فهرست مطالب

Natural Environment Change - Volume:1 Issue: 1, Summer - Autumn 2015

Natural Environment Change
Volume:1 Issue: 1, Summer - Autumn 2015

  • تاریخ انتشار: 1395/05/20
  • تعداد عناوین: 7
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  • Hassan Farajzadeh, Mohammad Saligheh, Bohloul Alijani, Andreas Matzarakis Pages 1-20
    The present study compared simple thermal indices and the indices derived from energy budget models in the northwest of Iran. For this purpose, the air temperature, solar radiation, relative humidity, cloud, cover and wind speed of 13 meteorological stations in the northwest of Iran during the the period of 1986 to 2007 were selected for comparison. The results which were extracted using Bioklima and RayMan models, showed that the indices based on human energy balance had a significant correlation with each other (with R2 above 90%), and the lowest R2 (70%) was related to Subjective temperature index (STI). The indices based on relatively simple formulas had low correlation with Universal Thermal Climate Index (UTCI) and Physiologically Equivalent Temperature (PET). The probable reason for this lack of conformity was the lack of radiation factor in the equations. Furthermore, UTCI was very sensitive to the changes in air temperature, solar radiation, relative humidity and wind speed, especially. In this regard, it represented the response of the human body. The findings of this analysis indicated that UTCI and PET indices were the most suitable indices which could be used in determining thermal comfort conditions.
    Keywords: human thermal comfort, meteorological variables, northwest Iran, thermal indices
  • Manouchehr Farajzadeh, Mohammad Kamangar, Fahimeh Bahrami Pages 21-29
    As special depositional environments which are adjacent to the seas, deltas have provided a field for human habitat establishment. Geomorphic features of deltas are in constant transformation due to their dynamic features. Constructing dams on rivers can intensify these changes and cause either negative or positive consequences. Minab delta in Hormozgan Province of Iran is a round or crescent-shaped delta which has Esteghlal Dam constructed on its creating river. Minab Dam is constructed upstream of Minab Delta in Hormozgan Province. The research aimed to derive landscape metrics of delta and assess their changes before and after the construction of dams. Landsat Satellite images of 1983 and 2013 provided the four classes as abandoned delta, active delta, subaqueous deltaic plain and aquatic environment, using maximum likelihood method, with a Kappa Coefficient accuracy of 86.55 and 88.42 for revealing changes quantitatively. To quantify landscape metrics, percentage of landscape (PLAND), Number of Patch (NP) and Mean Patch Size (MPS) metrics were computed. As indicated by the results, the NP metric increased in all the classes except active delta, and all classes showed a reduction in MPS metric. The amount of NP, Mean Nearest Neighbor (MNN) and Largest Patch Index (LPI) increased to the 22, 19 m and 1.43 percent, respectively, which clearly reveals landscape fragmentation, along with growing NP metric and a reduction in MPS.
    Keywords: dam, delta, landscape, Minab, Morphology
  • Gholamreza Roshan, Jose A. Orosa Pages 31-48
    This present research work was carried out to evaluate the energy consumption in a typical Iranian building based on the forecast of climatic variables. Thus, the LARS-WG model was validated for some northwest stations of Iran, including Tabriz, Ardebil, Oromieh, Kermanshah, Hamedan, Sannandaj, Qazvin, and Zanjan. The average monthly outdoor temperature was forecasted from 2011 to 2100. The relevant data were generated when this model was used in three phases, including calibration, meteorological data generation, and meteorological data analysis. In the model, HADCM3 general atmospheric circulation model data was extracted each day, and a special LARS-WG model-based scenario is compiled for each general atmospheric circulation model network. The results of this study showed a delay of one month in the future yearly temperature curve and an average increment of 4°C in all the eight Iranian cities. Furthermore, as a result of these expected changes, the future maximum and minimum outdoor temperatures will be higher in the winter and reduced in autumn. Another related result of this temperature variation is a decrease in the heating energy consumption in the months of February and March and an increment in the months of November and December. On the other hand, there will be an increment in the cooling energy consumption in the months of May and June and a decrement in the months of August and September. Generally, some kinds of parameters, like the thermal inertia of the buildings and number of air changes, were combined as design proposals to define future building constructions with the lowest energy consumption. Thus, with half changes in the air and in the heating season, the energy consumption is reduced to one quarter of the initial forecast value, and in the cooling season, the energy consumption will be slightly higher, reaching the energy consumption defined today. Finally, it can be concluded that it is now the right moment to define future building design criteria.
    Keywords: building, Climate Change, energy consumption, Iran
  • Mojtaba Yamani, Alireza Arabameri Pages 49-62
    Today, environmental crisis and loss of natural resources are the principle causes of the creation of environmental management systems. The optimal management of natural resources requires the assessment and classification of ecological and environmental potentials. Using this method, the abilities and restrictions of resources can be recognized, and their future trends can be predicted. Nebka landscape is the natural reaction of ecosystem against the stress of wind erosion and ecosystem tries to adjust wind stress by creating this landscape. Therefore, the development of Nebka is the best and most suitable method for quicksand stabilization in the study area, and the most adaptable type of Nebka species must be identified and selected for the development of the ecosystem. This important aim will not be achieved except through careful and scientific investigation of Nebka phenomenon. According to the present environmental conditions, a suitable method with high accuracy is required in order to evaluate and manage natural resources and environment for achieving sustainable development. The aim of this study was to select the best Nebka species for quicksand stabilization using their morphometric parameters analysis by multi attribute decision making (MADM) methods. The results of this study show that in three models, Haloxylon obtained the highest point. Therefore, it has the highest effect in stabilization of quicksand. For implementation of stabilization projects of mobile sands in the study area, development of Haloxylon Nebka systems have the highest importance and efficiency. The results of this study will be beneficial in systemic management of desert regions and stabilization projects of quicksand.
    Keywords: Chah Jam Erg, multi attribute decision making (MADM) models, Nebka, plant species
  • Mohammad Ali Sharifi, Saeed Farzaneh Pages 63-69
    Ionospheric slab thickness is defined as the ratio of TEC to maximum electron density of the F-region (NmF2), proportional to the square of the F2-layer critical frequency (foF2). It is an important parameter in that it is linearly correlated with scale height of the ionosphere, which is related to electron density profile. It also reflects variation of the neutral temperature. Therefore, ionospheric slab thickness is a significant parameter representative of the ionosphere. In this paper, the International Reference Ionosphere (IRI) model, South African Bottomside Ionospheric Model (SABIM), and measurements from ionosondes in the South African Ionosonde Network were combined within their own limitations to develop a map of foF2 values for the South African region. This parameter and vertical TEC values derived from the map using the IRI model were used to compute ionospheric slab thickness. Finally climatology of the slab thickness is described by diurnal and seasonal variations.
    Keywords: Fof2, ionospheric slab thickness, IRI, NmF2, South Africa
  • Alireza Habibi, Mohammadreza Gharibreza Pages 71-83
    Iran is well known for having countless historical and instrumental records of tectonic events. Shahriary catchment, as a study area, is part of the Zagros collision seismic province. This research aimed to introduce a new method which is useful in identifying the relative active tectonic events of an area. The research method was designed in order to calculate the relative active tectonic index (IRAT) using geomorphic and seismicity indices. Accordingly, IRAT was determined based on the river length–gradient index (SL), drainage basin asymmetry (AF), transverse topographic symmetry factor (TP), hypsometric integral (HI) and the drainage basin shape index (BS). The obtained results showed that areas with relatively high, moderate and low tectonic activities comprised 71%, 19% and 10% of the study area, respectively. In addition, the calculated mean seismicity in Shahriary was 4.8±0.2 Ms, with an acceleration gravity of 0.3 g (i.e., a high-risk zone). The resultant data confirmed the ability of seismicity indices to estimate IRATs. Therefore, application of the proposed method for assessing the IRAT of an area is confidently recommended in watershed management planning.
    Keywords: geomorphic indices, relative active tectonics, Seismic, Shahriary
  • Zahra Jamali, Asadollah Khoorani Pages 85-94
    The aim of this paper is to project extreme precipitation events in an arid and a semiarid station. In order to project climate change based on general circulation models (GCMs), we have applied LARS-WG[1] downscaling tool. This stochastic weather generator down-scaled the climate of two synoptic stations using HADCM3 model and A2 emission scenario for 2040. We extracted extreme precipitation events, as daily 90th and 10th percentile for rainy days (considered if daily precipitation was greater than 1 mm), for based and projected data. The research outcomes showed an increase both in 90th percentile by 13 mm and in 10th percentile by 0.2 mm in arid station, Bandar Abbas. In the semiarid station, Shahrekord, the 90th percentile precipitation increased by 6.1 mm and the 10th percentile precipitation decreased by 3.4 mm. In total, for both stations, 90th percentile precipitations showed a more stable trend than the 10th percentile.
    1. Long Ashton Research Station-Weather Generator
    Keywords: 10th percentile, 90th percentile, HadCM3, LARS, WG, RMSE