Supplementary material for 'Revealing patterns of nocturnal migration using the European weather radar network'

This package contains data, filters and visualizations from Nilsson and Dokter et al. (2019).

Files

radar_metadata.csv: Metadata for the 84 European radars considered for this study. Includes radar code (odim_code = country + odim_code_3char and alternative radar code vp_radar), radar site location (location, latitude, longitude), radar site elevation (site_altitude_asl in meters above sea level) and radar altitude range used in this study (min_height_cut_asl and max_height_cut_asl in meters above sea level).

vp.zip: Vertical profiles of birds (vp) data, processed from the radar volume data following procedures described by Dokter et al. (2011), using the vol2bird algorithm in the R package bioRad. Zip file includes vp data for the 84 European radars considered for this study from September 19 to October 9, 2016 (21 days). This time period is characterized by strong passerine migration throughout Europe. Files are organized in radar (= odim_code), date and hour directories and follow the ODIM bird profile format specification. Data can be read with the R package bioRad.

vp_processing_settings.yaml: Data selection setting for this study, based on data quality criteria. File lists for each radar the altitudes to include (include_heights), time periods to exclude (exclude_datetimes) and reasons for exclusion (comments). 70 of the 84 radars were retained after filtering.

vp_processed_70_radars_20160919_20161009.csv: Processed vp data for 70 radars. Is the result of processing vp.zip with vp_processing_settings.yaml and radar_metadata.csv using vp-processing (Desmet & Nilsson 2018). Note: includes all timestamps: day and night & those marked for exclusion (marked in exclusion_reason). This data file forms the basis for analysis in the study.

Headers are:

• radar_id: odim_code of the radar
• datetime: timestamp
• HGHT: lower altitude of altitude bin (m above sea level)
• u: bird ground speed towards east (m/s)
• v: bird ground speed towards north (m/s)
• dens: bird density (birds/km3)
• dd: bird flight direction (degrees from north)
• ff: bird ground speed (m/s)
• DBZH: reflectivity factor (dBZ) in horizontal polarisation
• mtr: migration traffic rate (birds/km/h)
• day_night: timestamp occurs during day or night (based on sunrise/sunset)
• date_of_sunset: date at sunset, with night timestamps between midnight and sunrise belonging to the previous date
• exclusion_reason: reason timestamp is excluded in vp_processing_settings.yaml (if applicable). Excluded timestamps have NA values for u, v, dens, dd, ff, DBZH, and mtr.

vp_flowviz.csv: Input data for visualizations. Is the result of processing vp_processed_70_radars_20160919_20161009.csv using vp-to-flowviz.Rmd in vp-processing (Desmet & Nilsson 2018). Aggregates data in hourly bins for 200-2000m (altitude_band = 1) and above (altitude_band = 2). Only altitude band 1 is used in visualizations.

flowviz.mov: Screencast of vp_flowviz.csv visualized with Bird migration flow visualization v2 (Desmet et al. 2016, Shamoun-Baranes et al. 2016). The visualization extrapolates the migration over the entire sampling range (cropped in the screencast due to technical limitations and thus excluding the Bulgarian radar), not taking topography or water bodies into account, and shows the ground speed (length of arrows) and direction of migration over time. Note that density is not shown: low density movements can therefore appear as strong as high density movements when ground speeds are similar.

cartoviz.mov: Screencast of vp_flowviz.csv visualized as an interactive map with CARTO. Visualization shows migration density (size of circles) and mean direction (colour) over time. The interactive map is available at https://inbo.carto.com/u/lifewatch/builder/8685140f-8d8c-4d06-9e1e-25d051d43748/embed.