Climate change projections over three metropolitan regions in Southeast Brazil using the non-hydrostatic Eta regional climate model at 5-km resolution

Theoretical and Applied Climatology - The objective of this work is to assess changes in three metropolitan regions of Southeast Brazil (Rio de Janeiro, São Paulo, and Santos) based on the...     

Identification and assessment of heavy rainfall–induced disaster potentials in Taipei City

With increasing threat to lives and properties, identifying and assessing disaster potentials has become necessary and prior for effective disaster preparation and rescue planning. This study first introduces practical methods currently used in Taipei City, Taiwan, to identify and assess heavy rainfall–induced potential risks on flood, debris flow, and landslide. The identified disaster potential information is further applied to a series of deterministic and probabilistic risk analyses using Shilin District of Taipei City as a case study. The deterministic risk analyses are conducted to evaluate the impact of various heavy rainfall intensities on the residents. The probabilistic risk analyses are performed to establish risk curves for the population affected by heavy rainfall–induced hazards. The risk curve represents the relationships between the affected population and the annual exceedance probability. This study found the annual exceedance probability is very sensitive to the assumed coefficients of variation of the affected population. It is recommended historical statistical data on the correlation between affected population and rainfall intensity should be recorded and compiled in order to assess the actual probability distribution function of the affected population. Risk analysis results are further applied to assess the community evacuation capacity in this district. Last, short-term and long-term mitigation strategies and recommendations are discussed.     

Hydrochemical characteristics and controlling factors for waters’ chemical composition in the Tarim Basin,Western China

This paper covers the chemical and isotopic composition of river water, groundwater from wells (15–25 m), saline spring water and stagnant surface water providing evidence for controlling factors of water composition and water evolution process in the Tarim Basin, Xinjiang, western China. Analytical data for major and minor ions of totaling 537 water samples were obtained from both years of teamwork and old reference materials. It is found that the ion background value ratio SO₄/Cl for river water (2.75) of the Tarim Basin is two times higher than that of the Qaidam Basin (0.88) and 18 times higher than seawater (0.14); K/Cl of these two basins (0.06 and 0.07) are all two times higher than seawater (0.02). This reveals that material sources of Lop Nur are relatively richer in potassium and sulfate, while poorer in chloride. Gradual changes of stable isotopic compositions in waters clearly indicate the effect of evaporation on water evolution of the basin. Besides evaporation and weathering of surrounding rocks, wide distribution of chloride type water, which commonly exist in saline springs/brines and seldom exist in other waters, indicates that hydrothermal Ca–Cl brines discharged from deep within the earth join water evolution of the basin.     

The Inversion Problem of Phase Travel Time Perturbations in Acoustic Imaging

The three-dimensional distribution of change in phase travel time of an active region below the solar surface can be constructed with the technique of acoustic imaging. The interpretation of the distribution of measured phase travel time perturbation suffers from the finite spatial resolution of the acoustic lenses. In the ray approximation, the phase travel time perturbation measured in acoustic imaging can be expressed as an integral of the product of the relative sound-speed perturbation and a kernel. Forward computations show that the vertical resolution of phase travel time perturbation is poor even in the ray approximation. In this study, we discuss the inversion of phase travel time perturbations to estimate the relative sound-speed perturbation with a regularized least-squares inversion method. The tests with model perturbations of sound speed show that the inversion reasonably recovers the distribution of the model perturbation. We also apply the inversion method to the measured phase travel time perturbation of active region NOAA 7981.     

The Origin of Glitches in Pulsars—Phase Oscillation between Anisotropic Superfluid and Normal State of Neutrons in Neutron Stars

Considering neutron star heating by magnetic dipole radiation from 3PF2 super-fluid neutron vortices inside the star, we propose a neutron phase oscillation model between the normal neutron Fermi fluid and the 3PF2 superfluid neutron vortices at the transition temperature of T_(trans) = (2-3)×108 K. With this model we can qualitatively explain most of the observations on pulsar glitches up to date.     

东昆仑大干沟火山岩SHRIMP 锆石U-Pb测年及其地质意义

东昆仑大干沟以北地区造山后形成的牦牛山组磨拉石建造不整合覆盖于前泥盆系之上,其形成时代对限定柴达木盆地加里东造山作用的结束时间及晚古生代裂解作用的开始时间具有重要意义。应用单颗粒锆石离子探针质谱仪（SHRIMP）方法,对牦牛山组上部火山岩段的样品进行精确的锆石U-Pb测年。结果表明,牦牛山组上段火山岩样品DG01和DG02中的岩浆锆石206Pb/238U平均年龄分别为403.6±5.1Ma和409±3.4Ma。综合前人研究认为,造山后牦牛山组伸展型磨拉石的形成时代为晚志留世—早泥盆世,限定了晚古生代裂解的开始时间,也意味着早古生代加里东造山运动在晚志留世—早泥盆世之前已经结束。     

The status evaluation of the permafrost environment along the Chaida’er-Muli Railway in southern Qilian Mountains in northern Qinghai Province,China

Engineering construction has major influence on the permafrost environment.This paper analyzes the interaction between engineering construction and permafrost environment along the Chaidaer-Muli Railway(simply,CMR) based on the press-state-response(PSR) framework.The permafrost environmental system is divided into three subsystems,consisting of permafrost thermal stability,proneness to the freeze-thawing erosion and permafrost ecological fragility.Each subsystem considers its most important influencing factors.Catastrophe Progression Method(CPM) is applied to calculate the current environment condition along the railway.The result indicates that:(1) as far as the thermal stability is concerned,most sections along the CMR are mainly concentrated in rank Ⅲ(fair situation),and a few in Ⅱ(good situation) and Ⅳ(bad situation),respectively;(2) for the proneness tothe freeze-thawing erosion,the entire railway route falls largely in rank Ⅱ(good situation);(3) along the CMR,the ecological fragility of the permafrost environment is in rank Ⅱ(good situation),or slightly fragile;(4) overall,the permafrost environments along the CMR are in rank Ⅲ(fair situation) or Ⅱcondition(good situation).In general,the permafrost environment along the CMR is fair.It is mainly because a series of active measures of protecting permafrost were taken for stabilizing the CMR foundation soils.On the one hand,we should try our best to minimize the influences that engineering activities have exerted on ecology and environment,on the other hand,the positive measures have made improvements to prevent the permafrost environment from deterioration.     

云南兰坪盆地云龙组上段稀土、微量元素地球化学特征及其环境意义

沉积岩的地球化学特征蕴含了大量的地质信息,对于沉积环境的重塑及物源研究具有重要意义。云南兰坪盆地云龙组上段由一层碳酸盐岩及其上覆的碎屑岩组成。通过对碳酸盐岩和碎屑岩的主、微量及稀土元素含量等地球化学特征的研究表明:碳酸盐岩和碎屑岩∑REE总量分别为142.65×10-6~186.85×10-6和217.2×10-6~483.7×10-6,均值分别为167.44×10-6和358.7×10-6,(La/Yb)N值分别介于8.22~10.96和9.07~15.01之间,标准化曲线右倾,表明轻稀土相对重稀土富集。负Eu异常程度中等,3个泥岩样品负Ce异常强烈,其他样品无明显负异常。利用对氧化还原环境最敏感的Ce/Ce*判断,云龙组上段沉积时期主要为氧化环境,碳酸盐岩沉积时期呈弱氧化性,部分层位为还原环境,氧化性:泥岩粉砂岩碳酸盐岩。Sr/Ba比值0.75,表明当时为淡水沉积。根据∑REE和(La/Yb)n,结合Fe2O3/MnO、EFMn、CaCO3(%)和Al(%)等其他特征值判断,碎屑岩沉积时期以温暖湿润为主、碳酸盐岩沉积时期以干旱炎热为主的古气候条件,并且存在干湿交替的气候变化。沉积物源来自于上地壳,原始物质主要为长英质岩石,还有部分的中基性岩。     

Characterizing vertical contaminant distribution in a thick unconfined aquifer,Hanford site,Washington, USA

Drilling-intensive aquifer characterization techniques have been used to obtain depth-discrete water samples from a thick, hydrogeologically continuous unconfined aquifer system; groundwater results indicate that carbon tetrachloride contamination is widespread and extends deeper and at concentrations much higher than detected in monitoring networks at the water table. Carbon tetrachloride, a legacy waste, was used in the plutonium extraction process at the Hanford site in south-central Washington State. Vertical, depth-discrete groundwater samples were collected during well drilling throughout a 28-km² region to determine the concentration of carbon tetrachloride present as a dissolved phase in the aquifer. Results indicate that high concentrations of carbon tetrachloride, three orders of magnitude above the allowable regulatory limit, are present at depths greater than 25 m beneath the water table. In support of future efforts to remediate the carbon tetrachloride contamination, it is imperative to locate the remaining chemical inventory, determine the vertical as well as the lateral distribution of this contaminant and its physical form. Depth-discrete aquifer characterization throughout the uppermost-unconfined aquifer system is providing this information and improving the understanding of the contaminant distribution and the hydrogeologic framework through which it moves.