مجله ژئوفیزیک ایران
سال شانزدهم شماره 2 (پیاپی 55، تابستان 1401)

In this study, using remote sensing and calculating the physical parameters related to dust emission, the soil erodibility as a criterion of dust sources has been re-calculated and added to the WRF/Chem model, to replace the default dust sources (based on topography) in WRF/Chem, over West Asia. SEVIRI Dust RGB products, as the remote sensing data, and ECMWF-ERA5 meteorological data have been extensively used in the geographical identification of dust sources and calculation of their activity. Over 1100 dust sources have been identified by the aim of dust RGB images, and converted to dust frequency map, which at the next step, converted to the weighted frequency map, by applying the turbulence (friction and convection velocity), and 10m wind speed. One of the key innovations in this study is the combination of dust event frequencies (weighted frequencies) with the meteorological factors, including friction velocity, convection velocity, and 10m wind speed. The results show that the weighted dust frequencies are effective in improving the simulation of dust concentration. The spatial distributions of the new dust sources are similar to the default dust sources (based on Ginoux function), and different in many other regions. New redefined dust sources include regions in Iraq, Syria, eastern Iran, northern coasts of Oman Sea, and the Aral Sea. There are considerable regions in the new dust source map, including eastern coasts of Caspian Sea and southern coast of Persian Gulf, which in comparison to the default dust sources are not identified as active dust sources. The distribution and magnitude of the dust concentrations and the results of the WRF/Chem simulations of dust concentrations for two major dust episodes with the new dust sources and comparing them with the simulations with default dust sources show significant improvements. The new erodibility maps as the new West Asia dust sources, developed in this study, result in a relative improvement in the simulated dust concentration. It cannot be expected that all WRF/Chem dust simulations with the new dust sources in any region of the study area produce more accurate results.     One of the most important purposes of this study was to provide a new dust source map that makes the WRF/Chem results of dust concentration more reliable; therefore, it can be used in operational and warning advisory systems for sand and dust storms. It is shown that for some cases the simulated dust concentrations are not different, using the weighted dust frequencies or only the dust frequencies. But in some other cases (especially eastern Iran), there are major differences between the simulated dust concentration and station data, in a way that confirms the significant role of weighted frequencies in reaching better erodibility factors (dust sources) in comparison to the dust frequencies alone. The capability of the WRF model is a key factor in correcting the dust sources. Good accuracy of WRF in wind simulation makes it a capable model in predicting the temporal and spatial variability of the dust storms. However, the stochastic variables, including the turbulence, can affect the accuracy of model.

Mankind has long been faced with natural destructive phenomena, including earthquakes. Awareness of the time and place of major earthquakes is essential to warn before occurring an earthquake in order to reduce human and financial losses. At present, it may not be possible to predict the exact time of future earthquakes, but to some extent, by studying the data of past earthquakes, high-risk areas with high seismic potential can be identified, and knowledge of these high-risk areas can reduce the damage caused by earthquakes in these regions. The study of stress changes in the earth's crust can be used to estimate the probability of an earthquake. Coulomb stress change analysis has been used in many seismic regions of the world. These studies show that in most cases, the location of subsequent earthquakes is affected by changes in the Coulomb stress caused by previous earthquakes in that region. In this study, in order to investigate the possible location of large earthquakes, Coulomb stress changes of 29 historical earthquakes and one instrumental earthquake magnitude greater than 5.5 in NW Iran were calculated. The study of mechanical interaction among earthquakes shows the spatial relationship between them in some events. For example, Coulomb stress change caused by the historical earthquake of 858 AD on the NTF, led to the rupture of its adjacent part in 1042 AD. The 1042 earthquake ruptured a large part of the NTF and increased the stress on the west side on the 1273 faulting plane. The next event in this sequence was the 1304 earthquake in the NTF, which was located at the region of the increase in the Coulomb stress caused by the previous earthquakes. The 1641 earthquake occurred in Dehkharqan region of Tabriz due to the increase in the stress of the fault system events in the NTF.     In order to know about the areas that have highest probability, we compute the cumulative Coulomb stress change caused by the co-seismic deformation of earthquakes on strike-slip and dip-slip faults with optimal geometry. The results of these estimations show that the high-risk and probable areas for causing the next large earthquakes in the region Coulomb stress change increase due to previous earthquakes and have active faults in the direction of optimal strike-slip and dip-slip fractures. These areas for strike-slip faults are: the southeastern part of the NTF (Bostan-abad), the northern part of the faulting caused by the 1843 earthquake from the Maku fault and the southern part of the faulting caused by the 1840 earthquake. The areas for dip-slip faults are: Tasuj fault, between faultings caused by the earthquakes of 1807 and 1857, Mishu fault, the southern part of the faulting caused by the 1844 earthquake from Bozqush fault and the northern part of the faulting due to the 1879 earthquake from Bozghush fault.

The flexural strength and consequently the elastic thickness (Te) of the lithosphere are often calculated utilizing the statistical relationships between gravity anomalies and topography data. The elastic thickness of the lithosphere is one of the most important parameters in determining the geological properties and characteristics of the crust as well as its rheological behavior. This prospective study was designed to investigate the use of the gravity and topography data in order to calculate the two fundamental functions, i.e. admittance and coherence, which are the basic functions for determining the elastic thickness of the lithosphere. In this research, the theory of the two objective functions is modeled. The study offers some important insights into the involved parameter and how they affected the functions. Additionally, the results show the impact of initial assumptions of different parameters on the retrieved value of the Te parameter. Taking into account the initial assumptions about parameters such as the elastic thickness () of the plate, the loading ratio () and the degree of correlation () between the surface and subsurface loading regimes applied to the plate and using spectral methods, the value of these two functions are calculated. After examining the theoretical models, the real-data analysis is conducted in order to examine the observed values and compare them with the theoretical values. Based on what was mentioned in the following, this function can be able to retrieve the elastic thickness of the lithosphere. We concluded that:One of the more significant findings to emerge from this study, by examining the theoretical models, is that the best function to determine the elastic thickness of the lithosphere is to use the Bouguer coherence function. A comparison of the results reveals that the characteristic curves of the admittance function will change drastically with the change of the involved parameters. Consequently, having complete knowledge of the structure of the region and involved parameters is essential while using free air admittance in order to determining Te. As it was illustrated in this research, the characteristic curve of the coherence function can be used to determine Te based on the roll over wavelength. For the reason that there was no significant change in the shape of characteristic curve of the functions with the initial value of the loading ratio (), this parameter had less impact on the inversion process. Having considered rare correlation between free air gravity and topography, it is reasonable to accept that the free air coherence method is less applicable in determining Te than Bouguer coherence. The findings from previous studies provide support for the key arguments.

Earthquake ground motions are generally recorded by digital accelerometers in three orthogonal components (two horizontal and one vertical). The vertical component is typically ignored and two horizontal records are used for the response analysis of most structures. In two-dimensional time history analysis, a stronger horizontal component of the as-recorded ground motion is generally used to evaluate the structural responses. However, the horizontal strong ground motion depends on the orientation of the sensors as installed in the field. Simple trigonometric calculations demonstrate that by rotating the sensors, different waveforms are recorded for a specific ground motion. Considering that the orientation of the sensors is random compared to the orientation of the structures and causative fault, the question arises as to what percentage of confidence the use of as-recorded ground motions leads to the maximum desired responses.     To investigate this issue, based on the information and specifications of embankment dams in the earthquake-stricken areas of Kermanshah and considering the appropriate statistical distributions, 1000 numerical models of embankment dams were simulated using the Monte Carlo simulation method. In the next step, each of the 4 selected records of Sarpol-e Zahab, Kerand, Goorsfeid, and Javanrood were rotated in different angles from 0 to 180 degrees with 10-degree steps and applied to each of the numerical models of the dam. Equivalent linear time history analysis was performed for each of the simulated numerical models of the dam resulting in a total of 72,000 (18 * 4 * 1000) analyses. The values of maximum acceleration, velocity, displacement, and velocity-to-acceleration ratios of the dam crest (and the directions associated with each of these responses) were calculated for different stations. Using the simulation results, the probability that as-recorded accelerations would lead to critical responses was calculated. The results can be summarized as follow: Critical directions depend on the characteristics of the dam, input motions, and the type of the response; The probability of occurrence of critical responses in the case of using recorded accelerations depends on the input motion and the type of response considered; for example, the probability that the Sarpol-e-Zahab record would lead to critical displacement is close to 10%, while the same record with a probability of approximately 30% leads to a critical velocity or acceleration. In Javanrood station, the results are different from the previous results, and in the case of using the recorded acceleration, the probability of occurrence of critical displacement is close to 40%; Histograms of critical directions show that in general, no specific statistical distribution can be considered for critical directions; The higher the PGA value of the record, the lower the scatter of critical directions of the record.

The earthquake of November 12, 2017 Mw=7.3 Sarpol-e-Zahab is located in western Iran and between the two faults of the Mountain Front (MFF) and the High Zagros (HZF) of the Zagros tectonic seismic zone, Which is related to the rupture of MFF fault in Sarpol-e-Zahab area.The focal mechanism of this earthquake has a reverse fault with a low slope (16 degree) to the northeast. Studies in this field indicate the existence of a maximum slip of about 5 meters at a depth of 18 km. Due to the earthquake on November 12, 2017, Mw=7.3 Sarpol-e-Zahab, surface displacements, especially very large landslide of Mela-Kabod and many aftershocks occurred in the form of scattered clusters in the region. The occurrence of aftershocks in clusters indicates the activity of small secondary faults. In the present study, the fault causing the main earthquake (Mountain Front Fault, (MFF)) was modeled using 3d-def three-dimensional boundary element code and the surface displacements, especially displacement due to the landslide of Mela-Kabod and also the location of secondary faults were extracted using average of maximum and minimum principal stresses as a criterion for determining the location of secondary faults. In order to validate the modeling results for the displacements, comparing the results with the data obtained from the Interferometric Synthetic Aperture Radar (InSAR) method and the combined offset tracking method, it was observed that The results of the two methods are almost close to each other and there are differences in the position of the displacements and the amplitude of their changes in the two methods, so that the amplitude of the displacements resulting from satellite data in the earthquake zone, It is -35 to 80 cm, while this range is -15 to 100 cm for the results of the modeling. Also, for the location of secondary faults, the  average of maximum and minimum principal Stresses resulting from modeling are almost maximal in areas with aftershock density, especially in the southern part of the fault, and the depths with the most average of maximum and minimum principal stresses with depths that The aftershocks are high, except at a depth of 13 km, those are almost the same. In addition, to determine the sensitivity of the model to the input parameters, sensitivity analysis was performed, As a result, changes in dip angle and width of fault had the greatest effect on displacement output and also changes in Young modulus and length of fault had the greatest effect on  average of maximum and minimum principal stresses output. The boundary element method used in this paper is one of the numerical modeling methods that has many applications in numerical simulation of fault dynamics, and its results have provided a broad view of the physics of earthquake rupture. Also, the compatibility of numerical modeling results with the results of radar interferometry (InSAR) and combined offset tracking in this paper shows that the boundary element method is a suitable method for numerical modeling of faults.

Atmospheric currents, known as winds, are among the most important fields of study in different disciplines of science. One of the most important characteristics of wind is gustiness. Wind gust, among many other characteristics of the wind field, is studied extensively due to severe impacts that it may have on many aspects of human socio-economic activities. There are several models to predict wind gust speed. The results of these models always contain random and systematic errors that reduce the accuracy of predictions due to the lack of topographic resolution as well as the deficiencies of different physical schemes in the models. Consequently, post-processing is the most important process in the course of simulation and prediction using different types of models. Artificial neural network is one of the available tools that may be used to reduce errors of models by matching their outputs and observations.     The aim of this study was to evaluate the performance of two models and artificial neural network in forecasting wind gust in Iran. First, a study was designed to examine two methods of the non-convective wind gusts forecasting, i.e., the UK Meteorological Office (MOA) and WRF post-process diagnostic of wind gusts (WPD) performances. To investigate the performace of two methods, 1880 cases of non-convective wind gust observations of 32 synoptic stations in Iran, between 2013 and 2018, were studied. Four RMSE, MAE, MSE and R were used to measure the performace of those two methods. The results for WPD and MOA were 3.89, 3.07, 15.2, 0.66 and 4.37, 3.43, 19.1, 0.55, respectively. The results showed that the WPD method performed better than the MOA method. To post-process the wind gust forecasts with an artificial neural network, a feedforward multilayer perceptron with the back-propagation learning algorithm was designed. The model had a hybrid structure with a sigmoid activation function for the hidden layer and a linear transfer function in the output layer. Three training algorithms were used in the implementation of the model. Various combinations of normalized output variables of the WRF were used as input for network training and the target was observational wind gust speed. Seventy percent of the data were used for training, fifteen percent for testing and fifteen percent for validation.     The results showed that the best way to combine the input parameters is to use 10m wind, sea level pressure, temperature and relative humidity resulting from the output of the WRF model and the wind gust speed resulting from both methods mentioned above. Also, the best algorithm for neural network training was the Levenberg-Marquardt algorithm. Finally, the implemented artificial neural network was able to improve the results of both wind gust speed prediction methods (WPD and MOA). Due to the relatively higher accuracy of the WPD method compared with MOA method in predicting the wind gust speed in Iran, the artificial neural network that assumed the prediction of this method as input, was more accurate than MOA method (RMSE, MAE, MSE and R were 2.05, 1.6, 4.21, 0.83 and 2.37, 1.86, 5.2, 0.77, respectively).

In this study, to evaluate the spatiotemporal changes of total evapotranspiration (ET) in the southern part of the Aras river basin, the MODIS Global Terrestrial Evapotranspiration ET Product (MOD16) for collection 6 for a statistical period of 20 years (2000-2019) was used. The spatial resolution of this data is 500 meters, and its temporal resolution is 8-day. First, the product ET data was compared with the evaporation stations data, and the accuracy of the product was evaluated and validated using correlation, determination coefficient, Root Mean Squared Error (RMSE), and Mean Absolute Error (MAE). Then ET time series was calculated for the whole basin and its trend was plotted. Annual ET maps and their spatial change maps for the 20-year period were also mapped. In addition, the area of each ET class was calculated as a percentage, and the class changes over time were examined. The results showed that during the period in general, the west of the basin had lower average evapotranspiration than the east All maximum cores except Parsabd core, have existed since 2000, but the maximum core in Parsabad has been formed since 2001 and has gradually. The results showed, the percentage of the spatial coverage of classes larger than 300 mm in 2010 and especially in 2019 has increased compared to the average period. It has almost doubled to the number of their respective classes in 2000. The ET of the basin and the type of land use and land cover were investigated to find a possible relationship between them. The most increasing change in the ET amount at irrigated agro-use in Parsabad, dense forests in Khodaafarin and Kaleybar, high quality pastures southeastern and agricultural-horticultural mixture in Ardabil and in constant, the most decreasing change in the ET amount at rainfed agricultural use, a mixture of poor pastures and other uses in the south of Parsabad, Bilesvar and Garmi Moghan and to some extent poor pastures in the west of the basin were observed. The increasing change in ET in the mentioned areas was partly due to their land use change. Annual land use changes in these areas showed that it was largely due to the change and reduction of grassland (pasture) and bareland to irrigated fields and the increase in the percentage of dense forest at Khodaafarin and Kaleybar, which led to an increase in ET. Regarding irrigated agricultural uses, it emphasizes the increasing water needs of plants and the need for further research and revision of the type of irrigation system and the use of indoor canals instead of open canals. The increase in ET can also be due to the increasing changes in the meteorological variables that affect it, such as air temperature, wind speed, etc. and how water resources management, the clarification of which requires detailed research. Increased water needs of plants will be only one of the consequences of increasing ET.

In this study, we used the recent comprehensive earthquake catalogue of Mousavi-Bafrouei and Babaie Mahani (2020), including historical and instrumental earthquakes until the end of 2018, to calculate Probabilistic Seismic Hazard Assessment (PSHA) at eight metropolitans with a population of more than 1 million. These metropolitans include Ahvaz, Isfahan, Karaj, Mashhad, Qom, Shiraz, Tabriz, and Tehran. Our approach was implemented using a MATLAB code that was compiled for the purpose of this study. The historical seismicity within a 300-km radius was considered around each city, and the seismicity parameters were obtained in each case. We provided the hazard curve and uniform hazard spectrum for peak ground acceleration (PGA) and pseudo-response spectral acceleration (PSA) at periods of 0.04, 0.1, 0.2, 0.3, 1.0, and 3.0 sec for the return periods of 50, 475, and 2475 years, respectively. For hazard calculations, we used four ground motion prediction equations with equal weights; Boor et al. (2014), Idriss (2014), Kale et al. (2015), and Farajpour et al. (2019). Our PSHA results show that the highest hazard occurs in the cities of Shiraz and Tabriz, whereas the lowest hazard level happens in the city of Isfahan. Specifically, the largest PGA values at the bedrock ( = 760 m/sec) condition and for the return periods of 50, 475, and 2475 years are 77 cm/sec2 (Shiraz and Tabriz), 203 cm/sec2 (Shiraz and Tabriz), and 535 cm/sec2 (Tabriz), respectively. On the other hand, the smallest PGA values for the same return periods occur for the city of Isfahan at 29 cm/sec2, 77 cm/sec2, and 125 cm/sec2. We also compared our results with other PSHA studies obtained by other researchers, including Mousavi Befrouei et al. (2014), Salahshour et al. (2018), and Shahbazi and Mansouri (2019). In general, we found that our results show lower values in terms of ground motion amplitudes. For example, Mousavi-Bafrouei et al. (1393) obtained higher values by up to ~30% than those obtained in this study. This difference is probably due to the inclusion of different datasets for source characterization and calculation of seismicity parameters. In the approach used in this study and the works of Salahshour et al. (2018) and Shahbazi and Mansouri (2019), historical seismicity is the only source of information for the determination of seismic sources and their parameters, which resulted in similar ground motion values. However, Mousavi Befroui et al. (2014) used geological, geophysical, and seismotectonic evidence along with historical seismicity for source characterization.

The Kumamoto earthquake with magnitude Mj=7.3 was one of the destructive earthquakes in Japan which had more than 273 dead and 2809 injured. Investigation of temporal variation of coda wave attenuation before and after the earthquake, and also evaluating the lateral variation give important information about the crust and upper mantel beneath the studied area. Likewise, Attenuation of the seismic waves along with the velocity of wave propagation are among the important physical parameters that affect the propagation of the seismic waves. Careful investigation of these two parameters is required to determine the exact parameters of the earthquake source and also reduce the risk of earthquakes in the region. In the present study, the lateral changes of coda wave attenuation with time have been investigated. Here we checked the coda wave attenuations before and after the Kumamoto earthquake with the magnitude of 7.3 in the Kumamoto region of Japan. The estimation of Coda wave attenuation was performed using 474 local earthquakes recorded in 306 seismic stations by single back scattering method. This approach assumes that source and station are located at one point. The data used for estimation of attenuation have the epicentral distance between 1 and 200 km and the magnitude between 2.5 and 5.5. In order to considering the lateral variation of coda wave attenuation, the study area was divided into blocks with 0.3×0.3 degree in both dimension and the quality factor was calculated at the frequency of 1 Hz and lapse time of 30 seconds for the entire area. The results show the low quality factor Q0 and high frequency parameter n. So, the study area is tectonically active and has a high seismicity rate. Lateral changes in the quality factor indicate that the quality factor increases as it moves away from the epicenter of the main Kumamoto earthquake. The reason for this behavior can be attributed to the crushing of rocks due to multiple earthquakes, saturation and increased heterogeneity near the earthquake epicenter. Lateral attenuation changes before and after the main earthquake explain the fact that the quality factor decrease after the earthquake. After the main earthquake, the number of aftershocks occurred is greater than the number of pre-earthquakes. Increased earthquake occurrence in the region increases the fracture, crushes and saturation and as a result, reduces the quality factor. Comparison of the obtained quality factor in the region with other active regions in the world indicates the fact that the studied area is highly tectonically active and has also a high seismicity.

The aim of this study is to simulate stress variations and deformation of the continental plate in the subduction process. The main concept considered is that trench retreat during the subduction process can lead to the creation of an extensional stress regime in the overriding continental plate, and subsequent extension tectonics, and the thinning of the continental crust. The Iranian plate experienced distributed extension in the Eocene. One of the scenarios regarding this event considers the roll-back of the Neo-Tethys slab at that time as the cause of the extensional stress regime. Through numerical simulations to solve the conservation equations governing the flow and deformation in the crust and mantle, the role of rheology, thickness and age of the continental plate in the above-mentioned developments have been investigated. The results show that trench retreat can occur for a large range of physical parameters. Prolonged trench retreat can lead to a localized extensional tectonic regime near the edge of the continental plate above the subduction zone, 7 to 12 million years after the initiation of subduction. For a lithosphere with strong rheology, this tectonic regime results in negligible thinning, too small to be observable in the geological record. In contrast, for weaker continental plate, as well as a thin lithosphere, a wide-range of extensional deformations can occur, some of them comparable in terms of amplitude and time-scale with the events of the Eocene in central Iran.

The Makran zone, with a length of more than 900 km in southeastern Iran and southern Pakistan, is the only part of the Iranian plateau in which the oceanic crust of the Arabian plate with a slight slope to the north subducts beneath the continental crust of Iran. Makran is surrounded by two continental-continental zones of the Zagros and the Himalayas. Subduction of the oceanic crust along fault surfaces with a slope to the north has begun from the Early Cretaceous. Due to tectonic activity, continued subduction and the existence of a long megathrust zone in the northern part of Makran subduction and the northern shore of the Oman Sea has caused that this region has a very high risk of strong earthquakes and tsunamis. In this study, the Makran zone was evaluated by considering the concepts of seismicity parameters considered in the Gutenberg-Richter relationship. In other words, the statistical characteristic of earthquakes is considered in accordance with their spatial and temporal distribution. For this purpose, the basic data of fault and seismicity associated with the magnitude of earthquakes are investigated by the distribution of earthquakes and faults. The basis of the calculation of the b-value parameter is estimated using a frequency–magnitude distribution and correlation integral methods. Contrary to other methods, in this method, the time and space distribution of the parameters, the cumulative properties of the data and the tectonic stress level of the region associated with different earthquake seismic processes. In order to calculate these parameters, different seismic catalog (internal and external bases) have been used. Considering the distribution of earthquakes and magnitude data seismicity parameter was calculated and it is changed between 0.8<b<1.6 values. Considering the b-value quantity at any point, the map of differential stress (σ1-σ3) is calculated according to MPA (62-450 MPa).     Based on the study of changes in seismicity parameters in the Makran zone and clustering of large earthquakes that form areas with high-stress concentration, the heterogeneity of seismicity parameters covers a significant part of the study area. Large b-values indicate the random occurrence of small earthquakes, indicating low-stress structures in parts of the region. Heterogeneity of seismic zones leads to changes in the value of b. Based on the seismicity parameters calculated in the Makran zone, the highest concentration of seismic potential for destructive earthquakes with probability is located in the southern terminal of Nehbandan, Bam, Gowk fault systems (connection zones of Nehbandan fault system terminal, Chaman, OrnachNal and Qazband with the thrust faults of Makran zone).

The wind is one of the main factors in determining the weather condition and the daily air quality of urban spaces depends on the wind. Therefore, to achieve the dominant behavioral patterns of wind direction and intensity, various simulation models are used. This study considers the weather research and forecasting model (WRF). To simulate wind zonal and meridional components, the role of ECMWF (ERA5) and NCEP (FNL) boundary condition data with 7 physical schemas (Exp1 to Exp7) in two modes: 1) with default static data and 2) with high-resolution static data DEM (Aster satellite image with a spatial resolution of 30 m) instead of the default data with a spatial resolution of approximately 1 km, the land use/cover of Copernicus with a resolution of 100 m instead of the modis data with a spatial resolution of approximately 500 m to 1 km) for January, May, July, and October 2018 was evaluated as representative of seasons. Observational data of wind direction and speed with a 3-hour UTC scale in 2018 for 4 synoptic stations of Mehrabad, Chitgar, Geophysics, and Shemiran were obtained from the Meteorological Organization, and by applying 180 degrees to the weather direction, the vector orientation was obtained. Then, using the Rewind plugin in the developed R software, the zonal and meridian components of observational wind were calculated. By examining the correlation coefficient of wind zonal component in 4 selected stations in both default and high-resolution conditions with ERA5 and FNL boundary conditions, Shemiran station had the lowest correlation in January, May, and October, while Chitgar station on the suburban of the city had the weakest correlation in July; However, Shemiran station had the strongest correlation in July by a significant margin. Due to the location of the Shemiran station, the main reason for the weakness and strength of the simulations is the topography and height of this station. The results show that the simulation of the wind zonal component, except July in most schemas with the default static data and high resolution, is much better than the meridional component. Proper configuration of schemas, selection of ideal boundary conditions, determination of appropriate spatial resolution, and replacement of static data with a high resolution instead of default data can bring the model simulation much closer to the observation data. According to the results of the average output of 4 correlations, bias, mean square error, and mean absolute error statistics, considering the same weight coefficient of each statistic in Mehrabad, Geophysics, Shemiran, and Chitgar stations for each schema, FNL boundary conditions with default static data for the component Wind except July, and ERA5 boundary conditions were selected as the best boundary conditions for the meridional wind component except January with the best performance. Among the seven schemas tested for zonal and meridional components under the ERA5 and FNL boundary conditions with default and high-resolution data, Exp (1) (YSU) and Exp (6) (ACM2) generally yielded the best results for Tehran wind simulation.

Landmines buried in the sea or land threaten a large number of people around the world, and many people die as a result of these unexploded ordnance. Such ammunition needs to be identified by non-destructive methods. Numerous methods have been used to identify, discriminate and detect them. One of these methods in geophysics is electromagnetism in the time and also frequency domain, by which such anomalies are detected and their physical and geometric parameters are estimated. The electromagnetic induction method (EMI) is one of the frequency domain methods used for this purpose. This technique takes into account Eddy-Current Response (ECR) induced on the conducting marine mines as well as Current-Channeling Response (CCR) associated with the perturbation of currents induced in the conductive marine environment. Sea water is a good conducting medium in low-frequency range. Thus, displacement current can be neglected. The effect of noise due to the background medium can also be neglected. The sphere has often been used as a tractable model of a conducting anomaly in studying the response of electromagnetic induction (EMI) system. A large amount of unexploded ordnance is simulated in the simplest form with a sphere and a spheroid (for more accurate approximation).In this study, using the electromagnetic induction responses which are caused by eddy currents generated on the surface of the object and also the channel current in the host environment, the depth and radius of the buried object are obtained for four different modes of receiver and transmitter coil orientation. The transmitting and receiving coils can be approximated as magnetic dipoles. The incident fields emanating from the transmitting coil are uniform over the extent of the object. The object is considered as a perfect conductor compared to the host environment. To determine the depth and radius, the particle swarm optimization (PSO) algorithm is proposed. This technique is a global optimization method that can be used to solve problems whose answer is a point or surface in a multidimensional space. PSO is adjusted with random particles (models) and searches for targets by updating generations. The algorithm is implemented on the noise-free and noisy data respectively to evaluate the algorithm performance. The simulation results indicate that this method can be an effective way to estimate the depth and radius of the sphere. For noise-free data, the error is almost zero, and when noise is added to detect them, the depth of the anomaly and the radius are calculated with a perfectly acceptable error.

Surface albedo is a climatic parameter that is a function of surface type. In this study, to investigate the relationship between albedo and Elevation components in Iran from the combined data (Terra / Aqua) of Modis sensor in the period 3/20/2000 to 3/20/2019 (6940 days) on a daily basis and in a spatial resolution of 500 Meters were utilized. Also, Iran's Digital Elevation Model (DEM) data in spatial resolution of 500 meters and with a sinusoidal projection system coordinated with the spatial resolution and projection system of albedo data were downloaded from the NASA website. In the DEM data used, In data used, in addition to the elevation of the points, the slope and aspect information for each pixel is also in decis. Prior to data usage, some preprocessing was performed on digital data. Based on nearly 60 billion pixels, the albedo and DEM showed a linear fragmentary pattern. The results showed that the amount of albedo has 5 different patterns with increasing elevation. The first pattern shows the whiteness behavior at elevation below sea level. In these zones, albedo increases sharply with increasing elevation due to rising land surface temperature(LST). So that the albedo goes from 4% to about 16%. The second pattern shows the uniform behavior of the albedo at an elevation of 0-800 m. The third pattern of albedo decreasing behavior with elevation is revealed in the 1300-800 m belt. One of the reasons for the decrease in albedo in these elevation belts can be the expansion of cities and consequently the decrease in albedo due to the smooth surface of the asphalt of the streets and the paving of the streets. In the fourth pattern, a direct connection of albedo with elevation is observed in the belt of 3500-1300 meters. One of the main reasons for the increase in albedo in this elevation belt is the increase in snow cover in this elevation belt. The fifth pattern also shows a direct link between albedo and elevation above 3500 meters and is a continuation of the fourth pattern, with the difference that this pattern loses some of its order and shows a scattered pattern. The correlation of albedo and slope also showed that due to more sun exposure, the southern aspect of Iran has about 3% more albedo than the northern aspect. The correlation between the albedo and the slope is a straight line. As the albedo decreases to a slope of 30 °, the albedo will increase on slopes above 30 °.