Climatology
Yagob Dinpashoh; Saina Vakili Azar
Abstract
In this study, storm patterns were analyzed in three rain gauge stations in Gilan province. All the storms were divided into the three distinct classes which are: i) 0-6 hrs, ii) 6-12 hrs, and iii) >12hrs. Analysis performed separately for each of the classes. Huff curves were plotted and the pattern ...
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In this study, storm patterns were analyzed in three rain gauge stations in Gilan province. All the storms were divided into the three distinct classes which are: i) 0-6 hrs, ii) 6-12 hrs, and iii) >12hrs. Analysis performed separately for each of the classes. Huff curves were plotted and the pattern of rainfall identified using the quartile approach. The pattern of storms obtained using an innovation method based on vertical distances of 90 and 10 percent Huff curves and 50% Huff curve (d50) at 25, 50 and 75% of duration. Results showed that most of patterns were the second quartile type. Comparing the V-values, it was found that the V-value of Hashtpar in the less than 12 hours classes was high in all the three durations (i.e. 25, 50 and 75 percent). This indicates that the storms variability in Hashtpar was more than others. In more than 12-hours class, the station Kharajgil at 25 and 50 percent duration shows large value of V. However,, in the station Galeh Rudkhan, the large V observed at 75% time duration. Moreover, results showed that the station Kharajgil had large value of d50 at 25, 50 and 75 percent of durations in the class of 0-6 hours comparing the two other stations. This implies that rainfall intensities at station Kharajgil were more than the two other stations. In the class of 6-12 hours, the large value of d50 at 25 percent of time at station Kharajgil was observed. However, the large value of d50 observed at 50 and 75 percent of duration at station Galeh Rudkhan. At the class of more than 12 hours, the station Kharajgil showed large d50 values in 25 and 50 percent durations. The value of d50 for station Hashtpar in 75 percent duration was large among all the stations.
Climatology
Yagob Dinpashoh; Saeid Jahanbakhsh-Asl; Asma Azadeh Garebagh
Abstract
In this study the values of potential reference crop evapotranspiration were calculated using the FAO-56 Penman Monteith method in six stations located in southern shores of Caspian Sea. Trends in annual ET0 values of the stations were analyzed using the Mann-Kendall test. Then to determine the relative ...
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In this study the values of potential reference crop evapotranspiration were calculated using the FAO-56 Penman Monteith method in six stations located in southern shores of Caspian Sea. Trends in annual ET0 values of the stations were analyzed using the Mann-Kendall test. Then to determine the relative importance of climatic variables on ET0 in a certain station factor analysis conducted. To do this, correlation matrix (R) of seven variables also called similarity matrix was constructed. The significance of correlation coefficients were tested. Results of trends in ET0 showed that in all the stations (except Noshahr) trends of annual ET0 were upward and significant. The slopes of trend lines were positive in all the stations. Factor analysis showed that the first two factors accounted the total variance in the range of 56.5 per cent in the Rasht to 79.6 per cent in the Sari. The largest loading of the first factor is attributed to sunshine hours in the station Rasht, however, it was maximum air temperature in all other sites. In the case of the second factor, the largest loading belonged to wind speed (in Rasht, Gorgan, Sari and Noshahr) and precipitation (in Ramsar and Astara). The findings of this study can be helpful in optimum management of regional water resources.
