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New Methods for Radar-Based Rainfall Nowcasting in Urban Areas

New Methods for Radar-Based Rainfall Nowcasting in Urban Areas

Reliable nowcasts of rainfall and flooding are critical for the society in densely populated urban areas. New methods were developed using a dense radar network deployed in a metropolitan area.

The term nowcast refers to a rapidly updated short-range forecast of rainfall (1-3 hours). Such forecasts are particularly important in densely populated urban areas, where heavy rainfall can trigger hazardous floods. In addition, the small size of typical catchments in urban areas necessitates the use of high-resolution nowcasts. Computationally efficient methods were developed for this purpose.

The research was carried out by using the CASA radar network deployed in the Dallas-Fort Worth area. The network consists of eight X-band radars covering an urban metroplex with over six million inhabitants. The used technology allows obtaining rainfall measurements with a higher resolution than by using conventional weather radars (250 meters and one minute). Thus, valuable information was obtained about the potential benefits of such a radar network, and the results are significant for future radar deployments in Finland. In addition, the results are relevant for urban hydrologists who are interested in using the nowcasts as inputs to flood forecasting models.

The research was carried out as a part of the HAZARD-SEES programme funded by the US National Science Foundation and a grant admitted by the Finnish Academy of Science and Letters via the Foundations' Post Doc Pool. The grant is intented for a two-year research visit of the principal author to the Colorado State University in the research team led by prof. V. Chandrasekar.

Further information:

Seppo Pulkkinen, researcher, Finnish Meteorological Institute,

Pulkkinen, S., Chandrasekar, V., and Harri, A.-M., Fully Spectral Method for Radar-Based Precipitation Nowcasting, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2019,

Pulkkinen, S., Chandrasekar, V., and Harri, A.-M., Stochastic Spectral Method for Radar-Based Probabilistic Precipitation Nowcasting, Journal of Atmospheric and Oceanic Technology, 2019,

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