A5023898528- Meteorological Phenomena and Simulations
- Wind and Air Flow Studies
- Wind Energy Research and Development
- Climate variability and models
- Atmospheric aerosols and clouds
- Atmospheric and Environmental Gas Dynamics
- Fluid Dynamics and Turbulent Flows
- Cryospheric studies and observations
- Plant Water Relations and Carbon Dynamics
- Atmospheric Ozone and Climate
- Ocean Waves and Remote Sensing
- Atmospheric chemistry and aerosols
- Aerospace and Aviation Technology
- Oceanographic and Atmospheric Processes
- Fluid Dynamics and Vibration Analysis
- Tropical and Extratropical Cyclones Research
- Arctic and Antarctic ice dynamics
- Remote Sensing and LiDAR Applications
- Aeolian processes and effects
- Geophysics and Gravity Measurements
- Precipitation Measurement and Analysis
- Methane Hydrates and Related Phenomena
- Air Traffic Management and Optimization
- Icing and De-icing Technologies
- Energy Load and Power Forecasting
Bjerknes Centre for Climate Research
2016-2025
University of Bergen
2016-2025
Earth Science Institute of the Slovak Academy of Sciences
2006-2017
Uganda National Meteorological Authority
2017
Chr. Michelsen Institute
2016-2017
Makerere University
2017
Dar es Salaam Institute of Technology
2017
Woods Hole Oceanographic Institution
2016
University of Connecticut
2016
Ludwig-Maximilians-Universität München
1997-2006
Abstract. Due to the major role of sun in heating earth's surface, atmospheric planetary boundary layer over land is inherently marked by a diurnal cycle. The afternoon transition, period day that connects daytime dry convective night-time stable layer, still has number unanswered scientific questions. This phase cycle challenging from both modelling and observational perspectives: it transitory, most forcings are small or null turbulence regime changes fully convective, close homogeneous...
The Small Unmanned Meteorological Observer SUMO has been developed as a cost-efficient measurement system with the aim to close existing observational gap of atmospheric systems in between meteorological masts/towers and radiosondes. is highly flexible capability for insitu ABL measurements unique spatial temporal resolution. based on light-weighted styrofoam model airplane, equipped an autopilot autonomous flight missions its recent version sensors temperature, humidity pressure. With...
Small unmanned aircraft systems (sUAS) are rapidly transforming atmospheric research. With the advancement of development and application these systems, improving knowledge best practices for accurate measurement is critical achieving scientific goals. We present results from an intercomparison data Lower Atmospheric Process Studies at Elevation-a Remotely piloted Aircraft Team Experiment (LAPSE-RATE) field campaign. evaluate a total 38 individual sUAS with 23 unique sensor platform...
Abstract As the size of offshore wind turbines increases, a realistic representation spatiotemporal distribution incident field becomes crucial for modeling dynamic response turbine. The International Electrotechnical Commission (IEC) standard turbine design recommends two turbulence models simulations field, Mann spectral tensor model, and Kaimal exponential coherence model. In particular, floating turbines, these are challenged by more sophisticated ones. characteristics depend on...
This study shows that turbulent kinetic energy (TKE) estimates, derived from static LiDARs in Doppler Beam Swing (DBS) mode, permit a qualitative and quantitative characterization analysis of structures as wind turbine wakes, convective or shear generated eddies the lower atmospheric boundary layer. The analysed data, collected by WINDCUBE™ v1 park Austria, is compared to sonic data WINd Turbine Wake EXperiment Wieringermeer (WINTWEX-W). Although turbulence measurements with are limited...
Abstract Surface processes in high latitudes play an important role global climate and thus understanding the physics of these systems is critical for improving projections. The characterization stable water isotopologue flux between surface atmosphere offers potential to constrain parameterizations physical exchange numerical models. In addition, observations fluxes allow evaluation as a process influencing formation signal retrieved from ice core records. Here, we present record measured...
Abstract The Iceland and Greenland Seas are a crucial region for the climate system, being headwaters of lower limb Atlantic Meridional Overturning Circulation. Investigating atmosphere–ocean–ice processes in this often necessitates use meteorological reanalyses—a representation atmospheric state based on assimilation observations into numerical weather prediction system. Knowing quality reanalysis products is vital their proper use. Here we evaluate surface‐layer meteorology surface...
The aim of the research project “Innovative Strategies for Observations in Arctic Atmospheric Boundary Layer (ISOBAR)” is to substantially increase understanding stable atmospheric boundary layer (SBL) through a combination well-established and innovative observation methods as well by models different complexity. During three weeks February 2017, first field campaign was carried out over sea ice Bothnian Bay vicinity Finnish island Hailuoto. were based on ground-based eddy-covariance (EC),...
Abstract Surface-layer-resolving large-eddy simulations (LESs) of free-convective to near-neutral boundary layers are used study Monin–Obukhov similarity theory (MOST) functions. The LES dataset, previously for the analysis MOST relationships structure parameters, is extended mean vertical gradients and standard deviations potential temperature, specific humidity, wind. Also, local-free-convection (LFC) studied. data suggest that functions universal unique. gradient horizontal wind display...
Leading edge erosion (LEE) of wind turbine blades causes decreased aerodynamic performance leading to lower power production and revenue increased operations maintenance costs. LEE is caused primarily by materials stresses when hydrometeors (rain hail) impact on rotating blades. The kinetic energy transferred these impacts a function the precipitation intensity, droplet size distributions (DSD), hydrometeor phase rotational speed which in turn depends at hub-height. Hence, there need better...
Wind farm-induced wakes can propagate dozens of kilometres, decreasing the power production and fatigue lifetime wind turbines between neighbouring farms. This phenomenon termed hereinafter "wind theft", may lead to legal conflicts farm operators even States as from a is affected by wake effects generated another, reducing output. theft substantially slow down development offshore if it not regulated clear framework. In this study, we present case Sørlige Nordsjø II, large area that opened...
This study presents a computational fluid dynamics (CFD) based approach to determine the optimal positioning for an atmospheric turbulence sensor on rotary-wing uncrewed aerial vehicle (UAV) with X8 configuration. The vertical (zBF) and horizontal (xBF) distances of UAV center reduce effect propeller-induced flow are investigated by CFD simulations k−ϵ model actuator disc theory. To ensure realistic geometric design simulations, tilt angles test in flight were measured flying drone along...
Abstract. Long time series of observations atmospheric dynamics and composition are collected at the French Pyrenean Platform for Observation Atmosphere (P2OA). Planetary boundary layer depth is a key variable climate system, but it remains difficult to estimate analyse statistically. In order obtain reliable estimates convective height (Zi) allow long-term analyses, new restitution algorithm, named CALOTRITON, has been developed. It based on an ultra-high-frequency (UHF) radar wind profiler...
Doppler LiDAR measurements are already well established in the wind energy research and their accuracy has been tested against met mast data up to 100 m above ground. However, new generation of scanning have a much higher range thus it is not possible verify at altitudes. Therefore, Measurement Campaign Sola (LIMECS) was conducted airport Stavanger from March August 2013 compare radiosonde winds. It collaborative test campaign between University Bergen, Norwegian Meteorological Office (MET),...
A ‘no-flow-sensor’ wind estimation algorithm for Unmanned Aerial Systems (UAS) is presented. It based on ground speed and flight path azimuth information from the autopilot's GPS system. The has been tested with help of simulation option in Paparazzi autopilot software using artificial profiles. retrieval accuracy predefined profiles by its sensitivity to vertical aircraft velocity, diameter helical pattern different data sampling methods have investigated. a correspondingly optimized set...
Floods due to intense rainfall are a major hazard both people and infrastructure in western Norway. Here steep orography enhances precipitation the complex terrain channels runoff into narrow valleys small rivers. In this study we investigate flooding event October 2014. We compare high-resolution numerical simulations with measurements from rain gauges deployed impacted region. Our has two objectives: (i) understand dynamical processes that drove high (ii) importance of grid resolution...
The vertical temperature profile in the lowest 1000 m of atmosphere determines a number important physical processes and meteorological phenomena such as high concentrations anthropogenic air pollutants urban areas.Long-term monitoring profiles at temporal resolution has only become feasible recently with introduction affordable angular scanning microwave radiometers.In this study, we analyzed 2 years continuous measurements MTP-5HE instrument urbanized coastal Bergen valley, Norway.The data...
Abstract. The effect of terrain heterogeneities in one-point measurements is a continuous subject discussion. Here we focus on the order magnitude advection term equation evolution temperature as generated by documented and estimate its importance surface energy budget (SEB), for which turbulent fluxes are computed using eddy-correlation method. estimated from satellite model fields scales near 1 km or broader, while smaller through direct with remotely piloted aircraft thermal cameras also...
Abstract The Innovative Strategies for Observations in the Arctic Atmospheric Boundary Layer Program (ISOBAR) is a research project investigating stable atmospheric boundary layer (SBL) processes, whose representation still poses significant challenges state-of-the-art numerical weather prediction (NWP) models. In ISOBAR ground-based flux and profile observations are combined with remote sensing methods extensive usage of different unmanned aircraft systems (UAS). During February 2017 2018...
Leading edge erosion on wind turbine blades is a common issue, particularly for turbines placed in regions characterized by high speeds and precipitation. This study presents the development of rain atlas Scandinavia Finland, based ERA5 reanalysis NORA3 mesoscale model data rainfall intensity speed over five years. The IEA 15 MW reference used as an example to evaluate impingement water impact onset time commercial coating material. damage progression modeled combining with empirical that...
The diurnal wind system of the Kali Gandaki Valley in Nepal was explored September and October 1998 a field campaign using pilot balloons as main observational tool. This valley connects Plateau Tibet with Indian plains. river crosses Himalayas forming deepest on Earth. Intense upvalley winds blow up this during day. Observations were made along at various spots selected between exit point from source close to Tibet. strongest found Marpha Chuksang typical speeds 15–20 m s−1. sets first...
Measurements of erythemally weighted UV radiation during about 600 days at different sites in Bolivia and Germany ranging from 550 to 5240 m above sea level have been used derive the altitude effect AE under cloud‐free conditions. In Germany, values between 7 16%/km obtained. Bolivia, lowlands Bolivian plateau reached 5–10%/km. An 8–23%/km has measured a high‐mountain station. accordance with previous studies these results indicate that irradiance cannot be described by single number %/km,...