A geographical approach to some demographic features of the Moslem countries

This paper considers some demographic aspects of the world's Moslem population. Main sources of information are evaluated, and a definition is laid down for a Moslem country. Proportions of Moslem population are given for some 20 Asiatic and 30 African countries. Geographical distribution of Moslem countries as well as of the total world population are studied in some detail with due attention being devoted to Moslem minorities in non-Moslem countries such as China and the USSR. Population density, annual growth rate, life expectancy, age and language distributions are among the demographic features discussed comparatively at country and continent levels. Special attention is given to urbanization in the Moslem world. Finally future trends are discussed by using the usual statistical methods. It is thus established that by the year 2000 the proportion of world's Moslem population will rise to 22.4% as compared with 18.3% in 1975 and that the pressure on natural resources of the Moslem countries will be more than twice that in 1975 which is an alarming fact. It is hoped that the study will assist Moslem leaders in adopting sound population policies in their respectivie countries.     

Development of stochastic dynamic Nash game model for reservoir operation II. The value of players’ information availability and cooperative behaviors

Stochastic dynamic game models can be applied to derive optimal reservoir operation policies by considering interactions among water users and reservoir operator, their preferences, their levels of information availability and cooperative behaviors. The stochastic dynamic game model with perfect information (PSDNG) has been developed by [Ganji A, Khalili D, Karamouz M. Development of stochastic dynamic Nash game model for reservoir operation. I. The symmetric stochastic model with perfect information. Adv Water Resour, this issue]. This paper develops four additional versions of stochastic dynamic game model of water users interactions based on the cooperative behavior and hydrologic information availability of beneficiary sectors of reservoir systems. It is shown that the proposed models are quite capable of providing appropriate reservoir operating policies when compared with alternative operating models, as indicated by several reservoir performance characteristics. Among the proposed models, the selected model by considering cooperative behavior and additional hydrologic information (about the randomness nature of reservoir operation parameters), as exercised by reservoir operator, provides the highest attained level of performance and efficiency. Furthermore, the selected model is more realistic since it also considers actual behavior of water users and reservoir operator in the analysis.     

Developing an agricultural flood loss estimation function (case study: rice)

In recent years, flood control has been replaced by flood management concept in terms of living with flood, making benefit of it, and minimizing its losses. Succeeding in flood management in any region depends on the evaluation of different types of flood losses. Because of providing water resources and suitable arable lands, especially in arid and semiarid countries, floodplains are very important for agricultural activities. These lands are naturally vulnerable to flood; henceforth, determining the degree of protection and acceptable risk in flood damage-reduction projects without agricultural flood loss evaluation could be unrealistic. In this research, effective hydraulic parameters for flood loss estimation were determined and a set of laboratory tests were performed to evaluate the loss of rice, as the main crop in the study region, under different hydraulic conditions. In this regard, flow parameters like depth, velocity, multiplication of depth and velocity, shear stress, the Froude number, and the Reynolds number were employed for different rice growth stages including after transplanting, shooting, clustering, and harvesting. Analyzing the results showed that the Reynolds number, as a dimensionless parameter, is the best one for simulation of flood physical factor-loss function. Statistical analysis revealed that the logarithmic function is the best regression equation fitted to the Reynolds number-loss function. The amount of loss depends on growth stage; therefore, the time of flood occurrence is of vital importance for agricultural loss estimation. In this research, it was realized that the amount of loss is increased in the following order: after transplanting, shooting, harvesting, and clustering.     

Two solution methods for dynamic game in reservoir operation

During the last decade, a number of models have been developed to consider the conflict in dynamic reservoir operation. Most of these models are discrete dynamic models which are developed based on game theory. In this study, a continuous model of dynamic game and its corresponding solutions are developed for reservoir operation. Two solution methods are used to solve the model of continuous dynamic game, namely the Ricatti equations and collocation methods. The Ricatti equations method is a closed form solution, requiring less computational efforts compared with discrete models. The collocation solution method applies Newton's method or a quasi-Newton method to find the problem solution. These approaches are able to generate operating policies for dynamic reservoir operation. The Zayandeh-Rud river basin in central Iran is used as a case study and the results are compared with alternative water allocation models. The results show that the proposed solution methods are quite capable of providing appropriate reservoir operating policies, while requiring rather short computational times due to continuous formulation of state and decision variables. Reliability indices are used to compare the overall performance of the proposed models. Based on the results from this study, the collocation method leads to improved values of the reliability indices for total reservoir system and utility satisfaction of water users, compared to the Ricatti equations method. This is attributed to the flexible structure of the collocation model. When compared to alternative water allocation models, lower values of reliability indices are achieved by the collocation method.     

Radar Observations of Leonid Meteor Shower 2003

Observations carried out during Leonid meteor shower 2003, by using Indian MST radar (13.46^N, 79.18^E; dip 12.5^N) are used to determine the number density of meteoroids through the cross section of the meteor streams. Cross sections are calculated for a number of classes of echo duration (particle size). They are also used to determine the relative flux of the shower in particle size ranges producing radar meteor echoes having durations <0.4 s, 0.4–1 s and >1 s. Mean activity profiles along the Earth's passage through the stream show a systematic change of the peak activity and the width of the stream depending on the distribution of echo durations across the stream. The patterns of mass distribution index s are presented and discussed.     

Low latitude E-region irregularities studied using Gadanki radar,ionosonde and in situ measured electron density

In this paper, we attempt to identify the driving forces responsible for the generation of low-latitude E-region field-aligned irregularities (FAIs). It is evident that the low-latitude E-region FAIs occur both during the day and night with preferential occurrence being most during local sunrise period. Simultaneous measurements are made with Gadanki radar and nearby located Ionosonde for understanding the low-latitude Es–FAIs relationship. The observations suggest that the occurrence and SNR of FAIs have a close relationship with f _t E _s −−f _b E _s . Finally, using the past electron density profiles and reasonable values of electric field, we have shown that it is generally difficult with the gradient drift instability to explain low-latitude E-region FAIs when electric field alone is considered as driving agency. We hypothesize that neutral winds play important role for the generation of irregularities at low latitudes outside the electrojet belt either by forming sharp Es layers or by enhancing the differential drift of electrons and ions or by both.     

Grain yield reliability analysis with crop water demand uncertainty

A new method of reliability analysis for crop water production function is presented considering crop water demand uncertainty. The procedure uses an advanced first-order second moment (AFOSM) method in evaluating the crop yield failure probability. To determine the variance and the mean of actual evapotranspiration as the component of interest for AFOSM analysis, an explicit stochastic optimization model for optimal irrigation scheduling is developed based on the first and second-order moment analysis of the soil moisture state variables. As a result of the study, the violation probabilities of crop yield at different levels were computed from AFOSM method. Also using the optimization results and the double bounded density function estimation methodology, the weekly soil moisture density function is derived which can be used as a short term reliability index. The proposed approach does not involve any discretization of system variables. The results of reliability analysis and optimization model compare favorably with those obtained from simulation.     

Regional analysis of wind climatic erosivity factor: a case study in fars province, southwest Iran

Wind erosion climatic erosivity is a measure of the climatic tendency to produce conditions conducive to wind erosion. This research develops a method to determine the regional climate’s tendency to cause wind erosion on the basis of a physically based climatic factor (CE) and linear moment analysis (L-moments) in Fars province, southwest Iran. CE is calculable from wind speed quantiles and other available meteorological data. The wind quantiles can be estimated by a frequency analysis of the available wind data. Wind speed data are often either not available or are of short record length, and thus, CE estimates from such data have large standard errors. In such a situation, data from several sites can be used to estimate wind speed quantiles at each site based on a regional frequency analysis. Monthly averages of maximum daily wind speed of 19 meteorological stations in Fars province were used for regional analysis. Based on L-moment analysis, two homogeneous regions were determined. Regional wind speed quantiles were calculated, and the results were used to calculate CE values for two 6-month wet and dry periods for each homogeneous region. Furthermore, CE values were estimated for each station in the study area using a Weibull distribution, and the results were compared with the regional-based CE values. It showed that CE values estimated using the regional-based approach have smaller sampling variance compared to those obtained from the Weibull method. The proposed method can be used to evaluate the regional risk of wind erosion in arid and semi-arid environments.     

Geminid Meteor shower activity 2003–2005 as observed by Gadanki radar

The distribution of meteor signals reflected from a backscatter radar is considered according to their duration. This duration time (T) is used to classify the meteor echoes and to calculate the mass index (S) of different meteoroids of shower plus sporadic background. Observational data on particle size distribution of the Geminid meteor shower are very scarce, particularly at low latitudes. In this paper the observational data from Gadanki radar (13.46°N, 79.18°E) have been used to determine the particle size distribution and the number density of meteoroids inside the stream of the Geminid meteor shower. The mean variation of meteor number density across the stream has been determined for three echo duration classes, T<0.4, T=0.4–1 and T>1 s. We are more interested in the appearance of echoes of various durations and therefore meteors of various masses in order to understand more on the filamentary structure of the stream. It is observed that the faint particle flux peaks earlier than the larger particles. We found a decreasing trend in the mass index values from the day of peak activity to the next observation days. The mass index profile was found to be U-shaped with a minimum value near the time of peak activity. The observed minimum s values are 1.64±0.05 and 1.65±0.04 in the years 2003 and 2005, respectively. The activity of the shower indicates the mass segregation of meteoroids inside the stream. Our results are best comparable with the “scissors” structure model of the meteoroid stream formation of Ryabova [2007. Mathematical modeling of the Geminid meteoroid stream. Mon. Not. R. Astron. Soc. 375, 1371–1380] by considering the asteroid 3200 Phaethon as an extinct comet.