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In the last decades, the frequency of dust storms has increasingly emerged in the central regions of Iran. This study investigated the SDS sources in the Salt Lake basin of Qom using daily visibility, wind speed, dust weather codes and NCEP/NCAR data, and MODIS and Sentinel-1 sensor datasets. Sample SDS days were selected by daily visibility and dust weather codes with 3-h interval ranging from 2000 to 2017. These sample SDS days were related to the 19 synoptic stations of the Salt Lake basin. Dust entry trajectories were determined through the HYSPLIT model and evaluated with the MODIS Deep Blue aerosol optical depth and atmospheric patterns. SDS sources were identified using Sentinel-1 radar images of IW mode and SLC type through radar i
Introduction: Earth subsidence is one of the natural hazards under several conditions, including over-exploitation of groundwater, large dams, mining, extraction of fluids from the earth, tectonic and so on. The subsidence causes changes in the geomorphic phenomena of arid and semi-arid regions, which are important due to the occurrence of human complications on different forms, the study of changes due to subsidence in these phenomena is important. Due to the fact that the rate of change in land subsidence as well as the speed of the geomorphological phenomenon is very slow and slow, measuring instruments are of great importance. In this case, static technique is not suitable for monitoring, and dynamic techniques should be used. One techn
Extended Abstract Introduction Coastal management needs to be organized at scales which are fully representative of the dynamics of the coastal system. A littoral cell is a coastal compartment that contains a complete cycle of sedimentation including sources, transport paths, and sinks. The cell boundaries delineate the geographical area within which the budget of sediment is balanced, providing the framework for the quantitative analysis of coastal erosion and accretion. The sediment sources are commonly streams, sea cliff erosion, onshore migration of sandbanks, and material of biological origins such as shells, coral fragments, and skeletons of small marine organisms. The coast of the Hormozgan province is marginal sea type and geomorpho
Today, a wide range of spatial analysis models are used in environmental risk zoning. Some models, such as hierarchical and fuzzy analyzes, despite the inclusion of uncertainty in the input variables, are unable to explain quantitatively the output uncertainty. In this study, the aim of evaluating the capabilities of the Dempster-Schaeffer algorithm is to explain the uncertainty in the outcomes for landslide hazard zonation in the south of Chalus. Therefore, after field studies and review of similar studies, a map of 10 factors was provided in the GIS environment and was introduced as input data along with a map of the distribution of landslides to the model. Landslide hazard zonation was performed by integrating different weights in the De
The aim of this research is watershed prioritization using morphometric parameters and Multiple Criteria-Decision-Making (MCDM) by Geographic Information System (GIS) and Remote Sensing (RS) techniques. For this purpose, First digital elevation model (DEM) was developed of study area using low frequency radar data, then, 17 watershed extraction for prioritization in ArcGIS10. 2. After preprocessing and preparation of digital elevation model 14 morphometric parameters extracted including 5 Shape morphometric Parameters (Form factor, Elongation Ratio, Circularity Ratio, Compression ratio), 2 linear parameters (bifurcation ratio, Stream length), 5 areal parameters (Drainage Density, Drainage texture rate, Constant of channel maintenance, Strea
This research has been tried to evaluate the spatial and temporal variability of surface soil moisture (SM) in a semi-arid and cold region of Ardabil Province in Iran with an area of about 10,000?km2. The used SM data is the SMAP Enhanced L2 Radiometer Half-Orbit 9?km Soil Moisture, provided by NASA. The study area was subdivided into 120 locations consisting 10 ? 12 grids, matching with the pixels of the SMAP images. In order to evaluate the spatial variations of SM, the relation of mean SM with coefficient of variation and standard deviation has been evaluated and, then, the representative location for mean SM of the area has been identified using the index of temporal stability. Moreover, the effect of topographic fact
Since the population increasing and the development of agricultural activities in the south-western plain of Tehran have led to increasing underground water drainage, the assessment of the vulnerability of the areas exposing to subsidence has become more important. In this research, the vulnerability of the south-western plain of Tehran to subsidence has been investigated using ALPRIFT method in ArcGIS and optimization of the ALPRIFT method has been performed using SVM. In order to implement the ALPRIFT method, effective parameters including aquifer media, land use, groundwater pumping, recharge, aquifer thickness, faults distance and groundwater decline were used to assess the subsidence susceptibility. These are ranked in seven separate l
Introduction Synthetic aperture radar (SAR) systems have been widely used in the past two decades to produce high-resolution mapping and other remote sensing applications (Calabro et al. 2010; Sun et al. 2011). The ability of penetrating to the cloud , snow dry soil as well as day and-night operation made the SAR systems with more capability compared to optical imagery (after Karjalainen et al. 2012). SAR data are widely applied for several studies geophysical and geographical approach forestry and vegetation, biomass measurements, soil moisture, natural hazards and etc. ?(Lardeux et al. 2011,Herrera et al. 2013). The present study deal with morphological landform Identification over the area covered with dense forest. ?Where is the landfor
The instability and mobility of sand dunes is a major concern for those involved in the planning processes and management of arid coastal plains. Dune systems are created due to several factors and elements. Regarding environmental planning and the management of coastal zones, the study of their formation and development processes is of great importance. The present study aims at identifying the most influential factors in the dispersion of sand masses in the western region of the Makran Plain. The data for this study consisted of spatial maps of landform distributions, wind velocities and directions, fetch lengths as well as dynamic waves. Thematic topographical and geological maps, satellite images, GPS, and software such as WRPLOT View,
Resilience are concepts that are finding increasing currency in several fields of research as well as in various policy and practitioner communities engaged in global environmental change science, climate change, sustainability science, disaster risk-reduction and famine interventions (Vogel, et. al, 2007)……
Mangrove wetlands exist in the transition zone between terrestrial and marine environments and have remarkable ecological and socio-economic value. This study uses climate change downscaling to address the question of non-stationarity influences on mangrove variations (expansion and contraction) within an arid coastal region. Our two-step approach includes downscaling models and uncertainty assessment, followed by a non-stationary and trend procedure using the Extreme Value Analysis (extRemes code). The Long Ashton Research Station Weather Generator (LARS-WG) model along with two different general circulation model (GCMs) (MIRH and HadCM3) were used to downscale climatic variables during current (1968–2011) and future (2011
Airborne particulate matter with a diameter of 2.5 microns or less (PM 2.5), as well as slightly bigger particles (PM 10), arrive from the westerly direction and collect in the city centre of Tehran, the capital of Iran. The statistical characteristics and daily trend of the air quality index (AQI) in Theran were studied over an 11-year period (2002-2012). Various statistical analyses were applied including descriptive statistics, correlation analysis, trend analysis and the sequential nonparametric Mann-Kendall test. The significance of the series was investigated by regression analysis and Kriging interpolation. It was found that Tehran’s daily AQI increased by 11.8% over the study period, with the frequency distribution of days with go
denderogeomorphology is using trees as natural archives or" silent witnesses". denderogeomorphology refers to dating of tree rings science that studying the annual growth rings of trees by measuring the number and change in thickness of the ring that create. But'dendrogeomorphology'is one of the subfields of dendroecology and has been widely used to study and date past geomorphic processes. dendrogeomorphology review the spatial and temporal aspects of the surface processes by analysis the annual growth rings and growth form of trees. Also enables the reconstruction of events with annual and sometimes even seasonal precision. In this paper, we attempt to study and analysis the erosion and deposition processes on the Neka river channel by us
1. Introduction Wood is the long-term memory of the history of a tree which is records the environmental changes by anatomic and formic changes. denderocronology uses the trees as natural evidences or "silent witnesses" to reconstructing the past environmental characteristics. ‘dendrogeomorphology’ is one of the subfields of dendroecology which has been widely used for study of past geomorphic processes. dendrogeomorphology is detected of spatial and temporal aspects of the surface processes by analyzing of annual growth tree rings and disturbances in tree forms. Also dendrogeomorphology enables to precise the event occurrences in annual and even seasonal time scales. Based on the principle of dendrogeomorphology affected trees by geo
This study was conducted to apply the enhanced differential interferometric process to interferometric data obtained from C-band Advanced Synthetic Aperture Radar (ASAR) and Phased Array type L-Band Synthetic Aperture Radar (PALSAR) systems, in the Marand plain, Iran. In advance, the capability of each sensor was examined with regard to the signal coherency for sensor–target interactions, which emphasized on the terrific excellency of PALSAR (L-band) to ASAR (C-band) measurements in study area. In the interferometric process, in addition to resolving the topography and baseline related errors (which is conventional in the standard D-InSAR process), subtle quantitative methods were outlined to minimize the secondary, but momentous errors (
Mangrove tide etangs which are placed at border line between the? arid and sea-land, have a considerable ecological? and social–economical value. This study uses (LARS-WG) along with two GCM models (MIRH and HadCM3) and the A1B scenarios to simulate? climatic variables of minimum and maximum temperature and rainfall in the past and future periods. In reviewing the uncertainties, the? results indicate? the high capability of? LARS-WG model in simulation of? climatic variables simulation specially in arid ecosystems. Based on MIHR downscaling results, minimum and maximum temperatures will increase in cold season from November to March up to ~+4.21?C and +4.7?C respectively. While increasing up to ~+3.62?C and +3.55?C in the warm season from