A numerical method to generate high temporal resolution precipitation time series by combining weather radar measurements with a nowcast model

• Published in: Atmospheric research 2014-03, Vol.138, p.1-12
• Main Authors: Nielsen, Jesper E., Thorndahl, Søren, Rasmussen, Michael R.
• Format: Article
• Language: English
• Subjects: Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; External geophysics; Geophysics. Techniques, methods, instrumentation and models; Laser disdrometers; Meteorology; Natural hazards: prediction, damages, etc; Quantitative precipitation estimates; Temporal interpolation of radar data; Water in the atmosphere (humidity, clouds, evaporation, precipitation); Weather radar
• ISSN: 0169-8095; 1873-2895
• DOI: 10.1016/j.atmosres.2013.10.015

The topic of this paper is temporal interpolation of precipitation observed by weather radars. Precipitation measurements with high spatial and temporal resolution are, in general, desired for urban drainage applications. An advection-based interpolation method is developed which uses methods for vector field estimation already known from short-term weather radar nowcasting. However, instead of forecasting the weather radar rainfall, the proposed interpolation method exploits the advection of the rainfall in the interpolation. The interpolated rainfall fields are validated by measurements at ground level from laser disdrometers. The proposed interpolation method performs better when compared to traditional interpolation of weather radar rainfall where the radar observation is considered constant in time between measurements. It is demonstrated that the advection-based interpolation method reconstructs a significant part of the temporal variations of the rainfall. Moreover, the interpolated precipitation fields estimate accumulated rain depths more accurately. •Weather radar measurements are interpolated temporally using a numerical advection-model known from radar nowcasting.•The interpolation is able to reconstruct fine scale temporal variations of the rainfall.•This improves both the peak estimation and the accuracy of hour accumulated rain depths.•Improvements are verified by laser-based disdrometers.