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Future Changes in Climate and Hydroclimate Extremes in East Africa
Get PDFClimate change is affecting the agriculture, water, and energy sectors in East Africa and the impact is projected to increase in the future. To allow adaptation and mitigation of the impacts, we assessed the changes in climate and their impacts on hydrology and hydrological extremes in East Africa. We used outputs from seven CMIP-6 Global Climate Models (GCMs) and 1981–2010 is used as a reference period. The output from GCMs are statistically downscaled using the Bias Correction-Constructed Analogs with Quantile mapping reordering method to drive a high-resolution hydrological model. The Variable Infiltration Capacity and vector-based routing models are used to simulate runoff and streamflow across 68,300 river reaches in East Africa. The results show an increase in annual precipitation (up to 35%) in Ethiopia, Uganda, and Kenya and a decrease (up to 4.5%) in Southern Tanzania in the 2050s (2041–2070) and 2080s (2071–2100). During the long rainy season (March–May), precipitation is projected to be higher (up to 43%) than the reference period in Southern Ethiopia, Kenya, and Uganda but lower (up to −20%) in Tanzania. Large parts of Kenya, Uganda, Tanzania, and Southern Ethiopia show an increase in precipitation (up to 38%) during the short rainy season (October–December). Temperature and evapotranspiration will continue to increase in the future. Further, annual and seasonal streamflow and hydrological extremes (droughts and floods) are projected to increase in large parts of the region throughout the 21st century calling for site-specific adaptation.publishedVersio
Self-Attenuation of Drillstring Torsional Vibrations Using Distributed Dampers
Get PDFDuring drilling operations, drillstring vibrations cause many downhole dysfunctions, resulting in underperformance, equipment failure, and possibly wellbore damage. Current drillstring vibration mitigation solutions are generally located at a single site, either at the topdrive or close to the bit. However, because the sources of vibration excitation are distributed along the whole drillstring, these single-point vibration damping solutions do not succeed in removing all vibration modes. A distributed vibration damping solution is investigated, wherein damping subs are placed at intervals along the drillstring. The drillpipe rotates on bearings inside the damping subs, thereby reducing mechanical torque. The damping sub has a slightly larger diameter than the neighboring tool joints, lifting the drillstring off the borehole wall and thus eliminating most of the mechanical friction between the damping subs. Viscous friction is introduced in the form of rotary eddy current brakes within the damping subs, which cause the damping of torsional oscillations. The damping sub moves axially on spur wheels supported by bearings, thereby reducing drag forces. The decoupling of rotary and axial movement is a key element for removing a source of excitation. Simulations made with a 4n degree-of-freedom (DOF) transient torque and drag model confirm the expected results. The results of simulations for a use case based on a complex 3D trajectory are presented. With damping subs every 30 m and a damping coefficient of 20 N·s/rd, the topdrive torque is reduced to 40% of that of a plain drillstring, and torsional stability is obtained across the topdrive speed range of 60 to 180 rev/min. By comparison, conventional nonrotating pipe protectors (NRPPs) would have reduced the topdrive torque to 30%, but torsional stability would have not been achieved because the expected damping coefficient was less than 0.02 N·s/rd. The design of the damping sub relies on readily available technological components that can sustain very high pressures and temperatures. The damping subs are therefore compatible with high-pressure/high-temperature applications, including geothermal drilling.Self-Attenuation of Drillstring Torsional Vibrations Using Distributed DamperspublishedVersio
The emergence of projected scaled patterns of extreme temperatures over Europe
Get PDFThis work investigates the scalability of extreme temperatures over the European domain with global warming levels. We have used the EURO-CORDEX ensemble of regional model simulations at 0.11° resolution for daily minimum and maximum temperatures to analyze future changes in extreme weather daily events. Scaling with the annual mean global warming modeled by the driving GCM was applied to future extreme temperature indices changes. Regional changes in each index were scaled by corresponding global warming levels obtained from GCMs. This approach asserts that regional patterns of climate change and average global temperature change are linearly related. It can provide information regarding climate change for periods or emission scenarios when no simulations exist. According to the results, the annual minimum of the lowest temperature of the day (TNn) increases more than the annual maximum of the highest temperature of the day (TXx) for Europe. The multi-model mean of the changes in scaled patterns of extreme temperatures emerges early, around 2020, even before it becomes robust. Individual scaled patterns of TNn and TXx emerge from around 2040.publishedVersio
Environmental DNA reveals spatial patterns of fish and plankton diversity at a floating offshore wind farm
Get PDFIn this study, we collected water eDNA from sampling stations at the first full scale floating offshore wind farm (OWF), the Hywind Pilot Park, east of Peterhead, UK, and a nearby reference area. We combined targeted droplet digital PCR (ddPCR) quantification of two commercially important species, Atlantic mackerel (Scombrus scombrus) and Atlantic herring (Clupea harengus), with metabarcoding of fish and plankton communities. The goal of this study was to assess the performance of eDNA data to characterize pelagic communities and its use for environmental monitoring. The metabarcoding recovered 26 fish species including both pelagic and demersal taxa. The plankton data were dominated by dinoflagellates (Karenia) and calanoid copepods. We found that both specific quantification of eDNA from mackerel and herring and eDNA metabarcoding of fish communities were able to reveal spatial patterns: Mackerel was most abundant in the surface across both OWF and reference sites; herring was present at a wider depth range. While ddPCR and metabarcoding data for these two species were broadly congruent, we observed detection/non-detection mismatches for both methods, highlighting the need for robust sampling design. There was no consistent OWF versus reference area pattern in the demersal fraction of fish assemblages. We interpret our findings as representing a snapshot of fish school location around the time of sampling, and do not consider the single timepoint data from this pilot study to be sufficient to attribute any effects to the OWF itself. As a non-invasive tool, we conclude that eDNA has a high potential in future environmental monitoring of OWFs. We recommend further ground-truthing and biomass correlation of eDNA data with catch data and establishing eDNA time series as next steps towards implementation of eDNA in OWF environmental monitoring.publishedVersio
The Performance of Distributed Acoustic Sensing for Tracking the Movement of Road Vehicles
Get PDFIn this paper we introduce Distributed Acoustic Sensing (DAS) and discuss its potential application in Intelligent Transportation Systems (ITS). We present the fundamentals of the technology and data processing methods required for converting the raw data into information that can be used to track the position of vehicles along a road in real time. We present and discuss the results of experiments that explore the dependency of defined DAS signal quality metrics as a function of vehicle speed, size and distance from the fiber, as well as how the cables are installed. The experiments indicate that decisions concerning cable installation could influence data signal to noise by up to ~10 dB. Finally, we demonstrate that DAS systems that operate by measuring phase shifts of laser light backscattered along the fiber, are capable of tracking smaller and slower moving traffic than DAS systems that rely only on measuring the intensity of the backscatter.publishedVersio
Tiltak for å øke produksjonen av laks og ørret i Nordhordland
Get PDFDenne rapporten ser på bedrifts- og samfunnsøkonomiske effekter av å delvis lukke oppdrettslokaliteter i Nordhordland. Oppdretterne i Nordhordland er i PO4, et geografisk produksjonsområde som siden 2020 har vært farget rødt i trafikklyssystemet, og dermed gitt 2 etterfølgende nedtrekk i maksimal tillatt biomasse (MTB). Nedtrekk gir en direkte negativ effekt på den delen av verdiskapingen som genereres av havbruksnæringen og verdikjeden. Fortsetter nedtrekkene i denne regionen, vil verdiskapingen og produksjonen falle ytterligere. Med to nedtrekk vil verdiskapingen i PO4 bli redusert med om lag 1,7 mrd kr. per år. En delvis lukking av anlegg hvor konvertering til lukkede anlegg på 50 prosent av lokalitetene kombinert med en økning på 25 prosent i MTB kan verdiskapingen øke med nesten 4 mrd. kr per år sammenlignet med en situasjon med 2 nedtrekk. Tilsvarende vil en lukking av 25 prosent av lokalitetene vil gi omtrent like stor økning i verdiskaping som en reversering av 2 nedtrekk. Beregningene viser at der er stor forskjell på å fortsette som nå med rød PO og nedtrekk, og en koordinert og samlet strategi for å snu situasjonen.Tiltak for å øke produksjonen av laks og ørret i NordhordlandpublishedVersio
Gytefisktelling i Daleelva, Teigdalselva, Ekso, Modalselva, Tysseelva, Matreelva, Haugsdalselva og Dalselva høsten 2022
Get PDFHøsten 2022 utførte LFI gytefisktellinger av laks og sjøaure i åtte elver hvor BKK er vassdragsregulant; Tyssevassdraget i Samnanger, Daleelva i Vaksdal, Ekso, Teigdalselva i Vossovassdraget, Modalselva, Matreelva, Haugsdalselva og Dalselva (Storelva i Dale). Det ble registret fra 0 -719 gytefisk av laks og fra 14 – 942 sjøaure i de aktuelle vassdragene. Dalselva i Sunnfjord hadde den største gytebestanden av laks mens Daleelva i Vaksdal hadde den største gytebestanden av sjøaure. Gytebestanden av laks i Daleelva var dominert av fettfinneklippet fisk som stammer fra utsettinger av settesmolt fra klekkeriet, og disse utgjorde 70 % av gytebestanden.
I de fleste elvene har gytebestandene blitt overvåket årlig i en årrekke, og i enkelte av vassdragene siden 1991. Utviklingen i gytebestandene varierer noe mellom elvene, men fem av de syv vassdragene hadde en økning i laksebestanden sammenliknet med året før. De fleste sjøaurebestandene viser en negativ trend gjennom perioden det foreligger tellinger, noe som også gjelder flere av de øvrige vassdragene i regionen.publishedVersio
Kartlegging og uttak av rømt oppdrettslaks i elver i Sognefjorden etter rømming fra Floteneset høsten 2022
No full textHøsten 2022 utførte LFI NORCE, i samarbeid med Rådgivende Biologer AS, utfisking av rømt oppdrettslaks i 13 vassdrag i Vestland og Rogaland etter avtale med oppdrettsnæringens sammenslutning for utfisking av rømt oppdrettsfisk (OURO). Hensikten var å redusere risiko for genetisk påvirkning på ville laksebestander ved å fjerne rømt oppdrettsfisk fra vassdragene. Forekomst av oppdrettsfisk ble kartlagt ved snorkling/drivtelling. Utfisking ble utført med harpun, garn, not, samt lokal utfisking ved stangfiske av lokale grunneierlag/fiskerlag etter ordinær fiskesesong. Totalt ble det høsten 2022 fisket ut 273 oppdrettsfisk fra de aktuelle vassdragene, fordelt på 266 oppdrettslaks og 7 regnbueaure.publishedVersio
Controlled Interactivity - lean-back media experiences based on lean-forward technologies
No full textInteractive rendering technologies like maps, timelines, and plots can be powerful tools for data visualization and exploration. In the context of media, such tools are often referred to as lean-forward, implying that the user is actively telling his own story by using control primitives such as skip, pan, tilt, adjust, scroll, rewind, reorder, zoom, play and more. We are interested in using such lean-forward technologies in the context of broadcasted lean-back experiences, for instance as a secondary for a radio program or a TV show. Importantly, the idea is not to record these experiences as video, as this removes all flexibility and interactivity. Instead, the idea is to let media providers actively remote-control client-side, interactive technologies, as part of production. To this end, we present State Trajectory, a technical concept for shared control state, with built-in support of online sharing, dynamic state changes, and timeline-consistent playback.Controlled Interactivity - lean-back media experiences based on lean-forward technologiessubmittedVersio
A Regime View of ENSO Flavors Through Clustering in CMIP6 Models
Get PDFEl Niño-Southern Oscillation (ENSO) flavors in the tropical Pacific are studied from a regime perspective. Five recurring spatial patterns or regimes characterizing the diversity of ENSO are established using a clustering approach applied to the HadISST sea surface temperature (SST) anomalies. Compared to previous studies, our approach gives a monthly characterization of the diversity of the warm and cold phases of ENSO established from observations but commonly applied to models and observations. Two warm (eastern and central El Niño), two cold (basin wide and central La Niña) and a neutral reference regimes are found. Simulated SST anomalies by the models from the latest Coupled Model Intercomparison Project Phase 6 are then matched to these reference regimes. This allows for a consistent assessment of the skill of the models in reproducing the reference regimes over the historical period and the change in these regimes under the high-warming Shared Socio-economic Pathway (SSP5.8.5) scenario. Results over the historical period show that models simulate well the reference regimes with some discrepancies. Models simulate more intense and spatially extended ENSO patterns and have issues in capturing the correct regime seasonality, persistence, and transition between regimes. Some models also have difficulty simulating the frequency of regimes, the eastern El Niño regime in particular. In the future, both El Niño and central La Niña regimes are expected to be more frequent accompanied with a less frequent neutral regime. The central Pacific El Niño and La Niña regimes are projected to increase in amplitude and variability.publishedVersio