filter by:
Articles
Journal of the Indian Society of Remote Sensing (09743006)51(6)pp. 1297-1307
Environmental changes such as ablation of ice and snow, drying of lakes, deforestation, desertification and urbanization may affect the thermal properties of the land surface, and hence, it affects the land surface temperature (LST). MODIS LST data, make it possible to investigate the variations in the frequency distribution of LST. In this research, 16 years of MODIS\Aqua LST data (2002–2022) have been analyzed using principal component analysis. This study shows that the frequency distribution of LST in Iran depends to a great extent on altitude and then depends on the terrain surface features. Lakes, river systems, sand dunes, deserts, woodlands, forests and metropolitan areas are among the terrain surface features that affect the frequency distribution of LST. Hence, analysis of the frequency distribution of LST may be considered as a tool for identifying the geographical boundaries of these terrain features. Additionally, it could be a robust tool for tracking the changes in the boundaries of such geographical phenomena over time. Frequency analysis of LST in Iran reveals many natural and anthropogenic environmental changes. For example, the analysis shows that the drying out of Zayanderud downstream and Urmia Lake is related to man-made changes in the upstream. The comparison of the interdecadal of LST shows that the frequency of LST has increased in some temperature categories and decreased in some other temperature categories. In general, the frequency shift of LST both during the day and at night has been toward higher temperatures. © 2023, Indian Society of Remote Sensing.
Landscape and Ecological Engineering (18601871)17(2)pp. 147-156
The cities that are built on the arid biomes with the hot and dry climates can adjust the temperature (oasis effect) and create the urban cool island (UCI) during the day. As the background climate of the Isfahan metropolis is warm and dry, we can expect an UCI during the day. The MODIS land cover product data were used to distinguish between the urban and nonurban areas. The MODIS/Terra/LST data from 2000 to 2016 were then used for day-time view to examine the UCI. In the next step, the UCI intensity index was calculated by the spatial correlation representative pixel method for the city and the background. This study showed that due to the passage of the Zayandehrood river from the middle of the city and the expansion of vegetation in the urban environment, the metropolitan area of Isfahan is 3.5° cooler than the suburban barren lands during the day. The UCI intensity index has been intensified over the last few years and has fallen below − 4.5°. The studies have shown that the UCI intensity index is weakened during the cold months and intensified in the warm months of the year. The seasonal changes in UCI intensity in the metropolitan area of Isfahan can be related to the high variability of vegetation throughout the year. © 2021, International Consortium of Landscape and Ecological Engineering.
Physical Geography (02723646)42(3)pp. 283-295
Despite its adjacency to seas in the north and the south, Iran suffers from relatively low humidity. Spatial distribution of the atmospheric humidity across Iran is a function of altitude, distance to water bodies, and moisture advection. The analysis of the daily data on precipitable water from the MODIS Aqua sensor for a period of 15 years shows that average precipitable water across Iran is 12 mm. This quantity is maximal near the coasts, with the coasts of the Oman Sea exhibiting the highest values of precipitable water. In the vicinity of the Caspian Sea, the maximum precipitable water is observed at about 4 km to the shoreline, while it is 11 km away from the shoreline when it comes to southern coasts of Iran. In the areas far from the sea where the altitude exceeds 366 m, the precipitable water is mainly affected by the altitude and decreases logarithmically with the altitude. © 2020 Informa UK Limited, trading as Taylor & Francis Group.
Advances in Space Research (02731177)66(9)pp. 2094-2112
The goal of this study is to examine the capability of the TRMM 3B42 product to detect spatial and temporal patterns in extreme precipitation events over southwestern Iran during the period of 1998–2016. A ground-based gridded precipitation dataset was created using a dense network of surface observations for the evaluation process. Various extreme precipitation indices in the three categories of fixed threshold indices, grid-related threshold indices, and non-threshold indices were examined and compared with the ground-based gridded precipitation dataset. The findings suggest that the TRMM 3B42 product is able to capture the spatial and temporal behavior of many extreme indices especially for fixed and non-threshold indices. In terms of the spatial error metrics, the satellite product has better performance over mid-elevated areas in the south and southeastern parts of the study region. © 2020 COSPAR
Climate Research (16161572)82pp. 55-73
Characterizing the errors in satellite-based precipitation estimations for drought monitoring is of great importance, as these estimations provide both spatially and temporally complete records. The aim of this study was to evaluate satellite-based quantitative precipitation estimates to monitor meteorological drought in southwestern Iran. The reliability of the Tropical Rainfall Measuring Mission Version 7 products (3B42 and 3B43) in estimating the standardized precipitation index (SPI) was evaluated against a ground-based gridded precipitation dataset at 0.25° spatial resolution for 1998−2016. The analysis conducted for the SPI at various time scales revealed that both products (3B42 and 3B43) are capable of capturing the spatial and temporal behavior of drought events over the study region, with the best performance at SPI6. 3B43 is also more efficient in the identification of shorter severe drought events compared to 3B42. The findings suggest that both satellite products, particularly 3B43, are suitable to be used directly for SPI computation in the region for drought monitoring and early warning in terms of the accuracy and the spatial and temporal resolutions they provide. © Inter-Research 2020 · www.int-res.com
Journal of the Indian Society of Remote Sensing (09743006)48(2)pp. 263-270
The population of Isfahan City has been increased by ten times during the last six decades. This increase has had extensive environmental consequences. In this period, drying up of Zayandehrood River, increase in temperature and variability of precipitation has exacerbated the environmental conditions. Formation of the heat island is only one of the consequences of environmental changes in the last decades. The heat island also has many consequences in terms of health and water and energy consumptions. In this research, the land surface temperature (LST) data corresponding to daytime and nighttime using MODIS Aqua/LST from 2000 to 2016 are utilized. Using these data, the background climate of Isfahan metropolis was detected by the distance–azimuth diagram method. Then, the representative pixel within the city and the representative pixel of the background climate were identified. Based on time series of LST over these two pixels, SUHI index of Isfahan metropolis was calculated. Investigations showed that Isfahan metropolis area is colder than suburbs during the day but at night is about 2 K warmer than its surroundings. The intensity of the SUHI is maximal in January and turns weaker in summer. Regarding the temporal and spatial behavior of Isfahan metropolis SUHI, it seems that changes created by the urban concerning the moisture, albedo and composition of the atmosphere have a great role in the formation of the SUHI. Zayandehrood River has a major role in mitigation of temperature at the land surface, and its drying up has environmental consequences. © 2019, Indian Society of Remote Sensing.
Modern Applied Science (discontinued) (19131852)9(1)pp. 68-82
Today, uncontrolled exploitation of ground water has doubled water scarcity problem, while proper control and management of these resources can solve water shortage problem to some extent. One of the approaches for managing groundwater resources is artificial recharging of groundwater and determining the best location for this. This study aimed at ranking Shahroud-Bastam watershed using ELECTRE and linear assignment methods and the results of these two methods are compared. These two models are of multiple-criteria decision making compensation and coordinated subgroup models. The findings indicate that among the seven zones in ELECTRE method mentioned above, zones (3, 4,5) with four dominations and 2 defeats and 2 points are in the first ranking and are the most suitable zones for artificial recharge. Zone (1) with six defeats and no dominations and (-6) points is in the last ranking and is not suitable for artificial recharge of ground water. Zones (2, 6, 7) respectively with (2, 2, 1) dominations and (4, 4, 5) defeats and with (-2, -2, -4) points are in the next rankings respectively. Zones (1, 2, 6, 7) must be removed because the number of their defeats is more than the number of their dominations and have negative points. In linear assignment method, among 7 zones, zone 3 has the first rank and is the best zone for artificial recharge and zone 7 is in the last ranking and is not suitable for artificial recharge. Zones (4, 2, 5, 6, 1) are in the next rankings respectively. Between these two methods, the results of linear assignment method are more consistent with reality and are more accurate. © 2014, by the author(s).
Asian Social Science (discontinued) (19112025)11(1)pp. 130-141
Regional planning results from spatial development and economic planning in order to construct a co-ordinate and balanced construction in the regions and districts and to reduce regional imbalances by three elements of space, activity and human. Hence, it is crucial to realize the regional discrepancies and to understand their potential and weaknesses and to distinguish regional imbalances to establish a comprehensive socio-economic plan in the region. By employing quantitative methods and criteria for classification, the researcher intends to recognize, decrease and eliminate the existing inequalities .The current paper is going to specify the development degree of the counties of Qazvin province using the descriptive analysis approach. The researcher has used 48 development indices in population, infrastructure, economic-social, cultural and hygienic fields which have been extracted from statistical annals of 2011. The researcher has applied the main elements on the correlative coefficient of the data, and then employed SPSS to analyze these indices and classified them into four meaningful and significant categories which contain 100% data processing. The results show that Qazvin is the most developed county and Takestan, Bouein Zahra, Abyek and Alborz have respectively been ranked from second to fifth counties which are benefited from development factors. Then, regarding the development level, the researcher has used cluster analysis approach and classified the above mentioned counties in three equal groups. Qazvin has been the most developed and is placed in the first group, and then Takestan and Bouein Zahra have been classified in the second group (nearly developed) after that Abyek and Alborz are the least developed and have been placed in the third group for which cluster dendogram has been drawn. © 2015, Canadian Center of Science and Education.
Asian Social Science (discontinued) (19112025)11(1)pp. 119-129
In this study, it is attempted to rank plant species in order to stabilize sand by the application of ELECTRE, and Liner assignment methods in Rig, Sirjan, Iran. The results suggest that in linear assignment method among 7 plant species, milk vetch species is in the first ranking with one score, and is the best species to stabilize sand in the studied area and the Camel's thorn species lies at the bottom of the ranking chart and can't be suitable for sand stabilization. Artichoke, Espand, Glasswort, Sagebrush and Charkha lie in the next rankings respectively by their importance. In ELECTRE method, among 7 plant species studied in this research, the milk vetch species with four dominances and one defeat with 3 scores is in the first ranking and the Camel's thorn and Artichoke species with five defeats and no dominance with (-5) score lie at the bottom of the ranking. Glasswort, Charkha, Espand and Sagebrush with (1,1,1,3) dominances and (4,4,4,2) defeats with (-3,-3,-3,1) scores respectively lie in the next ranks. It should be noticed that Artichoke, Camel's thorn, Glasswort, Charkha and Espand species must be omitted because the number of their dominances were less than the number of their defeats. The results of the linear method were more compatible with reality and were more accurate and precise. © 2015, Canadian Center of Science and Education.
