Soil erosion potential hotspot zone identification using machine learning and statistical approaches in eastern India     

Chakrabortty  Rabin  Pal  Subodh Chandra  Sahana  Mehebub  Mondal  Ayan  Dou  Jie  Pham  Binh Thai  Yunus  Ali P. 《Natural Hazards》2020,104(2):1259-1294

Natural Hazards - Land degradation is very severe in the subtropical monsoon-dominated region due to the uncertainty of rainfall in the long term, and most of the rainfall occurs with high...  相似文献   

Flood risk assessment and mapping based on a modified multi-parameter flood hazard index model in the Guanzhong Urban Area,China     

Xinyi?Dou  Jinxi?SongEmail author  Liping?Wang  Bin?Tang  Shaofeng?Xu  Feihe?Kong  Xiaohui?Jiang 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(4):1131-1146

The aim of this study is to promote appropriate land development policies and to improve operations of flood risk in urban areas. This study first illustrated a multi-parameter flood hazard index (FHI) model for assessing potential flood risk areas in the Guanzhong Urban Area (GUA), a large-scale urban area in northwestern China. The FHI model consisted of the following seven parameters: rainfall intensity, flow accumulation, distance from the river network, elevation, land use, surface slope, and geology. The parameter weights were assigned using an analytical hierarchy process and the sum weight of the first three parameters accounted for 71.21% of the total weight and had significant influence on flooding. By combining with population factor, the FHI model was modified to estimate the flood control area in the GUA. The spatial distribution of the flood risk was obviously different in the flood hazard area and flood control area. The very low risk and medium risk area in the flood control area increased by 11.19% and reduced by 9.03% compared to flood hazard area, but there were no obvious differences in other levels of risk areas. The flood control assessment indicated that very high flood risk areas were principally concentrated along river banks (the Weihe River and its tributaries) and in the middle of the Guanzhong Plain. Land use and population distribution are related to flooding. Especially, forestland was located in 84.48% of the very low risk area, while low risk areas were mainly located in 91.49% of high population dispersion area.  相似文献   

Research on ultrasonic-based investigation of mechanical properties of ice     

Xiaomin Chang  Wenhao Liu  Guangyu Zuo  Yinke Dou  Yan Li 《海洋学报(英文版)》2021,40(10):97-105

Arctic sea ice area and thickness have declined dramatically during the recent decades. Sea ice physical and mechanical properties become increasingly important. Traditional methods of studying ice mechanical parameters such as ice-coring cannot realize field test and long-term observation. A new principle of measuring mechanical properties of ice using ultrasonic was studied and an ultrasonic system was proposed to achieve automatic observation of ice mechanical parameters (Young’s modulus, shear modulus and bulk modulus). The ultrasonic system can measure the ultrasonic velocity through ice at different temperature, salinity and density of ice. When ambient temperature decreased from 0°C to ?30°C, ultrasonic velocity and mechanical properties of ice increased, and vice versa. The shear modulus of the freshwater ice and sea ice varied from 2.098 GPa to 2.48 GPa and 2.927 GPa to 4.374 GPa, respectively. The bulk modulus of freshwater ice remained between 3.074 GPa and 4.566 GPa and the sea ice bulk modulus varied from 1.211 GPa to 3.089 GPa. The freshwater ice Young’s modulus kept between 5.156 GPa and 6.264 GPa and sea ice Young’s modulus varied from 3.793 GPa to 7.492 GPa. The results of ultrasonic measurement are consistent with previous studies and there is a consistent trend of mechanical modulus of ice between the process of ice temperature rising and falling. Finally, this ultrasonic method and the ultrasonic system will help to achieve the long-term observation of ice mechanical properties of ice and improve accuracy of sea ice models.  相似文献   

Seismic Inventory Simulation and Conformance Test Based on the Monte Carlo Method——A Case Study of the Fenhe-Weihe Belt     

Shao Xiaoyi  Wang Xiaoqing  Dou Aixi  Yuan Xiaoxiang 《中国地震研究》2018,32(4):533-548

Artificial earthquake catalogue simulation is one of the ways to effectively improve the incompleteness of the existing earthquake catalogue,the scarcity of large earthquake records and the improvement of seismological research.Based on the Poisson distribution model of seismic activity and the Gutenberg-Richter magnitude-frequency relationship, the Monte Carlo method which can describe the characteristics of the stochastic nature and the physical experiment process is used.This paper simulates the future seismic catalogues of the Fenhe-Weihe seismic belt of different durations and conducts statistical tests on them. The analysis shows that the simulation catalogue meets the set seismic activity parameters and meets the Poisson distribution hypothesis,which can obtain a better simulated earthquake catalogues that meets the seismic activity characteristics.According to the simulated earthquake catalogues,future earthquake trends in this region are analyzed to provide reference for seismic hazard analysis.  相似文献   

2017年5月11日新疆塔什库尔干5.5级地震生命损失评估对比分析     

丁香  王晓青  袁小祥  窦爱霞 《震灾防御技术》2019,14(2):431-437

2017年5月11日,新疆喀什地区塔什库尔干县发生5.5级地震。地震造成8人死亡、31人受伤以及财产损失,属于典型的“小震大灾”。按照一般的地震灾害损失快速评估方法,得到的评估结果与实际结果差别较大。为探讨评估结果偏离的原因,本文对不同地震损失评估方案进行比较分析,探讨了地震致灾性（地震影响场分布）、承灾体（人口）分布等因素对地震损失评估结果的影响。结果表明在此次地震快速评估中,基于宏观震中确定的地震影响场较微观震中更接近实际分布;地震烈度衰减的平均估计模型给出的地震烈度区面积明显小于实际面积;极震区存在抗震能力相对低的土木、砖木结构房屋,是造成该地震震级相对小而生命损失相对大的“小震大灾”的重要原因。对比分析结果表明,提高人口、房屋建筑等风险暴露数据的空间精准性,改善地震震中定位与地震影响场估计的准确性,将有助于提高地震应急损失评估的准确性。  相似文献   

A Type-Curve Method for the Analysis of Pumping Tests with Piecewise-Linear Pumping Rates     

Chao Zhuang  Yabing Li  Zhifang Zhou  Walter A. Illman  Zhi Dou  Jinguo Wang  Long Yan 《Ground water》2020,58(5):788-798

Aquifer hydraulic parameters are commonly inferred from constant-rate pumping tests, while variable pumping rates are frequently encountered in actual field conditions. In this study, we propose a generally applicable dimensionless form of the analytical solution for variable-rate pumping tests in confined aquifers. In particular, we adopt a piecewise-linear fitting of variable pumping rates and propose a new type-curve method for estimating the hydraulic conductivity (K ) and specific storage (S_s ) of the investigated confined aquifer. For each test, a series of type curves, which depend on the variable pumping rates, the location of observation wells and the introduced first dimensionless inflection time, need to be provided for matching the observed drawdown data on a log-log graph. We first demonstrate the applicability and robustness of this method through a synthetic pumping test. Subsequently, we apply this method to analyze drawdown data from four pumping tests conducted within a multilayered aquifer/aquitard system in Wuxi city, Jiangsu Province, China. The parameter estimates are then compared with those reported by PEST. The K and S_s values estimated by the new type-curve method are found to be quite close to PEST-based estimates. Parameter estimation results demonstrate the difference in K and S_s values between observation wells. The difference could be attributed to the spatial heterogeneity in K and S_s . A future research topic may focus on the characterization of K and S_s heterogeneity with the currently available drawdown data from variable-rate pumping tests.  相似文献   

关于无线遥测传输设备的改进          下载免费PDF全文

豆耀华 《地震工程学报》1995,17(2):87-88

关于无线遥测传输设备的改进１前言单路无线遥测地震传输设备，即７８－１１机（４７ｍＨｚ）经过多年的运行，部分机元器件老化，可靠性逐年下降，尤其在接收中心随着改革开放的潮流各种民用固定和移动电台数量剧增，使接收中心的干扰场强发生了很大的变化。为了提高接收...  相似文献   

天山北坡一次大雾天气的数值模拟分析          下载免费PDF全文

窦刚  陈春艳 《沙漠与绿洲气象(新疆气象)》2023,17(3):26-34

利用常规气象观测数据、NCEP再分析资料和WRF4.0中尺度数值模式，对2019年12月8—15日新疆天山北坡出现的一次持续性大雾天气的成因进行分析。结果表明：此次大雾天气出现在500 hPa新疆脊控制、850 hPa暖中心维持、地面蒙古冷高压影响的环流背景下。雾开始和维持阶段，地面1 200 m存在逆温强度为0.9℃/100 m的强逆温层，为大雾的形成和维持提供了静力稳定条件；大雾一般出现在辐射降温最明显的傍晚前后；大雾天气出现后2 m气温和地面温度温差始终维持在5℃左右，地、气温差使地面积雪一直升华，为大雾天气持续提供了充足的水汽条件；近地层大气一直存在2.0 m/s以下的微风，形成的湍流维持了雾滴悬浮的平衡状态。当逆温层中上层出现6～10 m/s偏东风时，雾层厚度增加；中上层风速过大或地面～600 m风向一致时，雾减弱或消散。  相似文献