Evaluation of very high-resolution simulations with the non-hydrostatic numerical weather prediction model Lokalmodell for urban air pollution episodes in Helsinki, Oslo and Valencia

Abstract. The operational numerical weather prediction model Lokalmodell LM with 7 km horizontal resolution was evaluated for simulations of the meteorological conditions during observed urban air pollution episodes. The resolution was increased to experimental 2.8 km and 1.1 km resolution by one-way interactive nesting without introducing urbanisation of physiographic parameters or parameterisations. The episodes examined are two severe winter inversion-induced episodes in Helsinki in December 1995 and Oslo in January 2003, three suspended dust episodes in spring and autumn in Helsinki and Oslo, and a late-summer photochemical episode in the Valencia area. The evaluation was basically performed against observations and radiosoundings and focused on the LM skill at forecasting the key meteorological parameters characteristic for the specific episodes. These included temperature inversions, atmospheric stability and low wind speed for the Scandinavian episodes and the development of mesoscale recirculations in the Valencia area. LM forecasts often improved due to higher model resolution especially in mountainous areas like Oslo and Valencia where features depending on topography like temperature, wind fields and mesoscale valley circulations were better described. At coastal stations especially in Helsinki, forecast gains were due to the improved physiographic parameters (land fraction, soil type, or roughness length). The Helsinki and Oslo winter inversions with extreme nocturnal inversion strengths of 18°C were not sufficiently predicted with all LM resolutions. In Helsinki, overprediction of surface temperatures and low-level wind speeds basically led to underpredicted inversion strength. In the Oslo episode, the situation was more complex involving erroneous temperature advection and mountain-induced effects for the higher resolutions. Possible explanations include the influence of the LM treatment of snow cover, sea ice and stability-dependence of transfer and diffusion coefficients. The LM simulations distinctly improved for winter daytime and nocturnal spring and autumn inversions and showed good skill at forecasting further episode-relevant meteorological parameters. The evaluation of the photochemical Valencia episode concentrated on the dominating mesoscale circulation patterns and showed that the LM succeeds well in describing all the qualitative features observed in the region. LM performance in forecasting the examined episodes thus depends on the key episode characteristics and also the season of the year with a need to improve model performance in very stable inversion conditions not only for urban simulations.

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Chapter 4.4 Final results of the model inter-comparison of very high-resolution simulations with numerical weather prediction models for eight urban air pollution episodes in four European cities

Air Pollution Modeling and Its Application XVIII - Developments in Environmental Science ◽

10.1016/s1474-8177(07)06044-5 ◽

2007 ◽

pp. 383-394

Author(s):

B. Fay ◽

L. Neunhäuserer ◽

A. Baklanov ◽

G. Bonafé ◽

S. Jongen ◽

...

Keyword(s):

Prediction Models ◽

Weather Prediction ◽

Urban Air Pollution ◽

Urban Air ◽

European Cities ◽

Urban Air Pollution Episodes ◽

Very High ◽

Numerical Weather Prediction Models ◽

Air Pollution Episodes ◽

Pollution Episodes

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International symposium on prediction, monitoring and control of urban air pollution episodes with special reference to the severe pollution episode of 14–21 January 1985 over Europe

Atmospheric Environment (1967) ◽

10.1016/0004-6981(87)90178-8 ◽

1987 ◽

Vol 21 (12) ◽

pp. 2493

Keyword(s):

Air Pollution ◽

International Symposium ◽

Special Reference ◽

Urban Air Pollution ◽

Urban Air ◽

Monitoring And Control ◽

Urban Air Pollution Episodes ◽

And Control ◽

Air Pollution Episodes ◽

Pollution Episodes

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Use of Episodic Controls to Reduce Frequency and Severity of Air Pollution Events

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1587-05 ◽

1997 ◽

Vol 1587 (1) ◽

pp. 35-43

Author(s):

Mario E. Jorquera

Keyword(s):

Air Pollution ◽

Control Strategies ◽

Urban Air Pollution ◽

Urban Air ◽

Short Term ◽

Success Stories ◽

Urban Air Pollution Episodes ◽

Main Barrier ◽

The Cost ◽

Pollution Events

Most common urban air pollution episodes occur during readily identifiable meteorological conditions that contribute to the problem. In contrast, most air pollution controls concentrate on permanent curtailments of emissions. The argument is put forth that episodic emission control strategies can be an effective supplement to traditional measures, at a fraction of the cost. Questions regarding the legality of episodic controls have been the main barrier to their implementation. These legal issues are discussed. In addition, the forecasting and modeling implications of episodic controls are considered. Several areas have implemented episodic air pollution controls or used accurate short-term forecasts to warn the public through health advisories of pending air pollution events. Some of these success stories are highlighted. A scheme for assisting the prediction of emissions reductions based on the degree to which episodic measures are voluntary or mandatory is proposed. This method may help resolve emission reduction credit and enforcement issues, making approval of episodic measures for state implementation plans and conformity more likely. The transportation sector has the potential to make episodic measures successful. Furthermore, some of these measures are eligible for federal transportation dollars. The potential for funding transportation-related episodic controls is explored. While episodic controls cannot replace traditional controls, they can be an incremental or short-term solution that may evolve into, or be used in conjunction with, other plans. Transportation professionals are incited to develop creative short-term solutions to the pervasive, yet short-term, problem of urban air pollution.

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Potential and Shortcomings of Numerical Weather Prediction Models in Providing Meteorological Data for Urban Air Pollution Forecasting

Urban Air Quality — Recent Advances ◽

10.1007/978-94-010-0312-4_4 ◽

2002 ◽

pp. 43-60 ◽

Cited By ~ 2

Author(s):

Alexander Baklanov ◽

Alix Rasmussen ◽

Barbara Fay ◽

Erik Berge ◽

Sandro Finardi

Keyword(s):

Air Pollution ◽

Numerical Weather Prediction ◽

Prediction Models ◽

Meteorological Data ◽

Weather Prediction ◽

Urban Air Pollution ◽

Urban Air ◽

Numerical Weather ◽

Numerical Weather Prediction Models ◽

Air Pollution Forecasting

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Integrated systems for forecasting urban meteorology, air pollution and population exposure

Atmospheric Chemistry and Physics ◽

10.5194/acp-7-855-2007 ◽

2007 ◽

Vol 7 (3) ◽

pp. 855-874 ◽

Cited By ~ 77

Author(s):

A. Baklanov ◽

O. Hänninen ◽

L. H. Slørdal ◽

J. Kukkonen ◽

N. Bjergene ◽

...

Keyword(s):

Air Pollution ◽

Air Quality ◽

Health Effects ◽

Weather Prediction ◽

Urban Air Pollution ◽

Urban Air Quality ◽

Population Exposure ◽

Quality Information ◽

Urban Air ◽

Initial Development

Abstract. Urban air pollution is associated with significant adverse health effects. Model-based abatement strategies are required and developed for the growing urban populations. In the initial development stage, these are focussed on exceedances of air quality standards caused by high short-term pollutant concentrations. Prediction of health effects and implementation of urban air quality information and abatement systems require accurate forecasting of air pollution episodes and population exposure, including modelling of emissions, meteorology, atmospheric dispersion and chemical reaction of pollutants, population mobility, and indoor-outdoor relationship of the pollutants. In the past, these different areas have been treated separately by different models and even institutions. Progress in computer resources and ensuing improvements in numerical weather prediction, air chemistry, and exposure modelling recently allow a unification and integration of the disjunctive models and approaches. The current work presents a novel approach that integrates the latest developments in meteorological, air quality, and population exposure modelling into Urban Air Quality Information and Forecasting Systems (UAQIFS) in the context of the European Union FUMAPEX project. The suggested integrated strategy is demonstrated for examples of the systems in three Nordic cities: Helsinki and Oslo for assessment and forecasting of urban air pollution and Copenhagen for urban emergency preparedness.

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Integrated systems for forecasting urban meteorology, air pollution and population exposure

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-6-1867-2006 ◽

2006 ◽

Vol 6 (2) ◽

pp. 1867-1913 ◽

Cited By ~ 8

Author(s):

A. Baklanov ◽

O. Hänninen ◽

L. H. Slørdal ◽

J. Kukkonen ◽

N. Bjergene ◽

...

Keyword(s):

Air Pollution ◽

Air Quality ◽

Health Effects ◽

Weather Prediction ◽

Urban Air Pollution ◽

Urban Air Quality ◽

Population Exposure ◽

Quality Information ◽

Urban Air ◽

Initial Development

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Overview of the European project FUMAPEX

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-11679-2005 ◽

2005 ◽

Vol 5 (6) ◽

pp. 11679-11702 ◽

Cited By ~ 1

Author(s):

A. Baklanov

Keyword(s):

Air Pollution ◽

Prediction Models ◽

Meteorological Data ◽

Weather Prediction ◽

Urban Air Pollution ◽

Population Exposure ◽

Urban Air ◽

Exposure Models ◽

Numerical Weather Prediction Models

Abstract. The quality of the urban air pollution forecast critically depends on the mapping of emissions, the urban air pollution models, and the meteorological data. The quality of the meteorological data should be largely enhanced by using downscaled data from advanced numerical weather prediction models. These different topics, as well as the application of population exposure models, have traditionally been treated in distinct scientific communities whose expertise needs to be combined to enhance the possibilities of forecasting air pollution episodes in European cities. For this purpose the EU project ''Integrated Systems for Forecasting Urban Meteorology, Air Pollution and Population Exposure'' (FUMAPEX) (http://fumapex.dmi.dk), involving 22 organizations from 10 European countries, was initiated. The main objectives of the project are the improvement of meteorological forecasts for urban areas, the connection of numerical weather prediction models to urban air pollution and population exposure models, the building of improved Urban Air Quality Information and Forecasting Systems, and their application in cities in various European climates. This paper overviews the project items and first two-years results, it is an introduction to the whole ACP issue.

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Evaluation of high-resolution forecasts with the non-hydrostaticnumerical weather prediction model Lokalmodell for urban air pollutionepisodes in Helsinki, Oslo and Valencia

Atmospheric Chemistry and Physics ◽

10.5194/acp-6-2107-2006 ◽

2006 ◽

Vol 6 (8) ◽

pp. 2107-2128 ◽

Cited By ~ 18

Author(s):

B. Fay ◽

L. Neunhäuserer

Keyword(s):

Prediction Model ◽

Meteorological Parameters ◽

Weather Prediction ◽

Atmospheric Stability ◽

Model Performance ◽

Late Summer ◽

Horizontal Resolution ◽

Urban Air ◽

Wind Speeds ◽

Physiographic Parameters

Abstract. The operational numerical weather prediction model Lokalmodell LM with 7 km horizontal resolution was evaluated for forecasting meteorological conditions during observed urban air pollution episodes. The resolution was increased to experimental 2.8 km and 1.1 km resolution by one-way interactive nesting without introducing urbanisation of physiographic parameters or parameterisations. The episodes examined are two severe winter inversion-induced episodes in Helsinki in December 1995 and Oslo in January 2003, three suspended dust episodes in spring and autumn in Helsinki and Oslo, and a late-summer photochemical episode in the Valencia area. The evaluation was basically performed against observations and radiosoundings and focused on the LM skill at forecasting the key meteorological parameters characteristic for the specific episodes. These included temperature inversions, atmospheric stability and low wind speeds for the Scandinavian episodes and the development of mesoscale recirculations in the Valencia area. LM forecasts often improved due to higher model resolution especially in mountainous areas like Oslo and Valencia where features depending on topography like temperature, wind fields and mesoscale valley circulations were better described. At coastal stations especially in Helsinki, forecast gains were due to the improved physiographic parameters (land fraction, soil type, or roughness length). The Helsinki and Oslo winter inversions with extreme nocturnal inversion strengths of 18°C were not sufficiently predicted with all LM resolutions. In Helsinki, overprediction of surface temperatures and low-level wind speeds basically led to underpredicted inversion strength. In the Oslo episode, the situation was more complex involving erroneous temperature advection and mountain-induced effects for the higher resolutions. Possible explanations include the influence of the LM treatment of snow cover, sea ice and stability-dependence of transfer and diffusion coefficients. The LM simulations distinctly improved for winter daytime and nocturnal spring and autumn inversions and showed good skill at forecasting further episode-relevant meteorological parameters. The evaluation of the photochemical Valencia episode concentrated on the dominating mesoscale circulation patterns and showed that the LM succeeds well in describing all the qualitative features observed in the region. LM performance in forecasting the examined episodes thus depends on the key episode characteristics and also the season of the year with a need to improve model performance in very stable inversion conditions not only for urban simulations.

Download Full-text