Operational quality control and enhancement of radar data to support regional flash flood warning systems

TitleOperational quality control and enhancement of radar data to support regional flash flood warning systems
Publication TypeJournal Article
Year of Publication2017
AuthorsModrick TM, Georgakakos KP, Shamir E, Spencer C.R
JournalJournal of Hydrologic Engineering
Volume22
Date Published2017/05
Type of ArticleArticle
ISBN Number1084-0699
Accession NumberWOS:000398544700013
Keywordsmean-field bias; rainfall estimation
Abstract

The paper draws from recent experience with operational regional flash flood warning systems deployed worldwide that utilize radar precipitation data as input to provide regional warnings at high spatial resolution. This paper focuses on radar precipitation data quality control and adjustments in context of making the radar data useful in hydrologic application specific to flash flood warnings. Aspects discussed are radar precipitation preprocessing for hydrologic application, identifying regions of inappropriate radar data for hydrologic use, developing bias adjustment strategies using limited rain gauge networks under the radar umbrella, and impacts of radar precipitation uncertainty on soil water estimates that impact in turn predictions and warnings. The bias adjustment strategies presented are twofold: (1)adjusting for the long-term mean bias in the radar precipitation data (climatological bias adjustment), and (2)accounting for event-specific, temporal deviations from the climatological bias (through dynamic bias adjustment). The development of radar data masks for regions of inappropriate radar data are based on the spatial distribution of the probability of detection of positive precipitation as compared to that produced by rain gauges under the radar umbrella. Climatological bias adjustment of radar data in regions not masked is accomplished through a probability matching procedure that involves transformed data from the rain gauges under the radar umbrella and from their embedding radar grid boxes. This allows for intensity-dependent climatological bias adjustment. An adaptive Kalman filter is used for dynamic bias adjustment of radar data to account for temporal deviations of the bias from the climatological values. The use of adjusted radar data as forcing for the land-surface component of the flash flood warning system produces more realistic soil water state for the flash flood warning systems than the unadjusted radar data does. The discussion uses examples from Romania and Mexico. (C) 2016 American Society of Civil Engineers.

DOI10.1061/(asce)he.1943-5584.0001345
Short TitleJ. Hydrol. Eng.
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