mahin hanifepour

Introduction and Goal:

The decreasing trend of precipitation in many regions of the country, including the northwestern provinces, has made it more necessary to investigate new methodologies to complete the databases of the country's watersheds. In this regard, understanding the changes in precipitation barycenters, as an emerging concept, that indicates the long-term spatial distribution of regional precipitation is especially important for the administration of watershed management issues such as reducing drought effect, flood control, and water resource conservation. To this end, the present study analyzes the precipitation barycenter and its relationship with the spatial distribution of the rain gauge network in Ardabil Province.

To calculate the precipitation amount, the statistics of 49 meteorological stations during the statistical period of 45 years (1971-2016) were used. Based on the principle of station extraction and considering the rationality of the lowest density and uniformity, five stations were determined as the minimum possible number. Then, densities of 10, 20, 30, and 40 stations were extracted randomly to compare the distribution of precipitation centroids with the density of the station network. The statistics above were used to implement the gravity center model, calculate the standard deviation ellipse in the ArcMap 10.8 software environment, and conventional correlation analysis on monthly, seasonal, and annual time scales using XLSTAT.

The results showed that in spring (April to June), the direction of movement of the precipitation barycenter was significantly different and the movement distance was 18.17 km. In summer (July to September), the precipitation barycenter mainly moved 20.18 km to the north. In autumn (October to December), the precipitation barycenter mainly moves 20.49 km to the south and has the longest movement distance among the seasons. In winter (December to March), the precipitation barycenter moves in different directions and has the smallest movement distance (8.35). The annual precipitation barycenter migrated mostly in the southeast direction. The maximum migration of barycenter for 1979 was towards the northwest with 111.78 km. Besides, the annual precipitation barycenter in Ardabil Province in the three decades of 1971-1981 migrated mostly to the northwest and in the other decades to the southeast. The stational network density was positively correlated with changes in the precipitation barycenter (CCA = 0.65 at a significance level of 5%).

Conclusion and Suggestion:

The highest conventional correlation coefficient of 0.80 was obtained for the density of 40 stations among different densities of 5, 10, 20, 30, 40, and 50, and the lowest coefficient of 0.04 was obtained for the minimum density of 5 stations. Based on the results of this study, changes in the movement of precipitation patterns that can be effective in drought and wet periods were identified. It is suggested that the relationship between climate change and elevation factors with spatial-temporal changes in the precipitation center of gravity be investigated.

The characteristics of drought as one of the environmental events may affect climate changes in the future. The purpose of this study is to evaluate the effect of meteorological drought on vegetation dynamics from 2001 to 2021 in the Golestan province, northern Iran, using remote sensing satellite images. First, using MATLAB software, the Standardized Precipitation Evapotranspiration Index (SPEI) was calculated in time scales of 3, 6, 9, and 12 months for the Golestan province with a statistical period of 20 years and zoned in ArcGIS software with IDW (Inverse Distance Weighting) Interpolation Method. In the next step, we obtained the maximum value of the Enhanced Vegetation Index (EVI) per month from the MODI3Q1 product of the MODIS spectrometer. Also, using Tersest software, the correlation and line slope of EVI index changes were calculated based on SPEI index changes. The results of correlation analysis showed that in 54.19% of the area of Golestan province, 6-month SPEI changes have the maximum correlation with the EVI index compared to SPEI in other periods. As a result, the highest impact of drought on vegetation in most parts of the study area is related to the 6-month SPEI in May. The results of vegetation sensitivity to meteorological drought showed that in the south of Golestan province, which is covered with dense forest conditions and includes the eastern slopes of Alborz spread in the form of a strip from the west to the east of the province, the vegetation has relatively low sensitivity to the phenomenon of drought due to suitable climatic conditions and the relative humidity of the air. The research results can be used in long-term planning for sustainable natural resources management.

Sand dunes are one of the most important landforms in arid and semi-arid regions, whose mobility varies depending on climatic factors, especially the speed and frequency of erosive winds, rainfall, and the amount of evaporation and transpiration, which always causes many problems for the activity of these dunes. Therefore, monitoring climatic factors and analyzing dust events can be a positive step toward knowing the factors affecting their activity and predicting their mobility status in the future. Lut desert, with its huge amount of sand masses, is one of the most active places concerning changes in wind speed and direction. The eastern part of this region, which includes the largest sand mass of Iran, the Yalan sand, is dominated by the 120-day winds, which doubles the importance of investigating the winds and their shaping role during the blowing season of these winds. Based on this, the current research was conducted to analyze the mobility of quicksands in Lut plain stations in the past and predict their conditions in the future.

The study area includes the Lut desert located in Kerman province. To conduct this research, average monthly values of climatic elements including temperature, rainfall, hourly data related to horizontal field of view, wind speed and direction, and the code of various dust phenomena were used. These data were received from the Meteorological Organization of seven synoptic stations that have statistics for 20 years (2002 to 2021). Investigating the changes of climatic parameters over 20 years, investigating the temporal and spatial mechanism pattern of dust, wind and storm rose, calculating the amount of evaporation and transpiration using the Torrent-White method, investigating the condition of dunes using the Lancaster index were the main steps of the current research. The mobility of quicksands was texted using a sensitivity analysis and at the end, the zoning maps of the final sand transport potential were prepared using ArcGIS software.

The results showed that the stations leading to Lut plain are facing a decrease in rainfall and an increase in temperature, evaporation, and transpiration. The changes in wind speed are high in Shahdad station and low in Baft station, and the prevailing wind direction in most of the studied stations is west and north. The highest frequency of local and extra-local winds is related to Nehbandan station with 1090 days and Bam station with 791 days, and the lowest frequency of winds is Local and extra-local corresponding to Baft station with 23 and 31 days, respectively. The calculation of the aridity index of the stations showed that the index of prevailing climatic conditions in the region is dry, ultra-arid, and semi-arid due to the activeness of wind deposits and the peak time of local events in the stations located in plain areas, and this means Shahdad station has become a real desert in terms of desertification risk, Baft station is under severe desertification risk, and other five stations are under very severe desertification risk. With the reduction of the UNEP aridity index and the increase of the aridity of the environment, the amount of sand mobility in the whole Lut plain is increased and the risk of desertification in the region is intensified. Based on the sensitivity analysis, if in the future the frequency of winds exceeds the erosion threshold by 30%, the activity and movement of dunes will increase by 30%, while with a 30% increase in rainfall, the dune activity will decrease by 43%. Also, the sand mobility index has a positive relationship with changes in evaporation and transpiration. With a 30 % increase in evaporation and transpiration and the speed of erosive winds, the activity and movement of dunes increase by up to 70 %, and with a 30 % decrease in these two meteorological indicators, the activity and movement of dunes decrease by 50 %.

By calculating the Lancaster index, the potential activity of dunes has been determined and the active and inactive areas have been separated. The results of the zoning of this index showed that in the studied area, the activity level of dunes is mostly completely active and active at the top of the dunes. It is inactive only in Bam station, which has been done to stabilize and reduce dust activity and management measures such as planting trees, hand-planting desert forests, dunes, and mulching. However, due to the activity of the dunes in other stations, these measures are not enough and need new management and planning. The results of the present research can be used to predict the future condition of dunes and determine appropriate management measures to control and reduce possible damage to other land uses in the region.

By referring to different organizations and taking a deep and expert look at the communication process in these organizations, it becomes clear to any observer that one of the important and always noticeable problems in organizations that employees complain about are, lack of communication skills among their managers. One of the most important and key issues that has caught the attention of the organization and the foundation of the organization society in this period of time is the organizational commitment of the employees of an organization. This issue can have many factors and dimensions. The present study was conducted with the aim of investigating the level of employee satisfaction with the performance of Baghershahr municipal managers.

The statistical population of the research is all the employees of Baghershahr municipality. Due to the unlimitedness of the statistical population, the formula for determining the sample size in Cochran's unlimited population was used to determine the sample size. Therefore, considering the error level of 0.05, the sample size was estimated to be 242 people. The data collection tool was a questionnaire.

The results extracted from the above research emphasize the existence of a strong effect of job satisfaction on the commitment of the organization's employees, and it seems that the managers of all levels of this municipality can, with sufficient and accurate knowledge of the individual differences between their employees to know them better, more accurately and more completely, and as a result, by taking actions that are most compatible with the level of the heart desires of the employees, on the level of their desire and motivation, satisfaction and commitment in the direction of development and Intelligent movement in the direction of increasing the organization's goals. The level of satisfaction regarding the examined components of job satisfaction is average, managers are high, and for the components related to welfare, it is below 40%.

This shows that the employees of the municipality have little or very little satisfaction with the amenities in the municipality.

Sand dunes are one of the most important landforms sensitive to wind erosion, the extent of which varies depending on the severity of the impact of various climatic and environmental factors. Sand dunes cover large areas of the land and are located mainly in arid areas. Long-term monitoring of these factors along with the mobility of sands dune in different areas can have a significant effect on reducing their adverse effects. Most of the stabilized sand dunes were most active in the late glacial period.  Vegetation is one of the factors modulating and weakening the action of wind on sand, the growth of which can lead to the stabilization of sand dunes.The phenomenon of moving sand dunes as one of the important processes of land degradation is a serious challenge in Iran. Therefore, studying and recognizing these factors in terms of their impact on the occurrence and intensification of mobility of sand dune is an undeniable necessity to prevent the aggravation of environmental crises in the future. Knowing the status of sand dunes can help us to protect them.

The study area, Sirjan desert, is located in Kerman province. For this purpose, for the present study, the average monthly values of climatic elements such as temperature, rainfall, hourly data related to the horizontal field of view, wind speed and direction and the code of various dust phenomena are required. In total, 100 meteorological codes (99-00) have been defined by the World Meteorological Organization for various phenomena, of which the code of 10-code represent local dust and one code (06) represents extraterrestrial events. To examine wind data including monitoring time and date, wind direction and speed, field of view and dust phenomena code including codes of 6, 7, 8, 9, 30, 31, 32, 33, 34 and 35 for statistical period 10 year (2011-2020) has been obtained from the Meteorological Organization of the country. In order to determine the direction of local dusty winds, hourly data related to speed and wind.  direction in local dusty hours were used. While to determine the direction of trans-local winds from the data related to code 06 was used, which indicates dust originating from outside the station. Rainfall and temperature data were used to calculate the amount of evapotranspiration by the Torrent White method. After calculating the percentage of erosive winds and drought index, the mobility status of sand dunes in the area was investigated using the Lancaster index. Sensitivity analysis test was used to predict the effect of possible change of climatic factors on the mobility of moving sand dunes.

On a monthly basis, the maximum speed of the strongest wind in the study area is in July. The prevailing wind direction in most months of the year is southeast. The highest and lowest frequencies of dusty days occurred in April and September, respectively. The results of wind speed frequency classification showed that about 89% of winds were blown at a speed of less than 6 m /s. The results of the analysis of the relationship between Lancaster index and the number of local dusty days showed that the impact of local dusty days from sand dune activity studies was 42% in the study area. The results of correlation analysis between climatic variables of sand mobility index showed that there is a significant negative relationship between rainfall and sand dunes activity in Sirjan desert synoptic station. As during the statistical period, the decrease in rainfall has increased the amount of sand dunes mobility index. Two-variable regression analysis between Lancaster index and drought index showed that there was a statistically significant relationship at 95% confidence level between these variables. In other words, 65% increase in wind sediment activity was due to changes in climatic conditions due to changes in rainfall and evapotranspiration potential of this region. About 90% of the statistical years were at high risk of desertification in terms of climate. Accordingly, with decreasing the amount of UNEP drought index and increasing environmental drought, the mobility of sand dunes in the whole study area and the risk of desertification will increase. The annual Lancaster index values at this station indicate that the status of active sand dunes is only at the top of the sand dunes. Based on the sensitivity analysis, it was found that if the frequency of erosive winds and evapotranspiration increases by 30%, the activity of sand dunes will increase by 69%. In other words, the active state of just at the top of the sand dines will change to the active sand dune state. Due to the combined reduction of the two mentioned parameters by the same amount, the activity of sand dunes will decrease by 51% and will change from active only at the top of the sand dunes to inactive.

In the study area, most forms of sand dunes are active type, and 90% of the statistical years were at high risk of desertification in terms of climate.  Around 65% of the increase in wind sediment activity was due to changes in climatic conditions due to changes in rainfall and potential evapotranspiration in this region.  It is predicted that the combined change of climatic elements, especially the speed of erosive winds and evapotranspiration in the future can affect the intensity of desertification in this region of the country.

In recent years, droughts, frequent storms, industrial and mining activities have caused a rise in dust in suburbs Tehran, and developing west of the province of Teheran.  The Mallard County is located in the west of the province of Tehran with arid and desert climate and has been selected as the study area. This study aims to determine the soluble metals, minerals and morphology of the original sediments and particulates in Mallard County and to determine the origin of the dust. Dust sediment was collected seasonally at 30 stations using dust collector. Soil and surface sediment sampling were conducted systematically and randomly on 14 pediment and playa facies and a total of 83 samples were taken from the work units. Scanning electron microscope (SEM) was used to determine the shape and size of dust particles, and X-ray diffraction (XRD) identified the minerals found in dust particles. The results showed that most of the chemical compounds in the dust particles consist of magnesium, phosphorus, potassium, iron, chromium, vanadium, nickel, lithium, molybdenum, caesium, scandium, zirconium and titanium. These elements are in the form of quartz, calcite and gypsum clay minerals with a coating of dolomite, hematite and muscovite minerals, with an internal origin that have been transported into the region from close distances or through wind flow. According to the results of the SEM analysis, the particle morphology is angular and semi-circular. Most dust particles can be evidence of the existence of a local and human source and are transported closely.

Drought is known as one of the environmental phenomena and it is also considered as a direct impact of climatic changes that can occur in any geographical area. 

In this study, monthly and annual rainfall data of 17 rain gauge stations belonging to the Meteorological Organization from 1972 to 2017 in Guilan Province have been used to investigate the severity, duration, and extent of drought. To evaluate and compare the capabilities of meteorological and hydrological drought, the standardized precipitation index (SPI) and streamflow drought index (SDI) were calculated (Lui et al., 2012) for the whole province in the periods of three, six, nine, 12-month, and annual scale depending on the capability of the index, severity, and duration of drought spells. 

To investigate the extent of drought, zoning maps were prepared using the inverse distance weighting method. According to statistics and information obtained from a statistical period from 1972 to 2017, the amount of the three-month SPI index is determined as a wet period. The results of drought severity zoning in Guilan Province showed that the SPI values in six, nine, and 12-month time scales were categorized as dry periods. In most of the cities of the study province, the drought was observed with the highest probability and had positive changes in the area of drought extent. 

The maps obtained from SPI interpolating in four statistical periods showed that the value of standardized precipitation index has increased in 2017 compared with 1972, and most cities in the studied province are covered by more drought-prone areas. In addition, the main drought in the region is observed in the meteorological stations located in the south and southeast of the region. According to the SDI values, it can be concluded that most of the river gauge stations are without or with moderate drought.

Managing the optimal use of water resources is one of the most important issues in sustainable development. Considering the importance of studying groundwater in the field of drinking, industry and agriculture, the study of water qualitative changes can be important for humankind. In this study, groundwater level depletion and electrical conductivity (EC) were used to investigate the quantitative and qualitative changes of groundwater in Karaj plain. The water level hydrographs were drown using Thiessen method based on the piezometric wells data and the groundwater depletion, the elevation contour line, and iso- electrical conductivity maps were provided using GIS. Quantitative changes were studied with reading of each well in different months in a 15-year period (2001-2016). The obtained results showed that the vast range of Karaj plain was depleted due to the lack of proper recharge as well as the over-exploration of groundwater. In addition, the relation between EC and anions and cations (such as Ca2+, Mg2+, K+, Cl-, Na+, SO42-, HCO3-) were determined. The calculated Standard Index of Annual Precipitation (SIAP) in five meteorological stations showed groundwater depletion due to rainfall reducing and drought. Electrical conductivity had direct relation with concentration of ions in all cases. According to the hydrographs, the average level of groundwater decreased to 1.02 m over 15 years and the groundwater level depletion consequently decreased the water quality.