosols in heterogeneous chlorine activation, (iii) an improved scheme of polar stratospheric cloud (PSC) processes that includes heterogeneous nucleation of nitric acid trihydrate (NAT) and ice on non-volatile background aerosol leading to better model parameterisations with respect to denitrification, and (iv) long transient simulations with a chemistryclimate model (CCM) updated based on the results of RECONCILE that better reproduce past ozone trends in Antarctica and are deemed to produce more reliable predictions of future ozone trends. The process studies and the global simulations conducted in RECONCILE show that in the Arctic, ozone depletion uncertainties in the chemical and microphysical processes are now clearly smaller than the sensitivity to dynamic variability.
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