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.
2012
Sammendrag
Our aim is to investigate the temporal dynamics of the Fraction of Absorbed Photosynthetically Active Radiation (fAPAR) on a global scale and its relation to the main meteorological variables across space. We focus on complex patterns in time, which are neither regular (trend and seasonality) nor random (noise), but somewhere in between. We quantify complexity and information content or entropy using methods from order statistics and complexity sciences.Time series with high entropy are difficult to predict, whereas time series with high complexity are difficult to describe. This leads to a spatially explicit characterization of complex patterns in a very sensitive way. We use FAPAR observations (SeaWiFS and MERIS, 1998 to 2012) along with gridded global surface air temperature, precipitation and shortwave radiation.All these time series are explored on a pixelbypixel basis and clustered according to a very recent classification system of the land surface. In addition, we quantify the time reversal asymmetry of these data. We compare environmental time series with data from a stochastic candidate process temporally symmetric and long range correlated artificial knoise.Results were plotted in the ComplexityversusEntropy plane (CH plane), showing the particular footprint of each variable in a very sensitive way. Visualized in world maps, results revealed unexpected complex pattern in some dry regions, in particular on pixels surrounding deserts and in eastern Sahara. In this respect, the results provide a new classification of the climate and the biosphere. http://dames.pik-potsdam.de/Abstracts.pdf
Forfattere
Holger LangeSammendrag
We calculate entropy and complexity of runoff time series and artificially generated series with long-range correlations. Entropy and complexity of data series may be represented against each other in a two-dimensional diagram which we will refer to as Complexity-Entropy Causality Plane, or CECP. We use a recently developed framework for these two indicators based on order statistics. It is well-known that runoff, as all other environmental time series actually measured, is a mixture of deterministic (signal) and stochastic (noise) parts, the latter due to noise inherent in the measurement process and externally induced by natural processes. The distinction between signal and noise is notoriously difficult and subject to much debate. In our approach, the observed series are compared to purely stochastic but long-range correlated processes, the k noise, where k is a parameter determining the strength of the correlations. Although these processes resemble runoff series in their correlation behavior and may be even tuned to any runoff series by changing the value of k, the CECP locations and in particular the order pattern statistics reveals qualitative differences between runoff and k noise. We use these differences to conclude on the deterministic nature of the (short-term) dynamics of the runoff time series. The proposed methodology also represents a stringent test bed for hydrological models.
Forfattere
Camilla Østerud M. Ashraful Islam Jorunn Elisabeth Olsen Dag-Ragnar Blystad Sissel Torre Anne Kathrine Hvoslef-Eide Jihong Liu ClarkeSammendrag
Det er ikke registrert sammendrag
Forfattere
Even Riiser Ingrid Holtsmark Hege Særvold Steen S. Swaminathan Navin Khanna Ralph Bock Jihong Liu ClarkeSammendrag
Det er ikke registrert sammendrag
Forfattere
Even Riiser Ingrid Holtsmark Hege Særvold Steen S. Swaminathan Navin Khanna Ralph Bock Jihong Liu ClarkeSammendrag
The global spread of dengue fever threatens a large percentage of the world’s population. The disease causes great human suffering, a high mortality from dengue haemorrhagic fever and its complications, and major costs. There is currently no vaccine to prevent dengue virus infection. Our project aims to express a tetravalent vaccine candidate in tobacco chloroplasts, a cost effective system, and hence to contribute to innovation and bio-economy as a long term goal.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
I 2011 var det en nedgang i helsetilstanden hos bartrær, og hos gran ble det observert en del toppskranting og avdøing i hogstklasse 3 og 4. Vi registrerte få insekt- og soppskader på gran der 1 % av trærne var angrepet, mens 1,2 % av furutrærne hadde slike biotiske skader. Antall abiotiske skader (stort sett snø- og vindrelaterte) hos bartrærne var omtrent på samme nivå som tidligere i overvåkingsperioden (1,7 og 1,2 % for hhv. gran og furu). Av treslagene gran, furu og bjørk er det fortsatt bjørk som er mest utsatt for skader: 10,6 % av bjørketrærne var angrepet og skadet av insekter, hovedsakelig av fjellbjørkemåleren, mens 14,2 % av bjørketrærne var angrepet av bjørkerustsopp eller andre sopper og 3,5 % hadde skader med abiotiske årsaker....
Forfattere
Ashraful Islam Sissel Haugslien Dag-Ragnar Blystad Sissel Torre Jorunn Elisabeth Olsen Henrik Lütken Jihong Liu ClarkeSammendrag
Det er ikke registrert sammendrag
Forfattere
Ashraful Islam Sissel Haugslien Dag-Ragnar Blystad Sissel Torre Jorunn Elisabeth Olsen Henrik Lütken Jihong Liu ClarkeSammendrag
Poinsettia is one of the most important potted ornamentals for Christmas. Appropriate plant height is an important trait in poinsettia production. Concern about the negative effects of chemical growth retardants has limited their availability and use. Generation of compact poinsettia plants by genetic transformation has become a promising approach.
Forfattere
Dag-Ragnar Blystad Jihong Liu Clarke Sissel Haugslien Astrid H Sivertsen Gry Skjeseth Zhang Zhibo John Harald Rønningen Helen Otter Søgnen Peter van der Ende Bjørnar BjellandSammendrag
Det er ikke registrert sammendrag