Morphological activity of a diverted glacier stream in Western Norway

In connection with the construction of a tunnel collecting water beneath a glacier (Bondhusbreen/Folgefonni) in SW Norway the amount of sediments transported by meltwater has been investigated. According to the values obtained the volume of the sedimentation chamber which has to take a one-years-amount of sediment was fixed at 5000 m³. In 1978 there has been a sedimentation of 3000 m³ of coarse material. The results obtained are not only of practical value, but also of scientific interest.     

Coastal and near-shore changes correlated with die-back in eel-grass (Zostera Marina,L.)

The die-back of eel-grass (Zostera marina, L.) is found to have played an important role with regard to near-shore sedimentation and coastal changes.In a natural harbour at Kyholm, Denmark a hiatus is found between silty sediments that date from about 4000 BC and overlying modern sandy sediments. It is suggested that this is a consequence of the die-back of eel-grass in the nineteen-thirties, resulting in mobilisation and disturbance of nearshore sediments and the shoreward movement of mobilised sandy material into the harbour. The coastal morphology of Kyholm was relatively stable from 1802 to 1933, but between 1933 and 1978 there have been two periods of drastic progradation correlated with die-back of eel-grass.     

Paleoclimate deduced from a multidisciplinary study of a half-million-year-old stalagmite from rana, northern Norway

A 7-cm-thick flowstone sequence has been dated by extended Uranium series techniques to less than 1.25 myr, with a probable growth interval of ≥350,000–≤730,000 yr B.P. The time span is in accordance with paleomagnetic results revealing normal polarity for the whole sequence, i.e., a depositional age of <730,000 yr B.P. Oxygen isotope variations suggest deposition during three warm periods, interrupted by two isotopically cold hiatuses characterized by bulk resolution and detrital laminae. Calculations suggest that climatic transitions may have involved a shift of 1.1–2.4°C in mean annual temperatures. Contemporary flooding of the cave due to adjacent glacier expansion provides evidence for the widely held view that speleothem deposition is halted by glacier proximity. The flowstone matrix contained appreciable amounts of pollen (pine, birch) as well as larger amounts of charcoal dust. The pollen assemblage suggests a climate comparable with the present, implying that Norway has experienced at least three glacial/interglacial transitions during the growth interval of the speleothem. The warmer periods were characterized by a forest environment, with ample evidence of fire.     

Existence of the frequentistic estimate for power-law regression with a location parameter, with applications for making discharge rating curves

Practical application of the power-law regression model with an unknown location parameter can be plagued by non-finite least squares parameter estimates. This presents a serious problem in hydrology, since stream flow data is mainly obtained using an estimated stage–discharge power-law rating curve. This study provides a set of sufficient requirements for the data to ensure the existence of finite least squares parameter estimates for a power-law regression with an unknown location parameter. It is shown that in practice, these requirements act as necessary for having a finite least squares solution, in most cases. Furthermore, it is proved that there is a finite probability for the model to produce data having non-finite least squares parameter estimates. The implications of this result are discussed in the context of asymptotic predictions, inference and experimental design. A Bayesian approach to the actual regression problem is recommended.     

Modeling of prominence threads in magnetic fields: Levitation by incompressible MHD waves

The nature of thin, highly inclined threads observed in quiescent prominences has puzzled solar physicists for a long time. When assuming that the threads represent truly inclined magnetic fields, the supporting mechanism of prominence plasma against gravity has remained an open issue. This paper examines the levitation of prominence plasma exerted by weakly damped MHD waves in nearly vertical magnetic flux tubes. It is shown that the wave damping, and resulting `radiation pressure', caused predominantly by ion-neutral collisions in the `cold' prominence plasma, may balance the acceleration of gravity provided the oscillation frequency is 2 rad s^–1 (f0.5 Hz). Such short wave periods may be the result of small-scale magnetic reconnections in the highly fragmentary magnetic field of quiescent prominences. In the proposed model, the wave induced levitation acts predominantly on plasma – neutral gas mixtures.     

The heat goes on—changes in indices of hot extremes in Poland

Theoretical and Applied Climatology - On the basis of temperature observations at 60 meteorological stations in Poland, changes in the indices associated with the presence of extremely high air...     

Comparison of geomorphological field mapping and 2D‐InSAR mapping of periglacial landscape activity at Nordnesfjellet,northern Norway

The ability to continuously monitor the dynamic response of periglacial landforms in a climate change context is of increasing scientific interest. Satellite radar interferometry provides information on surface displacement that can be related to periglacial processes. Here we present a comparison of two‐dimensional (2D) surface displacement rates and geomorphological mapping at periglacial landform and sediment scale from the mountain Nordnesfjellet in northern Norway. Hence, 2D Interferometric Synthetic Aperture Radar (InSAR) results stem from a 2009–2014 TerraSAR‐X dataset from ascending and descending orbits, decomposed into horizontal displacement vectors along an east–west plane, vertical displacement vectors and combined displacement velocity. Geomorphological mapping was carried out on aerial imagery and validated in the field. This detailed landform and sediment type mapping revealed an altitudinal distribution dominated by, weathered bedrock blockfields, surrounded primarily by slightly, to non‐vegetated solifluction landforms at the mountain tops. Below, an active rockslide and associated rockfall deposits are located on the steep east‐facing side of the study area, whereas glacial sediments dominate on the gentler western side. We show that 2D InSAR correctly depicts displacement rates that can be associated with typical deformation patterns for flat‐lying or inclined landforms, within and below the regional permafrost limit, for both wet and dry areas. A net lowering of the entire landscape caused by general denudation of the periglacial landforms and sediments is here quantified for the first time using radar remote sensing. Copyright © 2018 John Wiley & Sons, Ltd.     

The 14th international workshop on wave hindcasting and forecasting and the 5th coastal hazards symposium

Following the 14th International Workshop on Wave Hindcasting and Forecasting and 5th Coastal Hazards Symposium in November 2014 in Key West, Florida, a topical collection has appeared in recent issues of Ocean Dynamics. Here, we give a brief overview of the 16 papers published in this topical collection as well as an overview of the widening scope of the conference in recent years. A general trend in the field has been towards closer integration between the wave and ocean modelling communities. This is also seen in this topical collection, with several papers exploring the interaction between surface waves and mixed layer dynamics and sea ice.     

A re-investigation of the bloom-forming unarmored dinoflagellate Karenia longicanalis (syn. Karenia umbella ) from Chinese coastal waters

The dinoflagellate genus K arenia is known for recurrent harmful blooms worldwide. However, species diversity of the genus is generally overlooked owing to the difficulty of identifying small unarmored dinoflagellates. We have established four clonal cultures of K arenia longicanalis isolated from the type locality, Hong Kong harbor(strain HK01) and other three locations along the Chinese coasts(strains YB01, DT01, and NJ01). The morphology of the strain was studied by light and scanning electron microscopy(LM and SEM) and the pigment composition analyzed by high-performance liquid chromatography. We provide the first molecular data of K. longicanalis based on the large subunit(LSU) rRNA gene sequence and internal transcribed spacer(ITS). The four strains showed identical LSU rDNA sequences with a similarity of 99.4% to the holotype of K arenia umbella(strain KUTN05) from Australia. In the ITS phylogeny, the sequence of K. umbella branched between the Chinese strains of K. longicanalis. A careful comparison of the morphology of K. longicanalis and K. umbella reveals the similarity in the diagnostic characters. Diff erences may appear due to the sample treatment for SEM. We conclude that K. umbella is a junior synonym of K. longicanalis.