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71.
72.
Abstract

The SWAT model was tested to simulate the streamflow of two small Mediterranean catchments (the Vène and the Pallas) in southern France. Model calibration and prediction uncertainty were assessed simultaneously by using three different techniques (SUFI-2, GLUE and ParaSol). Initially, a sensitivity analysis was conducted using the LH-OAT method. Subsequent sensitive parameter calibration and SWAT prediction uncertainty were analysed by considering, firstly, deterministic discharge data (assuming no uncertainty in discharge data) and secondly, uncertainty in discharge data through the development of a methodology that accounts explicitly for error in the rating curve (the stage?discharge relationship). To efficiently compare the different uncertainty methods and the effect of the uncertainty of the rating curve on model prediction uncertainty, common criteria were set for the likelihood function, the threshold value and the number of simulations. The results show that model prediction uncertainty is not only case-study specific, but also depends on the selected uncertainty analysis technique. It was also found that the 95% model prediction uncertainty interval is wider and more successful at encompassing the observations when uncertainty in the discharge data is considered explicitly. The latter source of uncertainty adds additional uncertainty to the total model prediction uncertainty.
Editor D. Koutsoyiannis; Associate editor D. Gerten

Citation Sellami, H., La Jeunesse, I., Benabdallah, S., and Vanclooster, M., 2013. Parameter and rating curve uncertainty propagation analysis of the SWAT model for two small Mediterranean watersheds. Hydrological Sciences Journal, 58 (8), 1635?1657.  相似文献   
73.
对流层延迟误差是GPS定位中的一项主要误差源,一般可采用模型改正或待定参数的方法进行处理。本文首先介绍如何使用WAAS模型进行对流层延迟改正,然后给出一种网络RTK的对流层延迟误差的处理方法,最后通过对实测数据的处理,证明本文方法可有效地用于网络RTK用户对流层延迟实时改正和分析。  相似文献   
74.
近30年西藏地区雷暴变化特征   总被引:3,自引:1,他引:2  
利用西藏地区38个观测站点1979-2008年雷暴资料,采用旋转EOF分析、合成分析、小波分析及趋势分析等统计方法对西藏地区雷暴的时空变化规律进行了研究.结果表明:两藏地区以午后短时热力性雷暴为主,雷暴平均总次数存在准15年的周期变化,年雷暴平均总次数呈逐年减少趋势,2000年以后这种趋势更为明显.雷暴持续期变短,但也...  相似文献   
75.
Ash samples from tephra layers correlated with the Pomici di Avellino (Avellino Pumice) eruption of Somma-Vesuvius were collected in distal archives and their composition and particle morphology investigated in order to infer their behaviour of transportation and deposition. Differences in composition and particle morphologies were recognised for ash particles belonging to the magmatic Plinian and final phreatomagmatic phases of the eruption. The ash particles were dispersed in opposite directions during the two different phases of the eruption, and these directions are also different from that of coarse-grained fallout deposits. In particular, ash generated during magmatic phase and injected in the atmosphere to form a sustained column shows a prevailing SE dispersion, while ash particles generated during the final phreatomagmatic phase and carried by pyroclastic density currents show a general NW dispersion. These opposite dispersions indicate an ash dispersal influenced by both high and low atmosphere dynamics. In particular, the magmatic ash dispersal was first driven by stratospheric wind towards NE and then the falling particles encountered a variable wind field during their settling, which produced the observed preferential SE dispersal. The wind field encountered by the rising ash clouds that accompanied the pyroclastic density currents of the final phreatomagmatic phase was different with respect to that encountered by the magmatic ash, and produced a NW dispersal. These data demonstrate how ash transportation and deposition are greatly influenced by both high and low atmosphere dynamics. In particular, fine-grained particles transported in ash clouds of small-scale pyroclastic density currents may be dispersed over distances and cover areas comparable with those injected into the stratosphere by Plinian, sustained columns. This is a point not completely addressed by present day mitigation plans in case of renewal of activity at Somma-Vesuvius, and can yield important information also for other volcanoes potentially characterised by explosive activity.  相似文献   
76.
首都圈地区现今地壳垂直形变特征   总被引:1,自引:1,他引:0  
利用首都圈地区1998、2001、2005、2007年151期精密水准复测资料,分析该区近十年来地壳垂直形变状态与动态特征。结果表明,形变场以继承性运动为主,即山区上升、盆地及平原下降。值得注意的是首都圈西部地区等值线分布密集有序,有些象限图形特征,东西升,南北降,其最大差值为10mm/a,可能预示该区应力场处于逐步积累及有所加强的势态,虽然异常形变数值及所涉面积均较小,但仍需跟踪关注。  相似文献   
77.
三峡库区奉节县宝塔坪小区大型复杂滑坡特征及成因机制   总被引:12,自引:1,他引:11  
张加桂 《地质论评》2000,46(4):431-436
奉节县新城宝塔坪小区的地质灾害问题是当前学术界关注的焦点,也是库区具有普遍性问题。本文首次提出,在小区发育有5个复杂结构的滑坡。滑坡具3种成因:(1)碎裂-溶蚀-杏黄色泥质条带发育-滑坡;(2)碎裂-溶蚀-T2b^2粉砂质泥岩顶层泥化-滑坡;(3)T2b^4泥岩溶蚀-滑坡。岩溶蚀作用为主导作用。断裂的发育为溶蚀作用提供了通道。  相似文献   
78.
79.
The aim of this study is to analyse the effects in space and time of relict sand-dredging activities on macrobenthic assemblages, in an area situated offshore Montalto di Castro (central Tyrrhenian Sea, Italy), and to analyse the recolonisation processes of macrobenthos in the dredged areas. The area in question is characterised by relict sand deposits (Holocenic paleo-beaches), used for beach nourishment along the Latium coast. The effects of sand extraction on benthic assemblages were investigated before, during and after three dredging operations. The sites analysed are located within the dredged areas (inside stations) and in neighbouring, not dredged, areas (outside stations). The results showed that the impact of sand extraction was confined to the dredged stations and to the areas in proximity to the dredged areas. During dredging activities, the structure of benthic assemblages within the impacted stations was characterised by low species richness and diversity. Both the direct removal of sediment and the re-suspension and consequent deposition of fine sediment affected benthic assemblages of the impacted stations. A few months after the dredgings, a recolonisation process was still observed at all the impacted stations. A gradual recolonisation process was observed at those stations affected by only one dredging, whereas a different recolonisation was observed at those stations affected by two dredgings over time. This study suggests that differences of re-colonisation processes of benthic assemblages are related to the intensity of dredging operations in terms of dredging frequency.  相似文献   
80.
Recent pore-scale observations and geomechanical investigations suggest the lack of true cohesion in methane hydrate-bearing sediments (MHBSs) and propose that their mechanical behavior is governed by kinematic constrictions at pore-scale. This paper presents a constitutive model for MHBS, which does not rely on physical bonding between hydrate crystals and sediment grains but on the densification effect that pore invasion with hydrate has on the sediment mechanical properties. The Hydrate-CASM extends the critical state model Clay and Sand Model (CASM) by implementing the subloading surface model and introducing the densification mechanism. The model suggests that the decrease of the sediment available void volume during hydrate formation stiffens its structure and has a similar mechanical effect as the increase of sediment density. In particular, the model attributes stress-strain changes observed in MHBS to the variations in sediment available void volume with hydrate saturation and its consequent effect on isotropic yield stress and swelling line slope. The model performance is examined against published experimental data from drained triaxial tests performed at different confining stress and with distinct hydrate saturation and morphology. Overall, the simulations capture the influence of hydrate saturation in both the magnitude and trend of the stiffness, shear strength, and volumetric response of synthetic MHBS. The results are validated against those obtained from previous mechanical models for MHBS that examine the same experimental data. The Hydrate-CASM performs similarly to previous models, but its formulation only requires one hydrate-related empirical parameter to express changes in the sediment elastic stiffness with hydrate saturation.  相似文献   
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