Runoff and water budget of the Liudaogou Catchment at the wind–water erosion crisscross region on the Loess Plateau of China     

Huang Jinbai  Wen Jiawei  Hinokidani Osamu  Yasuda Hiroshi 《Environmental Earth Sciences》2014,72(9):3623-3633

The objectives of this study were to examine the runoff characteristics and to estimate water budget at the wind–water erosion crisscross region on the Loess Plateau of China. A small catchment known as Liudaogou that has representative meteorological and hydrological conditions of the wind–water erosion crisscross region was chosen as the study location. A numerical model for rainfall-runoff was developed and verified; rainfall-runoff calculation for 5 years (2005–2009) was performed. The observed data and numerical result of the surface runoff were used for evaluating runoff characteristics and estimating the annual water budget. Runoff rate was proportional to average intensity of rain. Even though rainfall duration was for few minutes, surface runoff was generated by intensity of more than 2.6 mm × 5 min^?1, when rainfall duration exceeded 10 h; surface runoff was generated by an intensity of 0.6 mm × 5 min^?1, while annual runoff rate was 10–15 %. The unit area of 1 km² was adopted as the index area for estimating annual water budget. Runoff, evapotranspiration, variation of water storage, and habitant water consumption accounted for 20.4, 75.6, 0, and 4 % of the total annual precipitation, respectively. Results of this study provide the basis for further research on hydrology, water resources, and sustainable water development and utilization at the wind–water erosion crisscross region on the northern Loess Plateau where annual water resources are relatively deficient.  相似文献   

A compound-specific n-alkane δC and δD approach for assessing source and delivery processes of terrestrial organic matter within a forested watershed in northern Japan     

Osamu Seki  Takeshi Nakatsuka  Hideaki Shibata 《Geochimica et cosmochimica acta》2010,74(2):599-613

We measured molecular distributions and compound-specific hydrogen (δD) and stable carbon isotopic ratios (δ¹³C) of mid- and long-chain n-alkanes in forest soils, wetland peats and lake sediments within the Dorokawa watershed, Hokkaido, Japan, to better understand sources and processes associate with delivery of terrestrial organic matter into the lake sediments. δ¹³C values of odd carbon numbered C₂₃-C₃₃n-alkanes ranged from −37.2‰ to −31.5‰, while δD values of these alkanes showed a large degree of variability that ranged from −244‰ to −180‰. Molecular distributions in combination with stable carbon isotopic compositions indicate a large contribution of C3 trees as the main source of n-alkanes in forested soils whereas n-alkanes in wetland soil are exclusively derived from marsh grass and/or moss. We found that the n-alkane δD values are much higher in forest soils than wetland peat. The higher δD values in forest samples could be explained by the enrichment of deuterium in leaf and soil waters due to increased evapotranspiration in the forest or differences in physiology of source plants between wetland and forest. A δ¹³C vs. δD diagram of n-alkanes among forest, wetland and lake samples showed that C₂₅-C₃₁n-alkanes deposited in lake sediments are mainly derived from tree leaves due to the preferential transport of the forest soil organic matter over the wetland or an increased contribution of atmospheric input of tree leaf wax in the offshore sites. This study demonstrates that compound-specific δD analysis provides a useful approach for better understanding source and transport of terrestrial biomarkers in a C3 plant-dominated catchment.  相似文献   

An integrated model simulating the initiation and motion of earthquake and rain induced rapid landslides and its application to the 2006 Leyte landslide   总被引：10，自引：7，他引：3  

Kyoji?SassaEmail author  Osamu?Nagai  Renato?Solidum  Yoichi?Yamazaki  Hidemasa?Ohta 《Landslides》2010,7(3):219-236

A gigantic rapid landslide claiming over 1,000 fatalities was triggered by rainfalls and a small nearby earthquake in the Leyte Island, Philippines in 2006. The disaster presented the necessity of a new modeling technology for disaster risk preparedness which simulates initiation and motion. This paper presents a new computer simulation integrating the initiation process triggered by rainfalls and/or earthquakes and the development process to a rapid motion due to strength reduction and the entrainment of deposits in the runout path. This simulation model LS-RAPID was developed from the geotechnical model for the motion of landslides (Sassa 1988) and its improved simulation model (Sassa et al. 2004b) and new knowledge obtained from a new dynamic loading ring shear apparatus (Sassa et al. 2004a). The examination of performance of each process in a simple imaginary slope addressed that the simulation model well simulated the process of progressive failure, and development to a rapid landslide. The initiation process was compared to conventional limit equilibrium stability analyses by changing pore pressure ratio. The simulation model started to move in a smaller pore pressure ratio than the limit equilibrium stability analyses because of progressive failure. However, when a larger shear deformation is set as the threshold for the start of strength reduction, the onset of landslide motion by the simulation agrees with the cases where the factor of safety estimated by the limit equilibrium stability analyses equals to a unity. The field investigation and the undrained dynamic loading ring shear tests on the 2006 Leyte landslide suggested that this landslide was triggered by the combined effect of pore water pressure due to rains and a very small earthquake. The application of this simulation model could well reproduce the initiation and the rapid long runout motion of the Leyte landslide.  相似文献   

The 3D spiral structure pattern in the atmosphere   总被引：3，自引：0，他引：3  

Liu Shi  Xin Guojun  Liu Shikuo  Liang Fuming 《大气科学进展》2000,17(4):519-524

1. IntroductionSpiral structures of vortices in different scales have been widely studied. From thesynoptic map we can see that the trough line orientation of Rossby wave changes with latitude. A barotropic model in the polar coordinate system was established for the explanationof this observational fact (Chao and Ye, 1977). In the framework of the wave propagationtheory, the spiral structure would be organized by the phase isoline of Rossby wave and be responsible for the trough line tiltin…  相似文献   

Continental basalts in the accretionary complexes of the South-west Japan Arc: Constraints from geochemical and Sr and Nd isotopic data of metadiabase     

Hiroo Kagami  Masaki Yuhara  Shigeru Iizumi  Yoshiaki Tainosho  Masaaki Owada  Yasuo Ikeda  
  Osamu Okano  Shuji Ochi  Yoshikazu Hayama and  Terukazu Nureki 《Island Arc》2000,9(1):3-20

Abstract The Ryoke Belt is one of the important terranes in the South‐west Japan Arc (SJA). It consists mainly of late Cretaceous granitoid rocks, meta‐sedimentary rocks (Jurassic accretionary complexes) and mafic rocks (gabbros, metadiabases; late Permian–early Jurassic). Initial ?_Sr (+ 25– + 59) and ?_Nd (? 2.1–?5.9) values of the metadiabases cannot be explained by crustal contamination but reflect the values of the source material. These values coincide with those of island arc basalt (IAB), active continental margin basalt (ACMB) and continental flood basalt (CFB). Spiderdiagrams and trace element chemistries of the metadiabases have CFB‐signature, rather than those of either IAB or ACMB. The Sr–Nd isotope data, trace element and rare earth element chemistries of the metadiabases indicate that they result from partial melting of continental‐type lithospheric mantle. Mafic granulite xenoliths in middle Miocene volcanic rocks distributed throughout the Ryoke Belt were probably derived from relatively deep crust. Their geochemical and Sr–Nd isotopic characteristics are similar to the metadiabases. This suggests that rocks, equivalent geochemically to the metadiabases, must be widely distributed at relatively deep crustal levels beneath a part of the Ryoke Belt. The geochemical and isotopic features of the metadiabases and mafic granulites from the Ryoke Belt are quite different from those of mafic rocks from other terranes in the SJA. These results imply that the Ryoke mafic rocks (metadiabase, mafic granulite) were not transported from other terranes by crustal movement but formed in situ. Sr–Nd isotopic features of late Cretaceous granitoid rocks occurring in the western part of the Japanese Islands are coincident with those of the Ryoke mafic rocks. Such an isotopic relation between these two rocks suggests that a continental‐type lithosphere is widely represented beneath the western part of the Japanese Islands.  相似文献   

不同时间尺度下气候变化基本特征的探索   总被引：5，自引：1，他引：4  

荣平平  刘式达 《气候与环境研究》1997,2(1):77-82

气候物理量的序列是非平稳的,多层次的,奇异突变的。本文利用子波变换的方法研究一个（长度为１３４年的北半球）气温距平序列的突变点数目随变换尺度的变化,得到该数目随变换尺度减小呈幂律增加的结论,即若以突变点数为测度,上述距平序列是一个标度律为１．２的自相似集。温度突变点数随变换尺度的变化曲线在双对数坐标中的行为与魔鬼楼梯相似,本文称之为“气候魔鬼楼梯”。该楼梯的本征分辨率序列近似以等比（比值在１．６～１．７之间）延伸,与Ｆｉｂｏｎａｃｃｉ数相邻元素之比（黄金分割比）１．６１８近似。将子波变换曲面的槽脊线投影在变换尺度和时间构成的平面上,得到极值线分岔图,据此图分析分岔沿变换尺度发生的速度  相似文献   

Did boninite originate from the heterogeneous mantle with recycled ancient slab?          下载免费PDF全文

Susumu Umino  Kyoko Kanayama  Keitaro Kitamura  Akihiro Tamura  Osamu Ishizuka  Ryoko Senda  Shoji Arai 《Island Arc》2018,27(1)

Boninites are widely distributed along the western margin of the Pacific Plate extruded during the incipient stage of the subduction zone development in the early Paleogene period. This paper discusses the genetic relationships of boninite and antecedent protoarc basalt magmas and demonstrates their recycled ancient slab origin based on the T–P conditions and Pb–Hf–Nd–Os isotopic modeling. Primitive melt inclusions in chrome spinel from Ogasawara and Guam islands show severely depleted high‐SiO₂, MgO (high‐silica) and less depleted low‐SiO₂, MgO (low‐silica and ultralow‐silica) boninitic compositions. The genetic conditions of 1 346 °C at 0.58 GPa and 1 292 °C at 0.69 GPa for the low‐ and ultralow‐silica boninite magmas lie on adiabatic melting paths of depleted mid‐ocean ridge basalt mantle with a potential temperature of 1 430 °C in Ogasawara and of 1 370 °C in Guam, respectively. This is consistent with the model that the low‐ and ultralow‐silica boninites were produced by remelting of the residue of the protoarc basalt during the forearc spreading immediately following the subduction initiation. In contrast, the genetic conditions of 1 428 °C and 0.96 GPa for the high‐silica boninite magma is reconciled with the ascent of more depleted harzburgitic source which pre‐existed below the Izu–Ogasawara–Mariana forearc region before the subduction started. Mixing calculations based on the Pb–Nd–Hf isotopic data for the Mariana protoarc basalt and boninites support the above remelting model for the (ultra)low‐silica boninite and the discrete harzburgite source for the high‐silica boninite. Yb–Os isotopic modeling of the high‐Si boninite source indicates 18–30 wt% melting of the primitive upper mantle at 1.5–1.7 Ga, whereas the source mantle of the protoarc basalt, the residue of which became the source of the (ultra)low‐Si boninite, experienced only 3.5–4.0 wt% melt depletion at 3.6–3.1 Ga, much earlier than the average depleted mid‐ocean ridge basalt mantle with similar degrees of melt depletion at 2.6–2.2 Ga.  相似文献   

Evaluation of flood season segmentation using seasonal exceedance probability measurement after outlier identification in the Three Gorges Reservoir     

Zhengke?Pan  Pan?LiuEmail authorView author&#;s OrcID profile  Shida?Gao  Maoyuan?Feng  Yangyang?Zhang 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(6):1573-1586

Flood season segmentation, which partitions an entire flood season into multiple subseasons, constitutes a considerable water resources management task. Moreover, the risks associated with various schemes for flood season segmentation should be evaluated. Preliminary analysis in this study used the principal component based outlier detection (PCOut) algorithm to identify possible outlying observations to reduce the uncertainty involved in flood season segmentation. Then, a quantitative measurement, the seasonal exceedance probability (SEP), was proposed to evaluate various segmentation schemes. The SEP quantifies the risk that the maximum observation occurs outside the main flood season. Several findings were derived based on a case study of China’s Three Gorges Reservoir (TGR) and daily streamflow records (1882–2010). (1) The PCOut algorithm was found effective in identifying outliers, and the estimation uncertainty of the segmentation evaluation due to outliers decreased when the end date of main flood season (EDMFS) was postponed. (2) The proposed SEP measurement was shown capable of supporting quantitative evaluation of the segmentation schemes in the flood season. (3) The current flood segmentation scheme based on an EDMFS of September 10 is sufficiently safe for the TGR. The findings of this study could help in the proper operation of the TGR.  相似文献   

Seasonal changes in the sediment flux on steep hillslopes in a humid diurnal frost environment          下载免费PDF全文

Fumitoshi Imaizumi  Osamu Suzuki  Asako Togari‐Ohta 《地球表面变化过程与地形》2017,42(3):389-398

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