Reflectivity PPI data
The dataset is a time series of reflectivity grids for each radar. It is structured as follows:
\ppi \radar1_date1.zip // Compressed data for first day of this radar radar1_date1_time1.txt // Grid of reflectivity data for this radar and timeframe radar1_date1_time2.txt radar1_date1_time3.txt ... ... \radar1_date7.zip // Compressed data for last day of this radar \radar2_date1.zip ... \position radar1_latitudes.txt // Grid of the latitudes around this radar radar1_longitudes.txt // Grid of the longitudes around this radar radar2_latitudes.txt radar2_longitudes.txt ...
The radar reflectivity plan position indicator (PPI) data has been derived from the radar reflectivity data from a single scan of each radar. It is represented as a 120x120km Cartesian grid centered on the radar, with a horizontal resolution of 1km. In the data (e.g.
radar1_date1_time1.txt) it is formatted as 120 rows and 120 columns, with each field (i.e. grid node) containing the radar reflectivity factor, given in dBZ.
In addition, the geospatial positions of the 5 grids are given in position, as the latitude and longitude for each grid node.
The conversion from the measured radar reflectivity factors on a polar grid to a Cartesian grid is carried out as follows:
- Construct Cartesian grid with a size of 120x120 km, centered around the radar, with a 1km resolution
- For each Cartesian grid node, determine the coordinates in the radar polar coordinate system
- Determine which polar pixel is closest to the Cartesian grid node
- Assign the reflectivity of that polar pixel to the Cartesian pixel
The radar scans used for these PPIs are:
- 6260 (De Bilt, Netherlands): 0.8 degrees elevation angle; height increases from 44m at the radar to 1094m at 60km from the radar
- 6234 (Den Helder, Netherlands): 0.8 degrees elevation angle; height increases from 51m at the radar to 1101m at 60km from the radar
- 6410 (Jabbeke, Belgium): 1.2 degrees elevation angle; height increases from 52 m at the radar to 1520m at 60km from the radar
- 6451 (Zaventem, Belgium): 1.0 degrees elevation angle; height increases from 73m at the radar to 1332m at 60km from the radar
- 6477 (Wideumont, Belgium): 1.2 degrees elevation angle; height increases from 592m at the radar to 2060m at 60km from the radar