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This study developed a one‐dimensional model of downslope rain splash transport based on field experiments and previous studies. The developed model considers soil detachment processes, ground cover, probability densities, and the effect of overland run‐off in preventing detachment. Field monitoring was conducted to observe precipitation run‐off, ground cover, and sediment production on steep hillslopes. Field‐observed data were used to develop the splash detachment rate equation, probability densities for splash transport, and the maximum splash transport distance. Observed and estimated splash transport showed overall agreement, with some differences for small storm events or events with relatively low intensity, probably caused by variation of overland run‐off depth and connectivity as well as differences in soil surface cohesion at various degrees of wetness. Our model can provide insights on the interactions among rainfall intensity, soil surface condition, soil wetness, and splash transport on forested hillslopes. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Chunling Du Masato Shinoda Kaoru Tachiiri Banzragch Nandintsetseg Hiroshi Komiyama Shusuke Matsushita 《Natural Hazards》2018,92(1):3-17
The livelihoods of people inhabiting inland Eurasia have long been jeopardized by repeated natural hazards associated with a harsh environment and a cold, arid climate. Dzud is a Mongolian word indicating harsh winter conditions. In the present study, we considered dzud damage (e.g., livestock loss) to result from a combination of climate hazard (e.g., cold surges) and herders’ socioeconomic vulnerability. For this study, we integrated crucial socioeconomic factors accounting for major spatiotemporal variations in Mongolia by applying principal component analysis (PCA) to a comprehensive province-level, multiyear dataset. We subsequently characterized the regionality of herders’ vulnerability to the dzud event that occurred during the 2009/2010 winter by conducting a cluster analysis of the provincial principal component (PC) scores for the pre-dzud year (2009). Our results revealed a distinct geographical pattern of vulnerability. Herding households in the northern and northeastern (relatively wet and plain) areas were found to be well prepared for harsh winters, with shelters against wind and availability of forage, including hay, as well as easy access to major urban markets. By contrast, herding households in the southern and southwestern (arid and mountainous) areas were poorly prepared, with inadequate circumstances that facilitate pursuing of otor (movement of nomadic herders in search of better pastures) and lack of access to markets and dzud relief support because of their remote locations. The time coefficients of PC 2, related to winter preparedness, indicated that vulnerability increased between 2003 and 2009 (the pre-dzud year). This was partly responsible for the record-level mortality observed in 2010 across the southern and southwestern rural region, in conjunction with harsh winter weathers. 相似文献
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Laboratory based continuous bedload monitoring in a model retention basin: Application of time domain reflectometry 
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下载免费PDF全文 In this study, we applied time domain reflectometry (TDR) to determine the deposition height and porosity of sediment at a fine spatiotemporal resolution, and developed a continuous bedload monitoring method that can be applied to pools in steep mountain rivers. The TDR monitoring system consisted of sensor probes, a cable tester, multiplexers and coaxial cables. When the embedded probes penetrated both water and sediment, the boundaries of the sediment and water were consistent with the transition points in the observed waveforms of each TDR measurement. A semi‐automatic analysis of the recorded TDR waveforms, which did not require calibration or parameter fitting, was conducted to establish continuous monitoring. In addition, a flume experiment was performed to test the monitoring system in a model retention basin connected to a flume, with sand of uniform grain size (1.4 mm diameter) supplied for 30 min. The sediment volume in the container representing the model basin was monitored using a load cell underlying the container and eight sensor probes, with a length of almost 0.27 m. The sediment thickness determined by the TDR indicated a gradual deposition, and was consistent with manual measurements. Despite a marginal overestimation of 13% for a sand feed of 30 kg, the sediment volume in the model retention basin and the bedload transport rate were successfully estimated. A combination of our monitoring system and other indirect methods, such as geophones, can potentially serve as useful tools for better understanding bedload transport processes in steep mountain streams. Copyright © 2018 John Wiley & Sons, Ltd. 相似文献
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Development of new sensor systems for continuous bedload monitoring using a submerged load‐cell system (SLS) 下载免费PDF全文
下载免费PDF全文 Takahiro Itoh Takahiko Nagayama Rei Utsunomiya Masaharu Fujita Daizo Tsutsumi Shusuke Miyata Takahisa Mizuyama 《地球表面变化过程与地形》2018,43(8):1689-1700
It is important to evaluate bedload discharge and temporal changes of the bed surface, and bed deformation can be estimated during floods if the bedload discharge is properly evaluated in an arbitrary cross‐section. With the exception of grain size and its distribution within the bedload, bedload discharge has been measured using both direct and indirect methods. Bedload slot is a direct method but cannot be used to measure bedload during a flood because of volume limitations. Indirect methods require correlation between the signals and sediment volume measured using another method. In the present study, a small, automatically recording bedload sensor with an iron plate and a pair of load cells is developed in order to evaluate not only large particles but also sand particles as bedload. Bedload mass is calculated by integrating with respect to both the velocity of sediment particles and the averaged particle weight as measured by a pair of load cells, and, as an example, the velocity is estimated by the cross‐correlation function of weights measured by load cells. The applicability of the proposed sensor is discussed based on the results of flume tests in the laboratory (2014) and the observation flume of the Hodaka Sedimentation Observatory of Kyoto University in Japan (2015). The system was installed in the observation flume in November of 2012, and flume data were obtained using natural sediment particles. In particular, it was difficult to estimate the velocity of averaged bedload particles, and it was better to apply a cross‐correlation function in the laboratory tests. However, it appears that the previous estimation can estimate these velocities in the observation flume using a connecting tube and submerged load‐cell systems. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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Habibie Muhammad Iqbal Noguchi Ryozo Shusuke Matsushita Ahamed Tofael 《GeoJournal》2021,86(2):777-807
GeoJournal - Maize is one of the potential crops can help in regional food production with self-sufficiency of foods in the drought prone areas of East Java in Indonesia. The purpose of this... 相似文献
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