Anna Sjöblom

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• Professor
• Professor (Full) at University Centre in Svalbard

Different observation techniques for atmospheric turbulent fluxes of momentum and sensible heat were tested in a High-Arctic valley in Svalbard during two consecutive summers (June-August in 2010 and 2011). The gradient method (GM) and the bulk method (BM) have been compared to the more direct eddy covariance method (ECM) in order to evaluate if re...

The problem of icing on wind turbines in cold climates is addressed using probabilistic forecasting to improve next-day forecasts of icing and related production losses. A case study of probabilistic forecasts was generated for a 2-week period. Uncertainties in initial and boundary conditions are represented with an ensemble forecasting system, whi...

From observations in a High Arctic valley and ice-free fjord in Svalbard during March and April 2013 we show that, while some caution needs to be applied, ordinary slow-response instruments placed over a snow-water-snow surface can be effectively used as a proxy for more sophisticated measuring techniques at complex sites such as leads or a polynya...

Thermally-driven circulations are a frequent meteorological phenomenon in complex Arctic terrain, but the Arctic fjord breeze, a combined sea-breeze and up-valley wind, has received little attention. A field campaign was conducted in the valley Adventdalen in Svalbard in summer 2022 using a Scanning Doppler Lidar and automatic weather stations. It...

EU urgently needs to increase the development of secure and green energy, and this includes renewables such as Offshore wind energy. An expansion of Offshore wind will include the Baltic where sea ice is one of the major uncertainties. To ensure that the wind turbines are safe for people and the environment, while keeping them economically competit...

Wind power in the High Arctic is little developed, and understanding of the local wind conditions is needed. Therefore, the average wind characteristics in the Svalbard valley Adventdalen are investigated using primarily observations from wind profilers and weather stations. Low-level jets (LLJs) are frequent in calm synoptic conditions because the...

The Norwegian Arctic archipelago Svalbard is in the phase of transitioning to renewable energy supply. Therefore, the development of wind power is considered. Because it is a unique place in a harsh climate and complex terrain, local knowledge of the wind climate is needed to facilitate the transition. Concentrating on a large valley in Svalbard, w...

Svalbard has the opportunity to become a showcase for renewable energy and a sustainable society. The current coal based energy system will switch in autumn 2023 to a short transition period with diesel and then moving towards a more renewable off-grid system. Since no renewable energy systems are specifically designed for the High Arctic they must...

The estimation of the wind power density (WPD) in a specific place requires wind speed measurements over long periods, typically at least one year. In Svalbard, these estimations are even more challenging due to large interannual weather variability, complex terrain, which leads to very local climatic differences, and weather conditions adverse to...

Wind energy production at high latitudes is becoming increasingly common. Even in Svalbard (78° N), wind turbines are being investigated as components of a modern power system. However, the high Arctic poses special features relevant for wind power, such as low temperatures, midnight sun and polar night, or complex terrain with fjords, valleys, mou...

A transition to renewable energy is becoming increasingly more urgent in the High Arctic. In Svalbard (78°N), the previously coal based energy system is now, with a short transition period with diesel, moving to a completely renewable off-grid system. Both solar and wind energy are possible contributors to the energy mix. However, no renewable ener...

The High Arctic is a remote region with a harsh climate where communities mainly rely on fossil energy sources. In Longyearbyen, located in the archipelago of Svalbard at 78°N, solar energy is considered as one of the future energy sources. The available solar radiation must therefore be estimated to have solar energy as part of the energy mix. To...

Research and education on renewable energy in Svalbard

A probabilistic machine learning method is applied to icing related production loss forecasts for wind energy in cold climates. The employed method, called quantile regression forests, is based on the random forest regression algorithm. Based on the performed tests on data from four Swedish wind parks available for two winter seasons, it has been s...

This article aims to investigate if the proportion of the rotor area of a wind turbine that is in the refractive shadow zone according to a ray tracing algorithm coupled to meteorological forecast data is correlated to sound levels and amplitude modulation. The acoustic station is situated 950 m from a wind farm in Northern Sweden and the measureme...

An analysis of the effect of low‐level wind maxima (LLWM) below hub height on sound propagating from wind turbines has been performed at a site in northern Sweden. The stably stratified boundary layer, which is typical for cold climates, commonly features LLWM. The simplified concept for the effects of refraction, based on the logarithmic wind prof...

Amplitude modulation is assumed to be a major annoyance factor of wind turbine sound. However, studies on the generation of amplitude modulation and the impact of atmospheric conditions on amplitude modulation are limited, especially in cold climates. Long-term acoustic and meteorological measurements in the vicinity of a wind farm in northern Swed...

Eddy-covariance measurements made in the marine atmospheric boundary layer above a high Arctic fjord (Adventfjorden, Svalbard) are analyzed. When conditions are unstable, but close to neutral −0.1 < z/L < 0, where z is the height, and L is the Obukhov length, the exchange coefficient for sensible heat CH is significantly enhanced compared with that...

The problem of icing on wind turbines in cold climates is addressed using probabilistic forecasting to improve next-day forecasts of icing and related production losses. A case study of probabilistic forecasts was generated for a 2-week period. Uncertainties in initial and boundary conditions are represented with an ensemble forecasting system, whi...

Ground temperatures in the top few centimetres of the soil profile are key in many biological processes yet remain very poorly documented, especially in the polar regions or over longer timescales. They can vary greatly seasonally and at various spatial scales across the often highly complex and heterogeneous polar landscapes. It is challenging and...

The impact of snow on sound propagating from a wind farm in northern Sweden has been investigated. Simultaneous acoustic and meteorological measurements, combined with daily snow observations, have been analysed for the snow season in 2013 to 2014. Such measurements are crucial since significant knowledge gaps exist, especially for conditions in co...

The problem of icing on wind turbines in cold climates is addressed using probabilistic forecasting to improve next- day forecasts of icing and related production losses. A case study of probabilistic forecasts was generated for a two- week period. Uncertainties in initial and boundary conditions are represented with an ensemble forecasting system,...

In Arctic fjords and high-latitude seas, strong surface cooling dominates during a large part of the year, generating water-side convection (w* w) and enhanced turbulence in the water. These regions are key areas for the global carbon cycle; thus, a correct description of their air-sea gas exchange is crucial. CO2-data were measured via the eddy co...

The summer atmospheric boundary layer over a fjord in the High Arctic has been investigated during three consecutive years (2008–2010). Measurements of turbulent surface layer fluxes of momentum and sensible heat using a sonic anemometer and slow-response instruments were taken from a tower on the coast of Isfjorden, Svalbard, and analysed for seas...

The vertical structure of the atmospheric boundary layer (ABL), simulated with the mesoscale model Weather Research and Forecasting (WRF) as well as with its polar optimized version Polar WRF, was compared to tethered balloon soundings and mast observations taken in March and April 2009 from two Arctic fjords in Svalbard. From twelve short (48 h) s...

Sonic anemometer and profile mast measurements made in Wahlenbergfjorden, Svalbard Arctic archipelago, in May 2006 and April 2007 were employed to study the atmospheric boundary layer over sea-ice. The turbulent surface fluxes of momentum and sensible heat were calculated using eddy correlation and gradient methods. The results showed that the lite...

Air temperature and specific humidity inversions and low-level jets were studied over two Svalbard fjords, Isfjorden and Kongsfjorden, applying three tethersonde systems. Tethersonde operation practices notably affected observations on inversion and jet properties. The inversion strength and depth were strongly affected by weather conditions at the...

Momentum and sensible heat exchange are studied in an Arctic fjord system in Spitsbergen, Svalbard (Norway), based on tower measurements taken in January–June 2008. Due to ice-free conditions, the surface layer was unstable for most of the time, occasionally very unstable. The shape of the fjord and the surrounding topography have a large influence...

The solar eclipse on 1 August 2008 was studied on Svalbard (93% totality), an archipelago in the High Arctic, where midnight sun had been present for several months. Simultaneous observations over land and over a large fjord showed that the eclipse triggered downslope winds in the valleys surrounding the fjord, thereby creating low-level clouds ove...

The atmospheric boundary layer (ABL) over Arctic fjords is poorly understood and many processes occur on spatial scales that cannot be resolved by climate and weather prediction models. The meteorological conditions over a fjord are largely affected by surrounding complex topography, sea ice cover and oceanographic phenomena. This study addresses t...

On 1 August 2008, a total solar eclipse took place in the Arctic and in Longyearbyen, the main settlement in the High Arctic archipelago of Svalbard (78° 13' N, 15° 37' E), the maximum solar coverage was 93%. The eclipse had a large impact on the atmospheric boundary layer and the local weather in general around Longyearbyen triggering a fog that l...

There are over 500 species of arthropods recorded from Svalbard. These animals overwinter either within the soil or on the ground surface, and have to tolerate an environment where the ground is frozen for over 9 months each year. Three cold-tolerance strategies have been described from Svalbard invertebrates: freeze avoidance, freeze tolerance and...

Monitoring and modelling snow avalanches in Svalbard Ole Humlum 1,3, Hanne H. Christiansen 1, Ulrich Neumann 1, Markus Eckerstorfer 1, Anna Sjöblom 1, Knut Stalsberg 2 and Lena Rubensdotter 2. 1: The University Centre in Svalbard (UNIS). 2: Geological Survey of Norway (NGU) 3: University of Oslo Ground based transportation in Svalbard landscape all...

The atmospheric boundary layer (ABL) in polar areas is poorly understood, especially where complex topography has an influence on its structure. Air-ice-sea interactions have been studied during several field campaigns (e.g. SHEBA, Uttal et al., 2002) that usually took place further away from coast and from significant influence of topography. In a...

A comparison of momentum fluxes determined by the eddy-correlation method(ECM) and the inertial dissipation method (IDM) has been performed using longterm measurements over the sea. The measurements were made on the island ofstergarnsholm in the middle of the Baltic Sea. The results show that a`classical' form of the inertial dissipation method, i....

The understanding of the marine atmosphere boundary layer (MABL) is presented. The measurement analyzed have been made at the Östergarnsholm station for air/sea interaction research. It consists of an instrumented 30 m high tower situated at the southernmost peninsula of the low island Östergarnsholm, 4 km east of the big island Gotland in the Balt...

Seven years worth of meteorological tower data from the site Östergarnsholm in the Baltic Sea have provided new information on the structure of the marine atmospheric boundary layer, of high relevance for off-shore wind energy siting. The present paper is a review based on a series of original papers, which have appeared recently or are about to ap...

Spectra of longitudinal and vertical velocity have been studied at a marine site, stergarnsholm, in the Baltic Sea during a period of six days with near-neutral or slightly unstable conditions, when the wave state gradually changed from pure wind sea to strong swell having approximately the same direction as the wind. During the pure wind sea phase...

The structure of the marine atmospheric boundarylayer and the validity ofMonin–Obukhov similarity theory over the seahave been investigated using longterm measurements. Three levels of turbulencemeasurements (at 10 m, 18 mand 26 m) at stergarnsholm in themiddle of the Baltic Sea have beenanalysed. The results show that turbulentparameters have a st...

The terms in the turbulent kinetic energy (TKE) budget have been analyzed according to stability, wave age, and wind speed, using long-term measurements over the sea. The measurements were performed at the island Östergarnsholm in the middle of the Baltic Sea. The results show that there is an imbalance between normalized production and normalized...

In order to improve climate- and weather forecasting models, a better knowledge of the physical processes taking place in the lowest part of the atmosphere over the oceans is essential. In these models it is often assumed that the atmospheric boundary layer over sea behaves in the same way as that over land. But, the results show that the processes...

I. Task 1.1B. Field trials of improved Solent R3 anemometer/thermometer instrumentation. Results from four turbulence instrument inter-comparison field tests have been analysed. Three types of turbulence instruments have been employed: (i) the MIUU instrument, which is basically a wind-vane-mounted three-axis hot-film instrument with additional pla...