Abstract
Estimating the AAR (Areal Average Rainfall) is an essential process when determining the accurate amount of available water resources and building the input data which is integral to the Rainfall-Runoff Analysis. To estimate the AAR, using rain gauge networks that are spatially well distributed is ideal. In this study, the spatial characteristics of the rain gauge networks for the five major river basins in South Korea are considered and the amount of influence the spatial distribution has on the estimation of the AAR is evaluated. For this purpose, the estimation error for AAR is calculated for two cases. The first case (Analysis 1) compares the value of the estimation error of the AAR from two different basins where one has well distributed rain gauges while the other does not. The second case (Analysis 2) estimates the estimation error of two different rain gauge distributions for the same basin. The spatial characteristic of the rain gauge network is evaluated by using the NNI (Nearest Neighbour Index), while the Arithmetic Mean Method, Thiessen Method and the Estimation Theory are applied to calculate the AAR. From Analysis 1, we are able to prove that the estimation error of the AAR is relatively small in the basins with that have spatially well distributed rain gauge networks whereas the estimation error is relatively large when the spatial distribution of the rain gauge network is clustered. Also, results from Analysis 2 showed that not only is the spatial distribution of the rain gauge networks important, but that the density has a significant influence on accurately calculating the AAR. The results from this study can be applied towards the ideal establishment of the rain gauge networks.
Highlights
The spatial distribution of the rain gauge networks is relevant for soil development, plant distribution and water resources
When evaluating the rain gauge stations, whether a sufficient number of rain gauges have been established within the basin and whether they are appropriately established to satisfy the purpose of the rain gauge stations must first be considered
This study examines the spatial characteristics of the rain gauge stations within the 5 major river basins of South Korea and how it influences the estimation error of the AAR
Summary
The spatial distribution of the rain gauge networks is relevant for soil development, plant distribution and water resources. The focus is placed on the estimation accuracy of AAR and estimation accuracies of point rainfall at individual ungauged sites are not of major concern [5] These rain gauge networks, which are established for such specific purposes are evaluated by the entropy theory, principal component regression analysis, as well as correlation analysis [6,7,8,9,10]. True mean areal rainfall and its distributions will always remain unknown variable even various techniques of AAR estimation exist [28,29] These previous studies show that uniform spatial distribution and dense rainfall station network are important to estimate more accurate AAR. To eliminate the effect from the differences of characteristics and to only consider the spatial distribution and density of the rain gauges when calculating the AAR, the number and distribution of the rain gauge stations are rearranged within the same basin (Analysis 2). These methods are excluded from this study because they complement the missing data or estimate the rainfall at ungauged point indirectly
Published Version (Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have