This case study is based on data from five operational weather radars (De Bilt and Den Helder in the Netherlands; Jabbeke, Zaventem and Wideumont in Belgium) from 5 April 2013 00:00 UTC to 12 April 2013 00:00 UTC. The methods described in (Dokter et al., 2011) were used to process the radar data and extract bird migration altitude profiles applying a calibration for passerine migration to convert reflectivity into bird densities (birds km-3). The processed data consists of an altitude profile extracted every 5 minutes per radar from all pulse volumes within 5-25 km of each radar station up to a sampling altitude of 4000 m above the radar station, including the start and end date and time (UTC) of each 5 minute scan, the 200m altitude bin (from 0.1 up to 5.9 km), the standard deviation of the radial velocity (σ_r,the speed of targets relative to the radar), the bird reflectivity (cm2 km-3) converted to bird density (ρ_bird, birds km-3), the vertical and horizontal ground speed components (u and v components towards east and north respectively in m/s).
The lowest altitude bin (0-200 m, 0.1 km in dataset) contains influence of ground clutter -radar reflectivity generated by targets on the ground- and is best excluded from visualisations. It is also best to consider altitude bands up to 4000 m following (Dokter et al., 2011, Kemp et al., 2010, Van Gasteren et al., 2008).
- Dokter_2011a - TODO
- Annoni_2001a - A. Annoni, C. Luzet, E. Gubler and J. Ihde. Map Projections for Europe. Institute for Environment and Sustainability, European Communities, 2003. URL: http://ec.europa.eu/eurostat/documents/4311134/4366152/Map-projections-EUROPE.pdf
- TODO: add reference to new paper