Singularity-sensitive gauge-based radar rainfall adjustment methods for urban hydrological applications
File(s)
Published version
Author(s)
Wang, LP
Ochoa-Rodriguez, S
Onof, C
Willems, P
Type
Journal Article
Abstract
Gauge-based radar rainfall adjustment techniques have been widely used to improve the applicability of radar rainfall estimates to large-scale hydrological modelling. However, their use for urban hydrological applications is limited as they were mostly developed based upon Gaussian approximations and therefore tend to smooth off so-called "singularities" (features of a non-Gaussian field) that can be observed in the fine-scale rainfall structure. Overlooking the singularities could be critical, given that their distribution is highly consistent with that of local extreme magnitudes. This deficiency may cause large errors in the subsequent urban hydrological modelling. To address this limitation and improve the applicability of adjustment techniques at urban scales, a method is proposed herein which incorporates a local singularity analysis into existing adjustment techniques and allows the preservation of the singularity structures throughout the adjustment process. In this paper the proposed singularity analysis is incorporated into the Bayesian merging technique and the performance of the resulting singularity-sensitive method is compared with that of the original Bayesian (non singularity-sensitive) technique and the commonly used mean field bias adjustment. This test is conducted using as case study four storm events observed in the Portobello catchment (53 km2) (Edinburgh, UK) during 2011 and for which radar estimates, dense rain gauge and sewer flow records, as well as a recently calibrated urban drainage model were available. The results suggest that, in general, the proposed singularity-sensitive method can effectively preserve the non-normality in local rainfall structure, while retaining the ability of the original adjustment techniques to generate nearly unbiased estimates. Moreover, the ability of the singularity-sensitive technique to preserve the non-normality in rainfall estimates often leads to better reproduction of the urban drainage system's dynamics, particularly of peak runoff flows.
Date Issued
2015-09-29
Date Acceptance
2015-09-14
Citation
Hydrology and Earth System Sciences, 2015, 19 (9), pp.4001-4021
ISSN
1027-5606
Start Page
4001
End Page
4021
Journal / Book Title
Hydrology and Earth System Sciences
Volume
19
Issue
9
Copyright Statement
© Author(s) 2015. This work is distributed
under the Creative Commons Attribution 3.0 License. http://creativecommons.org/licenses/by/3.0/
under the Creative Commons Attribution 3.0 License. http://creativecommons.org/licenses/by/3.0/
License URL
Subjects
Science & Technology
Physical Sciences
Geosciences, Multidisciplinary
Water Resources
Geology
ERRORS
RUNOFF
SCALE
VARIABILITY
PREDICTION
ACCURACY
MODELS
IMPACT
GAGES
0406 Physical Geography and Environmental Geoscience
0905 Civil Engineering
0907 Environmental Engineering
Environmental Engineering
Publication Status
Published
Date Publish Online
2015-09-29