排序方式： 共有18条查询结果，搜索用时 187 毫秒
1.
A process‐based, spatially distributed hydrological model was developed to quantitatively simulate the energy and mass transfer processes and their interactions within arctic regions (arctic hydrological and thermal model, ARHYTHM). The model first determines the flow direction in each element, the channel drainage network and the drainage area based upon the digital elevation data. Then it simulates various physical processes: including snow ablation, subsurface flow, overland flow and channel flow routing, soil thawing and evapotranspiration. The kinematic wave method is used for conducting overland flow and channel flow routing. The subsurface flow is simulated using the Darcian approach. The energy balance scheme was the primary approach used in energy‐related process simulations (snowmelt and evapotranspiration), although there are options to model snowmelt by the degree‐day method and evapotranspiration by the Priestley–Taylor equation. This hydrological model simulates the dynamic interactions of each of these processes and can predict spatially distributed snowmelt, soil moisture and evapotranspiration over a watershed at each time step as well as discharge in any specified channel(s). The model was applied to Imnavait watershed (about 2·2 km2) and the Upper Kuparuk River basin (about 146 km2) in northern Alaska. Simulated results of spatially distributed soil moisture content, discharge at gauging stations, snowpack ablations curves and other results yield reasonable agreement, both spatially and temporally, with available data sets such as SAR imagery‐generated soil moisture data and field measurements of snowpack ablation, and discharge data at selected points. The initial timing of simulated discharge does not compare well with the measured data during snowmelt periods mainly because the effect of snow damming on runoff was not considered in the model. Results from the application of this model demonstrate that spatially distributed models have the potential for improving our understanding of hydrology for certain settings. Finally, a critical component that led to the performance of this modelling is the coupling of the mass and energy processes. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
2.
Volkan Numan Bulut Mehmet Tufekci Celal Duran Mustafa Soylak Halit Kantekin 《洁净——土壤、空气、水》2010,38(7):678-683
A selective and sensitive method for the preconcentration, separation, and determination of palladium with flame atomic absorption spectrometry using 4,15‐bis[(4‐methylphenyl)sulfonyl]‐20,21‐dinitro‐2,3,4,5,6,7,9,10,12,13,14,15,16,17‐tetradecahydro‐8,11‐ethano‐1,18,4,8,11,15‐benzodioxa tetraaza cycloicosine (TNACIN) on XAD‐2010 was developed. TNACIN–Pd(II) complex formed acidic aqueous solution (0.075–0.100 M HNO3) was accumulated on XAD‐2010 and then eluted with 1 M HCl in acetone. The effects of some analytical parameters including pH, TNACIN amount, sample volume, eluent type, and concentration, sample flow rate and matrix ions were studied for optimization of the method. Detection limit and precision were calculated for Pd(II). This method was also verified with CRM and internal standard, and satisfactory results were obtained. 相似文献
3.
Operation analysis of Eleviyan irrigation reservoir dam by optimization and stochastic simulation 总被引：1，自引：0，他引：1
M. Taghi Sattari Halit Apaydin Fazli Ozturk 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(8):1187-1201
Rainfall distributions in Iran are spatially and temporally heterogeneous, a fact probably linked to the mostly arid and semi-arid
climate of the country. On the other hand, water demand is increasing with increasing population and improving life style.
At present, the optimal utilization of water resources and irrigation dams is the primary concern of water resource managers.
The Eleviyan dam (with a capacity of 60 hm3) was constructed to meet the irrigation and municipal water needs of the Maraghan region (Northwestern Iran). In this study,
the efficiency of the Eleviyan irrigation dam system was investigated in three phases by setting up the optimization model
that maximized the water release for irrigation purposes after municipal water need were met. In the first phase, the inflows
measured in the 21 years prior to the construction of the reservoir, and in the second, the inflows generated by the Monte
Carlo simulation method, and in the third phase, the inflows after the construction of the reservoir were used. The results
demonstrate that the capacity determined during the preliminary studies was accurate and the operation carried out in the
recent periods of operation life was up to a satisfactory standard. 相似文献
4.
5.
Natural Hazards - Hospitals are the first point of contact for people in the face of disasters that interfere with the daily functioning of life and endanger health and social life. All... 相似文献
6.
This paper presents the calibration of Omori's aftershock occurrence rate model for Turkey and the resulting likelihoods. Aftershock occurrence rate models are used for estimating the probability of an aftershock that exceeds a specific magnitude threshold within a time interval after the mainshock. Critical decisions on the post-earthquake safety of structures directly depend on the aftershock hazard estimated using the occurrence model. It is customary to calibrate models in a region-specific manner. These models depend on rate parameters(a, b, c and p) related to the seismicity characteristics of the investigated region. In this study, the available well-recorded aftershock sequences for a set of Mw ≥ 5.9 mainshock events that were observed in Turkey until 2012 are considered to develop the aftershock occurrence model. Mean estimates of the model parameters identified for Turkey are a =-1.90, b = 1.11, c = 0.05 and p = 1.20. Based on the developed model, aftershock likelihoods are computed for a range of different time intervals and mainshock magnitudes. Also, the sensitivity of aftershock probabilities to the model parameters is investigated. Aftershock occurrence probabilities estimated using the model are expected to be useful for post-earthquake safety evaluations in Turkey. 相似文献
7.
Dongdong Liu Zhaojie Guo Marc Jolivet Feng Cheng Yan Song Ziya Zhang 《International Journal of Earth Sciences》2014,103(3):737-756
Situated in the southwest of the Central Asian Orogenic Belt (CAOB), the South Tian Shan (STS) Block is a key area for understanding the final accretion of the CAOB. A suite of volcanic rocks interbedded with continental sediments from the Xiaotikanlike Formation lies along the southwestern edge of the Tian Shan orogen. Laser-ablation-inductively coupled plasma-mass spectrometer U–Pb dating provided a crystallization age of 295.0 ± 2.8 Ma (MSWD = 1.3), suggesting an Early Permian magmatic event. The volcanic rocks show a variable composition, with dominant rhyolites and dacites, subordinate basaltic andesites and few basalts. The felsic rocks are enriched in K and exhibit remarkably negative anomalies in Ba, Sr, Eu, P and Ti. These anomalies associated with their high negative ε Nd(t) values and old Nd model ages suggest that they are most likely sourced from ancient lower crustal rocks. The mafic rocks are characterized by high Mg#, Cr, Ni contents, negative Nb, Ta anomalies and pronounced enrichment in light rare earth elements as well as mild enrichment in large-ion lithophile elements. The mafic rocks are thus inferred to derive from enriched subcontinental lithospheric mantle. The petrographic and geochemical characteristics of the Xiaotikanlike Formation volcanic rocks indicate that they were generated under a post-collisional regime. Therefore, the final collision between the Tarim Craton and the Kazakhstan–Yili terrane took place before Early Permian, most probably at Late Carboniferous. Differing from other tectonic units of the CAOB, the recycling of ancient lithospheric crust played a significant role in the continental growth of the STS Block. 相似文献
8.
Shamloo Nazila Sattari Mohammad Taghi Apaydin Halit 《Theoretical and Applied Climatology》2022,149(1-2):39-51
Theoretical and Applied Climatology - Drought is a natural, global and recurring phenomenon caused by climatic anomalies and inevitable meteorological changes. Lake Urmia in northwestern Iran has... 相似文献
9.
In this study, daily rainfall–runoff relationships for Sohu Stream were modelled using an artificial neural network (ANN)
method by including the feed-forward back-propagation method. The ANN part was divided into two stages. During the first stage,
current flows were estimated by using previously measured flow data. The best network architecture was found to utilise two
neurons in the input layer (the delayed flows from the first and second days), two hidden layers, and one output layer (the
current flow). The coefficient of determination (R
2) in this architecture was 81.4%. During the second stage, the current flows were estimated by using a combination of previously
measured values for precipitation, temperature, and flows. The best architecture consisted of an input layer of 2 days of
delayed precipitation, 3 days of delayed flows, and temperature of the current. The R
2 in this architecture was calculated to be 85.5%. The results of the second stage best reflected the real-world situation
because they accounted for more input variables. In all models, the variables with the highest R
2 ranked as the previous flow (81.4%), previous precipitation (21.7%), and temperature. 相似文献
10.
This study investigate the potential of M5 model tree in predicting daily stream flows in Sohu river located within the municipal borders of Ankara, Turkey. The results of the M5 model tree was compared with support vector machines. Both modelling approaches were used to forecast up to 7-day ahead stream flow. A comparison of correlation coefficient and root mean square value indicates that M5 model tree approach works equally well to the SVM for same day discharge prediction. The M5 model tree also works well up to 7-day ahead discharge forecasting in comparison of SVM with this data set. An advantage of using M5 model tree approach is the availability of simple linear models to predict the discharge as well use of less computational time. 相似文献