Particle size and velocity distributions from a Thies Clima 3D Stereo disdrometer installed at the Casale Calore site in L'Aquila (Italy), monthly netCDF archive

Disdrometric data from a Thies Clima 3D Stereo disdrometer, with 22 size classes and 20 velocity classes, located at the instrumented site of Casale Calore in L'Aquila (Italy, 42.3831 N, 13.3148 E, 683 m a.s.l.), managed by the University of L'Aquila and the Center of Excellence Telesensing of Environment and Model Prediction of Severe Events (CETEMPS). 

Mid values and widths of the classes and instrument ancillary data are provided. One-minute spectra are aggregated every 5 minutes and saved in monthly netCDF files.

Metadata available at https://antarcticdatacenter.cnr.it/geonetwork/srv/eng/catalog.search#/metadata/27e2bd39-097e-4512-96f0-fb213cd59a00

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Example of netCDF file structure:

File "LAQ_3DS_202301_5min.nc"

  dimensions:
    diameter = 22;
    velocity = 20;
    n_image = 20;
    y_image = 12;
    x_image = 12;
    time = UNLIMITED;   // (8741 currently)
  variables:
    long time_UTC(time=8741);
      :description = "Measurement time. Timestamp indicates the end of the observation interval, e.g. 01-Mar-2020 00:05:00 represents the particle counts registered between 01-Mar-2020 00:00:01 and 01-Mar-2020 00:05:00.";
      :time_zone = "UTC";
      :units = "Seconds since 1970-01-01 00:00:00 (Unix time).";
      :_ChunkSizes = 512U; // uint

    float diameters(diameter=22);
      :description = "Mid values of the size classes";
      :units = "mm";

    float velocities(velocity=20);
      :description = "Mid values of the velocity classes";
      :units = "m s^-1";

    float diameters_width(diameter=22);
      :description = "Width of the size classes";
      :units = "mm";

    float velocities_width(velocity=20);
      :description = "Width of the velocity classes";
      :units = "m s^-1";

    int spectrum(diameter=22, velocity=20, time=8741);
      :description = "Matrix of particle counts in each of the 22 diameter sizes and 20 velocity ranges over 5 minutes.";
      :units = "counts";
      :_ChunkSizes = 22U, 20U, 1U; // uint

    float PSD(diameter=22, time=8741);
      :description = "Particle size distribution, 5 minutes interval, normalized by the observed volume.";
      :units = "m^-3 mm^-1";
      :_ChunkSizes = 22U, 1U; // uint

    double monthlySpectrum(diameter=22, velocity=20);
      :description = "Matrix of particle counts in each of the 22 diameter sizes and 20 velocity ranges over the entire month.";
      :units = "counts";

    double monthlyPSD(diameter=22);
      :description = "Particle size distribution for the whole month, normalized by the observed volume.";
      :units = "m^-3 mm^-1";

    int images(x_image=12, y_image=12, n_image=20, time=8741);
      :description = "Images of samples of the detected precipitating particles. Images are 48x12 pixel maximum, for a max of 4 stacked 12x12 images. Most of the time less than 4 images are provided.";
      :units = "0-255 pixel values";
      :_ChunkSizes = 12U, 12U, 20U, 1U; // uint

    int image_count(time=8741);
      :description = "How many images are registred by the instrument in the minute.";
      :units = "0-4 count";
      :_ChunkSizes = 1024U; // uint

    int precip_type(n_image=20, time=8741);
      :description = "Precipitation type as classified by the instument based on shape, size, velocity and presence of water, according to the following table with 11 entries (0-10): 0-reserved value, 1-false positive, 2-rain or graupel, 3-drizzle, 4-drizzle with rain, 5-rain, 6-rain with snow, 7-snow, 8-ice prisms, 9-graupel, 10-hail.";
      :units = "0-10 code";
      :_ChunkSizes = 20U, 1U; // uint

    int particle_diam(n_image=20, time=8741);
      :description = "Main diameter of the particles shown in the images.";
      :units = "mm";
      :_ChunkSizes = 20U, 1U; // uint

  // global attributes:
  :title = "Thies Clima 3D Stereo disdrometer data, aggregated to 5min, monthly netCDF archive.";
  :comment = "Particle counts diveded in 22 size classes and 20 velocity classes. Note that this data has been processed regardless of precipitation type.";
  :time_label = "Jan 2023";
  :institution = "CNR-ISAC, Rome (IT)";
  :contact_person = "Luca Baldini, CNR-ISAC, Rome, l.baldini@isac.cnr.it";
  :source = "TC 3DS disdrometer at MZS (Antarctica)";
  :location = "Mario Zucchelli Station (74°42\'S, 164°07\'E,  15 m a.s.l.)";
  :author = "Giacomo Roversi, Ca\' Foscari University, Venice (IT) and CNR-ISAC, Rome (IT), g.roversi@isac.cnr.it";
  :creation_date = "23-Oct-2024 11:13:22 UTC";
  :coverage = "Monthly coverage (Jan 2023): 100 %";
  :time_resolution = "5 minutes";
  :history = "Created from raw TC telegram TDD 163, aggregated to 5min temporal resolution with a sum of the 1-minute counts if least 3 out of 5 are not NaN.";