Assessing climate change impacts on California hydropower generation and ancillary services provision     

Kate Forrest  Brian Tarroja  Felicia Chiang  Amir AghaKouchak  Scott Samuelsen 《Climatic change》2018,147(3-4):395-409

Climate change is already affecting species and their distributions. Distributional range changes have occurred and are projected to intensify for many widespread plants and animals, creating associated risks to many ecosystems. Here, we estimate the climate change-related risks to the species in globally significant biodiversity conservation areas over a range of climate scenarios, assessing their value as climate refugia. In particular, we quantify the aggregated benefit of countries’ emission reduction pledges (Intended Nationally Determined Contributions and Nationally Determined Contributions under the Paris Agreement), and also of further constraining global warming to 2 °C above pre-industrial levels, against an unmitigated scenario of 4.5 °C warming. We also quantify the contribution that can be made by using smart spatial conservation planning to facilitate some levels of autonomous (i.e. natural) adaptation to climate change by dispersal. We find that without mitigation, on average 33% of each conservation area can act as climate refugium (or 18% if species are unable to disperse), whereas if warming is constrained to 2 °C, the average area of climate refuges doubles to 67% of each conservation area (or, without dispersal, more than doubles to 56% of each area). If the country pledges are fulfilled, an intermediate estimate of 47–52% (or 31–38%, without dispersal) is obtained. We conclude that the Nationally Determined Contributions alone have important but limited benefits for biodiversity conservation, with larger benefits accruing if warming is constrained to 2 °C. Greater benefits would result if warming was constrained to well below 2 °C as set out in the Paris Agreement.  相似文献   

High-resolution spatiotemporal distribution of precipitation in Iran: a comparative study with three global-precipitation datasets     

Ali Khalili  Jaber Rahimi 《Theoretical and Applied Climatology》2014,118(1-2):211-221

High-resolution precipitation datasets are used for numerous applications. However, depending on the procedures for obtaining these products, such as number of observations, quality checking, error-correction procedures, and interpolation techniques, they include many uncertainties. Therefore, the accuracy of these products needs to be evaluated over different regions. In this study, the Iranian National Dataset (INDS), a new 1?×?1 km precipitation dataset based on precipitation data of 1,441 quality-controlled stations for the climatic period from 1961 to 2005, was constructed using the digital elevation model, correlation method, and Kriging interpolation procedure. Iran's annual precipitation values at grids and stations were extracted from Climatic Research Unit (CRU) CL 2.0, CRU TS 3.10.01, and WorldClim datasets, and differences between corresponding values in each of the three datasets and INDS were calculated and analyzed. The coefficient of determination (R ²) between the national network stations' data and the CRU CL 2.0, CRU TS 3.10.01, and WorldClim datasets were 0.50, 0.13, and 0.62, respectively. Moreover, R ² values between the grids of each dataset and INDS were 0.51, 0.40, and 0.60, respectively. To determine the global datasets' efficiency for displaying temporal patterns of precipitation, the monthly values gathered from them at 11 stations (as representative of Iran's various precipitation regimes) were compared with the real values at these stations. The results showed that in term of temporal patterns, the concurrences among the three global datasets and the INDS was more acceptable, especially in the case of CRU CL 2.0. In general, it is concluded that the global datasets could be deployed for the primary assessment of the annual precipitation distribution; however, for more precise studies, use of local data is highly recommended.  相似文献   

Predicting the expansion of an urban boundary using spatial logistic regression and hybrid raster–vector routines with remote sensing and GIS     

Amin Tayyebi  Phillips Christian Perry  Amir Hossein Tayyebi 《International journal of geographical information science》2014,28(4):639-659

This paper presents an urban growth boundary model (UGBM) which utilizes spatial logistic regression (SLR), remote sensing, and GIS to simulate the differentially expanding geometry of a dynamic urban boundary over decadal time periods. SLR is used as the core algorithm in a UGBM quantifying how biophysical factors influence the rate at which all edges of an urban boundary expand over time. Spatial drivers selected from a raster-based environment are used as input predictor variables to the SLR UGBM, the output response variable being the distance between time-separated urban boundary intersections along arcs extending radially from a point centered at the urban core relative to the maximum distance. Percent area match (PAM) quantity and location goodness-of-fit metrics, fit of the predicted distance versus observed distance, and the sensitivity of the SLR UGBM to the contribution of each predictor variable are used to assess the agreement between predicted and observed urban boundaries. The model is built, tested, and validated using satellite images of the city of Las Vegas, United States of America, collected in 1990, 2000, and 2010. We compare urban boundary simulation of full and reduced SLR UGBMs to a null UGBM lacking in specificity of predictor variables. Results indicate that the SLR UGBM has a better goodness of fit compared to a null UGBM using PAM quantity and location goodness-of-fit metrics. Then, we use the SLR UGBM to predict urban boundary expansion between the years 2000 and 2010 and describe how this model can be used to plan ahead for future boundary expansions given what is known about current edge conditions.  相似文献   

The permeability of fault zones: a case study of the Dead Sea rift (Middle East)     

Gabay Ran  Shalev Eyal  Yechieli Yoseph  Sagy Amir  Weisbrod Noam 《Hydrogeology Journal》2014,22(2):425-440

Fault zone architecture plays an important role in flow regimes of hydrological systems. Fault zones can act as conduits, barriers, or conduits/barrier systems depending on their spatial architecture. The goal of this study is to determine the fault-zone permeability structure and its effect on the local hydrogeological system in the Dead Sea fault system. Permeability was measured on small-scale outcrop plug samples at four faults along the Dead Sea fault system, and large-scale slug tests in four boreholes, in different parts of the fault, at Yair fault in Israel. The research results show that values in the damage zone are two to five orders of magnitude higher than those of the fault core (~3.5?×?10^?10, 1?×?10^?15 m² respectively), resulting in an anisotropic permeability structure for the overall fault zone and preferable flow parallel to the fault. A set of injection tests in the Yair fault damage zone revealed a water-pressure-dependent behavior. The permeability of this zone increases when employing a higher water pressure in the fault fracture-dominated damage zone, due to the reopening of fractures.  相似文献   

Assessing the impacts of climate and land use change on streamflow,water quality and suspended sediment in the Kor River Basin,Southwest of Iran     

Amir Asadi Vaighan  Nasser Talebbeydokhti  Alireza Massah Bavani 《Environmental Earth Sciences》2017,76(15):543

This research addressed the separate and combined impacts of climate and land use change on streamflow, suspended sediment and water quality in the Kor River Basin, Southwest of Iran, using (BASINS–WinHSPF) model. The model was calibrated and validated for hydrology, sediment and water quality for the period 2003–2012. The model was run under two climate changes, two land use changes and four combined change scenarios for near-future period (2020–2049). The results revealed that projected climate change impacts include an increase in streamflow (maximum increases of 52% under RCP 2.6 in December and 170% under RCP 8.5). Projected sediment concentrations under climate change scenarios showed a monthly average decrease of 10%. For land use change scenarios, agricultural development scenario indicated an opposite direction of changes in orthophosphate (increases in all months with an average increase of 6% under agricultural development scenario), leading to the conclusion that land use change is the dominant factor in nutrient concentration changes. Combined impacts results indicated that streamflows in late fall and winter months increased while in summer and early fall decreased. Suspended sediment and orthophosphate concentrations were decreased in all months except for increases in suspended sediment concentrations in September and October and orthophosphate concentrations in late winter and early spring due to the impact of land use change scenarios.  相似文献   

Effect of $$\hbox {CO}_2$$ solubility on dissolution rate of calcite in saline aquifers for temperature range of 50–100 $$^{\circ } \hbox {C}$$∘C and pressures up to 600 bar: alterations of fractures geometry in carbonate rocks by $$\hbox {CO}_2$$-acidified brines     

Mohammad A. Nomeli  Amir Riaz 《Environmental Earth Sciences》2017,76(9):352

An empirical model is developed to predict the dissolution rate of calcite in saline solutions that are saturated with respect to dissolved \(\hbox {CO}_2\) over a broad range of both subcritical and supercritical conditions. The focus is on determining the rate of calcite dissolution within a temperature range of 50–100 \(^\circ \hbox {C}\) and pressures up to 600 bar, relevant for \(\hbox {CO}_2\) sequestration in saline aquifers. A general reaction kinetic model is used that is based on the extension of the standard Arrhenius equation with an added, solubility-dependent, pH term to account for the saturated concentration of dissolved \(\hbox {CO}_2\). On the basis of this kinetic model, a new rate equation is obtained using multi-parameter, nonlinear regression of experimental data to determine the dissolution of calcite as a function of temperature, pressure and salinity. Different models for the activity coefficient of \(\hbox {CO}_2\) dissolved in saline solutions are accounted for. The new rate equation helps us obtain good agreement with experimental data, and it is applied to study the geochemically induced alterations of fracture geometry due to calcite dissolution.  相似文献   

Impact of tailings dam failure on spatial features of copper contamination (Mazraeh mine area,Iran)     

Amir Khamseh  Farzin Shahbazi  Shahin Oustan  Nosrattollah Najafi  Nasser Davatgar 《Arabian Journal of Geosciences》2017,10(11):244

Mining activities pose a potential risk of metal contamination around mining sites. On May 6, 2010, a tailings dam failure of the Mazraeh copper mine near Ahar in East Azerbaijan province, Iran, released vast amounts of mine wastes. To better understand the magnitude of copper contamination in the waste-affected soils, it is important to assess the spatial distribution of soil copper content at unsampled points. A total of 30 soil samples and their surficial sediments together with the 6 uncontaminated control samples (0–10 and 10–30 cm) were collected along the stream flow that joined Ahar-Chai River. Some of soil properties as well as total copper concentration were determined in all samples. The mean value of the latter in the surface contaminated soils was found to be approximately two times more than controls. Furthermore, the mean concentration of copper in the surface loaded material was 10 times more than the soils. High copper concentrations were observed in surficial sediments of the soils near the broken tailings dam. The Inverse Distance Weighting (IDW) method was employed in data analysis. The spherical and Gaussian semivariogram models were properly fitted to the data of copper contents in soils and surficial sediments.  相似文献   

Study on the improving method for gas production prediction in tight clastic reservoir     

Amir Maher Sayed Lala  Hany Maher Sayed Lala 《Arabian Journal of Geosciences》2017,10(3):70

Relative permeability and resistivity index are important parameters for the exploration and development in a tight sandstone gas field. In the splitting method which uses permeability (K), reservoir thickness (H), and relative permeability (K), briefly referred to as the KHK splitting method, the accuracy of the relative permeability is crucial. According to the relationship between resistivity index and relative permeability of the Mesozoic Lower Safa Formation at Obaiyed Field in the Western Desert of Egypt, we improved the split method and made it more in line with the real situation by adopting Pairoys’ model which is more suitable to our study area. In this paper, we use a radial basis function (RBF) to establish the relationship between logging data and the gas production split point to point in tight sandstone gas reservoirs. To compare with the result by support vector regression (SVR), our method is better as indicated by mean absolute error values. In order to solve the problem that the relative permeability is difficult to obtain in the well logging evaluation, we also provide a convenient method and application example.  相似文献   

Preservation of organic matter in soils of a climo-biosequence in the Main Range of Peninsular Malaysia     

Amir Hossein Jafarzadeh-Haghighi  Jusop Shamshuddin  Jol Hamdan  Norhazlin Zainuddin 《山地科学学报》2017,14(9):1763-1775

Limited information is available about factors of soil organic carbon(SOC) preservation in soils along a climo-biosequence. The objective of this study was to evaluate the role of soil texture and mineralogy on preservation of SOC in the topsoil and subsoil along a climo-biosequence in the Main Range of Peninsular Malaysia. Soil samples from the A and B-horizons of four representative soil profiles were subjected to particle-size fractionation and mineralogical analyses including X-ray diffraction and selective dissolution. The proportion of SOC in the 250-2000 μm fraction(SOC associated with coarse sand) decreased while the proportion of SOC in the 53 μm fraction(SOC associated with clay and silt)increased with depth. This reflected the importance of the fine mineral fractions of the soil matrix for SOC storage in the subsoil. Close relationships between the content of SOC in the 53 μm fraction and the content of poorly crystalline Fe oxides [oxalate-extractable Fe(Fe_o) – pyrophosphate-extractable Fe(Fe_p)] and poorly crystalline inorganic forms of Al [oxalateextractable Al(Al_o) – pyrophosphate-extractable Al(Al_p)] in the B-horizon indicated the importance of poorly crystalline Fe oxides and poorly crystalline aluminosilicates for the preservation of SOC in the Bhorizon. The increasing trend of Fe_o-Fe_p and Al_o-Al_p over elevation suggest that the importance of poorly crystalline Fe oxides and poorly crystalline aluminosilicates for the preservation of SOC in the Bhorizon increased with increasing elevation. This study demonstrates that regardless of differences in climate and vegetation along the studied climobiosequence, preservation of SOC in the subsoil depends on clay mineralogy.  相似文献