Component Web Services and Service Chaining
The composite trajectory service consists of services for WCS data access, single trajectory calculation and trajectory aggregation.
The wind data are to be provided by servers that can deliver 4D model wind data (u,v,w,t).
The single trajectory service uses the 4D input winds for a specific region and time and calculates forward or backward trajectories. Back trajectories are diagnostic tools that help elucidating where dirty air came from. Forward trajectories indicate the transport from known source regions downwind. The same algorithm is used for the forecast and historical 4D trajectories. Since the calculation of trajectories is part science part art it is desireable to have several trajectory algorithms to choose from.
The trajectory aggregator is a compound service that can aggregate multiple trajectories using a variety of algorithms. Generally, the trajectory aggregator is linked to air quality monitoring data as the source of trajectory filter conditions.
The new elements for this proposed trajectory server would include:
- Real-time calculation of trajectories
- Remote access to forecast (Unidata) and historical (NCDC) winds
- WCS and netCDF-CF standards-based data access
- Persistents of the compound trajectory service as a network of chained services
With these services it is possible to build a variety of air quality analysis applications such as the Combined Aerosol Trajectory Tool, CATT, that has been developed over the past few years by community of air quality analysts. The new service would bring together and provide benefits to the air quality and meteorological communities.