Heiko Klein

Norwegian Meteorological Institute · Department of Research and Development

Accurate modelling of ash clouds from volcanic eruptions requires knowledge about the eruption source parameters including eruption onset, duration, mass eruption rates, particle size distribution, and vertical emission profiles. However, most of these parameters are unknown and must be estimated somehow. Some are estimated based on observed correl...

Releases of radionuclides to the atmosphere occasionally occur with no warning and with first observation at radioactivity monitoring stations. The Chernobyl accident of 1986 was first detected at Forsmark, Sweden, long before the official announcement by the Soviet Union, and the release of Ruthenium 106 detected across Europe in 2017 still has no...

The potential consequences for Norway should a nuclear accident at the Sellafield nuclear site occur, have been of concern for Norwegian authorities for several decades. Meteorological data from a 33-year period and the dispersion model ‘SNAP’ were used to evaluate meteorological conditions for which atmospheric transport of radionuclides from Sell...

Atmospheric dispersion models are crucial for nuclear risk assessment and emergency response systems since they rapidly predict air concentrations and deposition of released radionuclides, providing a basis for dose estimations and countermeasure strategies. Atmospheric dispersion models are associated with relatively large and often unknown uncert...

Short-term predictions for dispersion of radionuclides in the atmosphere following releases from nuclear incidents are associated with uncertainties originating from meteorology, source term and parameterization. Characterization of these uncertainties is of key importance for preparedness, decision making during an accident and for the further unc...

Despite significant reductions in nitrogen emissions achieved in Europe during the last three decades, eutrophication remains an environmental concern in the Baltic Sea basin. Recently, a number of comprehensive modelling studies have been conducted for the HELCOM Commission to inform the 2021 update of the Baltic Sea Action Plan. The calculations...

A description of the new air quality downscaling model-the urban EMEP (uEMEP) and its combination with the EMEP MSC-W model (European Monitoring and Evaluation Programme Meteorological Synthesising Centre West)-is presented. uEMEP is based on well-known Gaussian modelling principles. The uniqueness of the system is in its combination with the EMEP...

Predictions of the atmospheric dispersion of radionuclides accidentally released from a nuclear power plant are influenced by two large sources of uncertainty: one associated with the meteorological data employed, and one with the source term, i.e. the temporal evolution of the amount and physical and chemical properties of the release. A methodolo...

Abstract. A description of the new air quality downscaling model uEMEP and its combination with the EMEP MSC-W chemistry transport model is presented. uEMEP is based on well known Gaussian modelling principles. The uniqueness of the system is in its combination with the EMEP MSC-W model and the local fraction calculation contained within it. This a...

This paper describes the inversion procedure being used operationally at the Norwegian Meteorological Institute for estimating ash emission rates from retrieved satellite ash column amounts and a priori knowledge. The overall procedure consists of five stages: (1) generate a priori emission estimates; (2) run forward simulations with unit emissions...

During the pre-release and early phase of an accidental release of radionuclides into the atmosphere there are few or no measurements, and dispersion models are used to assess the consequences and assist in determining appropriate countermeasures. However, uncertainties are high during this early phase and it is important to characterise these unce...

In the framework of the European project CONFIDENCE, Work Package 1 (WP1) focused on the uncertainties in the pre- and early phase of a radiological emergency, when environmental observations are not available and the assessment of the environmental and health impact of the accident largely relies on atmospheric dispersion modelling. The latter is...

When a nuclear accident occurs, decision makers in the affected country/countries would need to act promptly to protect people, the environment and societal interests from harmful impacts of radioactive fallout. The decisions are usually based on a combination of model prognoses, measurements, and expert judgements within in an emergency decision s...

Waste tanks at the nuclear facility located at Sellafield, UK, represent a nuclear source which could release radionuclides to the atmosphere. A model chain which combines atmospheric transport, deposition as well as riverine transport to sea has been developed to predict the riverine activity concentrations of ¹³⁷Cs. The source term was estimated...

Comparison of ensembles of atmospheric dispersion simulations: lessons learnt from the confidence project about uncertainty quantification. 19th international conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, Bruges, Belgium

In the early phase of a nuclear accident, two large sources of uncertainty exist: one related to the source term and one associated with the meteorological data. Operational methods are being developed in AVESOME for quantitative estimation of uncertainties in atmospheric dispersion prediction resulting from uncertainties in assessments of both the...

Consequences for Norway in case of a hypothetical accident in Sellafield nuclear site have been of concern for Norwegian authorities for some time now. A 33-year period with meteorological data and the dispersion model SNAP was used to find out the meteorological conditions for which atmospheric transport of radioactive debris from Sellafield nucle...

As evidenced by the Fukushima Accident and events during 2017 in relation to 131I and 106Ru, estimation of the release term in the early phases of a nuclear accident is fraught with difficulties. Provision of an early estimate of quantitative and qualitative information regarding a release establishes a firm foundation for early actions and underpi...

Radioactive debris released to the atmosphere following a nuclear accident can result in severe contamination several hundreds of kilometers away from the source. Norway is located within the range of radioactive fallout from potential nuclear events involving dumped nuclear waste, nuclear power plants and other nuclear processing sites. Both the s...

Atmospheric dispersion models can be formulated and implemented in two different ways, e.g. as Eulerian and Lagrangian models. These implementations have both advantages and disadvantages concerning numerical requirements and accuracy. A combination of both implementations - a hybrid approach is also possible and, we show some improvement to a pure...

Objects containing radioactivity have been routinely dumped in Arctic waters near NW Russia up until the 1990s. One of the most radioactive objects in this region, the nuclear submarine K-27, was dumped in Stepogovo Fjord and contained spent nuclear fuel (SNF). Although the two K-27 submarine reactors were mothballed before dumping, concerns about...

Aerosols have important impacts on air quality and climate, but the processes affecting their removal from the atmosphere are not fully understood and are poorly constrained by observations. This makes modelled aerosol lifetimes uncertain. In this study, we make use of an observational constraint on aerosol lifetimes provided by radionuclide measur...

Aerosols have important impacts on air quality and climate, but the processes affecting their removal from the atmosphere are not fully understood and are poorly constrained by observations. This makes modelled aerosol lifetimes uncertain. In this study, we make use of an observational constraint on aerosol lifetimes provided by radionuclide measur...

The Russian nuclear submarine K-27 suffered a loss of coolant accident in 1968 and with nuclear fuel in both reactors it was scuttled in 1981 in the outer part of Stepovogo Bay located on the eastern coast of Novaya Zemlya. The inventory of spent nuclear fuel on board the submarine is of concern because it represents a potential source of radioacti...

The vision of the CryoClim initiative is to develop new operational services for long-term systematic climate monitoring of the cryosphere. The project develops services for sea ice and snow products of global coverage and glacier products covering Norway (mainland and Svalbard). The envisioned system will be provided as a web service based on stat...

In recent decades land-based emissions of air pollutants have been substantially reduced over Europe. At the same time emissions from shipping have continued to grow globally. Emissions from international shipping in sea areas surrounding Europe now contribute about 30% of the EU27 emissions of sulphur and NOx and affect ozone levels all over Europ...

We investigated 108Cd using a powerful combination of complementary gammagamma spectroscopic methods. Excited states were populated in the beta decay of 108In and with the 105Pd(alpha,n) fusion-evaporation reaction near the Coulomb barrier. From gammagamma angular correlation analyses we found dominant M1 character for decays of three 2+ states bet...

The nucleus 66Zn is investigated using γγ-coincidence studies following the β decay of the 0+ ground state of 66Ga. The data survey short-lived Jπ=1+,2+ states, E2/M1 mixing ratios, and, together with the previously known lifetimes, also absolute transition strengths B(σL). The proton-neutron mixed-symmetry states 2ms+ (isovector quadrupole excitat...

The one-phonon mixed-symmetry 21,ms+state and two-phonon mixed-symmetry 31,ms+ and 22,ms+ state have been identified in 96Ru based on intensity branching ratios, E2/M1 multipole mixing ratios, upper lifetime limits, and a comparison with the experimental data for 94Mo. The observables were obtained from Doppler-shift attenuation measurements and γγ...

The one-phonon mixed-symmetry 21,ms+ state and two-phonon mixed-symmetry 31,ms+ and 22,ms+ states have been identified in 96Ru based on intensity branching ratios, E2/M1 multipole mixing ratios, upper lifetime limits, and a comparison with the experimental data for 94Mo. The observables were obtained from Doppler-shift attenuation measurements and...

Mixed symmetry states in 94Mo and recently also in 96Ru were investigated in Köln, Stuttgart, and Yale. In order to understand the structure of the mixed symmetry states we made a shell model calculation. The resulting wave functions of low-lying J π = 2+ states for the near-spherical nucleus 94Mo are analyzed with respect to their collectivity and...

Single-particle states as well as collective states in the natural Bismuth isotope 209Bi were investigatedusing two Euroball Cluster detectors at the Cologne FN-tandem accelerator. The states were populated by the subcoulomb proton stripping reaction 208Pb(3He,d*γγ)209Bi at 20.5 MeV beam-energy. Forty-eight γ-transitions and 33 levels were observed...

An in-beam experiment with the subcoulomb reaction 209Bi(3He, d*γγ)210Po at 20.5 MeV was performed with two Euroball Cluster detectors in Cologne. It closed the gap between the low energy levels of the level-scheme and the high energy levels found in 209Bi(3He, d)210Po and 208Pb(4He, t)210Po particle experiments. New branchings have been found and...

We analyze for the first time the full γγ directional correlations from oriented states (DCO) in an experiment performed with the GASP detector array. Our analysis is based on a transformation of the directional information into expansion coefficients of an orthogonal basis. With this method, which we call SpeeDCO (spectral expansion of DCO), the c...

We analyzed for the first time the full gammagamma directional correlations from oriented states (DCO) in an experiment performed at the uc(gasp) detector array. Our analysis is based on a transformation of the directional information into expansion coefficients of an orthogonal basis. With this method, which we call SpeeDCO (Spectral Expansion of...