河南老湾金矿床上上河矿段矿床地质和成矿流体地球化学

河南桐柏老湾金矿床是桐柏-大别山(北坡)金银成矿带内大型造山带型金矿床之一。文章对该矿床的上上河矿段进行了矿床地质和成矿流体地球化学研究,旨在查明该矿段的流体成矿过程。根据矿脉穿插关系、矿石结构构造、矿物共生组合以及黄铁矿的粒度和晶形,将老湾金矿上上河矿段成矿过程划分为:石英粗粒自形黄铁矿(Ⅰ)、石英细粒半自形-他形黄铁矿(Ⅱ)、石英多金属硫化物(Ⅲ)及石英碳酸盐(Ⅳ)4个阶段。镜下观察显示,矿床中的包裹体类型有含CO_2包裹体(LH_2O+LCO_2+VCO_2)、纯CO_2包裹体(LCO_2+VCO_2)、液相包裹体(LH_2O+VH_2O)及少量含子晶包裹体(LH_2O+VH_2O+S)。第Ⅰ阶段、第Ⅱ阶段和第Ⅲ阶段均可见含CO_2包裹体、纯CO_2包裹体和液相包裹体,有时可见含CO_2包裹体与液相包裹体共存。流体包裹体显微测温结果表明,成矿流体可近似看做中温、低盐度、富CO_2的NaCl-H_2O-CO_2体系,纯CO_2包裹体和液相包裹体所代表的流体可能是由含CO_2包裹体所代表的Na Cl-H_2O-CO_2流体经不混溶形成的,三者在寄主矿物沉淀时,被同时捕获而共存。从第Ⅰ阶段到第Ⅳ阶段,成矿流体温度从303~379℃逐渐降低到138~195℃,盐度w(Na Cleq)从4.07%~9.59%逐渐降低到1.06%~2.74%。在成矿的第Ⅰ阶段成矿流体发生了不混溶作用,而在第Ⅱ阶段和第Ⅲ阶段流体中的CO_2起泡分离再次引发了不混溶作用。从第Ⅰ阶段到第Ⅲ阶段,成矿流体的δ18OH_2O从6.56‰~9.71‰经1.89‰~4.01‰变化到0.08‰,δDH_2O从-78.1‰~-64.2‰经-79.5‰~-76.3‰变化到-72.6‰,表明老湾金矿第Ⅰ阶段成矿流体主要为岩浆热液,第Ⅱ阶段成矿流体中有少量大气降水加入,第Ⅲ阶段成矿流体中大气降水的比例明显加大。     

Mesoscale numerical simulation study of warm fog dissipation by salt particles seeding

Based on the dynamic framework of WRF and Morrison 2-moment explicit cloud scheme, a salt-seeding scheme was developed and used to simulate the dissipation of a warm fog event during 6–7 November 2009 in the Beijing and Tianjin area. The seeding effect and its physical mechanism were studied. The results indicate that when seeding fog with salt particles sized 80 μm and at a quantity of 6 gm~(-2) at the fog top, the seeding effect near the ground surface layer is negative in the beginning period, and then a positive seeding effect begins to appear at 18 min, with the best effect appearing at 21 min after seeding operation. The positive effect can last about 35 min. The microphysical mechanism of the warm fog dissipation is because of the evaporation due to the water vapor condensation on the salt particles and coalescence with salt particles.The process of fog water coalescence with salt particles contributed mostly to this warm fog dissipation. Furthermore, two series of sensitivity experiments were performed to study the seeding effect under different seeding amounts and salt particles sizes. The results show that seeding fog with salt particles sized of 80 μm can have the best seeding effect, and the seeding effect is negative when the salt particle size is less than 10 μm. For salt particles sized 80 μm, the best seeding effect, with corresponding visibility of 380 m, can be achieved when the seeding amount is 30 g m~(-2).     

Ensemble simulation of land evapotranspiration in China based on a multi-forcing and multi-model approach

In order to reduce the uncertainty of offline land surface model(LSM) simulations of land evapotranspiration(ET), we used ensemble simulations based on three meteorological forcing datasets [Princeton, ITPCAS(Institute of Tibetan Plateau Research, Chinese Academy of Sciences), Qian] and four LSMs(BATS, VIC, CLM3.0 and CLM3.5), to explore the trends and spatiotemporal characteristics of ET, as well as the spatiotemporal pattern of ET in response to climate factors over mainland China during 1982–2007. The results showed that various simulations of each member and their arithmetic mean(Ens Mean) could capture the spatial distribution and seasonal pattern of ET sufficiently well, where they exhibited more significant spatial and seasonal variation in the ET compared with observation-based ET estimates(Obs MTE). For the mean annual ET, we found that the BATS forced by Princeton forcing overestimated the annual mean ET compared with Obs MTE for most of the basins in China, whereas the VIC forced by Princeton forcing showed underestimations. By contrast, the Ens Mean was closer to Obs MTE, although the results were underestimated over Southeast China. Furthermore, both the Obs MTE and Ens Mean exhibited a significant increasing trend during 1982–98; whereas after 1998, when the last big EI Ni ?no event occurred, the Ens Mean tended to decrease significantly between 1999 and 2007, although the change was not significant for Obs MTE. Changes in air temperature and shortwave radiation played key roles in the long-term variation in ET over the humid area of China, but precipitation mainly controlled the long-term variation in ET in arid and semi-arid areas of China.     

Incorporation of a dynamic root distribution into CLM4.5: Evaluation of carbon and water fluxes over the Amazon

Roots are responsible for the uptake of water and nutrients by plants and have the plasticity to dynamically respond to different environmental conditions. However, most land surface models currently prescribe rooting profiles as a function only of vegetation type, with no consideration of the surroundings. In this study, a dynamic rooting scheme, which describes root growth as a compromise between water and nitrogen availability, was incorporated into CLM4.5 with carbon–nitrogen(CN) interactions(CLM4.5-CN) to investigate the effects of a dynamic root distribution on eco-hydrological modeling. Two paired numerical simulations were conducted for the Tapajos National Forest km83(BRSa3) site and the Amazon, one using CLM4.5-CN without the dynamic rooting scheme and the other including the proposed scheme. Simulations for the BRSa3 site showed that inclusion of the dynamic rooting scheme increased the amplitudes and peak values of diurnal gross primary production(GPP) and latent heat flux(LE) for the dry season, and improved the carbon(C) and water cycle modeling by reducing the RMSE of GPP by 0.4 g C m~(-2)d~(-1), net ecosystem exchange by 1.96 g C m~(-2)d~(-1), LE by 5.0 W m~(-2), and soil moisture by 0.03 m~3m~(-3), at the seasonal scale, compared with eddy flux measurements, while having little impact during the wet season. For the Amazon, regional analysis also revealed that vegetation responses(including GPP and LE) to seasonal drought and the severe drought of 2005 were better captured with the dynamic rooting scheme incorporated.     

Factors controlling the interannual variations of MJO intensity

The interannual variations of intensity of the Madden-Julian Oscillation (MJO) during boreal winter are investigated by using the observed outgoing longwave radiation (OLR) and the reanalysis data of ECMWF and NCEP. The standard deviation of 20-80-day filtered OLR anomaly is used to measure the MJO intensity. The dominant spatial structure of the interannual variability is revealed by an EOF analysis of the MJO intensity field. It is found that the leading mode is associated with eastern Pacific type ENSO, whereas the second mode is related to central Pacific type ENSO. A simple atmospheric model is used to investigate the relative roles of background moisture and wind changes in affecting the overall strength of MJO. The numerical experiments indicate that the background moisture effect is dominant while the background wind change has a minor effect.     

中国东部7类暴雨异常环流型

近年来的研究发现,瞬变扰动天气图上的扰动场天气系统对区域暴雨的落区指示能力强于传统天气图上的总场天气系统。为供预报员在业务预报中参考,本文划分1998年发生在中国东部地区的41日次区域暴雨为7类扰动场天气系统。与区域暴雨相联系的7类异常环流型分别是:华南切变线、华南涡旋、华南倒槽、长江切变线与槽、沿江涡旋、华北涡旋和东北涡旋。无论是在对流层的垂直剖面上,还是在850 hPa水平分布上,扰动天气图上位势高度低值和风扰动辐合处并配合大的水汽扰动对应有区域暴雨,而传统天气图上的低值系统和高水汽区与暴雨之间存在位置上的偏移。由此建议,用实况大气变量和中期数值模式产品绘制扰动天气图有助于预报员确定区域暴雨落区。     

无人直升机搭载大气颗粒物采样装置的前期地面评估

与搭载气溶胶观测和分析仪器测量相比,利用无人直升机搭载气囊采集高空大气颗粒物是一种经济、便捷和安全的采集方式。为了解无人直升机采样装置的采样效果,选择2014年10月至2015年3月的4次重污染天气过程,由无人直升机搭载气囊采集大气颗粒物,然后利用气溶胶采样器采集气囊内的大气颗粒物样品并计算采样时间,再利用气溶胶采样器采集相同时间段内的地面大气颗粒物(气囊外),并将两者进行对比。结果表明:在稳定的污染天气条件下,采集气囊内的大气颗粒物,与相同时间段内利用气溶胶采样器直接采集气囊外的大气颗粒物相比,两种方式采集到的大气颗粒物质量最大差值29%,最小差值11%,平均为21%;利用无人直升机的大气采样装置采集大气颗粒物对碳气溶胶组分影响很小,气囊内与气囊外OC/TC最大相差2.0%,最小相差0.5%。上述结果表明,无人直升机的大气采样装置有比较好的采集效率,利用气囊这种经济、便捷、安全的方式,搭载在无人机平台上,采集高空大气是一种获取气溶胶垂直廓线的有效方法,有望在未来的气溶胶气候和环境研究中提供宝贵数据。     

内蒙古东乌旗早二叠世超镁铁岩的发现及其构造意义

为研究东乌旗晚古生代地幔性质和造山演化特征,对在东乌旗西部首次发现的超镁铁岩—辉闪橄榄岩进行系统的岩相学和元素地球化学研究。东乌旗辉闪橄榄岩主要由橄榄石、角闪石、斜方辉石及少量斜长石、单斜辉石组成,SiO_2含量介于42.84%~43.96%、MgO(24.10%~26.10%)、Na_2O+K_2O(1.52%~2.32%,小于3.5%),低m/f(3.03~3.54)比值和高FeO~T(12.67%~14.33%)的含量、高Mg~#(76.42~79.20),属铁质超镁铁岩和拉斑玄武岩系列。岩石稀土总量较高(∑REE=39.57×10~(-6)~83.32×10~(-6)),轻稀土(LREE)相对于重稀土(HREE)明显富集[(La/Yb)_N=4.04~7.66],Eu异常不明显(δEu=0.90~0.95),稀土元素球粒陨石标准化配分模式表现为轻稀土相对富集的右倾型。岩石富集大离子亲石元素(LILE)Cs、Rb、Ba、Sr、K等,相对亏损高场强元素(HFSE)Nb、Ta,具明显的Nb、Ta、Ti负异常,而又有别于强烈Nb、Ta亏损的岛弧岩浆岩;相容元素Cr(769×10~(-6)~2480×10~(-6))、Ni(454×10~(-6)~901×10~(-6))含量较高;低Th/U(2.54~3.03)、Nb/U(3.40~12.85)比值和高La/Nb(2.60~3.63)、Ba/Nb(43.11~72.52)、Zr/Y(5.45~7.83)比值。综上,结合区域最新研究成果,我们认为辉闪橄榄岩来源于受俯冲流体交代的尖晶石相地幔橄榄岩部分熔融,上升过程中受地壳物质不同程度的混染,形成于早二叠世板内伸展构造体制,与古亚洲洋闭合之后板内非造山作用有关。这一认识填补了早二叠世幔源岩浆事件和非造山阶段超镁铁质岩石记录的空白。     

现代专题地图制图研究进展与趋势分析

针对专题地图制作相关研究不足的问题,该文通过归纳总结专题地图理论与应用、网络共享等方面的研究进展,从功能转变、模式转变和内涵冲击三方面分析专题地图研究趋势,并探讨现有制图理论技术存在的不足之处。文章认为:研究专题地图符号的内在结构及统一构建方式,在符号学和微观语言学的理论框架下建立专题符号句法模式,注重对专题地图符号模型的整体描述,并通过相应制图模型的研究来优化制图过程,发掘和创新制图理论成果,将会促进专题地图理论的完善,深化专题符号的自适应表达。     

边坡单元的SAR数据特征

针对传统D-InSAR技术以栅格单元为研究对象而无法充分反映地形条件的问题,该文提出了以边坡单位为研究对象的D-InSAR数据特征分析。通过基于边坡单元的区域地形因子与后向散射系数和相干系数关系的分析方法,建立了研究区域SAR数据的可信区域滤波方法,提取出了研究区域SAR数据分析结果的可信区域。该方法提高了SAR数据的有效性,为滑坡早期监测提供了可靠的数据基础。通过对金沙江乌东德区域的SAR数据实例分析,验证了该方法的实用性。