nafise seyednezhad; Seied Hosein Sanaei-Nejad; B. Ghahraman; H. Rezaee Pazhand
Abstract
Regional analysis, estimating missing values, areal rainfall, estimating PMP and rainfall- runoff models in daily scale are essential in water resources and climatological researches. Modified inverse distance interpolation method based on Fuzzy Mathematics (MIDW-F) is a new, efficient method and independent ...
Read More
Regional analysis, estimating missing values, areal rainfall, estimating PMP and rainfall- runoff models in daily scale are essential in water resources and climatological researches. Modified inverse distance interpolation method based on Fuzzy Mathematics (MIDW-F) is a new, efficient method and independent of complex preconceptions hypothesis. The purpose of this paper is applying the new interpolation equation for above essential needs by calibration the daily rainfall of Mashhad Plain catchment. Screening and normalizing distances and elevations were done, then effects of fuzzy operations (Max, Min, Sum, Multiplication and SQRT) are Checked out and optimizing the parameters of MIDW-F by Genetic algorithms. The 215 daily precipitations (49 rain gauge stations) were analyzed and were calibrated. The results showed that the best operators are Minimum (Share58%), multiplying (Share35%) and total contribution rate of others are 6%. The MIDW-F was compared with the three others conventional methods (the Arithmetic mean, Thiessen polygon and IDW) and results showed that the errors of MIDW-F method were reduced noticeably. Largest Regional Mean Square errors (RMSE) is for Arithmetic mean (Max. 90.45, Min. 5.76, variance 686.8 and 70% Cv) and smallest RMSE belong to MIDW-F (Max. 56.67, Min. 4.6, variance 340.92 and 57% Cv). Zoning of daily rainfall at 22/3/2009 and 23/2/2010 and with MIDW-F and IDW methods were conducted and evaluated. The results showed that the zoning by MIDW-F proposed more details. So this method\ is proposed for the interpolation of daily precipitation in a homogeneous region.
Abstract
Assessing the level of reservoir’s Eutrophication has been regarded as one of the main issues in the water quality management by managers and policy makers. Estimating the eutrophication level is not possible by a determined method and complete certainty with respect to the high complexity of this ...
Read More
Assessing the level of reservoir’s Eutrophication has been regarded as one of the main issues in the water quality management by managers and policy makers. Estimating the eutrophication level is not possible by a determined method and complete certainty with respect to the high complexity of this phenomenon. Fuzzy theory is an approach by which the lack of transparency and uncertainty can be determined between the levels of eutrophication. In this study, Entropy- based Fuzzy Eutrophication Index (EFEI) and Trophic State index (TSI) were used for the trophic level classification of the Ilam reservoir epilimnion and hypolimnion during a year. These indexes were weighted with two scenarios based on the chlorophyll a, total phosphorus and oxygen saturation parameters. In the first scenario, the relative weights of indexes were calculated by the combination of entropy- based fuzzy approach and analytical hierarchy process. In second scenario, equal weight was considered for all parameters. The results showed that based on both scenarios and in most months of the year the trophic level of the epilimnion was oligotrophic with suitable certainty and it was only mesotrophic in July and August. In the hypolimnion, the trophic level was similar to the epilimnion, but uncertainties have been increased.
