GASLINK: Linking the GMES Pilot Atmospheric core Service (GAS) with the Stockholm Air Quality Service

Background and objectives

The Global Monitoring for Environment and Security (GMES) programme is specifically committed to bring data from space-based and in-situ earth observation capacities to the citizens of Europe. The objective is to introduce new services that make environmental and security-related information available to the people who need it.

The FP7 MACC (phase 1 and 2 project “Monitoring Atmospheric Composition and Climate”) will, at its end 2013, represent the pilot GMES Atmospheric core Service (GAS) and bring online air quality data and forecasts to the European community. In MACC, seven regional air quality models – of which one is SMHI’s MATCH model - are used to produce an ensemble of air quality forecasts and atmospheric composition information on the European scale. The present project GASLINK is linking the GMES Pilot Atmospheric core Service (GAS) to the Stockholm Air Quality Service, establishing a downstream production facility for air-quality forecasts on the urban scale.

The Stockholm-Uppsala Air quality Management Association (SULVF) manages the effects of air pollutants in the Stockholm-Uppsala Metropolitan area. The association contracts Stockholm Air Quality and Noise Analysis (SLB), part of Stockholm municipality, to do the operational air quality work of which air quality forecasts is one of the tasks. SULVF will translate GASLINK air quality results into health risk index forecasts on the web. The information can be used by asthmatics and other vulnerable parts of the population to a better planning of their medication and their physical outdoor activities.

Results

Air quality forecasts based on high resolution simulations with MATCH-Stockholm, using an European scale MATCH model result on the boundaries, have been implemented in the SULVF Airviro system. Daily forecasts of O3, NO2, NOx and PM10 are available, presently with a 1x1 km spatial resolution. There are currently two operational model options for the European scale forecasts, however the final solution will be to use the GMES core service, e.g. MATCH-MACC forecasts.

The quality of the MATCH model forecast and hindcast simulations have been analyzed through comparisons with monitor data at the Norra Malma rural background station and the Torkel Knutsson urban background station. Ozone forecasts show good quality, reproducing seasonal variations and high episodes in a realistic way, although with a certain underestimation of the one percent highest values. Also NO2 concentrations can be satisfactorily forecasted with the GASLINK nested model system. For PM10 the situation is promising, but more development must be performed to achieve a better quality of the long-range transported part of PM10, today determined by scaling up one of the PM fractions (secondary inorganic aerosols). For PM10 forecasts in Scandinavian cities a more realistic description of local PM10 emissions that includes road dust generation and resuspension is also needed. Although improvements of the GASLINK model components are expected within the coming years, it is suggested to link already now the GASLINK air quality forecasts of O3, NO2, NOx and PM10 to the Health Risk Index web page operated by the environmental authorities in the Stockholm-Uppsala region.