Measuring the relationships between landscape aesthetics suitability and spatial patterns of urbanized lands: an informed modelling framework for developing urban growth scenarios     

Yousef Sakieh  Abdolrassoul Salmanmahiny  Seyed Hamed Mirkarimi  Sepideh Saeidi 《国际地球制图》2017,32(8):853-873

This study develops an informed modelling approach that follows a bottom-up planning strategy to define plausible urban growth scenarios. In this case, landscape aesthetics suitability of the area was first generated using multi-criteria evaluation method. Then, a buffer zone of 1 km was considered to extract the average values of aesthetics suitability scores surrounding urban patches with medium physical size (10–30 hectares). The averaged values were considered as the dependent variable. In the next step, landscape metrics of these urban patches, as explanatory variables, were also computed to measure compositional and configuration-based attributes of urban clusters. Bivariate associations (Pearson correlation analysis) and statistical relationships (linear regression algorithm) between landscape metrics and their associated aesthetics values were measured and modelled. According to the results, both composition and configuration values are significantly correlated to the dependent variable in which configuration-based attributes depicted a stronger explanatory power.  相似文献   

Probabilistic Convective Initiation Nowcasting with Reduced Satellite - NWP Predictors over Iran     

Reza Khandan  Seyed Kazem Alavipanah  Arastoo Pour Biazar  Maryam Gharaylou 《Asia-Pacific Journal of Atmospheric Sciences》2018,54(3):431-443

Geostationary satellites are able to nowcast Convective Initiation (CI) for the next 0–6 h. Compared to using satellite predictors only, the incorporation of satellite and Numerical Weather Prediction (NWP) predictors can provide the possibility to reduce false alarm rates in 0–1:30 Convective Initiation Nowcasting (COIN). However, the correlation among these predictors not only can cause error in COIN, but also increases the runtime. In this study for the first time, all effective predictors in Satellite Convection Analysis and Tracking version 2 (SATCASTv2) and NWP were applied over Iran from 22nd March 2015 to 9th January 2016. In applying SATCASTv2 over Iran, it was necessary to make some modifications to the algorithm, such as removing case specific thresholds of satellite predictors and rearranging COIN predictors. Then, SATCASTv2 was tested and evaluated with both the full and reduced set of predictors. The results suggested that using fixed thresholds for temporal difference predictors could miss COIN in some cases. To investigate the possibility of improving computational efficiency, a dimension reduction was conducted by Factor Analysis (FA) and the number of predictors was reduced from 22 to 11. The NWP-satellite, reduced NWP-satellite, and satellite predictors were used as input in Random Forest (RF), as a parametric machine learning method, for COIN evaluation. The Combination of NWP model and satellite predictors had lower false alarm rates in contrast with satellite predictors. This is in agreement with previous studies. The results from statistical metrics showed that the reduced NWP-satellite predictors had comparable performance to the NWP-satellite predictors over study area, but decreased the run time by almost 50%. The results indicated that Convective Inhibition (CIN) was the most significant predictor when the reduced set of predictors was used.  相似文献   

On the relationship between MODIS Land Surface Temperature and topography in Iran     

Masoud Moradi  Seyed Abolfazl Masoodian 《自然地理学》2018,39(4):354-367

Land Surface Temperature (LST) is considered important in monitoring the energy flux between the land surface and atmosphere. Due to the diversity of topography in Iran and its effect on the climate diversity, we decided to study the effect of topography on the LST variations. To this end, the LST digital data derived from the observations of the MODIS Terra and Aqua were used. The results indicated that, during the daytime, from sea level up to a height of 400 meters, the LST increased, and then the temperature decreased with increasing altitude, and up to a height of 3000 meters, there was a strong correlation between the two. LST lapse rate was more during the daytime compared with that of the night time and it was more during the winter compared with the summer. LST lapse rate showed larger variability in diurnal cycle, but its monthly patterns were similar in different aspects. The aspect had substantial effect on LST inversion elevation. Furthermore, the inverse relationship between LST and slope was strong in slopes up to 20°.  相似文献   

Gorgan Bay:a microcosm for study on macrobenthos species-environment relationships in the southeastern Caspian Sea     

GHASEMI Amir Faraz  TAHERI Mehrsh  FOSHTOMI Maryam Yazdani  NORANIAN Maji  MIRA Seyed Sah  JAM Armin 《海洋学报(英文版)》2016,35(4):82-88

The relationship between spatial patterns of macrobenthos community characteristics and environmental conditions(salinity, temperature, dissolved oxygen, organic matter content, sand, silt and clay) was investigated throughout the Gorgan Bay in June 2010. Principal components analysis(PCA) based on environmental data separated eastern and western stations. The maximum(4500 ind./m²) and minimum(411 ind./m²) densities were observed at Stas 1 and 6, respectively. Polychaeta was the major group and Streblospio gynobranchiata was dominant species in the bay. According to Distance Based Linear Models results, macrofaunal total density was correlated with silt percentage and salinity and these two factors explaining 64% of the variability while macrofaunal community structure just correlated with salinity(22% total variation). In general, western part of the bay showed the highest number of species and biodiversity while, the highest density was found at Sta. 1 and in the middle part of the bay. Furthermore, relationship between diversity indices and macrobenthic species with measured factors is also discussed. Our results confirm the effect of salinity as an important factor on distribution of macrobenthic fauna in south Caspian brackish waters.  相似文献   

Tidal asymmetry in a tidal creek with mixed mainly semidiurnal tide,Bushehr Port,Persian Gulf     

Seyed Taleb Hosseini  Vahid Chegini  Masoud Sadrinasab  Seyed Mostafa Siadatmousavi  Sadegh Yari 《Ocean Science Journal》2016,51(2):195-208

This study investigated the tidal asymmetry imposed by both the interaction of principal tides and the higher harmonics generated by distortions within a tidal creek network with mixed mainly semidiurnal tide in the Bushehr Port, Persian Gulf. Since velocity and water-level imposed by principal triad tides K₁-O₁-M₂ are in quadrature, duration asymmetries during a tidal period in this short, shallow inverse estuary should be manifest as skewed velocities. The principal tides produce periodic asymmetries including a strong ebb-dominance and a weak flood-dominance condition during spring and neap tides respectively. The higher harmonics induced by nonlinearities engender a flood-dominance condition where the convergence effects are higher than frictional effects, and an ebbdominance condition where intertidal storage are extended. Since the triad K₁-O₁-M₂ driven asymmetry is not overcome by higher harmonics close to the mouth, the periodic asymmetry dominates within the creek in which higher harmonics reinforce the weak flood-dominance (strong ebb-dominance) condition in the convergent channel (divergent area). Also, the maximum flood and the maximum ebb from all harmonic constituents occurred close to high water slack time during both spring and neap tides in this short creek. Since occational wetting of intertidal areas happened close to the high water (HW) time during spring tide, the water level flooded slowly close to the HW time of the spring tide.  相似文献   

Effect of dry density,soil texture and time-spatial variable water content on the soil thermal conductivity     

Saeid Nikoosokhan  Hossein Nowamooz  Cyrille Chazallon 《Geomechanics and Geoengineering》2016,11(2):149-158

Study of the heat transfer process in saturated and unsaturated soils requires, basically, a relationship between thermal conductivity and the characteristics of the soil, such as water content, dry density and texture of the soil. This study intends to produce a generic model that can predict soil thermal conductivity with the help of easily measurable parameters. The proposed model is first calibrated using measured thermal conductivities from literature data. In order to validate the proposed model the predicted thermal conductivity of this proposed model as well as existing ones are compared with the measured thermal conductivity in literature for different soils. Validation of the proposed model was also performed on our experimental results obtained for a compacted Misillac sand and in-situ clay loam soils. The results show an average of 15% improvement in prediction accuracy for the proposed model compared to the existing models, considering all soil textures. Moreover, we perform a model to estimate thermal conductivity over time throughout the profile of soil in the context of seasonal variation of temperature. The proposed model shows an important effect of heterogeneity on the thermal conductivity variations of a double layered soil.  相似文献   

Impact of water source dynamics on dissolved reactive phosphorus loadings in heterogenous karst agroecosystems with phosphatic limestones     

Cory Radcliff  William I. Ford  Saeid Nazari  Christopher Shepard 《水文研究》2021,35(11):e14422

Karst landscapes underlain with phosphatic limestones are now recognized to be an important contributor of fluvial phosphorus (P) to coastal waters. Specifically, karst agroecosystems may be a hotspot for dissolved reactive P (DRP) due to chronic over-application of organic and inorganic fertilizers that create legacy P accumulation in surface soils. Nevertheless, few studies have assessed the hydrologic controls on DRP transport in these systems at the watershed scale, which is the focus of this study. We analysed soil moisture, soil water extractable P, and storm event hydrologic and water quality data from a small heterogenous karst watershed (10.7 km²) in the Inner-Bluegrass Region of Central Kentucky, USA. Four storm events were sampled in winter, 2020 and were analysed for flow pathways using hydrograph recession analysis and water source connectivity using a tracer-based unmixing model. Based on hydrograph separation results, multiple linear regression analysis was performed to assess drivers of DRP concentrations and loadings. Soil water extractable P results showed stark vertical gradients with greater concentrations at both the surface and deeper soil zones, and minimum concentrations in the root zone. Results for the storm event analysis showed that water source connectivity provided superior prediction of DRP concentrations over the flow pathway analysis, which reflected the heterogeneity of karst maturity masking intermediate flow pathways. Findings from the MLR and loading analysis suggest waters sourced from the soil/epikarst produced significantly higher loadings compared with phreatic and precipitation water source in the three largest events, although concentrations fell between the phreatic (low) and precipitation (high) sources. Findings highlight variable activation of matrix-macropore exchange at different depths throughout the event. Collectively these results suggest existing models and approaches to assess karst hydrology need revision to improve management strategies in this critical landscape.  相似文献   

A modi?ed failure criterion for transversely isotropic rocks     

Omid Saeidi  Vamegh Rasouli  Rashid Geranmayeh Vaneghi  Raoof Gholami  Seyed Rahman Torabi 《地学前缘(英文版)》2014,5(2):215-225

A modified failure criterion is proposed to determine the strength of transversely isotropic rocks. Me-chanical properties of some metamorphic and sedimentary rocks including gneiss, slate, marble, schist, shale, sandstone and limestone, which show transversely isotropic behavior, were taken into consider-ation. Afterward, introduced triaxial rock strength criterion was modified for transversely isotropic rocks. Through modification process an index was obtained that can be considered as a strength reduction parameter due to rock strength anisotropy. Comparison of the parameter with previous anisotropy in-dexes in literature showed reasonable results for the studied rock samples. The modified criterion was compared to modified Hoek-Brown and Ramamurthy criteria for different transversely isotropic rocks. It can be concluded that the modified failure criterion proposed in this study can be used for predicting the strength of transversely isotropic rocks.  相似文献   

The effects of hydrometer reading times on the spatial variability of soil textures in southeast Iran     

Alireza Owji  Isa Esfandiarpour Boroujeni  Ardavan Kamali  Seyed Javad Hosseinifard  Mohsen Bagheri Bodaghabadi 《Arabian Journal of Geosciences》2014,7(4):1491-1499

Soil texture is an important physical soil property that may contribute to variations in many soil functions as well as nutrient storage and availability, water retention, and soil erosion. Although several methods for determining the texture classes of soil particles have been proposed, differences among hydrometer reading times have presented challenges in determining the precise soil texture classes. Therefore, this study was conducted to evaluate the effects of hydrometer reading time on the spatial variability of soil textures in the Rafsanjan area, southeast Iran. To accomplish this, 77 soil samples were collected on a 500-m square sampling grid from depths of 0–40, 40–80, and 80–120 cm, and their particle sizes were determined through analysis for 40 s, 2 h, 6.5 h, and 8 h using the Bouyoucos hydrometer method. The results showed a strong spatial correlation in the soil particles among sampling soil layers and across the study area. Moreover, the differences among hydrometer reading times did not have a significant impact on determination of coarse soil texture classes, although they did influence determination of the finer classes. Although the 8 h reading time provided the most accurate response with respect to mechanical analysis of a soil, after 6.5 h the hydrometer could also largely (more than 80.0 %, on average) achieve this goal. Additionally, the 2 h hydrometer reading time could also be useful for the initial assessment or general overview of the soil texture in a certain region; however, it is not recommended for precision agriculture or site-specific management.  相似文献   

Seismic piezocone interpretation for shear wave velocity (<Emphasis Type="Italic">V</Emphasis><Subscript>S</Subscript>) determination in the Persian Gulf     

Aliakbar Hajimohammadi  Seyed Majdeddin Mir Mohammad Hosseini  Akbar Cheshomi 《Environmental Earth Sciences》2010,61(4):813-820

Shear wave velocity is one of the important factors representing the dynamic characteristics of soil layers. Hence, many researchers have focused their studies on determining shear wave velocity by direct field measurements or expressions developed by other soil parameters. The shear module and damping ratio of the soil layers also play a similar role in the majority of dynamic soil response analyses. Nevertheless, since they have to be measured in the laboratory by resonant column or cyclic triaxial tests on undisturbed samples, the possibility of preparing such samples and the reliability of the obtained results are of great concerns. In the present study, great effort has been made to determine the above dynamic factors by means of field data obtained from a versatile instrument, namely the seismic piezocone (SPCT_U), and to derive expressions correlating them with some parameters obtainable by much simpler instruments. The reliability of laboratory measurements on undisturbed samples is also evaluated. The seismic piezocone test apparatus has been employed to evaluate the soil properties at 1-m depth intervals by means of measuring tip resistance, sleeve resistance, pore pressure and shear wave velocity. The shear module and the damping ratio are calculated using field data. Meanwhile, in order to assess the laboratory measurements of these parameters, some resonant column tests and cyclic triaxial tests on undisturbed samples of the same soil layers have been carried out. In order to compare the field results of shear modulus and damping ratios with those obtained from laboratory tests, the influences of the soil nature and sample disturbance on the conventional laboratory methods are evaluated and discussed. The shear wave velocity is correlated to overburden pressure and the corrected tip resistance for two groups of fine soils, namely silty clays and carbonate clayey silts, which mainly cover the areas under study in this project, are located in southern parts of Iran near the Persian Gulf. According to the results of the present study, there are narrow limits of shear modulus regarding soils for which the laboratory tests and the field measurements yield approximately the same shear modulus. This limit of shear modulus is about 30–50(MPa) for clay deposits and 70–100 (MPa) for sandy deposits. Also the shear wave velocity can be calculated by a simple expression from total overburden pressure and the tip resistance of simple cone penetration test results conventionally available in many soil explorations prior to engineering practices. However, if the pore pressure inside the saturated soil deposits can be measured by a piezocone apparatus, the shear wave velocity may be calculated using another suggested equation in terms of effective overburden pressure in the present study. Regarding the shear module and the damping ratio, due to the disturbances of the stiff deposits in the sampling process and great deviations of laboratory results from field results, the laboratory measurements of these parameters out of the above limits are not recommended.  相似文献