TOC > MSC data > RDAQA > Regional Deterministic Air Quality Analysis on MSC Datamart
Regional Deterministic Air Quality Analysis (RDAQA) data in GRIB2 Format
This page describes the Regional Deterministic Air Quality Analysis (RDAQA) GRIB2 data. The system is run hourly to produce analysis of some pollutants such as hourly ozone (O3), nitrogen dioxide (NO2), or particulate matter with aerodynamic diameter smaller than 2.5 μm (PM2.5) fields on a North American grid.
Data location
MSC Datamart data can be automatically retrieved with the Advanced Message Queuing Protocol (AMQP) as soon as they become available. An overview and examples to access and use the Meteorological Service of Canada's open data is also available.
The data can be accessed at the following URLs:
where:
- HH : Analysis validity time, in UTC [00, 01, 02, ..., 22, 23]
An history of 24 hours of forecast is kept in this directory.
Technical specification of the grid
Table lists the values of various parameters of the rotated lat-lon grid:
| Parameter | Value |
|---|---|
| ni | 729 |
| nj | 599 |
| resolution at 60° N | 10 km |
| coordinate of first grid point (with respect to the used grid) | 32 ° S ; 39.5 ° W |
Note : The most recent versions of wgrib2 and GDAL support these rotated grids.
File nomenclature
The files have the following nomenclature:
{YYYYMMDD}T{HH}Z_MSC_{SYSTEM}_{VAR}_{LVLTYPE}_{grid}{resolution}_PT0H.grib2
where:
- YYYYMMDD: Year, month and day of the beginning of the forecast
- T : Time delimiter according to ISO8601 norms
- HH: Analysis validity time, in UTC [00, 01, 02, ..., 22, 23]
- Z : Time zone (UTC hour)
- MSC : Constant string indicating that the data is from the Meteorologcal Service of Canada (MSC)
- SYSTEM : Constant string indicating the system from which the analysis was generated [RDAQA; RDAQA-Prelim for the observation cut-off time within one hour of time YYYYMMDDHH, indicating that all observations may not have been collected; RDAQA-FW for analysis generated from the RAQDPS-FW system].
- VAR : Variables included in the file (see section below).
- LVLTYPE : Vertical level type [Sfc for the surface]
- grid : Horizontal grid [RLatLon]
- resolution : Resolution in degree 0.09 (about 10km) in both latitude and longitude directions
- PT0H: Forecast hours based on ISO8601 norms. P, T and H are constant character designating Period, Time and Hour. Here, PTOH indicates an analysis.
- grib2 : constant string indicating the GRIB2 format
Examples:
- 20230808T04Z_MSC_RDAQA-Prelim_PM10_Sfc_RLatLon0.09_PT0H.grib2
- 20230808T04Z_MSC_RDAQA_PM10_Sfc_RLatLon0.09_PT0H.grib2
- 20230808T04Z_MSC_RDAQA-FW_PM10_Sfc_RLatLon0.09_PT0H.grib2
List of variables
List of 2D variables available in the files:
Support
If you have any questions about this data, please contact us.
Announcements from the dd_info mailing list
Announcements related to this dataset are available in the dd_info list.