فهرست مطالب

  • Volume:1 Issue: 2, Summer and Fall 2021
  • تاریخ انتشار: 1400/05/25
  • تعداد عناوین: 6
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  • Mohammad Hossein Mokhtari *, Ibrahim Busu, Sara Parvizi Pages 1-15
    Background and objective
    Agricultural lands under pistachio crop are expanded in the Bahadoran area due to the high profitability of production. Therefore, accurate estimation of pistachio water requirements and efficient use of water is essential where water resources are insufficient. This study evaluates the performance of METRIC in estimating pistachio evapotranspiration in a semi-arid region.
    Materials and methods
    The satellite images utilized in this study were consisting of three clouds free LANDSAT TM5 data acquired on 28 April 2010, 17 Jul 2010, and 2 Aug 2010. These images in Tagged Image File Format were downloaded from the U.S. Geological Survey Global Visualization Viewer website. Geometric correction of images was performed by collecting 20 numbers of well-dispersed ground control points. First-order polynomial transformation with nearest neighbor resampling method was applied to each image to fit the image coordinate to the coordinate of ground control points. The accuracy of the geo-referencing was evaluated by calculation of root mean square error and it was controlled to be less than half the size of the original pixel. Then two other scenes were co-registered based on this image and a subset of interest areas was generated from image scenes. Radiometric and atmospheric calibration was performed first by converting original digital numbers to radiance. Results and
    conclusion
    METRIC estimates the average ET for the image on April 28, July 17, and August 2 at 2.9, 4.2, and 3.1 mm per day, respectively.
    Keywords: Pistachio, METRIC, Semi-arid region, Soil water balance, evapotranspiration
  • Mohamad Reza Dehestani Ardakani * Pages 16-26
    Background and objective
     The dust phenomenon is one of the important climatic hazards in arid and semi-arid regions of the world, which causes human and financial losses to humans. In recent decades, due to long-term droughts, the incidence of dust has increased. Considering that Iran is one of the centers affected by particulate matter and the damage caused by this phenomenon affects our country, special attention should be paid to the issue of increasing particulate matter. The purpose of this study is to investigate changes in the dust, vegetation density, and wind conditions in the geographical region of south and southeast of Iran and its neighbors, Afghanistan and Pakistan.
    Materials and methods
     Through NASA Giovanni online modeling and the use of MERRA-2 satellite imagery to study dust and wind stress and the MODIS-Terra satellite to study vegetation. During the last 40 years from 1980 to 2020, the state of dust and wind stress was examined. Vegetation has also been studied over the past 20 years and 10-year periods from 2000 to 2020. Dust monitoring from June 2018 to February 2021 was also analyzed using Google Earth Engine, using long-term monthly images of Sentinel5 satellites. Results and
    conclusion
     The results show that with increasing the amount of dust, the percentage of vegetation, increases, and decrease in wind stress. Although plants and wind have had a good trend in these years, this increase in dust can be due to lower water levels and increased dust collection sites as a result of not observing the water level of wetlands.
    Keywords: dust, Vegetation, Wind stress, satellite imagery, East of Iran
  • Abbas Bashiri *, Hasan Hasani Moghaddam, Mohamad Javad Khodam, Seyyed Mohammad Afghahi, Hassan Tabarsi Pages 27-37
    Background and objective
    Absolute and Relative Models of Radiometric Corrections Due to the relative information provided from different parts of the globe, there are always errors when correcting images, which has led many researchers to develop local models or design tools to obtain information about the situation of Atmospheric of the area under study when the satellite passes. The present study aims to present a new method for radiometric correction of satellite images.
    Material and methods
    To apply the proposed method for correcting the calibration of satellite images, a sun-photometer was first designed and developed that can obtain atmospheric data and attenuate sunlight in the range of 400 to 950 nm in a hyperspectral mode. Sentinel-2 satellite images related to the city of Tehran were selected as a sample and in 2 days with clean and high pollution, data were obtained and the coefficients obtained were applied through a sun-photometer.Results and
    conclusions
    Based on made assessments, the importance of radiometric corrections based on local information for satellite images become more apparent. Evaluation of the research results shows the high capability of the designed sun-photometer in accurately assessing the attenuation of sunlight in different spectral. The amount of sunlight attenuation in the green band is more than the blue and red bands, which indicates the type of urban pollution in the region, which had the greatest impact on the green band and the least impact on the red band.
    Keywords: Sun-photometer, radiometric calibration, Sentinel-2, atmosphere
  • Mohammad Hosein Ramesht *, Barbara Sponholz, Fatemeh Nematollahi Pages 38-55
    Background and objective
    One of the new topics in geomorphology is the concept of spatial memory and identity. Phenomenological geomorphology begins with a system of new terms, such as land-contexts and land-texts, and then concepts such as space syntax logic, memory, and space are introduced.
    Materials and methods
    Hence, the questions raised regarding the German geomorphology problem are: How many land contexts have been created in Germany? What is the space identity of these land contexts? This research is based on the analysis of the Litho Lex database and maps-EU-DEM.   Results and
    conclusion
    The results from a joint study by the Universities of Isfahan and Wurzburg, based on the analysis of the Litho Lex database and maps-EU-DEM, show that: Germany has three land-contexts in its space memory (periglacial, glacial, and ice sheet land-context). The ice-water equilibrium line (I.W.E) separates these three land contexts. Urban settlements owe their own space identity to the convergence law of glacier and river meandering, and to the rural settlement resulting from the development of social groups in forests. The significance of the subject becomes apparent when it comes to an analysis of the same process, which does not follow from the same result somewhere else.
    Keywords: Germany, Land-context, Space Identity, Space memory
  • Teodoro Teodoro Carlón Allende, Erna Martha López Granados, Manuel E Mendoza* Pages 56-74
    Background and objective

    The global average surface temperature increased by about 0.6°C, and global sea level increased by 15 to 20 cm during the last century. As the temperature rise, crops and forests will experience failure. In Baja California, Mexico, there is no systematic evaluation of the spatial variability of future temperature and precipitation. The aim of this research was to identify how the precipitation and temperature will change in the basins according to the Intergovernmental Panel on Climate Change climate projections.

    Materials and methods

    We used the MPI ECHAM5 model scenarios A2 (pessimistic) and B2 (optimistic) of total annual precipitation (TAP) and mean annual temperature (MAT) for 2030 and 2050; we also used the HADGEM1 model, (scenarios A2 and B2) of TAP and MAT (2030-2050). All procedures were carried out in a geographic information system.

    Results and conclusion

    We evaluate for the first-time which basins at the peninsula will be more affected by changes in TAP and MAP. The relative increase of MAT per basin depicted a trend north to south. The highest values reaching 6.0° to 6.5°, the minimum values are around 2.0°. The reduction of TAP will be 21 mm from the baseline to 2030. The model also depicted an increase in TAP in the south of the peninsula (12-40 mm). The northern basins will suffer by reduction of water availability, especially for agriculture activities. The southern basins could be affected more by flooding and landslides.

    Keywords: Spatial analysis, Climate models, Future climate patterns, (fifth-generation atmospheric general circulation model) MPI ECHAM5, (Hadley Centre Global Environment Model version 1) HADGEM1
  • Zahra Mojarad, Abdul Rahim Pazira, Tayebeh Tabatabaie * Pages 75-90
    Background and objective

     In this study, groundwater resources of Dayyer city in Bushehr province were investigated for the amount of different parameters. The use of nitrate fertilizers in the city of Dayyer and the diversion of agricultural effluents containing these compounds to water sources has increased the concentration of nitrate. Calculation of ion ratios showed that weathering was delayed in the aquifers of the city and the infiltration of salt water led to an increase in the concentration of chloride and sodium. The increase in the concentration of other ions, such as calcium and magnesium, has a geological origin.

    Materials and methods

      For this purpose, in three stages (October, November and December 2019), 7 wells located in this city were sampled and the amount of various parameters including electrical conductivity, pH, hardness, total alkalinity, total soluble solids, nitrate concentration, sulfate, Nitrite, chloride, calcium, magnesium, sodium, potassium, fluoride, iron and bicarbonate were determined using standard methods.

    Results and conclusion

     The results were analyzed using one-way analysis of variance and ArcGIS software was used to prepare zoning maps by kriging method. Nitrate and sulfate concentration parameters, electrical conductivity, total soluble solids, total hardness, chloride, calcium, magnesium, sodium, potassium, fluoride and bicarbonate concentrations are 17.9-56.4 and 1100-3800 mg/l, respectively, 3740-7460 micro siemens per centimeter, 2240-4480, 2828-1393.8, 635.26-2034.83, 315.12-630.24, 145.44-349.056, 274.19-1068.1, 13-20, 3.12-3.8, and 68.32-131.76 mg/l were obtained. The results showed that except for the parameters of iron concentration (0.03-0.05 mg /l) and nitrite (0.0099-0.03.63 mg /l) and pH (7.13-7.34), The value of the other parameters is too much. Sulfate concentration has increased due to oxidation of pyrite-containing soils and the presence of evaporative minerals such as gypsum. According to the results obtained from the measurement of groundwater quality index, the value of this index is between 51 to 61, which means the average quality of water resources in this city.

    Keywords: Water Pollution, Geology, Human Activities, Statistical Analysis, Zoning