鄂西地区二叠系孤峰组—大隆组沉积演化及其页岩气地质意义

鄂西地区二叠系发育孤峰组、吴家坪组和大隆组三套黑色岩系,为页岩气探勘新主力层系,其沉积背景、沉积环境及时空分布却不尽一致.本次在前人的研究基础上,通过野外剖面和最新的钻井资料综合分析,对该地区二叠系孤峰组—大隆组沉积演化进行了深入解剖,并通过岩相古地理图约束了富有机质页岩的空间分布特征,旨在为鄂西地区二叠系页岩气地质调查和选区评价提供基础资料.研究认为,鄂西地区孤峰组主要发育盆地相碳质硅质泥岩,局部地区发育外缓坡相富有机质泥质灰岩;吴家坪组炭山湾段主要发育潮坪相泥质粉砂岩夹煤层,并在利川地区发育陆棚相的碳质硅质泥岩;吴家坪组灰岩段主要为内缓坡相的生屑泥晶灰岩.大隆组主要发育盆地相碳质硅质泥岩,其次为外缓坡相富有机质泥质灰岩,利川见天坝可见发育内缓坡边缘点礁.综合前人对各层位研究的页岩气参数认为,鄂西地区孤峰组和大隆组具有有机质含量高(＞2％)、厚度大(＞20 m)、脆性矿物含量高(＞60％)等形成页岩气的基本地质条件,深水盆地相为有利相带;吴家坪组炭山湾段潮坪相的黑色泥岩较薄(＜10 m),连续性差,但利川地区吴家坪组炭山湾段深水陆棚相黑色泥岩厚度较大(～30 m),为潜在的页岩气勘探区域.     

Decadal Changes in Interannual Dependence of the Bay of Bengal Summer Monsoon Onset on ENSO Modulated by the Pacific Decadal Oscillation

Interannual variations of the Bay of Bengal summer monsoon (BOBSM) onset in association with El Ni?o?Southern Oscillation (ENSO) are reexamined using NCEP1, JRA-55 and ERA20C atmospheric and Hadley sea surface temperature (SST) reanalysis datasets over the period 1900?2017. Decadal changes exist in the dependence of the BOBSM onset on ENSO, varying with the Pacific Decadal Oscillation (PDO). A higher correlation between the BOBSM onset and ENSO arises during the warm PDO epochs, with distinct late (early) onsets following El Ni?o (La Ni?a) events. In contrast, less significant correlations occur during the cold PDO epochs. The mechanism for the PDO modulating the ENSO?BOBSM onset relationship is through the variations in SST anomaly (SSTA) patterns. During the warm PDO epochs, the superimpositions of the PDO-related and ENSO-related SSTAs lead to the SSTA distribution of an El Ni?o (La Ni?a) event exhibiting significant positive (negative) SSTAs over the tropical central?eastern Pacific and Indian Ocean along with negative (positive) SSTAs, especially over the tropical western Pacific (TWP), forming a strong zonal interoceanic SSTA gradient between the TWP and tropical Indian Ocean. Significant anomalous lower tropospheric easterlies (westerlies) together with upper-tropospheric westerlies (easterlies) are thus induced over the BOB, favoring an abnormally late (early) BOBSM onset. During the cold PDO epochs, however, the superimpositions of PDO-related SSTAs with El Ni?o-related (La Ni?a-related) SSTAs lead to insignificant SSTAs over the TWP and a weak zonal SSTA gradient, without distinct circulation anomalies over the BOB favoring early or late BOBSM onsets.     

广西气象业务内网功能设计与实现

通过对广西气象业务内网系统建设的总体设计、功能规划以及首页动态布局管理、产品自动加工流水线、产品回写CIMISS流程、WebGIS可视化展示等关键技术实现和系统展示效果等方面进行阐述,介绍了广西气象业务内网系统的整体开发思路及具体实现。系统的建成实现了广西省级气象数据和业务产品集约共享,形成国省两级互补,为省市县三级用户提供业务辅助支撑。     

The China Multi-Model Ensemble Prediction System and Its Application to Flood-Season Prediction in 2018

Multi-model ensemble prediction is an effective approach for improving the prediction skill short-term climate prediction and evaluating related uncertainties. Based on a combination of localized operation outputs of Chinese climate models and imported forecast data of some international operational models, the National Climate Center of the China Meteorological Administration has established the China multi-model ensemble prediction system version 1.0 (CMMEv1.0) for monthly-seasonal prediction of primary climate variability modes and climate elements. We verified the real-time forecasts of CMMEv1.0 for the 2018 flood season (June-August) starting from March 2018 and evaluated the 1991-2016 hindcasts of CMMEv1.0. The results show that CMMEv1.0 has a significantly high prediction skill for global sea surface temperature (SST) anomalies, especially for the El Nino-Southern Oscillation (ENSO) in the tropical central-eastern Pacific. Additionally, its prediction skill for the North Atlantic SST triple (NAST) mode is high, but is relatively low for the Indian Ocean Dipole (IOD) mode. Moreover, CMMEv1.0 has high skills in predicting the western Pacific subtropical high (WPSH) and East Asian summer monsoon (EASM) in the June-July-August (JJA) season. The JJA air temperature in the CMMEv1.0 is predicted with a fairly high skill in most regions of China, while the JJA precipitation exhibits some skills only in northwestern and eastern China. For real-time forecasts in March-August 2018, CMMEv1.0 has accurately predicted the ENSO phase transition from cold to neutral in the tropical central-eastern Pacific and captures evolutions of the NAST and IOD indices in general. The system has also captured the main features of the summer WPSH and EASM indices in 2018, except that the predicted EASM is slightly weaker than the observed. Furthermore, CMMEv1.0 has also successfully predicted warmer air temperatures in northern China and captured the primary rainbelt over northern China, except that it predicted much more precipitation in the middle and lower reaches of the Yangtze River than observation.     

An NGO disaster relief network for small and medium-scale natural hazards in China

Natural Hazards - As China is one of the world’s most vulnerable countries to small and medium-scale natural hazards (SMNHs), its NGOs have had a great deal of experience in dealing with...     

高孔砂岩断层内部微观结构及渗透性变化规律物理模拟

在油气勘探过程中,对于小位移断层分隔油水封闭能力的控制因素研究尚浅,野外也难以获得不同变形过程的断层带结构及其渗透性变化规律.因此,以高孔隙度纯净砂岩人造岩心为研究对象,采用自主研发的“高压~低速环形剪切装置”开展实验,实验后样品取心分别进行覆压孔渗测试、纳米CT扫描、铸体薄片分析等分析测试.以有效正应力和断层位移为实验变量开展了多组环剪实验,其研究结果表明:宏观上断层面上可观察到明显擦痕与粉末状碎裂岩,微观上确定了断层带内碎裂作用导致的颗粒粒度降低与颗粒的定向排列是孔渗降低的主要原因,断层带渗透率小于10 mD,较母岩降低2~3个数量级.随着断层有效正应力或断层滑动位移增加,断层带碎裂程度增大且粒径和孔径减小,断层带厚度增大,孔隙度和渗透率逐渐减小.这一结果可为小位移断层侧向封闭能力与油气勘探领域的研究奠定理论基础.      

羌塘盆地南坳陷布曲组白云岩储层孔喉结构及其分形特征研究

羌塘盆地中侏罗统布曲组白云岩为非均质性强的低孔、低渗储层,孔喉结构评价难度较大。选取南羌塘坳陷布曲组20件白云岩岩心样品,通过铸体薄片、扫描电镜观察,结合物性分析和常规压汞实验,研究其孔喉分布和分形特征,探索分形维数与白云岩储层物性参数、孔喉结构参数、孔隙成因之间的关系。结果表明：（1）研究区布曲组白云岩储集空间类型包括组构选择性孔隙、非组构选择性孔隙、裂缝3类,依据毛管压力曲线特征将其孔喉结构分为5种类型,其分形曲线具有明显的转折点,转折点为孔喉分布峰值,代表连通性好的大尺度孔喉向连通性差的小尺度孔喉的转变;（2）小尺度孔喉的层内非均质性较弱、层间非均质性强,大尺度孔喉的分形维数比小尺度孔喉小,但分布区间较宽,样品间差异明显,表明大尺度孔喉复杂多样,层间（整体）非均质性比小尺度强;（3）大尺度孔喉的分形维数与储层参数、孔喉结构参数相关性较好,可用于布曲组白云岩储层的孔喉结构定量表征,大尺度孔喉分形维数越小,储层物性越好,大尺度孔喉占比越多对储层整体渗透能力的贡献越大;（4）该套储层的储集空间与孔喉结构以沉积形成的碳酸盐沉积物孔隙为基础,白云石化作用和溶蚀作用共同控制了孔喉结构的差异性。     

New CGSP Carbonate Matrix Reference Materials for LA-ICP-MS Analysis

Four CGSP (Chinese Geological Standard Powders) carbonate matrix element reference materials were prepared by a coprecipitation method. The major and trace elements were dissolved from natural rare earth carbonate raw materials in strong acid and precipitated with ammonium bicarbonate or ammonia to form carbonate matrix phases. The carbonate reference materials were ground and pressed into tablets for microanalysis. The element homogeneity and stability in CGSP reference materials were tested by LA-ICP-MS using a calibration strategy without an internal standard element and evaluated mainly following ISO Guide 35: 2017 and JJF 1343-2012. Although the homogeneity of most of elements in the CGSP series were comparable to the repeatability obtained from homogeneous glasses, some elements (e.g., Mo, Se, Ga, Ge, Cd, Ni, Co, U) were found to have some degree of heterogeneity. All of elements passed the t-test evaluation in a 32-month stability examination except for Mo in CGSP-A, Na, Ge, Mo in CGSP-B, Ni, Cd, Sn in CGSP-C, and Al, P, Tb, Ho in CGSP-D. The certified element mass fraction values and uncertainties were determined with the characterisation of a non-operationally defined measurand using various bulk analysis methods in eight laboratories. GGSPs will provide a new carbonate calibration reference option for microanalysis.     

Hydrogeological classification of municipal solid waste landfill sites in China and correlation with groundwater contaminant migration

Tens of thousands of municipal solid waste (MSW) landfill sites worldwide hold a high risk of contaminating groundwater. This study aimed to establish a practical hydrogeological classification system for MSW landfill sites and explores the correlation between the classification and the risk of groundwater contamination. Hydrogeological information and groundwater contamination data from 80 MSW landfill sites in China were collected and analyzed, and a general hydrogeological model was proposed. The key hydrogeological parameters in the model were identified and analyzed, including the relative depth to the water table, the ratio of the length of the MSW site’s recharge boundary to the combined length of the discharge boundary and hydrobalance boundary, the hydraulic conductivity of the bearing layer, and the background hydraulic gradient. On the basis of the general model, hydrogeological conditions at the landfill sites were categorized into seven subtypes. By using chloride, ammoniacal nitrogen and chemical oxygen demand as the characteristic contaminants, the migration features of groundwater contaminants within the seven subtypes of landfill sites were revealed. It was found that the maximum contaminant migration distance could be 2,000 and 300 m at the landfill sites with ‘plain and intensive runoff’ type and ‘valley and weak runoff’ type, respectively, and the corresponding concentration gradients of the characteristic contaminants were less than 10 mg/(L × m) and greater than 10 mg/(L × m). This work provides a guide for implementing cost-effective site investigation and environmental risk management at landfill sites with different types of hydrogeological conditions.

     

SPH-based simulation of flow process of a landslide at Hongao landfill in China

The cyclones over Bay of Bengal (BoB) have varied socio-economic impacts and meteorological importance. There are considerable uncertainties in predicting the track and intensity of cyclonic systems in the BoB. The present study examines the cyclogenesis characteristics over the BoB and addresses the regional impacts and their importance in terms of intensification of cyclones. An analysis of cyclone track data from 1971–2013 reveals that the cyclones generated in Andaman Sea (a regional sea of BoB) and propagating through central BoB sustain maximum life time. Furthermore, within the BoB, the cyclones originated from Andaman Sea are the most intensified and characterized by highest cyclogenesis potential index. Interestingly, we have found that higher value of mid-tropospheric relative humidity over Andaman Sea during the cyclone period is enhancing the cyclone’s intensity. Climatologically also the Andaman Sea is dominated by higher values of mid-tropospheric relative humidity compared to other regions of BoB. There is no significant distinction between Andaman Sea and rest of the BoB for other meteorological and oceanic parameters that supports cyclogenesis. Climatologically dominant east–west asymmetry in mid-tropospheric relative humidity is enhancing the intensity of cyclones from Andaman Sea. The results will be helpful in understanding the processes of cyclone intensification and useful in the statistical and dynamical prediction of cyclones.