【摘 要】
：
The significant reduction of sediment load flux into Lake Baikal from its main tributary-the Selenga River began in the mid-1970s,and can be explained by climate change and socio-economic activities.Integrated analysis was done of changes in hydro-meteoro
【机 构】
：
Limnological Institute of the Siberian Branch of Russian Academy of Sciences,Irkutsk,664033,Russia
论文部分内容阅读
The significant reduction of sediment load flux into Lake Baikal from its main tributary-the Selenga River began in the mid-1970s,and can be explained by climate change and socio-economic activities.Integrated analysis was done of changes in hydro-meteorological parameters (water discharge,sediment load,air temperature,and predpitation) and their tendencies over periods of 1946-1975 (baseline) and 1976-2017 (warming).Changes in natural processes and human activity were negligible during the baseline period.In the warming period,against the background of an increase in temperature,the water discharge had a slight decreasing trend (-13％) whereas the sediment load has significantly decreased(-53％) these are consist with the precipitation change (-9.4％).Analysis of hydro-climatic data using statistical methods showed that in the warming period the greatest reduction in river sediment runoff occurred in the interval 1996-2017.In this period the sediment load was 768 × 103 t/yr,which is less than the average value during the warming period-1048 × 103 t/yr.Considering sedimentation in the Selenga River delta,the actual sediment load flux from the Selenga River into Lake Baikal amounted to 515 × 103 t/yr,which is three times less than the average multiyear value 1535 × 103 t/yr for observation period (1946-2017).
其他文献
针对果园环境下,光照情况复杂、果实状态各异导致杨梅识别与定位准确率低的问题,提出一种基于局部滑窗技术的杨梅果实识别与定位方法.首先,采用限制对比度自适应直方图均衡化改善图像光照;然后,提出CbCr色差法,结合最大类间方差法、形态学操作和区域生长策略,提取杨梅果实潜在前景区域;接着,根据潜在前景区域提取结果,采用局部滑窗技术,获取杨梅果实待检测区域;最后,建立基于局部纹理特征的支持向量机,结合非极大值抑制滤除低匹配度背景等干扰,提升杨梅果实识别与定位准确率.实验表明,该方法在果园环境下,杨梅果实识别准确率和
为提升货物堆放高度,将集装箱门式起重机门腿进行加高改造.利用有限元建模对集装箱门式起重机加高门腿在3种工况下的结构强度、刚度等安全性能进行分析,并对结构稳定性进行验算,为加高改造后的相关设备整体安全性能研究提供一种新思路.
针对振动传感器不同类型故障诊断对准确率和实时性要求高的需求,提出基于逐轮淘汰制一对一RVM(OVO-RVM)的振动传感器故障诊断方法.首先,研究RVM二分类模型及其超参数优化、模型稀疏化方法;然后,分析分类准确率高的OVO-RVM多分类模型工作原理及分类速度慢的原因,研究逐轮淘汰制OVO-RVM振动传感器故障诊断方法,该方法在各轮分类中仅对相邻类别进行分类判别并淘汰包括本轮在内的前几轮分类决策概率和最低的类别,经过多轮分类和淘汰后获得最终分类类别;接着,提出按照平均分类可靠性最低的两类别尽可能远离和各相邻
为实现准确率高且计算复杂度低的阻塞性睡眠呼吸暂停(OSA)检测,根据血氧饱和度(SpO2)提出一种基于加法网络和自注意力机制的OSA检测方法.该方法引入加法网络用于SpO2的特征提取,以降低计算复杂度;采用自注意力机制调整采样点间的特征权重,以提高检测精度.在数据集Apnea-ECG上实现了敏感性94.56％、特异性96.91％的检测性能,且浮点运算数量为2.88 K FLOPs,比卷积操作减小了40％.实验结果表明:该方法在获得较高检测精度的同时,可以保持较低的计算复杂度.
针对一系列电梯检测仪器的控制仪存在功能相近、重复开发的问题,设计一种基于μC/OS-Ⅲ实时操作系统的电梯检测通用控制仪.该控制仪由信号采集、电机控制和手持控制等模块组成,且根据应用场景不同,可选择信号采集模块和电机控制模块的数量;各模块之间通过ZigBee无线网络通信.该控制仪适用于多种特种设备检测仪器,如电梯平衡系数检测仪、电梯超载开关检测仪、电梯无载静态曳引试验检测仪等,并具有较好的可扩展性,为后续产品开发节省成本、节约时间.
In the current research,the impact of the COVID-19 lockdown period on sediment quality of the Meri(c)-Ergene River Basin was evaluated by determining the potentially toxic elements (PTEs) in sediment samples collected from 25 sampling points in the basin.
River water and sediment embody environmental characteristics that give valuable eco-environmental information.Due to rapid industrialization,the aquatic environment of any urban river can be seriously polluted by heavy metals (HMs).The global concern is
The delayed response of fluvial rivers to external disturbances has been described by many researchers.To simulate such behavior,the rate law model (or the delayed response model) was developed by previous researchers,and has been applied to a series of r
The dispersion and influence of soluble and particulate trace elements (TEs) present in the materials from abandoned mines is an imminent problem on terrestrial and aquatic environments.The goal of this research is to provide a broader view of such transp
Selective removal of particles and nutrients by water erosion is a key factor in soil erosion studies.Most agricultural soils are located on gentle slopes where fertility is high;however,until now,the main attention on sediment transport mechanisms was pa