Abbasali Dadashi Roudbari; Gholamabbas Fallah Ghalheri; Mokhtar Karami; Mohammed Baaghide
Volume 3, Issue 7 , October 2016, , Pages 59-86
Abstract
Abbasali Dadashi Roudbari[1] Gholamabbas Fallah Ghalhari[2]* Mokhtar Karami[3] Mohammad Baaghide[4] Abstract Identifying the precipitation behavior is the most important principles in environmental planning. Identification of the precipitation behavior in long term period aggrades the way to local and ...
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Abbasali Dadashi Roudbari[1] Gholamabbas Fallah Ghalhari[2]* Mokhtar Karami[3] Mohammad Baaghide[4] Abstract Identifying the precipitation behavior is the most important principles in environmental planning. Identification of the precipitation behavior in long term period aggrades the way to local and regional planning. This research aim to advance knowledge ahead flood management and process modeling using spectral analysis techniques based on Aphrodite database output over the period 1951 to 2007 in the catchment area located in the southern part of Mazandaran province. The results showed that the coefficient of variation of precipitation over the basin in the warm months of the year was more than cold period. Also, according to the disperse statistics in the catchment area; the largest clusters are created in winter season that represents the relative order of precipitation in the study area. Spectral analysis of precipitation data has revealed significantly sinusoidal cycles 2-3, 5-3, 5-11 and 11 and older. This cycle can be attributed to the impact of macro-scale Atmospheric-ocean. Trend line slope for annual precipitation was obtained 7.67 mm per decade. Exiting of These cycles can be related to the influence of large scale ocean-climate factors in the study area. Of increasing the role of mechanisms wetter, warmer and wetter wet latest in the basin has revealed. The important mechanism that can be considered for increasing trend accompanied by temperature increasing trend is wet-gets-wetter. [1]- M.A. Student in Urban Climatology, Hakim Sabzevari University, IranEmail:dadashiabbasali@gmail.com. [2]- Assistant Professor in Faculty of Geography and Environmental Sciences, Hakim Sabzevari University, Sabzevar, Iran. (Corresponding Autor), [3]- Assistant Professor in Faculty of Geography and Environmental Sciences, Hakim Sabzevari University, Sabzevar, Iran. [4]- Assistant Professor in Faculty of Geography and Environmental Sciences, Hakim Sabzevari University, Sabzevar, Iran.
Vahid Nourani; Narges Azad; Mahsa Ghasemzade; Elnaz Sharghi
Volume 3, Issue 7 , October 2016, , Pages 141-159
Abstract
Vahid Nourani[1] Narges Azad*[2] Mahsa Ghasemzade[3] Elnaz Sharghi[4] Abstract This paper aims to detect trends and investigate the relationship between long-term time series of the Urmia lake water level and other hydro-climatologic parameters, including precipitation, runoff, temperature and relative ...
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Vahid Nourani[1] Narges Azad*[2] Mahsa Ghasemzade[3] Elnaz Sharghi[4] Abstract This paper aims to detect trends and investigate the relationship between long-term time series of the Urmia lake water level and other hydro-climatologic parameters, including precipitation, runoff, temperature and relative humidity, in monthly, seasonal and annual scales using Mann-Kendall (MK) and discrete wavelet transform (DWT). The MK test and sequential MK analysis were applied to different combinations of DWT to calculate components responsible for trend of time series.The results showed that 8-month period was important in the involved trend at the original monthly time series. Also there is a significant negative trend in different scales of lake water levels and runoff time series. In general, rainfall, relative humidity and temperature time series did not show significant trends.The results of this research indicate that downward trend in the rainfall time series has more effective role in Urmia lake drying. In addition, the sequential MK test was used to find the start points of changes in monthly time series. The results showed a significant decreasing trend from 1377 in the lake water level and runoff time series. Finally, the results of Sen’s trend analysis, also confirmed the results of the proposed wavelet-based MK test. [1]- Professor of Water Resources Engineering. [2]- Master Degree Student of Water Resources Engineering (Corresponding Author), Email:narges.azad1991@gamil.com [3]- Master Degree Student of Water Resources Engineering. [4]- Assistant Professor of Water Resources Engineering Department of Water Resources Engineering Faculty of Civil Engineering, University of Tabriz, Tabriz, Iran.
