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21.
Theoretical and Applied Climatology - Evapotranspiration is one of the main components of water balance and its accurate estimation is of great importance in planning and optimizing water... 相似文献
22.
ABSTRACT Karst aquifers and springs are important with respect to their potential for supplying drinking water in regions suffering from water scarcity in Iran. Accordingly, it is essential to determine the recharge potential of the catchment and the regions with higher obtainability potential. This study provides a road map for the Sheshpeer catchment in southern Iran. A recharge potential (RP) map was produced from which a recharge index (RI) was computed for several selected springs in the catchment. Furthermore, the unit discharge (q) – defined as the average annual discharge for a given catchment area and unit rainfall depth for each spring – was calculated. The plot of q versus RI for the springs showed a linear positive relationship between the two variables (R 2 = 0.9). Applying the trend equation of this plot to the whole Sheshpeer karstic catchment reveals that its long-term recharge coefficient is 0.74. 相似文献
23.
The phase-averaged characteristics of the turbulent velocity fields beneath steep short wind waves are investigated. A scheme
was developed to compute the phase of individual wind waves using spatial surface displacement data. This information was
used to analyze the two-dimensional velocity data acquired using particle image velocimetry (PIV) in a wind-wave tank. The
experiments were conducted at a fetch of 5.5m and at wind speeds that ranged from 4 to 10ms−1. Under these conditions previous studies have shown that a significant percentage of the waves are microscale breaking waves.
An analysis of the phase-averaged results suggests under these conditions (short fetches and moderate wind speeds) a wind-driven
water surface can be divided into three regions based on the intensity of the turbulence. These are the crests of microscale
breaking waves, the crests of non-breaking waves and the troughs of all waves. The turbulence is most intense beneath the
crests of microscale breaking waves. In the crest region of microscale breaking waves coherent structures were observed that
were stronger and occurred more frequently than beneath the crests of non-breaking waves. Beneath the crests of non-breaking
waves the turbulence is a factor of two to three times weaker and beneath the wave troughs it is a factor of six weaker. These
findings provide additional support for the hypothesis that approximately two-thirds of the gas and heat fluxes occur across
the turbulent wakes produced by microscale breaking waves. 相似文献
24.
Hydrogeochemical investigation using multivariate analytical methods in Esfadan basin,eastern Iran 总被引：1，自引：0，他引：1
The chemical analyses of 71 water-supply wells in the Esfadan area of eastern Iran were evaluated using statistical methods to determine the hydrogeochemical processes that control groundwater quality. Groundwater in the study area is mainly saline (Na–Cl type water), and statistical analyses show that there are three subgroups of groundwater quality, whose differences reflect the influences of geology. 相似文献
25.
We report on an experimental study conducted to investigate the influence of small-scale wind waves on the airflow structure
in the immediate vicinity of the air–water interface. PIV technique was used to measure the two-dimensional velocity fields
at wind speeds of 3.7 and 4.4 m s−1 and at a fetch of 2.1 m. The flow structure was analyzed as a function of wave phase. In the near-surface region, significant
variations were observed in the flow structure over the waveform. The phase-averaged profiles of velocity, vorticity, and
Reynolds stress showed different behavior on the windward and leeward sides of the wave in the near-surface region. The influence
of wave-induced velocity was restricted within a distance of three significant wave heights from the surface, which also showed
opposite trends on the windward and leeward sides of the crest. The results also show that the turbulent Reynolds stress mainly
supports downward momentum transfer whereas the wave-induced Reynolds stress is responsible for the upward momentum transfer
from wave to wind. In the immediate vicinity of the air–water interface, the momentum is transferred from waves to wind along
the windward side, whereas, the momentum transfer is from wind to waves along the leeward side. 相似文献
26.
We report on an experimental study conducted to investigate the influence of small-scale wind waves on the airflow structure in the immediate vicinity of the air–water interface. PIV technique was used to measure the two-dimensional velocity fields at wind speeds of 3.7 and 4.4 m?s?1 and at a fetch of 2.1 m. The flow structure was analyzed as a function of wave phase. In the near-surface region, significant variations were observed in the flow structure over the waveform. The phase-averaged profiles of velocity, vorticity, and Reynolds stress showed different behavior on the windward and leeward sides of the wave in the near-surface region. The influence of wave-induced velocity was restricted within a distance of three significant wave heights from the surface, which also showed opposite trends on the windward and leeward sides of the crest. The results also show that the turbulent Reynolds stress mainly supports downward momentum transfer whereas the wave-induced Reynolds stress is responsible for the upward momentum transfer from wave to wind. In the immediate vicinity of the air–water interface, the momentum is transferred from waves to wind along the windward side, whereas, the momentum transfer is from wind to waves along the leeward side. 相似文献
27.
Application of integrated geoelectrical methods in Marand (Iran) manganese deposit exploration 总被引：1，自引：0，他引：1
This paper addresses the application of integrated geoelectrical methods including induced polarization (IP), resistivity (RS), and self-potential (SP) for exploration and evaluation of the Marand (Iran) manganese deposit. The SP method was used for reconnaissance, in which five profiles were designed and surveyed with a reference electrode that was placed in a distance of at least 800 m far from the measurement points. For the conduct of RS and IP, a new array proposed by Ramazi (2005a), named combined resistivity profiling and sounding (CRSP) was used along nine profiles that made it possible to do sounding survey and produce apparent resistivity pseudo-sections. Some anomalies were detected by means of SP surveys along the profiles and some other were located from IP and RS pseudo-sections, and there was good consistency between anomalies detected by IP and RS and SP method. To check the efficiency of CRSP and in comparison with dipole–dipole array, in the location of profile no. 6, a profile with the dipole–dipole array was designed and surveyed. Finally, by integration of the results from the geoelectrical methods, some locations were suggested for borehole drilling. After drilling in those locations, cores were studied and compared with the results obtained from the geoelectrical methods that resulted in confirmation of the geoelectrical findings. The results obtained by the CRSP array have a match better than the drilling results. 相似文献
28.
Binh T. Pham Indra Prakash Khabat Khosravi Kamran Chapi Phan T. Trinh Trinh Q. Ngo 《国际地球制图》2013,28(13):1385-1407
AbstractIn this study, the main goal is to compare the predictive capability of Support Vector Machines (SVM) with four Bayesian algorithms namely Naïve Bayes Tree (NBT), Bayes network (BN), Naïve Bayes (NB), Decision Table Naïve Bayes (DTNB) for identifying landslide susceptibility zones in Pauri Garhwal district (India). First, landslide inventory map was built using 1295 historical landslide data, then in total sixteen influencing factors were selected and tested for landslide susceptibility modelling. Performance of the model was evaluated and compared using Statistical based index methods, Area under the Receiver Operating Characteristic (ROC) curve named AUC, and Chi-square method. Analysis results show that that the SVM has the highest prediction capability, followed by the NBT, DTNBT, BN and NB, respectively. Thus, this study confirms that the SVM is one of the benchmark models for the assessment of susceptibility of landslides. 相似文献
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30.
The stability of the horizontal multidrain wells is a crucial issue and several factors are involved in this matter, including in-situ stresses, magnitude and distribution as well as the mainbore trajectories. In this paper, this issue is evaluated by assuming different circumstances for the above mentioned factors, based on finite difference three-dimensional modeling by using the finite difference numerical software, FLAC3D. The stability of the mainbore and lateral branches is analyzed based on the Normalized Yielded Zone Area (NYZA) criterion, i.e. the ratio of the surrounding yielded cross-sectional area to the initial area of the well. Optimum mud pressures are obtained in the mainbore and lateral branches in different mainbore trajectories under three in-situ stress regimes. In addition, the stability of the junction where the lateral branches are bifurcated from the mainbore is assessed in those situations. The optimum trajectory of the mainbore, in which the junction has obtained the most stable condition, is selected in each stress regime. It was concluded that in the Normal Faulting (NF) stress regime, the mainbore and junction stability varies in relation to the mainbore trajectories, inversely. However, in the other two stress regimes, i.e. Strike Slip (SS) and Reverse Faulting (RF), the variations of the mainbore and junction stability are in the same trend with respect to the mainbore trajectory deviations. 相似文献