The continuity of precipitation data is critical in climate, hydrological and environmental studies. The main objective of this study is to improve the geographical coordinate (GC) method for filling gaps in annual precipitation observations. The altitude ratio (Ai) and the mean annual precipitation (MAP) were employed through a modification procedure to enhance the efficiency of the GC technique. In this respect, 24 precipitation gauge stations located in six different regions of Iran were taken into consideration in order to investigate the performance of the modified approach. Furthermore, estimates of methods such as the normal ratio (NR), the linear regression (LR) and also the conventional GC were compared with the outcomes obtained from the improved methodology to evaluate whether it has adequate suitability in a broad range of geo-climatic conditions. Average values of model accuracy measures and also results of the priority ranking process indicated that the best method was modified GC and the second priority technique was NR. It was also revealed that the conventional GC occupied no place in the first priority class for all stations, and more interestingly, the modified GC has not been in the lowest priority at all. Hence, the proposed methodology was proven to be a reliable procedure for estimating missing annual precipitation records. In addition to improved performance, the modified approach utilizes input data that are usually available in the most of data-limited areas such as developing countries.
کلید واژگان :modified, Iran
ارزش ریالی : 600000 ریال
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