1Department of Physics, University of Helsinki, Helsinki, Finland
2Colorado State University, Fort Collins, Colorado, USA
3ARPA Piemonte, Dipartimento Sistemi Previsionali, Turin, Italy
4Finnish Meteorological Institute, Helsinki, Finland
Received: 08 Mar 2016 – Discussion started: 18 Mar 2016
Abstract. High-spatial-resolution weather radar observations are of primary relevance for hydrological applications in urban areas. However, when weather radars are located within metropolitan areas, partial beam blockages and clutter by buildings can seriously affect the observations. Standard simulations with simple beam propagation models and digital elevation models (DEMs) are usually not able to evaluate buildings' contribution to partial beam blockages. In recent years airborne laser scanners (ALSs) have evolved to the state-of-the-art technique for topographic data acquisition. Providing small footprint diameters (10–30 cm), ALS data allow accurate reconstruction of buildings and forest canopy heights. Analyzing the three weather C-band radars located in the metropolitan area of Helsinki, Finland, the present study investigates the benefits of using ALS data for quantitative estimations of partial beam blockages. The results obtained applying beam standard propagation models are compared with stratiform 24 h rainfall accumulation to evaluate the effects of partial beam blockages due to constructions and trees. To provide a physical interpretation of the results, the detailed analysis of beam occultations is achieved by open spatial data sets and open-source geographic information systems.
Revised: 15 Sep 2016 – Accepted: 15 Sep 2016 – Published: 17 Oct 2016
Cremonini, R., Moisseev, D., and Chandrasekar, V.: Airborne laser scan data: a valuable tool with which to
infer weather radar partial beam blockage in urban environments, Atmos. Meas. Tech., 9, 5063-5075, doi:10.5194/amt-9-5063-2016, 2016.