科研之友
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摘要
In recent years, there has been a growing interest by different user communities to use radar-based rainfall products for identifying and quantifying heavy precipitation and other related information. A potentially viable product for such analyses is the National Weather Service (NWS) Stage IV Quantitative Precipitation Estimate (QPE), which covers the entire conterminous United States and is available at 1, 6, and 24h temporal resolutions. The current article focuses on data artifacts in the Stage IV product over its full record period (2002-2013) and assesses their impacts on the analysis and derivation of heavy rainfall statistics. Examining annual maximum series extracted from the Stage IV 1-h accumulation product revealed the presence of numerous artifacts that were mostly linked to erroneous rain gauge reports and which can be mistaken as rainfall maxima. Artifacts were found over many parts of the United States, including the west, south, southeast, and northeast. Other erroneous features that affect the spatial delineation of heavy precipitation include nonrainy lines and polygons in many regions over the product domain. The current analysis demonstrated that these artifacts had negative impacts on the estimation of parameters and quantiles of commonly used extreme value probability distributions. Additional exploratory analyses indicate that Stage IV 6-h and 24-h accumulations, as well as the longer-latency QPE archive from the regional River Forecasting Centers (RFCs), are mostly free from the artifacts shown in the Stage IV 1-h product. These comparative analyses revealed that the Stage IV product, at least over some of the RFC domains, misses on the benefits of human quality control that is introduced at a later stage at the RFCs, and suggested that caution be exercised in applying Stage IV as the basis for analysis of heavy precipitation.
- 出版日期2017-5
