Seasonal variation of solar irradiance and sunshine duration in Saudi Arabia

Saudi Arabia is a huge area with diverse climatic and topographical features. This diversity in climate is augmented by seasonal weather variations. The study discusses solar irradiance and sunshine duration in terms of seasonal weather systems. Sunshine duration and solar irradiance maps show that the East Mediterranean weather systems (such as Cyprus low) in winter affect the majority of the geographical regions in Saudi Arabia. In spring and autumn, Sudan low becomes more active than Cyprus low, especially in the west and central regions. Sunshine duration in April is 47% compared to 50% in January. Sunshine duration in the southwest region is affected by the rainy and wet summer monsoon which reduces sunshine duration to 33% in summer (July), while it is 43% in winter (January). In addition, the study uses the Angstrom equation to estimate solar irradiance. The absolute relative error between estimated and observed solar irradiance ranges between 2 and 10% in the majority of cases, with a few cases exceeding 13%.     

Development of storm hyetographs for flood forecasting in the Kingdom of Saudi Arabia

This paper presents the derivation of the design storm hyetograph patterns for the Kingdom of Saudi Arabia based on real rainfall events from meteorological stations distributed throughout the Kingdom. Two thousand twenty-seven rainfall storms for a 20–28-year period were collected and analyzed covering 13 regions of the Kingdom. Four distinct dimensionless rainfall hyetograph patterns have been obtained over the Kingdom, while two patterns have been obtained for each individual region because of the lack of data for long-duration storms in individual regions. The resulting dimensionless rainfall patterns for each region can be used to develop storm hyetographs for any design duration, total rainfall depth and return period. It has been shown that the developed storm hyetographs have different features from other storm patterns that are commonly used in arid zones. The study recommends using these curves for the design of hydraulic structures in Kingdom of Saudi Arabia and regions alike.     

Climatic constraints and potential corn production in Saudi Arabia —A study in agroclimate

A parametric crop yield model YIELD, which was developed by Prof. W. Terjung and his team at UCLA, was applied to calculate yield and water consumption for corn in Saudi Arabia. The model employs climatic and environmental data in order to simulate yield for several crops in different places all over the world. A network of 22 stations provided climatic data averaged over a period of 17 years (1967–1983). The nonclimatic data was derived from the FAO soil map of the world and the writer's personal experience. The main objectives of this paper are: [1] to determine suitable places and times for planting corn, under rainfed and irrigated conditions in Saudi Arabia; [2] to contrast irrigation water for corn in each province; and [3] to assess the potential yield for corn in the country in a year. This study concluded that highest yields of corn under fully-irrigated conditions (primary growing season) occurred in the mountainous region in SW Saudi Arabia (about 12,000 kg/ha, and more than 18,000 in Nimas) while lowest yields occurred in Tabuk and Al-Khawsh (about 4,000 kg/ha). Yields in most of the other stations were (5,000–8,000 kg/ha). Under rainfed conditions crop failed in all regions except in the SW region in which yields range between 2,000 kg/ha in Al-Khawsh and — 6,000 kg/ha as in Nimas. According to the findings of this study, the most suitable months for corn sowing in Saudi Arabia are December and January.     

The impact of moral conditions associated with culture on the traditional adoption-diffusion Model: The case of the Qassim Region of Saudi Arabia

The main objective of this paper is to develop a conceptual framework that views cooperative membership in Saudi Arabia as a function of both utilitarian and deontological (moral) perspectives. The research was conducted in the Qassim, an agricultural area located in the Central Region of Saudi Arabia. The sample includes 83 cooperative members, besides 136 non-members. Discriminant analysis is used to test the hypothesis derived in this research. Two models are examined, the first model is based on the traditional adoption-diffusion framework. Thus, discriminating variables included in the first model are related to the socioeconomic characteristics of respondents, information content, sources of information, and advantages of membership in agricultural cooperatives. In the second model, discriminating variables pertaining to moral conditions were used in addition to the original discriminating variables. Results of the discriminant analysis fit the theoretical framework of the study, meaning that farmers become members because of economic (utilitarian) expectations and also because of their desire to cooperate with other farmers. Deontology therefore plays an important role in distinguishing members from non-members.     

Synoptic analysis of dust storm over Arabian Peninsula: a case study on February 28, 2009

Sand and dust storms are causing hazards and problems in aviation as well as the dangers and distresses they cause on living things. The low meteorological visibility, the presence of strong winds with gust, and the transport of dust and sand particles by the wind are dangerous on landing and departure of aircrafts, and even on planes that are parked. The main aim of the study is to examine the meteorological conditions causing the dust storm that took place in the Arabian Peninsula on February 28, 2009, and to determine the source of dust caused dust storm, sand storm, blown sand, and blown dust at the airports. Within the scope of the study, aviation routine weather report (METAR) and aviation selected special weather report (SPECI) reports have been assessed at many airports over Arabian Peninsula (AP), the northern part of the AP and North Africa. As model outputs; NCEP–DOE Reanalysis 2 data, BSC–DREAM8B, and HYSPLIT model were used. In the satellite images; METEOSAT MSG dust RGB images, MODIS, and Kalpana-1 data were used. According to obtained results, dust storms were detected in Bahrain, Kuwait, Saudi Arabia, and United Arab Emirates (UAE). At Al-Ahsa Airport in Saudi Arabia, the lowest visibility measured on February 28, 2009, dropping to 200 m, which was dominated by blowing sand. The source region of the dust observed at Dubai Airport in UAE is the eastern regions of the Rub’al Khali Desert located between Saudi Arabia, Oman, and UAE.     

Hydrologic behavior and flood probability for selected arid basins in Makkah area, western Saudi Arabia

In arid regions, flash floods often occur as a consequence of excessive rainfall. Occasionally causing major loss of property and life, floods are large events of relatively short duration. Makkah area in western Saudi Arabia is characterized by high rainfall intensity that leads to flash floods. This study quantifies the hydrological characteristics and flood probability of some major wadis in western Saudi Arabia, including Na’man, Fatimah, and Usfan. Flood responses in these wadis vary due to the nature and rainfall distribution within these wadis. Rainfall frequency analysis was performed using selected annual maximums of 24-h rainfall from eight stations located in the area. Two of the most applied methods of statistical distribution, Gumbel’s extreme value distribution and log Pearson type III distribution, were applied to maximum daily rainfall data over 26 to 40 years. The Gumbel’s model was found to be the best fitting model for identifying and predicting future rainfall occurrence. Rainfall estimations from different return periods were identified. Probable maximum floods of the major wadis studied were also estimated for different return periods, which were extrapolated from the probable maximum precipitation.     

Integrated rainfall–runoff and flood inundation modeling for flash flood risk assessment under data scarcity in arid regions: Wadi Fatimah basin case study,Saudi Arabia

This paper presents a proposed integrated approach for flood hazardous evaluation in arid and semi-arid areas. Wadi Fatimah in Saudi Arabia is utilized for implementation of such an approach. The approach consists of four stages. In the first stage, a statistical analysis of rainfall data is performed to determine the design storms at specified return periods. In the second stage, geological and geomorphologic analyses are followed to estimate the geomorphic parameters. The third stage concerned with land use and land cover analyses linked with hydrological analysis to estimate the hydrographs. The fourth stage is related to the delineation of the inundation area under two scenarios: the presence and absence of the dam. The statistical analysis proved that some rainfall stations do not follow a Gumbel distribution. The presence of the dam reduces the inundation depth by about 10 %. The reduction in the inundation area due the presence of the dam is about 25 %.     

Seismic Hazard Assessment in the Tihamat Asir Region, Southwestern Saudi Arabia

The occurrence of earthquakes, faulting of Pleistocene sediments, uplifting of Pleistocene coral reefs, recent incised wadis and lava effusions in addition to hot springs all clearly indicate that southeastern Saudi Arabia is tectonically active. This paper reviews the tectonic features of southwestern Saudi Arabia and provides new approaches and maps for the interpretation of old and recent earthquake data for improved assessment of the regional tectonics. A regionalized variable approach is used to develop earthquake groundmotion hazard maps for the region, based on geostatistical methods using the kriging technique. This hazard must be considered in any design/construction of engineering structures in the region. The application of kriging for estimating the ground shaking in the study region succeeded clearly in accomplishing its ultimate aim where the generated groundmotions are well correlated with the instrumental magnitude and historical intensity of any earthquake occurrence in the study region.     

Economic potential of brines of Sabkha Jayb Uwayyid, Eastern Saudi Arabia

Sabkha Jayb Uwayyid is part of extensive sabkhas covering wide areas of eastern Saudi Arabia. Other than the production of salt for industrial and domestic purposes, no other economic utilization of sabkha brines is known in the region. Analyses from water samples collected in more than 20 shallow wells in Sabkha Jayb Uwayyid were used to estimate the concentrations and total mass of magnesium, potassium, calcium, and sodium. The total mass of each ion is calculated by multiplying the volume of water within the sabkha sands and the ion concentrations. The volume of water is the product of the saturated sabkha sediment thickness and the specific yield. The study shows that Sabkha Jayb Uwayyid brines are rich in some salts that exist in concentrations higher than that in seawater. The results show that Sabkha Jayb Uwayyid contains about 1.4, 0.4, 0.9, and 9.9 million metric tons of magnesium, potassium, calcium, and sodium, respectively. These amounts and probably more in other sabkhas potentially represent a significant untapped mineral resource in the eastern province of Saudi Arabia based on the current world production and market prices. The total mass estimates represent full extraction of brine from the sabkha and are based on a conservative specific yield estimate. Total recovery is unlikely and the actual amount will be limited by various logistical and climatic factors. Some uncertainty exists in the estimation of some parameters used in the calculations, including depth to the bedrock and hydraulic parameters.     

Quantitative indices for medical & personnel facilities

The status of medical facilities and personnel in the Kingdom of Saudi Arabia, at the end of the fourth five-year plan (1985–1990) was reviewed and analyzed regarding the standards of services and workload of health personnel for the different regions and urban/rural areas in the Kingdom. Innovative indices for the quantitative analysis of medical facilities were developed. The analysis of health facilities in Saudi Arabia shows that the Kingdom enjoys a high standard of medical facilities. However, there are maldistribution of clinical resources and personnel between regions and between urban/rural areas. Utilization of these indices for the reallocation of medical facilities and personnel to ensure even distribution of services for all inhabitants of the Kingdom was illustrated. In addition, indices give a guideline for the future planning and the rate of increase of these facilities that keeps the standard of medical services in the proper class desired with minimum resources wastage.     

Estimation of climatic transition in Riyadh (Saudi Arabia) in global warming perspectives

The present exercise is a study to enquire into the recent climatic transition, if any in Riyadh, Saudi Arabia. Conventional climatic indicators such as rainfall distribution, temperature regime, relative humidity, sunshine duration, wind velocity and evaporation characteristics were examined over a period of twenty six years of available meteorological data. The analyses showed a remarkable mutual resemblance and unidirectional trend in all the temperature parameters like absolute monthly maximum, absolute monthly minimum, mean monthly maximum, mean monthly minimum and mean monthly temperatures and the mean monthly maximum and mean monthly minimum relative humidities. Similarly, the trends in sunshine duration, wind velocity and pan evaporation were also supportingly in accordance to the general trends of climatic transition. The analysis based on a smaller period climatic data shows a good deal of agreement with the trends of studies on global warming projections made by simulated models on the basis of CO₂ concentration changes in the atmosphere.     

Hydrochemical classification and multivariate statistical analysis of groundwater from Wadi Sahba area in central Saudi Arabia

The central region of Saudi Arabia is underlain by thick sedimentary formations belonging to the Mesozoic and Cenozoic era. These sedimentary formations form a prolific aquifer supplying groundwater for agricultural and domestic usage in and around Riyadh. The region south of Riyadh City is well known for agricultural activities. Wadi Sahba, which is an eastward extension of Wadi Nisah, has readily available groundwater resources in the Cretaceous Biyadh sandstone aquifer to sustain agricultural activities. The objective of the present study was the hydrochemical assessment of groundwater in the area to understand the main hydrological processes which influence groundwater chemistry. To achieve this objective, 20 groundwater samples were collected from agricultural farms in the Wadi Sahba in central Saudi Arabia, and the major physiochemical constituents were analyzed and interpreted. The average TDS value of the analyzed samples is 1578.05 mg/l, whereas the average EC concentration is 3220.05 μS/cm. Groundwater facies classification inferred from the Piper plot shows that groundwater in the study area belongs to the Ca-SO₄-Cl type and Ca-Na-SO₄-Cl type. The Ca-SO₄-Cl type of groundwater facies is influenced mainly by gypsum dissolution and base ion exchange, whereas the Ca-Na-SO₄-Cl type is influenced by gypsum and halite dissolution. All the groundwater samples are undersaturated with respect to these two principal mineral phases. The Q-mode cluster analysis results in two main groups of groundwater samples, mainly based on the TDS content. Cluster 1 has an average TDS value of 1980 mg/l, whereas cluster 2 has an average TDS of 1176 mg/l. The groundwater facies identified through the Piper plot reflects the major hydrological processes controlling groundwater chemistry in the area and was found to be more useful in this study as compared to cluster analysis.     

Geological and geotechnical aspects of Saudi Arabia

Summary This paper presents a brief review of the geological and geotechnical aspects of the Kingdom of Saudi Arabia. The first part of the paper presents a brief summary of the geological aspects and the soil characteristics in different parts of the country. The second part gives a brief outline of the major geotechnical problems encountered in the regions of the Kingdom along with their geographical locations.     

Use of chloride-mass balance and environmental isotopes for evaluation of groundwater recharge in the alluvial aquifer, Wadi Tharad, western Saudi Arabia

Groundwater recharge estimation has become a priority issue for humid and arid regions, especially in regions like Saudi Arabia, where the precipitation varies over space and time as a result of topography and seasonality. Wadi Tharad is a typical arid area in western Saudi Arabia. Within its drainage area of 400 km², the groundwater system shows a graded hydrochemical zonation from the hydrocarbonate in the upper reach to the chloride zone in the lower reach. The saturation index (SI) varies depending on the concentrations of carbonate minerals; the mean for calcite and dolomite is about in equilibrium (e.g., zero value). As halite and gypsum indices are negative, it is undersaturated. Isotopic compositions of H and O in the groundwater show that the groundwater recharge resources are mainly from meteoric water. The chloride-mass balance method was refined to estimate the amount of recharge, which is probably 11% of the effective annual rainfall. These results can be used to improve the accuracy of future groundwater management and development schemes.     

The porosity and engineering properties of vesicular basalt in Saudi Arabia

The presence of non-connected vesicles in extensive basalt flows in western Saudi Arabia greatly affects their engineering properties such as compressive strength, modulus of elasticity, Poisson's ratio and sonic velocities. In order to evaluate some of these properties, the density and/or the porosity of the material must be known. Using conventional methods to determine the porosity or the density of irregular lumps proved to be erroneous. An image analysis technique is suggested to estimate the porosity of the vesicular basalt. The estimated values were correlated against the calculated porosity values using core samples, and were found to have excellent correlation (R=0.99). The estimated porosity values were also correlated against the static and dynamic properties of the basalt and a good level of correlation (R=0.77) was obtained.     

A GIS approach for the assessment of groundwater quality in Wadi Rabigh aquifer,Saudi Arabia

A classification approach has been implemented in the present work by integrating traditional water sample analysis methods and Geographic Information System (GIS) capabilities in order to classify zones with acceptable groundwater quality for drinking. GIS extrapolation capabilities with their multi-conditional layering facilities were integrated together in order to assess in the determination of areas suitable for drinking purposes. This technique was implemented in Wadi Rabigh, Western Saudi Arabia, due to its significance as one of the most promising areas in the Western Province in the Kingdom of Saudi Arabia, owing to the establishment of King Abdullah Commercial City and King Abdullah University for Science and Technology (KAUST) nearby. Results show that only a limited area in the aquifer can be used for domestic purposes. This area is located in two separate patches in the upstream part of the aquifer while most of the aquifer water is categorized as brackish which might be used for agriculture purposes to a certain extent. The downstream area of the aquifer is very saline due to sea water intrusion effect.     

Efficiency of seismic attributes in detecting near-surface cavities

The purpose of this study is to evaluate the efficacy of using seismic attributes to detect near-surface cavities. The methods used in this study include interpreting dispersion curves and amplitude mapping of the multichannel analysis of surface wave (MASW) technique and interpreting the delay in first arrivals of compressional waves. To test these methods, a seismic survey was conducted above a known near-surface cavity in Al-Suman Area, Saudi Arabia. The cause of the cavity is carbonization in the area; there are many cavities similar to this one. The seismic data were collected using a seismograph system with 48 vertical geophones. Both techniques show a tangible result for detecting the cavity. The 2D section of shear wave velocity, which was obtained by inverting the dispersion curves from the MASW technique, leads us to determine the shape of the cavity, as described by a low-velocity zone. Frequency against relative offset is plotted and shows a significant frequency drop in the presence of the cavity, which also provides an indication to the presence of cavity underneath. This interpretation is matched by the interpretation of observed delays in first arrivals of compressional waves. The integration of both P wave seismic refraction and MASW gives confidence in the result and matches observations of the existing cavity closely.     

中国东部中生代安山岩的定量化研究

我国东部广泛发育着中生代火山岩,除台湾省为海相火山岩外,其余绝大部分为陆相火山岩,这是一套基、中、酸性陆相火山岩,次火山岩杂岩体,可概括称为安山岩建造,是环太平洋安山质火山岩带的一部分。 对我国东部火山岩和含矿火山岩盆地,前人已进行过很多研究,这些工作提供了大量基本地质资料和重要成果。本文在前人工作的基础上,从数学地质角度,应用数学方法和电子计算机研究了中国东部安山岩问题,并得到了初步结果。     

华夏植物群及其与全球同期植物群的比较

文中研究的焦点是华夏植物群及其与全球同期植物群的比较 ,并论证了石炭纪和二叠纪的古植物地理再造。在石炭纪和二叠纪 ,华夏植物区和欧美植物区皆位于具热带气候的赤道区 ,在类似的气候条件下 ,这两个地区的一些植物具有形态上的相似性。此外 ,华夏植物群含有一些与欧美植物群共有的分子 ;因此 ,这两个植物群的关系比较密切。尽管华夏植物群具有相当数量的分子是与欧美植物群所共有的 ,但是在大羽羊齿类植物中 ,在种级上两者并没有相同的成分。华夏植物群是以热带雨林气候为特征。在二叠纪 ,华夏区的气候比欧美区的气候更为湿润。华夏植物群的分子不同于安加拉植物群的分子 ;此外 ,安加拉植物群代表了温带气候条件。在石炭纪和二叠纪 ,冈瓦纳植物群分布在南半球高纬度地区 ,不同于分布于北半球低纬度的华夏植物群的组成分子 ;因此 ,这两个植物群没有必然联系。在石炭纪和二叠纪 ,在北半球华夏植物群与欧美植物群的一些植物在形态上的相似性以及在南半球 (西藏、沙特阿拉伯、土耳其、新几内亚和伊拉克 )一些华夏型分子的分布可以是起因于类似的气候条件、大陆位置、板块运动、洋流作用、古地理环境等因素的影响。华夏植物群与其同期植物群的差异反映了植物群成分、古气候、古地理位置和陆地生态系在时?