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DOI	10.1016/j.jhydrol.2021.125954
	An unbiased estimator of coefficient of variation of streamflow
	Ye, Lei; Gu, Xuezhi; Wang, Dingbao; Vogel, Richard M.
通讯作者	Vogel, RM (corresponding author), Tufts Univ, Dept Civil & Environm Engn, Medford, MA 02155 USA.
来源期刊	JOURNAL OF HYDROLOGY
ISSN	0022-1694
EISSN	1879-2707
出版年	2021
卷号	594
英文摘要	Given increasing demand for high frequency streamflow series (HFSS) at daily and subdaily time scales there is increasing need for reliable metrics of relative variability for such series. HFSS can exhibit enormous relative variability especially in comparison with low frequency streamflow series formed by aggregation of HFSS. The product moment estimator of the coefficient of variation C, defined as the ratio of sample standard deviation to sample mean, as well as ten other common estimators of C, are shown to provide severely downward biased and highly variable estimates of C for very long records of highly skewed and periodic HFSS particularly for rivers which exhibit zeros. Resorting to the theory of compound distributions, we introduce an estimator of C corresponding to a mixture of monthly zero-inflated lognormal distributions denoted as a delta lognormal monthly mixture Delta LN3MM model. Through monthly stratification, our Delta LN3MM model accounts for the seasonality, skewness, multimodality, and the possible intermittency of HFSS. In comparisons among estimators, our Delta LN3MM based C estimator is shown to yield much more reliable and approximately unbiased estimates of C not only for small samples but also for very large samples (tens of thousands of observations). We document values of C in the range of [0.18, 42,000] with a median of 1.9 and an interquartile range of [1.34, 3.75] for 6807 daily streamflow series across the U.S. from GAGES-II dataset, with the highest values of C occurring in arid and semiarid regions. A multivariate analysis and national contour map reveal that extremely large values of C, never previously documented, tend to occur in arid watersheds with low runoff ratios, which tend to also exhibit a considerable number of zero streamflows.
英文关键词	Relative variability Skewness Intermittent Periodic Bimodal Zero-inflated Mixture
类型	Article
语种	英语
收录类别	SCI-E
WOS记录号	WOS:000641589600061
WOS关键词	SIMULATION-BASED APPROACH ; L-MOMENT ; DISTRIBUTIONS ; DIAGRAMS ; INTERVAL ; GAMMA ; TESTS
WOS类目	Engineering, Civil ; Geosciences, Multidisciplinary ; Water Resources
WOS研究方向	Engineering ; Geology ; Water Resources
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/368958
作者单位	[Ye, Lei; Gu, Xuezhi] Dalian Univ Technol, Sch Hydraul Engn, Dalian, Peoples R China; [Wang, Dingbao] Univ Cent Florida, Dept Civil Environm & Construct Engn, Orlando, FL 32816 USA; [Vogel, Richard M.] Tufts Univ, Dept Civil & Environm Engn, Medford, MA 02155 USA
推荐引用方式 GB/T 7714	Ye, Lei,Gu, Xuezhi,Wang, Dingbao,et al. An unbiased estimator of coefficient of variation of streamflow[J],2021,594.
APA	Ye, Lei,Gu, Xuezhi,Wang, Dingbao,&Vogel, Richard M..(2021).An unbiased estimator of coefficient of variation of streamflow.JOURNAL OF HYDROLOGY,594.
MLA	Ye, Lei,et al."An unbiased estimator of coefficient of variation of streamflow".JOURNAL OF HYDROLOGY 594(2021).