Use of mixed bivariate distributions for deriving inter-station correlation coefficients of rain rate

• Published in: Hydrological processes Vol. 21; no. 22; pp. 3078 - 3086
• Main Authors: Ha, Eunho, Yoo, Chulsang
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 30-10-2007; Wiley
• Subjects: bivariate mixed distribution; Earth sciences; Earth, ocean, space; Exact sciences and technology; Hydrology; Hydrology. Hydrogeology; inter-station correlation coefficient; intermittency; log-normal distribution; rain rate; Far East; South Korea; Korea; Korea, Rep; rivers; models; rainfall; Asia; rain water; inter-station correlation coefficient; rain rate; correlation coefficient; bivariate mixed distribution; intermittency; log-normal distribution; statistics
• ISSN: 0885-6087; 1099-1085
• DOI: 10.1002/hyp.6526

Even though rain rate is notorious for its spatial and temporal intermittency, its effect on the second-order statistics of rain rate, especially the inter-station correlation coefficients, has not been intensively evaluated before. This study has derived and compared the inter-station correlation coefficient of rain rate for three cases of data: (1) only the positive measurements at both locations; (2) the positive measurements at either one or both locations; (3) all the measurements including zero measurement at both locations. For these three cases, the inter-station correlation coefficients are analytically derived by applying the mixed bivariate log-normal distribution. As an application example, the model parameters are estimated using the rain rate data collected at the Geum River basin, Korea, and the resulting inter-station correlation coefficients are evaluated and compared with those estimated by applying the Gaussian distribution. We could find that highly biased inter-station correlation coefficients are unavoidable when simply estimating them under the assumption of Gaussian distribution, or even when using the log-transformed rain rate data. Copyright © 2007 John Wiley & Sons, Ltd.