Could CMIP6 climate models reproduce the early-2000s global warming slowdown?

The unexpected global warming slowdown during 1998–2013 challenges the existing scientific understanding of global temperature change mechanisms, and thus the simulation and prediction ability of state-of-the-art climate models since most models participating in phase 5 of the Coupled Model Intercomparison Project(CMIP5) cannot simulate it. Here, we examine whether the new-generation climate models in CMIP6 can reproduce the recent global warming slowdown, and further evaluate their capacities for simulating key-scale natural variabilities which are the most likely causes of the slowdown. The results show that although the CMIP6 models present some encouraging improvements when compared with CMIP5, most of them still fail to reproduce the warming slowdown. They considerably overestimate the warming rate observed in 1998–2013,exhibiting an obvious warming acceleration rather than the observed deceleration. This is probably associated with their deficiencies in simulating the distinct temperature change signals from the human-induced long-term warming trend and/or the three crucial natural variabilities at interannual, interdecadal, and multidecadal scales. In contrast, the 4 models that can successfully reproduce the slowdown show relatively high skills in simulating the long-term warming trend and the three keyscale natural variabilities. Our work may provide important insight for the simulation and prediction of near-term climate changes.     

基于细粒岩石类型对玛湖凹陷下二叠统风城组烃源岩分类评价

准噶尔盆地玛湖凹陷风城组页岩油勘探取得巨大突破,但是按照普遍认可的页岩油烃源岩评价标准,本区的烃源岩品质并不理想。为了科学评价玛湖凹陷烃源岩品质特征,本文在系统的岩心观察和有机地球化学分析的基础上,揭示烃源岩的形成环境,并按照矿物组成对烃源岩分类评价。玛湖凹陷风城组细粒岩主要沉积于正常半深湖、咸化半深湖、半咸化半深湖、含热液半深湖和滨浅湖环境中,各环境中细粒岩的有机质特征存在一定区别,其中半咸化半深湖有机质较为富集,w(TOC)均值在1%左右。进一步结合有机质类型判别图解,表明咸化半深湖和含热液半深湖有机质来源以湖泊生物为主,而其他环境中存在湖泊和陆源混合有机质来源。基于有机质生烃潜力评价和成熟度(V_re=0.74%)估算,表明目前风城组烃源岩中有机质正处于大量排烃的成熟阶段,且确定了细粒岩中的烃类为原生烃。由于不同矿物组成的烃源岩吸附能力的差异,按照陆相泥质烃源岩和碳酸盐质烃源岩开展分类评价,结果表明风城组沉积了累计厚度近250 m的的有效烃源岩,且富含以藻类体为主的有机质。     

两次区域性暴雨过程副高三维结构对比分析

为探讨夏季不同大气环流背景下区域性暴雨过程副高结构特征及其对降水的贡献,利用2005年6-7月降水量和NCEP／NCAR逐日再分析等资料,采用特征指数分析和物理量诊断方法,对比分析了2005年夏季两次区域性暴雨的副高三维结构特征。结果发现,夏季不同的大气环流背景下,两次区域性暴雨过程副高结构性质分别表现为热力性高压脊和动力性高压脊特征,从而导致两次暴雨过程的水汽供应条件和产生强烈上升运动的大尺度背景场存在差异。     

Influence of sedimentary environments on mechanical properties of clastic rocks

The sedimentary environments are the intrinsic factor controlling the mechanical properties of clastic rocks. Examining the relationship between rock sedimentary environments and rock mechanical properties gives a better understanding of rock deformation and failure mechanisms. In this study, more than 55 samples in coal measures were taken from seven different lithologic formations in eastern China. Using the optical microscope the sedimentary characteristics, such as components of clastic rocks and sizes of clastic grains were quantitatively tested and analyzed. The corresponding mechanical parameters were tested using the servo-controlled testing system. Different lithologic attributes in the sedimentary rocks sampled different stress–strain behaviors and failure characteristics under different confining pressures, mainly due to different compositions and textures. Results demonstrate that clastic rocks have the linear best-fit for Mohr-Coulomb failure criterion. The elastic moduli in clastic rocks are highly dependent upon confining pressures, unlike hard rocks. The envelope lines of the mechanical properties versus the contents of quartz, detritus of the grain diameter of more than 0.03 mm, and grain size in clastic rocks are given. The compressive strength or elastic modulus and the grain diameter have a non-monotonic relation and demonstrate the “grain-diameter softening” effect.     

利用地震属性预测煤层厚度及古河流冲刷带的方法

根据山西宁武煤田某煤矿2#煤层采掘及钻孔揭露情况,发现该井田中部和南部存在古河流冲刷带。通过对比基于优选的4个地震属性的四元一次、四元二次多项式回归模型与BP神经网络预测模型,决定将BP人工神经网络模型预测煤层厚度数据应用于整个测区古河流冲刷带的预判工作。首先利用GeoFrame系统和Landmark公司Poststack模块,提取2#煤层反射波的各类沿层切片,分析并圈定出2#煤层古河流冲刷带的大致范围,在此基础上,利用垂直时间剖面中2#煤层反射波的各种波形特征,进一步判别2#煤层古河流冲刷带解释的可靠性,然后结合BP神经网络预测模型获得的2#煤层厚度变化趋势图,最终解释出2#煤层古河流冲刷带范围:勘探区内2#煤层厚度变化范围0～5.3m,根据其煤层厚度变化趋势,将全区划分出一大二小3个古河流冲刷带。     

云南烤烟低温冷害风险区划

用云南93个烤烟种植县气象站1961—2010年4—9月逐日平均气温、逐日最低气温,逐月平均气温,平均最低气温资料结合各类型烤烟低温冷害指标,基于概率和强度结合权重指数,计算了各烤烟种植县的春季、夏季、秋初和全生育期综合低温冷害风险指数。使用低温冷害风险指数与海拔、纬度因子建立的空间推算回归模型,在ArcGIS 9.3平台下实现了低温冷害风险指数的空间精细化推算、订正及区划,进一步将其分类为5个风险等级,且对区划结果进行了分析。区划结果可为烤烟生产相关单位提供低温冷害防御的决策依据。     

Y11B航空物探(电/磁)综合站西北找水初步成果

1997年9月23日～10月8日,在甘肃省安西—敦煌地区用Y11B航空物探(电/磁)综合站和GPS导航定位进行了地下水勘查试生产工作。用均匀大地模型,结合已知的水文地质资料,初步圈定了淡水区、过渡类型水区、咸水区和苦水区及泉水湖。所推断的水质和土壤含盐量与大的水文地质单元和1:20万水文地质普查报告都吻合得很好,且细节更为清楚。对差异较大的地方做了分析和解释。     

综合地质-地球物理方法在金矿中的应用

河北省丰宁县坝州营金矿床赋存于五台期侵位的“变闪长岩”中,该区从太古代到中生代长期处于构造隆升剥蚀状态,发育多期岩浆侵位事件,为金矿提供了充分的成矿条件。根据区域地质背景及围岩蚀变、矿化等特征,推断本矿床属于受构造控制的中一低温热液石英脉型金矿。结合矿区地质特征开展地球物理工作,以高密度电法圈定了地下矿化体的范围,辅以音频大地电磁测量,实现探测相对深部断裂构造,并以钻探证实,取得了找矿突破,达到了推断控矿构造的走向和找矿前景等目的。     

去除EOS/MODIS 1B数据中"弯弓"效应的方法

分析了中分辨率成像光谱仪EOS／MODIS的扫描方式,在此基础上研究了EOS／MODIS1B数据集“弯弓”效应的成因。对EOS／MODIS1B数据02级产品HDF文件的格式进行了探讨,并以250m分辨率资料为例,在2002年7月13日10时的MODIS资料中选取鄱阳湖以北部分地区,读取其数据进行插值、Lambert投影、重采样等处理,从而消除了影响资料使用的“弯弓”效应,同时也完成了对EOS／MODIS数据的几何校正,取得了一定的效果,为EOS／MODIS遥感资料在今后得以广泛应用作了有益的尝试。