Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2019
Sammendrag
Due to the potential for land-use–land-cover change (LULCC) to alter surface albedo, there is need within the LULCC science community for simple and transparent tools for predicting radiative forcings (ΔF) from surface albedo changes (Δαs). To that end, the radiative kernel technique – developed by the climate modeling community to diagnose internal feedbacks within general circulation models (GCMs) – has been adopted by the LULCC science community as a tool to perform offline ΔF calculations for Δαs. However, the codes and data behind the GCM kernels are not readily transparent, and the climatologies of the atmospheric state variables used to derive them vary widely both in time period and duration. Observation-based kernels offer an attractive alternative to GCM-based kernels and could be updated annually at relatively low costs. Here, we present a radiative kernel for surface albedo change founded on a novel, simplified parameterization of shortwave radiative transfer driven with inputs from the Clouds and the Earth's Radiant Energy System (CERES) Energy Balance and Filled (EBAF) products. When constructed on a 16-year climatology (2001–2016), we find that the CERES-based albedo change kernel – or CACK – agrees remarkably well with the mean kernel of four GCMs (rRMSE = 14 %). When the novel parameterization underlying CACK is applied to emulate two of the GCM kernels using their own boundary fluxes as input, we find even greater agreement (mean rRMSE = 7.4 %), suggesting that this simple and transparent parameterization represents a credible candidate for a satellite-based alternative to GCM kernels. We document and compute the various sources of uncertainty underlying CACK and include them as part of a more extensive dataset (CACK v1.0) while providing examples showcasing its application.
Sammendrag
Vegetation optical properties have a direct impact on canopy absorption and scattering and are thus needed for modeling surface fluxes. Although plant functional type (PFT) classification varies between different land surface models (LSMs), their optical properties must be specified. The aim of this study is to revisit the “time-invariant optical properties table” of the Simple Biosphere (SiB) model (later referred to as the “SiB table”) presented 30 years ago by Dorman and Sellers (1989), which has since been adopted by many LSMs. This revisit was needed as many of the data underlying the SiB table were not formally reviewed or published or were based on older papers or on personal communications (i.e., the validity of the optical property source data cannot be inspected due to missing data sources, outdated citation practices, and varied estimation methods). As many of today's LSMs (e.g., the Community Land Model (CLM), the Jena Scheme of Atmosphere Biosphere Coupling in Hamburg (JSBACH), and the Joint UK Land Environment Simulator (JULES)) either rely on the optical properties of the SiB table or lack references altogether for those they do employ, there is a clear need to assess (and confirm or correct) the appropriateness of those being used in today's LSMs. Here, we use various spectral databases to synthesize and harmonize the key optical property information of PFT classification shared by many leading LSMs. For forests, such classifications typically differentiate PFTs by broad geo-climatic zones (i.e., tropical, boreal, temperate) and phenology (i.e., deciduous vs. evergreen). For short-statured vegetation, such classifications typically differentiate between crops, grasses, and photosynthetic pathway. Using the PFT classification of the CLM (version 5) as an example, we found the optical properties of the visible band (VIS; 400–700 nm) to fall within the range of measured values. However, in the near-infrared and shortwave infrared bands (NIR and SWIR; e.g., 701–2500 nm, referred to as “NIR”) notable differences between CLM default and measured values were observed, thus suggesting that NIR optical properties are in need of an update. For example, for conifer PFTs, the measured mean needle single scattering albedo (SSA, i.e., the sum of reflectance and transmittance) estimates in NIR were 62 % and 78 % larger than the CLM default parameters, and for PFTs with flat leaves, the measured mean leaf SSA values in NIR were 20 %, 14 %, and 19 % larger than the CLM defaults. We also found that while the CLM5 PFT-dependent leaf angle values were sufficient for forested PFTs and grasses, for crop PFTs the default parameterization appeared too vertically oriented, thus warranting an update. In addition, we propose using separate bark reflectance values for conifer and deciduous PFTs and demonstrate how shoot-level clumping correction can be incorporated into LSMs to mitigate violations of turbid media assumption and Beer's law caused by the nonrandomness of finite-sized foliage elements.
Sammendrag
Deforestation influences surface properties such as surface roughness, resulting in changes in the surface energy balance and surface temperature. Recent studies suggest that the biogeophysical effects are dominated by changing roughness, and it remains unclear whether this can be reconciled with earlier modeling studies that highlighted the importance of a reduction of evapotranspiration in the low latitudes and a reduction of net shortwave radiation at the surface in the high latitudes. To clarify this situation, we analyze the local effects of deforestation on surface energy balance and temperature in the MPI‐ESM climate model by performing three separate experiments: switching from forest to grass all surface properties, only surface albedo, and only surface roughness. We find that the locally induced changes in surface temperature are dominated by changes in surface roughness for the annual mean, the response of the diurnal amplitude, and the seasonal response to deforestation. For these three quantities, the results of the MPI‐ESM lie within the range of observation‐based data sets. Deforestation‐induced decreases in surface roughness contribute substantially to winter cooling in the boreal regions and to decreases in evapotranspiration in the tropics. By comparing the energy balance decompositions from the three experiments, the view that roughness changes dominate the biogeophysical consequences of deforestation can be reconciled with the earlier studies highlighting the relevance of evapotranspiration.
Forfattere
Nick Hodgetts Marta Cálix Eve Englefield Nicholas Fettes M. García Criado Lea Patin Ana Nieto Ariel Bergamini Irene Bisang Elvira Baisheva Patrizio Campisi A Cogoni Tomas Hallingbäck Nadya A. Konstantinova Neil Lochhart Marko Sabovljevic Norbert Schnyder Christian Schröck Cecília Sérgio Manuela Sim-Sim Jaroslav Vrba Catarina C. Ferreira Olga M. Afonina T.L. Blockeel Hans Blom Steffen Caspari Rosalina Gabriel Cesar Garcia Ricardo Garilleti J González Mancebo Irina Goldberg Lars Hedenäs David T. Holyoak Vincent Hugonnot Sanna Huttunen Mikhail S. Ignatov Elena A. Ignatova Marta Infante Riikka Juutinen Thomas Kiebacher Heribert Köckinger Jan Kucera Niklas Lönnell Michael Lüth Anabela Martins Oleg Maslovsky Beata Papp Ron Porley Gordon Rothero Lars Söderström Sorin Ştefǎnuţ Kimmo Syrjänen Alain Untereiner Jíri Vána Alain Vanderpoorten Kai Vellak Michele Aleffi J. W. Bates Neil Bell Montserrat Brugués Nils Cronberg Jo Denyer J.G. Duckett Heinjo During Johannes Enroth Vladimir E. Fedosov Kjell Ivar Flatberg Anna Ganeva Piotr Gorski Urban Gunnarsson Kristian Hassel Helena Hespanhol Mark O. Hill Rory Hodd Kristoffer Hylander Nele Ingerpuu Sanna Laaka-Lindberg Francisco Lara Vicente Mazimpaka Anna Mežaka Frank Müller Jose David Orgaz Jairo Patiño Sharon Pilkington Felisa Puche Rosa Maria Ros Fred Rumsey José Gabriel Segarra-Moragues Ana Séneca Adam Stebel Risto Virtanen Henrik Weibull Jo Wilbraham Jan ZarnowiecSammendrag
Det er ikke registrert sammendrag
Sammendrag
Svandalsfossen, som er en velkjent og hyppig besøkt turistattraksjon i Sauda kommune, påvirker ved høy vannføring trafikksikkerheten på fylkesvei 520 gjennom fossesprut som hindrer sikt. På grunn av den tidvis utfordrende trafikksituasjonen vurderes det nå tiltak for å begrense fossesprut på veien, enten ved å (1) sprenge vekk en fjellnabbe i fossen for å redusere fossesprut og/eller endre dens retning, eller (2) installere en vegg ved veien på sørsiden av fossen for å fysisk skjerme veien mot fossesprut. Samtidig er det registrert be-tydelige naturverdier ved Svandalsfossen: den rødlistede mosen kystfloke (Heterocladium wulfsbergii) og en fossesprøytsone (E05) med A-verdi (svært viktig) etter DN håndbok 13, som i dag omfatter de rødlistede naturtypene fosseberg og fosse-eng. Derfor undersøkte vi utbredelsen av kystfloke og rødlistede naturtyper ved Svandalsfossen og vurderte kon-sekvensene de ulike inngrepsalternativene vil ha for naturverdiene. Kystfloke ble funnet langs store deler av fossen, og det ble i tillegg oppdaget en annen rødlistet mose-art kyst-skeimose (Platyhypnidium lusitanicum), men begge forekom i områder som i liten grad vil påvirkes av de foreslåtte inngrepene. De rødlistede naturtypene fosseberg og fosse-eng fant vi derimot i tilknytning til inngrepsområdet. Disse naturtypene er helt avhengige av høy fuk-tighet og det forventes at en reduksjon i fosserøyk/-sprut vil ha tydelig negativ innvirkning på dem. Derfor frarådes det å sprenge vekk fjellmateriale i fossen og dermed redusere fosse-røyk/-sprut. Installasjon av en vegg endrer ikke tilførsel av fuktighet for naturverdiene ved Svandalsfossen og vil dermed ha langt mindre negativ innvirkning, særlig hvis den bygges av gjennomsiktig materiale som ikke skygger ut vegetasjonen.
Sammendrag
We distinguish five Xanthomendoza species in Norway, viz., X. borealis, X. fallax, X. fulva, X. oregana, and X. ulophyllodes, based on morphology and molecular evidence. This paper gives an updated taxonomy of the Norwegian species of Xanthomendoza, and addresses previous misconceptions. Xanthomendoza ulophyllodes is reported as occurring in Norway. The species was previously misunderstood in Norway and removed from the Nordic checklist. We show that the nuclear internal transcribed spacer (nrITS) is a useful barcode marker for the treated species. We provide a key and short descriptions of the species, with notes on specific issues, ecology, geographic distribution, illustrations, maps, and a DNA reference library (DNA barcoding).
Sammendrag
Det er ikke registrert sammendrag
Forfattere
O. Janne Kjønaas Ivika Ostonen Lars Vesterdal Raija Laiho Tuula Larmola Edda S. Oddsdóttir Zane Libiete Iveta Varnagirytė-KabašinskienėSammendrag
Det er ikke registrert sammendrag
Forfattere
Fatima Heinicke Xiangfu Zhong Manuela Zucknick Johannes Breidenbach Arvind Yegambaram Meenakshi Sundaram Siri Tennebø Flåm Magnus Leithaug Marianne Dalland Andrew Farmer Jordana M. Henderson Melanie A. Hussong Pamela Moll Loan Nguyen Amanda McNulty Jonathan M. Shaffer Sabrina Shore Hoichong Karen Yip Jana Vitkovska Simon Rayner Benedicte Alexandra Lie Gregor Duncan GilfillanSammendrag
High-throughput sequencing is increasingly favoured to assay the presence and abundance of microRNAs (miRNAs) in biological samples, even from low RNA amounts, and a number of commercial vendors now offer kits that allow miRNA sequencing from sub-nanogram (ng) inputs. Although biases introduced during library preparation have been documented, the relative performance of current reagent kits has not been investigated in detail. Here, six commercial kits capable of handling <100ng total RNA input were used for library preparation, performed by kit manufactures, on synthetic miRNAs of known quantities and human total RNA samples. We compared the performance of miRNA detection sensitivity, reliability, titration response and the ability to detect differentially expressed miRNAs. In addition, we assessed the use of unique molecular identifiers (UMI) sequence tags in one kit. We observed differences in detection sensitivity and ability to identify differentially expressed miRNAs between the kits, but none were able to detect the full repertoire of synthetic miRNAs. The reliability within the replicates of all kits was good, while larger differences were observed between the kits, although none could accurately quantify the relative levels of the majority of miRNAs. UMI tags, at least within the input ranges tested, offered little advantage to improve data utility. In conclusion, biases in miRNA abundance are heavily influenced by the kit used for library preparation, suggesting that comparisons of datasets prepared by different procedures should be made with caution. This article is intended to assist researchers select the most appropriate kit for their experimental conditions.
Forfattere
Arne SteffenremSammendrag
Det er ikke registrert sammendrag