Application of the Global Environmental Multiscale model GEM to local air quality studies - Kraków IM Project

Lech Łobocki1, Jacek W. Kamiński2, Małgorzata Zdunek1, Joanna Strużewska11Warsaw University of Technology, Poland; 2York University, Toronto, Canada

The problem

Air quality in Kraków, a former Poland’s capital, and a place of world’s cultural heritage-unfavourable climatic condition: river basin restricting ventillation, frequent calms-obsolete residential heating system as a major source of pollution-industrial Silesia region located 100 km upwind on a prevailing wind direction-local industry and trasportation contribute significantly to AQ problems

PM10 concentrations, as measured by the WIOŚ Małopolskiemonitoring network: daily averages

January 2005 February 2005

The model

GEM (Global Environmental Multiscale) of the Canadian Meteorological Centre (Cote et al.., 1998):- can be set on a variable-spaced grid, with global extent, and a high-resolution core- optionally nonhydrostatic: can be used with horizontal resolution finer than 10 km- semi-implicit, semi-Lagrangian numerical scheme, stable for fast modes- a wide set of physical parameterisations, applicable to wide range of scales- GEM-AQ: meteorological model combined on-line with atmospheric chemistry

Research context

IES-JRC „From toxic emissions to health effects – Integrated Methodology”:a pilot study in Kraków, for further development of air quality strategy & policy support tools for European cities (2005-6).Field measurement campaign: January 15 – February 6, 2005, in KrakówAQ modelling: several groups, model intercomparison

Aims & issues

- Basic goal: deliver 3D, high-resolution meteorological fields for AQ models, to project participants - Assess the meteorological forecast quality, identify inaccuracies as sources of errors in subsequent

AQ calculations- Nesting vs. variable-resolution grid approach: can VR be used effectively with fine meshes (2-3 km)?- How dense must the model grid be, in order to resolve key features of the local meteorology?

10 km 2,5 km

The results

I. 10 km resolution is sufficient for resolving flow distortion caused by major terrain features (mountain ridges), effects of smaller terrain features such as mountain and river basins require much finer grid, such as 2.5 km;in particular, complex structure of the temperature field becomes visible when the resolution is sufficiently fine; note foehn-type effects on the northern slopes of Tatra mountains

II. Verification: a comparison of 10 km and 2.5 km forecasts with measurements taken at meteorological and air quality monitoring stations: note coarse-grid forecast failures, and dramatic improvement in fine-grid, especially at stations located in mountain basins (Nowy Sącz, Zakopane). Note also urban heat island effects (Kraków-Balice vs. Kraków-Krowodrza), not included in the current model version.

Temperature Wind speed

III. Succesful forecasting ofcloudiness requires a propermodel spin-up.

34-hour forecast

10-hour forecast

Cloudiness

Acknowledgements: This work was supported by the Ministry of Science and Higher Education, special research project no. JRC/249/2006.

Satellite imagery (MODIS/TERRA), 06.02 10:35