气候变化领域集成服务门户(CCPortal): Quantitative precipitation estimation with weather radar using a data- and information-based approach

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DOI	10.5194/hess-23-3711-2019
	Quantitative precipitation estimation with weather radar using a data- and information-based approach
	Neuper M.; Ehret U.
发表日期	2019
ISSN	1027-5606
起始页码	3711
结束页码	3733
卷号	23 期号:9
英文摘要	In this study we propose and demonstrate a data-driven approach in an "information-theoretic" framework to quantitatively estimate precipitation. In this context, predictive relations are expressed by empirical discrete probability distributions directly derived from data instead of fitting and applying deterministic functions, as is standard operational practice. Applying a probabilistic relation has the benefit of providing joint statements about rain rate and the related estimation uncertainty. The information-theoretic framework furthermore allows for the integration of any kind of data considered useful and explicitly considers the uncertain nature of quantitative precipitation estimation (QPE). With this framework we investigate the information gains and losses associated with various data and practices typically applied in QPE. To this end, we conduct six experiments using 4 years of data from six laser optical disdrometers, two micro rain radars (MRRs), regular rain gauges, weather radar reflectivity and other operationally available meteorological data from existing stations. Each experiment addresses a typical question related to QPE. First, we measure the information about ground rainfall contained in various operationally available predictors. Here weather radar proves to be the single most important source of information, which can be further improved when distinguishing radar reflectivity-ground rainfall relationships (Z-R relations) by season and prevailing synoptic circulation pattern. Second, we investigate the effect of data sample size on QPE uncertainty using different data-based predictive models. This shows that the combination of reflectivity and month of the year as a two-predictor model is the best trade-off between robustness of the model and information gain. Third, we investigate the information content in spatial position by learning and applying site-specific Z-R relations. The related information gains are only moderate; specifically, they are lower than when distinguishing Z-R relations according to time of the year or synoptic circulation pattern. Fourth, we measure the information loss when fitting and using a deterministic Z-R relation, as is standard practice in operational radar-based QPE applying, e.g., the standard Marshall-Palmer relation, instead of using the empirical relation derived directly from the data. It shows that while the deterministic function captures the overall shape of the empirical relation quite well, it introduces an additional 60 % uncertainty when estimating rain rate. Fifth, we investigate how much information is gained along the radar observation path, starting with reflectivity measured by radar at height, continuing with the reflectivity measured by a MRR along a vertical profile in the atmosphere and ending with the reflectivity observed by a disdrometer directly at the ground. The results reveal that considerable additional information is gained by using observations from lower elevations due to the avoidance of information losses caused by ongoing microphysical precipitation processes from cloud height to ground. This emphasizes both the importance of vertical corrections for accurate QPE and of the required MRR observations. In the sixth experiment we evaluate the information content of radar data only, rain gauge data only and a combination of both as a function of the distance between the target and predictor rain gauge. The results show that station-only QPE outperforms radar-only QPE up to a distance of 7 to 8 km from the nearest station and that radar-gauge QPE performs best, even compared with radar-based models applying season or circulation pattern. © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License.
语种	英语
scopus关键词	Economic and social effects; Information theory; Information use; Meteorological radar; Probability distributions; Radar stations; Rain; Rain gages; Reflection; Uncertainty analysis; Deterministic functions; Discrete probability distribution; Estimation uncertainties; Microphysical precipitation; Operational practices; Probabilistic relations; Quantitative precipitation estimation; Synoptic circulations; Radar measurement; estimation method; precipitation (climatology); probability; quantitative analysis; radar; raingauge; satellite data; trade-off; uncertainty analysis
来源期刊	Hydrology and Earth System Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159611
作者单位	Neuper, M., Institute of Water Resources and River Basin Management, Karlsruhe Institute of Technology-KIT, Karlsruhe, Germany; Ehret, U., Institute of Water Resources and River Basin Management, Karlsruhe Institute of Technology-KIT, Karlsruhe, Germany
推荐引用方式 GB/T 7714	Neuper M.,Ehret U.. Quantitative precipitation estimation with weather radar using a data- and information-based approach[J],2019,23(9).
APA	Neuper M.,&Ehret U..(2019).Quantitative precipitation estimation with weather radar using a data- and information-based approach.Hydrology and Earth System Sciences,23(9).
MLA	Neuper M.,et al."Quantitative precipitation estimation with weather radar using a data- and information-based approach".Hydrology and Earth System Sciences 23.9(2019).