Ali Subyani - Academia.edu (original) (raw)

Papers by Ali Subyani

Research paper thumbnail of Groundwater Vulnerability Risk Maps Using GIS and DRASTIC Index Method for Jeddah City, Western Saudi Arabia

Journal of King Abdulaziz University-Earth Sciences, 2012

Research paper thumbnail of Rainfall analysis in the contest of climate change for Jeddah area, Western Saudi Arabia

Arabian Journal of Geosciences, 2016

Research paper thumbnail of الطرق الجيوإحصائية للمتغيرات المتعددة للمتوسط السنوي والفصلي للأمطار في جنوب غرب المملكة العربية االسعودية

Research paper thumbnail of Discussion of “Review of Geostatistics in Geohydrology. I: Basic Concepts” by the ASCE Task Committee on Geostatistical Techniques in Geohydrology of the Ground Water Hydrology Committee of the ASCE Hydraulics Division (May, 1990, Vol. 116, No. 5)

Research paper thumbnail of إستخدام نماذج الإرتفاعات الرقمية والطرق الإحصائية للمتغيرات المتعددة في تحليل المعاملات المورفومترية لبعض أودية غرب المملكة العربية السعودية

Research paper thumbnail of Flood Analysis in Western Saudi Arabia

Journal of King Abdulaziz University-Earth Sciences, 2011

Research paper thumbnail of Multivariate Statistical Analysis of Groundwater Quality in Wadi Ranyah, Saudi Arabia

Journal of King Abdulaziz University-Earth Sciences, 2010

... Ali M. Subyani and Masoud E. Al Ahmadi Hydrogeology Department, Faculty of Earth Sciences, Ki... more ... Ali M. Subyani and Masoud E. Al Ahmadi Hydrogeology Department, Faculty of Earth Sciences, King Abdulaziz University POBox 80206, Jeddah 21589,Saudi Arabia asubyani@hotmail.com Received:: 8/2/2009 Accepted: 30/8/2009 Abstract. ...

Research paper thumbnail of Physiographical and Hydrological Analysis of Yalamlam Basin, Makkah Al-Mukarramah Area

Journal of King Abdulaziz University-Earth Sciences, 2001

... Other research for these Wadis include those conducted by re-searches such as Hussien (1985);... more ... Other research for these Wadis include those conducted by re-searches such as Hussien (1985); Sadhan (1980); Jamaan (1978); Alehaideb ... various air masses and the rainfall pattern over the Kingdom are discussed and mapped by several investigators (McLaren, 1979; ˙Sen ...

Research paper thumbnail of Geostatistical modelling of the Wasia aquifer in Central Saudi Arabia

Journal of Hydrology, 1989

... A geostatistically based approach to the identification of the aquifer transmissivities in th... more ... A geostatistically based approach to the identification of the aquifer transmissivities in the Yolo Basin, California. J. Math. ... Variugram models for regional groundwater geochemical data. J. Math. ... Hydrogeology of the Wasia aquifer and its geostatistical modelling. Unpubl. MSc. ...

Research paper thumbnail of Discussion of “ Review of Geostatistics in Geohydrology. I: Basic Concepts ” by the ASCE Task Committee on Geostatistical Techniques in Geohydrology of the Ground Water Hydrology Committee of the ASCE Hydraulics Division (May, 1990, Vol. 116, No. 5)

Journal of Hydraulic Engineering, 1992

Research paper thumbnail of Digital elevation model and multivariate statistical analysis of morphometric parameters of some wadis, western Saudi Arabia

Arabian Journal of Geosciences, 2012

In arid regions, the analysis of wadi morphometric parameters and their interrelationships are fu... more In arid regions, the analysis of wadi morphometric parameters and their interrelationships are fundamental for describing the topographic, geologic evolution, structures and hydrologic potential efficiency of the watershed. Unfortunately, the spatial characteristics and the analyses of these variables are not taken into consideration in an efficient way, especially in arid regions. In this paper, digital elevation model, geographic information system and multivariate statistical techniques are integrated for the identification and the assessment of main morphometric parameters. For this purpose, Q and R modes of cluster analyses and principal component analysis (PCA) are applied to ten different-size watersheds in the western region of Saudi Arabia utilizing 18 morphometric descriptors (variables). The results show that the R-mode cluster analysis classifies the variables into three groups, whereas the Q-mode cluster analysis classifies watersheds according to the similarities in their major variables such as area, perimeter, total stream length and peak discharge. The first three components of PCA accounted for 86% of the total variance in the data and show more details concerning the parameter loadings and the degree of variable significance.

Research paper thumbnail of Multivariate geostatistical methods of mean annual and seasonal rainfall in southwest Saudi Arabia

Arabian Journal of Geosciences, 2009

A multivariate geostatistics (cokriging) is used for regional analysis and prediction of rainfall... more A multivariate geostatistics (cokriging) is used for regional analysis and prediction of rainfall throughout the southwest region of Saudi Arabia. Elevation is intruded as a covariant factor in order to bring topographic influences into the methodology. Sixty-three representative weather stations are selected for a 21-year period covering different microclimate conditions. Results show that on an annual basis, there is no significant change using elevation. On the seasonal basis, the cokriging method gave more information about rainfall occurrence values, its accuracy related to the degree of correlation between elevation and rainfall by season. The prediction of spring and winter rainfall was improved owing to the importance of orographic processes, while the summer season was not affected within its monsoon climatology.

Research paper thumbnail of IDF curves and daily rainfall generation for Al-Madinah city, western Saudi Arabia

Arabian Journal of Geosciences, 2015

ABSTRACT Due to the increase in global warming and climate change impact, especially in urban ari... more ABSTRACT Due to the increase in global warming and climate change impact, especially in urban arid regions, the intensity-duration-frequency (IDF) curves and rainfall generation procedures become essential for storm design and hydraulic structures dimensioning for future planning and management. Al-Madinah, the second holiest city for all Muslims, is located in the western part of Saudi Arabia. This city needs special attention for hydrologic and hydraulic structure projects due to highly developed and rapid expansion in land use. The purpose of this study is to develop an empirical formula from IDF curves, which have been generated from 43-year records for Al-Madinah rainfall station. The absence of some daily rainfall records led to the application of the reduction method to disaggregate daily rainfall to hourly time series for developing suitable IDF curves. The formula is derived using the analysis of the best fit of Gumbel and log-Pearson Type III frequency methods. An average empirical formula can be used for predicting any return period with a given storm duration for Al-Madinah area. Generating wet, dry, and rainfall intensities are also investigated using autorun analysis on a daily time step. The results show that the dry spell continues for 71 days while the wet spell is about 1.58 days on the average based on the rainfall intensity threshold of 5.9 mm/day. Based on the goodness of fit for the dry and wet spells and the rainfall intensities, the daily rainfall sequences can be generated for any duration, which is adopted here as for the next 43 years.

Research paper thumbnail of Groundwater Vulnerability Risk Maps Using GIS and DRASTIC Index Method for Jeddah City, Western Saudi Arabia

Journal of King Abdulaziz University-Earth Sciences, 2012

Research paper thumbnail of Rainfall analysis in the contest of climate change for Jeddah area, Western Saudi Arabia

Arabian Journal of Geosciences, 2016

Research paper thumbnail of الطرق الجيوإحصائية للمتغيرات المتعددة للمتوسط السنوي والفصلي للأمطار في جنوب غرب المملكة العربية االسعودية

Research paper thumbnail of Discussion of “Review of Geostatistics in Geohydrology. I: Basic Concepts” by the ASCE Task Committee on Geostatistical Techniques in Geohydrology of the Ground Water Hydrology Committee of the ASCE Hydraulics Division (May, 1990, Vol. 116, No. 5)

Research paper thumbnail of إستخدام نماذج الإرتفاعات الرقمية والطرق الإحصائية للمتغيرات المتعددة في تحليل المعاملات المورفومترية لبعض أودية غرب المملكة العربية السعودية

Research paper thumbnail of Flood Analysis in Western Saudi Arabia

Journal of King Abdulaziz University-Earth Sciences, 2011

Research paper thumbnail of Multivariate Statistical Analysis of Groundwater Quality in Wadi Ranyah, Saudi Arabia

Journal of King Abdulaziz University-Earth Sciences, 2010

... Ali M. Subyani and Masoud E. Al Ahmadi Hydrogeology Department, Faculty of Earth Sciences, Ki... more ... Ali M. Subyani and Masoud E. Al Ahmadi Hydrogeology Department, Faculty of Earth Sciences, King Abdulaziz University POBox 80206, Jeddah 21589,Saudi Arabia asubyani@hotmail.com Received:: 8/2/2009 Accepted: 30/8/2009 Abstract. ...

Research paper thumbnail of Physiographical and Hydrological Analysis of Yalamlam Basin, Makkah Al-Mukarramah Area

Journal of King Abdulaziz University-Earth Sciences, 2001

... Other research for these Wadis include those conducted by re-searches such as Hussien (1985);... more ... Other research for these Wadis include those conducted by re-searches such as Hussien (1985); Sadhan (1980); Jamaan (1978); Alehaideb ... various air masses and the rainfall pattern over the Kingdom are discussed and mapped by several investigators (McLaren, 1979; ˙Sen ...

Research paper thumbnail of Geostatistical modelling of the Wasia aquifer in Central Saudi Arabia

Journal of Hydrology, 1989

... A geostatistically based approach to the identification of the aquifer transmissivities in th... more ... A geostatistically based approach to the identification of the aquifer transmissivities in the Yolo Basin, California. J. Math. ... Variugram models for regional groundwater geochemical data. J. Math. ... Hydrogeology of the Wasia aquifer and its geostatistical modelling. Unpubl. MSc. ...

Research paper thumbnail of Discussion of “ Review of Geostatistics in Geohydrology. I: Basic Concepts ” by the ASCE Task Committee on Geostatistical Techniques in Geohydrology of the Ground Water Hydrology Committee of the ASCE Hydraulics Division (May, 1990, Vol. 116, No. 5)

Journal of Hydraulic Engineering, 1992

Research paper thumbnail of Digital elevation model and multivariate statistical analysis of morphometric parameters of some wadis, western Saudi Arabia

Arabian Journal of Geosciences, 2012

In arid regions, the analysis of wadi morphometric parameters and their interrelationships are fu... more In arid regions, the analysis of wadi morphometric parameters and their interrelationships are fundamental for describing the topographic, geologic evolution, structures and hydrologic potential efficiency of the watershed. Unfortunately, the spatial characteristics and the analyses of these variables are not taken into consideration in an efficient way, especially in arid regions. In this paper, digital elevation model, geographic information system and multivariate statistical techniques are integrated for the identification and the assessment of main morphometric parameters. For this purpose, Q and R modes of cluster analyses and principal component analysis (PCA) are applied to ten different-size watersheds in the western region of Saudi Arabia utilizing 18 morphometric descriptors (variables). The results show that the R-mode cluster analysis classifies the variables into three groups, whereas the Q-mode cluster analysis classifies watersheds according to the similarities in their major variables such as area, perimeter, total stream length and peak discharge. The first three components of PCA accounted for 86% of the total variance in the data and show more details concerning the parameter loadings and the degree of variable significance.

Research paper thumbnail of Multivariate geostatistical methods of mean annual and seasonal rainfall in southwest Saudi Arabia

Arabian Journal of Geosciences, 2009

A multivariate geostatistics (cokriging) is used for regional analysis and prediction of rainfall... more A multivariate geostatistics (cokriging) is used for regional analysis and prediction of rainfall throughout the southwest region of Saudi Arabia. Elevation is intruded as a covariant factor in order to bring topographic influences into the methodology. Sixty-three representative weather stations are selected for a 21-year period covering different microclimate conditions. Results show that on an annual basis, there is no significant change using elevation. On the seasonal basis, the cokriging method gave more information about rainfall occurrence values, its accuracy related to the degree of correlation between elevation and rainfall by season. The prediction of spring and winter rainfall was improved owing to the importance of orographic processes, while the summer season was not affected within its monsoon climatology.

Research paper thumbnail of IDF curves and daily rainfall generation for Al-Madinah city, western Saudi Arabia

Arabian Journal of Geosciences, 2015

ABSTRACT Due to the increase in global warming and climate change impact, especially in urban ari... more ABSTRACT Due to the increase in global warming and climate change impact, especially in urban arid regions, the intensity-duration-frequency (IDF) curves and rainfall generation procedures become essential for storm design and hydraulic structures dimensioning for future planning and management. Al-Madinah, the second holiest city for all Muslims, is located in the western part of Saudi Arabia. This city needs special attention for hydrologic and hydraulic structure projects due to highly developed and rapid expansion in land use. The purpose of this study is to develop an empirical formula from IDF curves, which have been generated from 43-year records for Al-Madinah rainfall station. The absence of some daily rainfall records led to the application of the reduction method to disaggregate daily rainfall to hourly time series for developing suitable IDF curves. The formula is derived using the analysis of the best fit of Gumbel and log-Pearson Type III frequency methods. An average empirical formula can be used for predicting any return period with a given storm duration for Al-Madinah area. Generating wet, dry, and rainfall intensities are also investigated using autorun analysis on a daily time step. The results show that the dry spell continues for 71 days while the wet spell is about 1.58 days on the average based on the rainfall intensity threshold of 5.9 mm/day. Based on the goodness of fit for the dry and wet spells and the rainfall intensities, the daily rainfall sequences can be generated for any duration, which is adopted here as for the next 43 years.