Papers by Sven-Erik Gryning
Renewable energies such as wind and solar energy will play an important, even decisive role in or... more Renewable energies such as wind and solar energy will play an important, even decisive role in order to mitigate and adapt to the projected dramatic consequences to our society and environment due to climate change. Due to shrinking fossil resources, the transition to more and more renewable energy shares is unavoidable. But, as wind and solar energy are strongly dependent on highly variable weather processes, increased penetration rates will also lead to strong fluctuations in the electricity grid which need to be balanced. Therefore, it is today appropriate to scientifically address the requirements to provide the best possible specific weather information for forecasting the energy production of wind and solar power plants within the next minutes up to several days. Weather Intelligence in the sense of specific accurate forecasting of "energy weather" is a key component for this. Towards such aims, Weather Intelligence will first include developing dedicated post-processing algorithms coupled with weather prediction models and with past and/or online measurement data especially remote sensing observations. Second, it will contribute to investigate the difficult relationship between the highly intermittent weather dependent power production and concurrent capacities such as transport and distribution of this energy to the end users. Selecting, resp. developing surface-based and satellite remote sensing techniques well adapted to supply relevant information to the specific post-processing algorithms for solar and wind energy production short-term forecasts is a major task with big potential. It will lead to improved energy forecasts and help to increase the efficiency of the renewable energy productions while contributing to improve the management and presumably the design of the energy grids in the future. The second goal will raise new challenges as this will require first from the energy producers and distributors definitions of the requested input data and new technologies dedicated to the management of power plants and electricity grids and second from the meteorological measurement community to deliver suitable, short term high quality forecasts to fulfill these requests with emphasis on highly variable weather conditions and spatially distributed energy productions often located in complex terrain. This topic has been selected for a new COST Action ES1002 under the title "Short-Term High Resolution Wind and Solar Energy Production Forecasts" which will start in the second half of 2010 for a duration of 4 years.
Vertical profiles of the horizontal wind speed and of the standard deviation of vertical wind spe... more Vertical profiles of the horizontal wind speed and of the standard deviation of vertical wind speed from Large Eddy Simulations of a convective atmospheric boundary layer are compared to wind LIDAR measurements up to 1400 m. Fair agreement regarding both types of profiles is observed only when the simulated flow is driven by a both time- and height-dependent geostrophic wind and a time-dependent surface heat flux. This underlines the importance of mesoscale effects when the flow above the atmospheric surface layer is simulated with a computational fluid dynamics model.
Bulletin of the American Meteorological Society, 2001
The Baltic Sea Experiment (BALTEX) is one of the five continental-scale experiments of the Global... more The Baltic Sea Experiment (BALTEX) is one of the five continental-scale experiments of the Global Energy and Water Cycle Experiment (GEWEX). More than 50 research groups from 14 European countries are participating in this project to measure and model the energy and water cycle over the large drainage basin of the Baltic Sea in northern Europe. BALTEX aims to provide a better understanding of the processes of the climate system and to improve and to validate the water cycle in regional numerical models for weather forecasting and climate studies. A major effort is undertaken to couple interactively the atmosphere with the vegetated continental surfaces and the Baltic Sea including its sea ice. The intensive observational and modeling phase BRIDGE, which is a contribution to the Coordinated Enhanced Observing Period of GEWEX, will provide enhanced datasets for the period October 1999-February 2002 to validate numerical models and satellite products. Major achievements have been obtained in an improved understanding of related exchange processes. For the first time an interactive atmosphere-ocean-land surface model for the Baltic Sea was tested. This paper reports on major activities and some results.
Fate of Pesticides in the Atmosphere: Implications for Environmental Risk Assessment, 1999
... W. ADDO J. VAN PUL1*, TERRY F. BIDLEMAN2, EVA BRORSTROM-LUNDÉN3, PETER JH BUILTJES4, SERGEY D... more ... W. ADDO J. VAN PUL1*, TERRY F. BIDLEMAN2, EVA BRORSTROM-LUNDÉN3, PETER JH BUILTJES4, SERGEY DUTCHAK5, JAN H. DUYZER4 ... These have been mainly for non-polar pesticides such as DDT, HCHs and chiordane (Pankow and Bidleman, 1992; Lane et al ...
Atmospheric Environment, 1998
This paper presents an analysis of wind field and atmospheric turbulence in Athens, Greece coveri... more This paper presents an analysis of wind field and atmospheric turbulence in Athens, Greece covering a typical late-summer period with prevailing northerly wind. The wind climatology study shows a distinct difference between the northern and southern parts of the urban area. In the northern part of Athens the northerly flows (315°–45°) occur more than 60% of the time and the
Theoretical and Applied Climatology, 2005
Summary The Basel UrBan Boundary Layer Experiment (BUBBLE) was a year-long experimental effort to... more Summary The Basel UrBan Boundary Layer Experiment (BUBBLE) was a year-long experimental effort to investigate in detail the boundary layer structure in the City of Basel, Switzerland. At several sites over different surface types (urban, sub-urban and rural reference) towers up to at least twice the main obstacle height provided turbulence observations at many levels. In addition, a Wind Profiler
In this study we focus on the lowest part of the urban boundary layer, which is connected to a ho... more In this study we focus on the lowest part of the urban boundary layer, which is connected to a horizontal scale of 2–3 km and a vertical scale covering the surface boundary layer. The structure of the urban surface boundary layer is discussed with an emphasis on the turbulence parameters controlling dispersion processes in it.
The mesoscale meteorological models have difficulties to predict the profiles, due to complex phe... more The mesoscale meteorological models have difficulties to predict the profiles, due to complex phenomena taking place in nature that are not accounted for in the ABL parameterizations currently used. Worldwide an effort is going on to emphasize the ...
Theoretical and Applied Climatology, 2001
Summary A mesoscale numerical model, incorporating a land-surface scheme based on Deardorffs’ a... more Summary A mesoscale numerical model, incorporating a land-surface scheme based on Deardorffs’ approach, is used to study the diurnal variation of the boundary layer structure and surface fluxes during four consecutive days with air temperatures well below zero, snow covered ground and changing synoptic forcing. Model results are evaluated against in-situ measurements performed during the WINTEX field campaign held in Sodankyl�,
ABSTRACT With the advancement in wind power meteorology and the growth of the modern wind turbine... more ABSTRACT With the advancement in wind power meteorology and the growth of the modern wind turbines, the need to measure and estimate meteorological parameters other than wind speed and direction has become more and more important. The effect on the wind profile, e.g. of the boundary-layer height h, has not (yet) been fully understood and investigated in the wind energy community, nor in the meteorological one. h has a significant effect on the wind profile at heights above 100 m and even lower when the atmospheric conditions are stable, e.g. during nighttime when low-level jets evolve. These heights are already being exploited by large wind turbines. A possible reason for the lack of use of h in wind power meteorology might be that it is interpreted in different fashions and estimated using different techniques. Common sources for the derivation of h are surface turbulence measurements, turbulence profiles, spectral characteristics of turbulence, sodar measurements, radiosoundings, aerosol lidars and RASS that give different estimates because aerosols, turbulence, temperature and fluxes do not necessarily behave similarly in the atmosphere. Furthermore, aerosol or turbulence flux profiles show different characteristics, such as maxima, minima, and inflexions that produce different estimates of h. A practical problem of the use of h as a parameter for its application in wind power meteorology is that it is not often routinely observed when performing wind resource assessment, in which 10-min averaging periods are used. Robust and accurate meteorological measurements of h are performed with radiosoundings launched every hour in the best of the cases. Nevertheless, this is not optimal since h might evolve in much shorter periods. The main idea of this work is to routinely observe the aerosol profile in the entire atmospheric boundary layer from two commercial long-range aerosol lidars, inter-comparing the main characteristics of the lidars' profiles and their estimations of h in the frame of wind power meteorology.
Journal of Atmospheric & Ocean Science, 2005
Precipitation and evaporation budgets over the Baltic Sea were studied in a concerted project cal... more Precipitation and evaporation budgets over the Baltic Sea were studied in a concerted project called PEP in BALTEX (Pilot study of Evaporation and Precipitation in the Baltic Sea), combining extensive field measurements and modelling efforts. Eddy-correlation-measurements of turbulent heat flux were made on a semi-continuous basis for a 12 month period at four well-exposed coastal sites in the Baltic Proper (the main basin of the Baltic Sea). Precipitation was measured at land-based sites with standard gauges and on four merchant ships travelling between Germany and Finland with the aid of specially designed ship rain gauges (SRGs). The evaporation and precipitation regime of the Baltic Sea was modelled for a 12 month period by applying a wide range of numerical models: the operational atmospheric High Resolution Limited Area Model (HIRLAM, Swedish and Finnish versions), the German atmospheric REgionalscale MOdel, REMO, the operational German Europe Model (only precipitation), the oceanographic model PROBE-Baltic, and two models that use interpolation of ground-based data, the Swedish MESAN model of SMHI and a German model of IFM-GEOMAR Kiel. Modelled precipitation was compared with SRG measurements on board the ships. A reasonable correlation was obtained, but the regional-scale models and MESAN gave some 20% higher precipitation over the sea than is measured. Bulk parameterisation schemes for evaporation were evaluated against measurements. A constant value of C HN and C EN with wind speed, underestimated large fluxes of both sensible and latent heat flux. The limited area models do not resolve the influence of the height of the marine boundary layer in coastal zones and the entrainment (on the surface fluxes), which may explain the observed low correlations between modelled and measured latent heat fluxes. Estimates of evaporation, E, and precipitation, P, for the entire Baltic Proper were made with several models for a 12 month period. While the annual variation was well represented by all predictions, there are still important differences in the annual means. Evaporation ranges from 509 to 625 mm year À1 and precipitation between 624 and 805 mm year À1 for this particular 12 month period. Taking the results of model verification from *Corresponding author. the present study into account, the best estimate of P-E is about 100 AE 50 mm for this particular 12 month period. But the annual mean of P-E varies considerably from year to year. This is reflected in simulations with the PROBE-Baltic model for an 18 year period, which gave 95 mm year À1 for the 12 month period studied here and 32 mm year À1 as an average for 18 years.
Boundary-layer Meteorology, 2001
Measurements carried out in Northern Finland on radiation and turbulent fluxes over a sparse, sub... more Measurements carried out in Northern Finland on radiation and turbulent fluxes over a sparse, sub-arctic boreal forest with snow covered ground were analysed. The measurements represent late winter conditions characterised by low solar elevation angles. During the experiment (12–24 March 1997) day and night were about equally long. At low solar elevation angles the forest shades most of the snow
Atmospheric Environment, 1998
... The tracer, a perfluorocarbon (PFC), was released in Brittany, France, transported eastward o... more ... The tracer, a perfluorocarbon (PFC), was released in Brittany, France, transported eastward over Europe and could be followed for more than 2000 km. ... At the rear of the trailing front, from Brittany to northern France, convective rain developed. ...
22nd Conference on Climate Variability and Change, Jan 18, 2010
SUMMARY The paper presents evaluation of model simulations against data on the vertical profiles ... more SUMMARY The paper presents evaluation of model simulations against data on the vertical profiles of mean meteorological parameters and surface turbulent momentum and heat fluxes for Sofia, Bulgaria. The simulation of the vertical profiles is currently a weak point in mesoscale modeling, and needs investigations in view of numerous practical applications.
Boundary-Layer Meteorology, 2014
ABSTRACT An investigation of the long-term variability of wind profiles for wind energy applicati... more ABSTRACT An investigation of the long-term variability of wind profiles for wind energy applications is presented. The observations consists of wind measurements obtained from a ground-based wind lidar at heights between 100 and 600 m, in combination with measurements from tall meteorological towers at a flat rural coastal site in western Denmark and at an inland suburban area near Hamburg in Germany. Simulations with the weather research and forecasting numerical model were carried out in both forecast and analysis configurations. The scatter between measured and modelled wind speeds expressed by the root-mean-square error was about 10 % lower for the analysis compared to the forecast simulations. At the rural coastal site, the observed mean wind speeds above 60 m were underestimated by both the analysis and forecast model runs. For the inland suburban area, the mean wind speed is overestimated by both types of the simulations below 500 m. When studying the wind-speed variability with the Weibull distribution, the shape parameter was always underestimated by the forecast compared to both analysis simulations and measurements. At the rural coastal site although the measured and modelled Weibull distributions are different their variances are nearly the same. It is suggested to use the shape parameter for climatological mesoscale model evaluation. Based on the new measurements, a parametrization of the shape parameter for practical applications is suggested.
Boundary-layer Meteorology, 1994
A model is presented for the height of the mixed layer and the depth of the entrainment zone unde... more A model is presented for the height of the mixed layer and the depth of the entrainment zone under near-neutral and unstable atmospheric conditions. It is based on the zero-order mixed-layer height model of Batchvarova and Gryning (1991) and the parameterization of the entrainment zone depth proposed by Gryning and Batchvarova (1994). However, most zero-order slab type models of mixed-layer
Abstract. The purpose of this paper is to test the ability of two quite different models to simul... more Abstract. The purpose of this paper is to test the ability of two quite different models to simulate the combined spatial and temporal variability of the internal boundary layer in an area of complex terrain and coastline during one day. The simple applied slab model of Gryning and ...
Boundary-Layer …, 1999
Abstract. The purpose of this paper is to test the ability of two quite different models to simul... more Abstract. The purpose of this paper is to test the ability of two quite different models to simulate the combined spatial and temporal variability of the internal boundary layer in an area of complex terrain and coastline during one day. The simple applied slab model of Gryning and ...
Boundary-Layer Meteorology, 1991
A slab model is proposed for developing the height of the mixed layer capped by stable air aloft.... more A slab model is proposed for developing the height of the mixed layer capped by stable air aloft. The model equations are closed by relating the consumption of energy (potential and kinetic) at the top of the mixed layer to the production of convective and mechanical turbulent kinetic energy within the mixed layer. By assuming that the temperature difference at the top of the mixed layer instantaneously adjusts to the actual meteorological conditions without regard to the initial temperature difference that prevailed, the model is reduced to a single differential equation which easily can be solved numerically. When the mixed layer is shallow or the atmosphere nearly neutrally stratified, the growth is controlled mainly by mechanical turbulence. When the layer is deep, its growth is controlled mainly by convective turbulence. The model is applied on a data set of the evolution of the height of the mixed layer in the morning hours, when both mechanical and convective turbulence contribute to the growth process. Realistic mixed-layer developments are obtained.
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Papers by Sven-Erik Gryning