Interannual Salinity Variability in the Tropical Pacific in CMIP5 Simulations

Salinity variability and its causes in the tropical Pacific are analyzed using observations, reanalysis products and model simulations. The mixed-layer salinity(MLS) budget analyses from observations and reanalysis products indicate that its interannual evolution is closely related to ENSO and is predominantly governed by surface forcing and surface advection in the western-central equatorial Pacific. It is found that the observed MLS tendency leads Nin?o3.4 by about 12 months due to the effect of negative freshwater flux(evaporation minus precipitation). These observation-based analyses are used to evaluate the corresponding simulation using GFDL-ESM2 M. It is evident that the model can simulate the spatiotemporal variations of MLS with some discrepancies compared to observations. In the warm pool of the equatorial Pacific the MLS tendency in the model is sensitive to ocean dynamics, however model biases cause the tendency to be underestimated. In particular, the freshwater flux is overestimated while the ocean surface zonal current and vertical velocity at the base of the mixed layer are underestimated. Due to model biases in representing the related physics, the effects of surface forcing on the simulated MLS budget are overestimated and those of subsurface and surface advection are relatively weak. Due to weaker surface advection and subsurface forcing than observed, the simulated compensations for surface forcing are suppressed, and the simulated MLS tendency that leads Nin?o3.4 by 8–10 months, which is shorter than the observed lead time. These results are useful for the interpretation of observational analyses and other model simulations in the tropical Pacific.     

内蒙古冬季极端多雪气候事件环流演变特征及季节预测信号

文章研究关注了内蒙古冬季极端多雪气候事件的季节预测问题,在对大量降水观测资料、海温及大气环流场资料进行统计、分析、研究的基础上,确定了历史上58a(1960—2017年)内蒙古冬季极端多雪和少雪气候事件样本,通过对大气环流场的对比分析发现极端多雪或少雪冬季环流场特征显著不同,分析后确定了影响内蒙古冬季降雪的主要环流系统,包括西太平洋副热带高压、极涡、东亚大槽、环流E型及南方涛动等系统。同时,探索了对这些主要环流系统具有预测意义的来自海洋和大气场的预测信号,对预测信号关键区做了标准化定量提取,确定了预测信号综合指数分段判别阈值,给出了预测概念模型,取得了较好预测效果。     

La3+ 离子掺杂钨酸铅单晶的微结构缺陷

钨酸铅晶体是一种非化学计量化合物,缺陷丰富,蕴含着利用掺杂产生新效应和开发新功能的广泛可能性。探讨了不同浓度La3 掺杂对于钨酸铅晶体发光性能的影响,如热释光、X射线激发发光、光致发光等。La3 掺杂有效地抑制了陷阱中心,使发光受到强烈的抑制,在高浓度掺杂的钨酸铅中,激发机制有所改变,通过XPS测试的结果分析了不同浓度La3 掺杂机制。低浓度掺杂中,La3 取代Pb2 ,形成缺陷复合体[2(La3Pb ).-(VPb)″];高浓度掺杂晶体中,La3 离子不但占据Pb2 位置,而且也会占据W6 位置(La3W ),产生La3 的自补偿机制,形成La3 的自补偿对[(La3W )-(La3Pb ).]-(VO)..或缺陷聚集体[3(LaP3b ).-(La3W )]。     

中亚造山带西段俯冲起始时限及机制探讨

中亚造山带是世界上最大的显生宙增生型造山带,是研究增生造山过程和大陆地壳生长的绝佳场所,其形成记录了新元古代—早中生代古亚洲洋发展演化历程,主要由一系列微陆块、岛弧、海山/大洋高原、增生杂岩及蛇绿混杂岩构成.中亚造山带西段蛇绿混杂岩物质组成基本一致,除了典型的蛇绿岩组分外,大多发育典型的海山岩石组合,即枕状玄武岩、火山...     

Spatial variation and driving mechanism of soil organic carbon components in the alluvial/sedimentary zone of the Yellow River

Alluviation and sedimentation of the Yellow River are important factors influencing the surface soil structure and organic carbon content in its lower reaches. Selecting Kaifeng and Zhoukou as typical cases of the Yellow River flooding area, the field survey, soil sample collection, laboratory experiment and Geographic Information System(GIS) spatial analysis methods were applied to study the spatial distribution characteristics and change mechanism of organic carbon components at different soil depths. The results revealed that the soil total organic carbon(TOC), active organic carbon(AOC) and nonactive organic carbon(NOC) contents ranged from 0.05–30.03 g/kg, 0.01–8.86 g/kg and 0.02–23.36 g/kg, respectively. The TOC, AOC and NOC contents in the surface soil layer were obviously higher than those in the lower soil layer, and the sequence of the content and change range within a single layer was TOCNOCAOC. Geostatistical analysis indicated that the TOC, AOC and NOC contents were commonly influenced by structural and random factors, and the influence magnitudes of these two factors were similar. The overall spatial trends of TOC, AOC and NOC remained relatively consistent from the 0–20 cm layer to the 20–100 cm layer, and the transition between high-and low-value areas was obvious, while the spatial variance was high. The AOC and NOC contents and spatial distribution better reflected TOC spatial variation and carbon accumulation areas. The distribution and depth of the sediment, agricultural land-use type, cropping system, fertilization method, tillage process and cultivation history were the main factors impacting the spatial variation in the soil organic carbon(SOC) components. Therefore, increasing the organic matter content, straw return, applying organic manure, adding exogenous particulate matter and conservation tillage are effective measures to improve the soil quality and attain sustainable agricultural development in the alluvial/sedimentary zone of the Yellow River.     

扬子板块西缘攀西地区白草矿区黄铁矿标型元素特征及其指示意义

黄铁矿是重要的金属硫化物矿物,在多种矿床中均有产出,其标型特征对矿床成因、矿体空间分布等具有重要的指示意义.以扬子板块西缘攀西地区白草矿区黄铁矿为研究对象,利用矿相学、电子探针等分析方法来对比研究浸染状、致密块状、斑杂状、网脉状矿石中黄铁矿的标型元素特征.结果表明:白草矿区黄铁矿Fe、S平均含量(质量分数,下同)分别为...     

地方嵌入对在华外资企业出口市场多元化的影响

外资企业通过直接出口和间接溢出效应对中国出口增长做出了巨大贡献.现有文献大多基于外资企业知识溢出研究其对本地出口和创新等方面的促进作用,较少关注外资企业自身的贸易活动.利用2000-2016年中国海关贸易数据库,在全球-地方互动视角下,搭建本地、目的国(地区)和本地-目的国(地区)联系三维度框架,重点关注外资企业地方嵌...     

洛阳市城市环境气象监测预报服务研究

利用洛阳市环境监测资料和气象资料,分析了洛阳市污染物浓度的日变化、季节变化、年际变化规律,并分析了污染物浓度与气象因子的关系.在此基础上,通过回归分析预报方法、污染潜势预报方法、CAPPS模式预报方法对洛阳市3种主要污染物的浓度和级别进行了24 h和48 h预测,并建立了气象局与环保部门共享的气象和污染数据库平台,为双方今后的合作奠定了基础.     

61～50kaBP亚洲季风百年尺度气候振荡的黔西南石笋记录

12个U/Th年龄测试结果显示,黔西南普安县雾露洞长度分别为667mm和830mm的两支石笋覆盖了61～50kaBP时段。据两支石笋999个δ18O数据建立了平均分辨率达15年的亚洲夏季风强度变化序列。雾露洞δ18O记录揭示了4个振幅达1.7‰的千年尺度季风增强事件,对应于格陵兰冰心DO17—DO14事件。在总体特征上,该记录峰谷振荡特征及振幅与贵州董歌洞、南京葫芦洞记录一致,进一步证实亚洲季风区大气降水同位素组成变化在大范围空间内具有一致性。在百年尺度上,亚洲季风区石笋δ18O清晰记录了MIS3早期6个DO亚旋回事件,而且在更短时间尺度上具有类似高纬气温振荡特征。这种低纬季风系统与北高纬气候变化的耦合关系表明,大气环流快速重组和传输可能是连接高低纬DO旋回及亚旋回气候变化的主要纽带。     

坠落物体产生的冲击荷载对海底管线的损伤分析

提出了坠落物体产生的冲击荷载对海底管线的损伤一种简易可行的分析方法。对坠落物体进行分类,然后进行运动形式分析,求得冲击速度,根据动力问题控制方程,使用著名商业软件‘ANSYS/LS-DYNA’,‘LS-DYNA’是世界上最著名的通用显式动力分析程序,对实际的工程算例进行了仿真模拟分析。得到的计算结果与已有经验方程结果是基本一致的。该方法可以和一般风险分析方法一起用作海底管线损伤分析和保护措施校核分析。