A Bayesian model for lithology/fluid class prediction using a Markov mesh prior fitted from a training image

We consider a Bayesian model for inversion of observed amplitude variation with offset data into lithology/fluid classes, and study in particular how the choice of prior distribution for the lithology/fluid classes influences the inversion results. Two distinct prior distributions are considered, a simple manually specified Markov random field prior with a first-order neighbourhood and a Markov mesh model with a much larger neighbourhood estimated from a training image. They are chosen to model both horizontal connectivity and vertical thickness distribution of the lithology/fluid classes, and are compared on an offshore clastic oil reservoir in the North Sea. We combine both priors with the same linearized Gaussian likelihood function based on a convolved linearized Zoeppritz relation and estimate properties of the resulting two posterior distributions by simulating from these distributions with the Metropolis–Hastings algorithm. The influence of the prior on the marginal posterior probabilities for the lithology/fluid classes is clearly observable, but modest. The importance of the prior on the connectivity properties in the posterior realizations, however, is much stronger. The larger neighbourhood of the Markov mesh prior enables it to identify and model connectivity and curvature much better than what can be done by the first-order neighbourhood Markov random field prior. As a result, we conclude that the posterior realizations based on the Markov mesh prior appear with much higher lateral connectivity, which is geologically plausible.     

塔里木沙漠公路沿线机械防沙体系效益分析

野外实测和室内风洞实验的数据分析表明,塔里木沙漠公路沿线高立式沙障和半隐蔽式沙障发挥了较大的防沙效益,平沙地上高立式沙障的防护距离在18H左右。3种高立式沙障防沙效益各不相同,以芦苇栅栏最佳,抗紫外线尼龙网栏次之,白尼龙网栏最差。随设置路段、地貌部位、风沙活动强度不同,各种高立式沙障使用年限有差异。沙漠腹地半隐蔽式沙障的掩埋速度为2.0~14.4m·a^-1左右,并随时间推移有一个加速的过程。     

Source mechanism and stress analysis of 23 October 2011 Van Earthquake (Mw = 7.1) and aftershocks

On 23 October 2011 at 1341 local time, a strong earthquake (Mw?=?7.1) occurred east of Lake Van (KOERI; Kandilli Observatory and Earthquake Research Institute). The focal parameters of the main shock and 29 aftershocks with M?≥?4.0 were obtained from regional broadband seismic data from KOERI network by using Regional Moment Tensor Inversion Code (Dreger 2002). It is confirmed that the main shock had thrust faulting mechanism. The stress tensor analysis was completed using the focal mechanism solutions and the software developed by (Gephart Comp Geosci 16: 953-989, 1990). The maximum principal stress (P compressional) of the main shock is aligned in a N-S (NNW/SSE) direction and the tensional axis (T dilatation) is aligned in an E-W (ENE-WSW) direction. The b value is calculated as 0.96 using the maximum likelihood method (Utsu 1999).     

Ozone Temporal Variability in the Subarctic Region: Comparison of Satellite Measurements with Numerical Simulations

Fourier and wavelet spectra of time series for the ozone column abundance in the atmospheric 0–25 and 25–60 km layers are analyzed from SBUV satellite observations and from numerical simulations based on the RSHU and EMAC models. The analysis uses datasets for three subarctic locations (St. Petersburg, Harestua, and Kiruna) for 2000–2014. The Fourier and wavelet spectra show periodicities in the range from ~10 days to ~10 years and from ~1 day to ~2 years, respectively. The comparison of the spectra shows overall agreement between the observational and modeled datasets. However, the analysis has revealed differences both between the measurements and the models and between the models themselves. The differences primarily concern the Rossby wave period region and the 11-year and semiannual periodicities. Possible reasons are given for the differences between the models and the measurements.     

Wave power statistics for individual waves

The paper provides a bivariate distribution of wave power and wave height, as well as a bivariate distribution of wave power and wave period; both bivariate distributions are for individual waves within a sea state. This is relevant for e.g. making assessments of wave power devices and their potential for converting energy from waves. The results can be applied to compare systematically the wave power potential for individual waves in a given sea state at different locations.     

海南岛存在类TTG岩系包体的证据及地质意义

海南岛西部中元古代花岗质片麻岩和海西—印支期似斑状花岗岩中发现了大量暗色包体。本对暗色包体进行了详细地研究，以确定其性质、来源和所揭示的地质意义。研究表明，暗色包体显示强烈剪切交形和糜棱岩化的特征，并可区分三期片理；包体为异源包体，具深源火成岩特征，成分与太古代TTG岩系类似，为高Al2O3大陆型英云闪长岩—花岗闪长岩岩石组合，产于大陆或大陆边缘俯冲带环境。结合Sr-Nd—Pb同位素结果，认为该暗色包体可能是海南岛存在太古宙最早陆核的标志，来源于亏损地幔、但可能含有地壳成分或受地壳强烈混染。海南岛西部类TTG岩系包体的发现，有可能为深入研究海南岛乃至华南古老结晶基底及地壳演化提供新的证据。     

混合结构体系高层建筑模拟地震振动台试验研究

随着现代建筑高度的不断增加,混合结构体系在超高层建筑中逐步广泛应用,因此对该结构体系在地震作用下的破坏机理和抗震性能展开深入的研究是一项有意义的工作。本文对一混合结构体系复杂超高层建筑进行1／35的模型模拟地震振动台试验,分析模型结构的动力特性和不同烈度地震作用下加速度、位移和应变反应,然后根据相似关系推算出原型结构的动力特性和反应,研究其在各水准地震作用下的破坏机理和破坏形式,最后对原型结构设计提出若干建议。     

Simulating the effects of the 1991 Mount Pinatubo volcanic eruption using the ARPEGE atmosphere general circulation model

The climate changes that occured following the volcanic eruption of Mount Pinatubo in the Phillippines on 15 June 1991 have been simulated using the ARPEGE atmosphere general circulation model （AGCM）. The model was forced by a reconstructed spatial-time distribution of stratospheric aerosols intended for use in long climate simulations. Four statistical ensembles of the AGCM simulations with and without volcanic aerosols over a period of 5 years following the eruption have been made, and the calculated fields have been compared to available observations. The model is able to reproduce some of the observed features after the eruption, such as the winter warming pattern that was observed over the Northern Hemisphere （NH） during the following winters. This pattern was caused by an enhanced Equator-to-pole temperature gradient in the stratosphere that developed due to aerosol heating of the tropics. This in turn led to a strengthening of the polar vortex, which tends to modulate the planetary wave field in such a way that an anomalously positive Arctic Oscillation pattern is produced in the troposphere and at the surface, favouring warm conditions over the NH. During the summer, the model produced a more uniform cooling over the NH.     

城市地理信息系统软件工具及其应用

本文首先在分析城市地理信息系统(UGIS)应用任务、专业内容和技术要求的基础上,提出了我国UGIS的研究内容及其软件发展的工具模式;接着,以GRAMS软件为例,论述了UGIS软件工具的总体结构、主要功能和技术特点;最后,还结合一些具体的应用系统,如中国城市信息系统、城市水资源信息系统以及城市环境信息系统等,介绍了UGIS软件工具的不同使用方式以及给人们带来的实际好处。     

Effects of a candidate antifouling compound (medetomidine) on pheromone induced mate search in the amphipod Corophium volutator

Environmental hazards associated with traditional, toxic antifouling coatings based on heavy metals calls for the development of alternative, environmentally acceptable antifouling compounds. Medetomidine ((±)-4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole) is a candidate antifouling biocide which impedes settlement of barnacles in the nanomolar range. Prior to introducing novel biocides it is of great importance to consider potential effects on non-target organisms. This study is the first to investigate the effects of medetomidine on the amphipod Corophium volutator, specifically effects on male mate search behaviour. In a laboratory, Y-maze bioassay, C. volutator males were allowed to follow female pheromones after 24 h exposure to 0 (control), 0.01 and 0.1 μg mL⁻¹ medetomidine. We found that exposure to medetomidine at both concentrations significantly reduced pheromone induced mate search (by 42–71%), with fewer males crawling towards female odour. The results obtained indicate that medetomidine may impair the reproductive fitness of non-target crustaceans, an aspect that needs to be considered before further commercialisation.