چکیده:
A rain gauge network should serve general as well as specific purposes such as water supply, hydropower generation, flood forecasting, irrigation, and flood control. The level of accuracy a network can achieve depends on the number and locations of gauges in the network. In this study, a rain gauge network was designed for Hormozgan province in the south of Iran. Monthly rainfall totals from 124 rain gauge stations in the period from 2000 to 2009 were used. This province can be logically divided to four regions using the De Martonne aridity index. Kagan’s approach was used to relocate the rain gauge network to obtain the optimal design. In this statistical method, the
correlations were classified based on distance. Exponential models were fitted to the average correlations against mean distances in all regions. The number of gauges and the distance between gauges were computed to satisfy user requirements. The results showed that Hajiabad had the minimum value for distance (125 km) and Bandar Lengeh had the maximum value for distance (588 km). Spatial variation of rainfall in Hajiabad was greater than for other stations. The results indicate that 40, 50, 20, and 55 stations were adequate to represent rainfall with 15% average error in the regions of Bandar Lengeh, Bandar Abbas, Hajiabad and Minab, respectively.
خلاصه ماشینی:
The results indicate that 40, 50, 20, and 55 stations were adequate to represent rainfall with 15% average error in the regions of Bandar Lengeh, Bandar Abbas, Hajiabad and Minab, respectively.
Rodriguez- Iturbe and Mejia (1974) applied a hypothetical analytical model of rainfall to present estimates of variance as a function of gauge density, area of interest, and correlation length scale.
In Hormozgan province, the locations of the rain gauges in the networks were chosen using unscientific methods and, thus, the configuration of stations is irregular.
This study proposed a rain gauge network evaluation and design approach focusing on accuracy assessment of point rainfalls across the study area using a statistical method.
2. Spatial Correlation Technique Kagan (1972) demonstrated that a network of stations at distance d is often described by the following two parameter exponential relation (Kagan, 1972; Stol, 1972):rain gauges can be designed to meet a specified d d (1) of rainfall can be quantified using a spatial where (d ) is the correlation between thecorrelation function.
The error of weight of average rainfall at a given area (Ea), and error of interpolation of rainfall at a given point (Ei), are the main factors for designing a rain gauge network (James, 1983; James and Sreedharan, 2.
The estimation of the number and location of rain gauge stations needed to provide adequate information regarding rainfall over a catchment is referred to as network design.
The results show that selecting 20% measurement average error decreased the number of rain gauges required in all regions except Bandar Abbas.