Ronny Berndtsson
Professor, Dep Director, MECW Dep Scientific Coordinator
Real-time tracking of convective rainfall properties using a two-dimensional advection-diffusion model
Author
Summary, in English
There is a need to improve rainfall forecasting capabilities for small ungaged urban catchments to reduce flooding hazards and pollution release. For this purpose, information is required on small-scale and short-term convective cell behavior. We use a two-dimensional stochastic advection-diffusion model to parameterize the space-time rainfall intensity from convective rainfall. The rainfall intensity resulting from different separable components of the rain cell, such as apparent turbulent diffusion and development/decay of rainfall intensity, is quantified for 10 observed and, for southern Sweden, representative high-intensity rainfall events. This is done following a Lagrangian approach. It is shown the used model was able to respond to rapid changes in observed rainfall intensity in both space and time, thus giving a small average root-mean-square error for all 10 events (0.06 mm min-1). When dividing the total rainfall intensity into apparent turbulent diffusion and development/decay terms, respectively, it was shown that D(y,center) and γ(center) contribute approximately equally to the observed rainfall intensity. The D(x,center) is usually only half the value of D(y,center), thus indicating less intensity contribution from this term and that the general elliptical shape of rain cells are elongated in the direction of movement. The observations indicate that the cumulus stage represents half and the dissipating stage half of the total cell development, respectively. The results can be used as first choice of parameter values when modeling rain cell movement over ungaged areas and the presented methodology can be used to study the effects of different cell components on total rainfall intensity.
Department/s
- Division of Water Resources Engineering
Publishing year
1997-12-31
Language
English
Pages
109-118
Publication/Series
Journal of Hydrology
Volume
203
Issue
1-4
Document type
Journal article
Publisher
Elsevier
Topic
- Meteorology and Atmospheric Sciences
Keywords
- High-intensity rainfall
- Real-time prediction
Status
Published
ISBN/ISSN/Other
- ISSN: 0022-1694