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ppi
README.md

README.md

Reflectivity PPI data

This dataset contains the radar reflectivity plan position indicator (PPI) data derived from the five weather radars used in this case study.

Description

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.

Conversion

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

Radar settings

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

Data

  • Bulk download PPI data: ppi
  • Bulk download geospatial positions: position

License

Creative Commons Zero

Contact

Hidde Leijnse