Petrogenesis of Early Cretaceous bimodal volcanic rocks in the Fanchang Basin,SE China: an energy-constrained assimilation–fractional crystallization model     

《International Geology Review》2012,54(8):917-940

Volcanic rocks in the Middle–Lower Yangtze River Valley (MLYRV) constitute a bimodal magmatic suite, with a significant compositional gap (between 50% and 63% SiO₂) between the mafic and felsic members. The suite is characterized by a relatively wide spectrum of rock types, including basalts, trachytes, and rhyolites. The basaltic rocks have low-to-moderate SiO₂ contents of 46.00–50.01%, whereas the trachytes and rhyolites possess SiO₂ contents in the range of 63.08–77.61%. Rocks of the bimodal suite show moderate enrichment of LILEs, negative Nb, Ta, and Ti anomalies, and are significantly enriched in LREEs. The basalts were most likely generated by parental mafic magmas derived from enriched lithospheric mantle with minor assimilation of crustal materials involving coeval crystal fractionation during magma evolution. The results of energy-constrained assimilation and fractional crystallization simulations demonstrate that the felsic magma was produced by the mixing of 5–20% lower crustal anatectic melts with an evolved mafic magma (～48% SiO₂) and accompanied by extensive clinopyroxene, plagioclase, biotite, and Fe–Ti oxide fractionation. Our model for the genesis of felsic rocks in bimodal suites is different from the traditional models of crustal melting and fractional crystallization or assimilation–fractional crystallization of basaltic liquids.  相似文献   

Seasonal Stratification Characteristics of Vertical Profiles of Water Body in Lake Lugu     

Wen Xinyu  Zhang Hucai  Chang Fengqin  Li Huayong  Duan Lizeng  Wu Han  Bi Rongxin  Lu Zhiming  Zhang Yang  Ouyang Chuntao 《地球科学进展》2016,31(8):858-869

For the purpose of exploring seasonal stratification characteristics of water hydrochemistry, the seasonal dynamics and vertical thermal stratification of water temperature in Lake Lugu, the vertical profiles of water temperature (Temp), Electrical Conductivity (EC), Dissolved Oxygen (DO), pH and Chlorophyll-a (Chl-a) of Lake Lugu were monitored in January, April, July and October 2015, respectively. The results indicated that water body of Lake Lugu appeared thermal stratification in spring, summer and autumn, however, in winter, the water temperature in vertical direction was homogeneous. The thermocline was located between 10 and 25 m, nevertheless, it moved down to range from 20 to 30 m in autumn. In addition, water temperature in hypolimnion was maintained almost as a constant and consistent with annual temperature, indicating water body was stable all along. The results showed that the thermal stratification had some influences on vertical distributions of DO, EC, pH and Chl-a. The significant stratification of DO, EC and pH was found, especially in summer, DO and pH values in thermocline peaked due to greatly stable thermal stratification and temperature increase. In hypolimnion, DO concentration and pH value were very small. Moreover, Chl-a concentration was higher in the surface and lower in the bottom water, implying that human should be highly alter to prevent the emergence of a large area of algae in Lake Lugu. EC took on decreasing variation, besides, lower in the thermocline. While,Lugu Lake water salinity was lower and substantially constant (~ 0.10‰), without considering the effects of salinity, both in vertical sections and in epilimnion, thermocline and hypolimnion, there all existed a simple linear function of the relationship between EC andwater temperature, showing that Lugu Lake was affected by natural climate and keeps natural state.  相似文献   

一次重秋风天气过程的EC96h500hPa预报场与实况场的对比检验   总被引：1，自引：0，他引：1  

林易  罗喜平  余清 《贵州气象》2003,27(1):7-10

对2002年一次重秋风天气的EC96h 500hPa预报场及EC的850hPa温度96h预报与实况场进行了对比分析，发现EC500hPa 96h预报场对大的环流形势预报较准确，EC的850hPa温度96h预报除个别时次误差较大外，其余时次的温度场预报均较成功，可以提前4d对一些重大天气过程作出准确地预报，大大提高了中期预报水平。  相似文献   

The EU as a frontrunner on greenhouse gas emissions trading: how did it happen and will the EU succeed?   总被引：1，自引：1，他引：1  

Atle C Christiansen  Jørgen Wettestad 《Climate Policy》2003,3(1):3

The objective of this paper is first to provide empirical evidence of what can be seen as a rather remarkable change in EU’s position on the use of greenhouse gas (GHG) emissions trading (ET) in climate policy, from the role of a sceptic in the run-up to Kyoto towards more of a frontrunner. The paper argues that there is a synergistic and multilevel mix of explanatory factors for this “U-turn”, including developments at the international, EU, Member State, sub-national, and even down to the personal level. Second, the paper explores and discusses the philosophy behind the Commission’s proposal for a directive on GHG ET. Third, the paper examines the prospects for ‘success’ of a scheme for EU-wide ET using a multifaceted set of metrics. In brief, we argue that output success—the chances for having a directive adopted—hinges on the resolution of two key issues. First, whether the preliminary phase is to be mandatory or voluntary, and second, incompatibilities with domestic ET schemes. Outcome success—steering and cost-effectiveness—will in turn depend on factors like the coverage of the scheme and inclusion of project-based credits, while more long-term political implications hinges on the successful adoption and operation of the scheme.

“The Proposal on emissions trading represents a major innovation for environmental policy in Europe. We are de facto creating a big new market, and we are determined to use market forces to achieve our climate objectives in the most cost-conscious way […]. The emissions trading system will be an important cornerstone in our strategy to reduce emissions in the most cost-effective way”.

Environment Commissioner Margot Wallström.  相似文献   

基于EC细网格数值预报产品的太阳辐照度订正技术     

武辉芹  时珉  赵增保  尹瑞 《气象科技》2020,48(5):752-757

太阳辐照度与光伏电站发电功率密切相关,其预报的准确性直接影响发电功率预报的准确性。根据光伏电站太阳辐照度实况、气象站实况、WRF(Weather Research and Forecast Model)模式辐照度预报、EC细网格数值预报以及太阳理论辐照度,利用逐步回归法开展太阳辐照度预报订正研究,得到以下结论:①太阳辐照度实况与太阳理论辐照度的比值与EC细网格数值预报中气象要素的相关性优于太阳辐照度实况与气象要素的相关性;②不同时刻影响太阳辐照度的气象因子存在差异,通过逐步回归法建立不同时刻太阳辐照度预报模型;③在非晴天情况下,回归预报辐照度相对均方根误差比WRF模式预报辐照度降低10%左右,减小了辐照度预报误差。该研究成果在光伏电站的新能源数值预报服务中有一定的应用价值。  相似文献   

Whole Earth Telescope observations of the hot helium atmosphere pulsating white dwarf EC 20058−5234     

D. J. Sullivan †  T. S. Metcalfe  D. O'Donoghue  D. E. Winget  D. Kilkenny  F. van Wyk  A. Kanaan  S. O. Kepler  A. Nitta  S. D. Kawaler  M. H. Montgomery  R. E. Nather  M. S. O'Brien  A. Bischoff-Kim  M. Wood  X. J. Jiang  E. M. Leibowitz  P. Ibbetson  S. Zola  J. Krzesinski  G. Pajdosz  G. Vauclair  N. Dolez  M. Chevreton 《Monthly notices of the Royal Astronomical Society》2008,387(1):137-152

  相似文献   

Identification of water-bearing fractures in hard rock terrain by electrical conductivity logs, India     

V. K. Saxena  N. C. Mondal  V. S. Singh  Dewashish Kumar 《Environmental Geology》2005,48(8):1084-1095

For the delineation of water-bearing fractures in hard rock areas, a new hydro-chemical technique has been developed which is based on electrical conductivity (EC) logs. The EC logs were carried out in experimental shallow bore wells (≈50 m) in three different parts of India. A sharp variation in EC was observed near water-bearing fractures in hard rock areas. To access applications of this technique, different locations in India were selected and experimental bore wells (≈50 m) were drilled. These were:

(1)	Maheswaram (30 km South of Hyderabad): nine shallow bore wells in a watershed of 60 km2 in granitic aquifers,
(2)	Wailpally (60 km East of Hyderabad): four shallow bore wells in a watershed of 50 km2 in granitic terrain.
(3)	Sadras (60 km SSW of Chennai): four shallow bore wells in a watershed 12 km2 in a charnokite aquifers.

Observations on EC logs were made at short intervals of 1.0 m from the water table (narrow spacing wherever required) until reaching the bottom of the wells. EC showed remarkable changes in value, which was attributed to the presence of water-bearing fractures in the hard rock areas. The results of this study are in good agreement with geophysical and geological findings. In addition to identifying the water-bearing fractures, the EC logs also provide various other hydrological and hydrochemical information, i.e., water table, total depth of the bore well, total dissolved solids (TDS), behavior of water–rock interaction, water quality, information about the chemistry of aquifers, etc.  相似文献   

Prevention and Control of Continuous Cropping Obstacle of Watermelon by Reductive Soil Disinfestation (RSD)     

ZHOU Kaisheng 《资源与生态学报(英文版)》2018,9(5):493-499

This study aimed to explore whether reductive soil disinfestation (RSD) is an effective method of controlling continuous cropping obstacle of watermelon. Samples of watermelon continuous cropping soils were treated by RSD in laboratory tests and pot experiments in August 2015 and from December 10, 2016 to April 10, 2017. The soil samples for the laboratory test were divided into 16 groups, and each group comprised three parallel samples of 100 g (dry soil weight). Except for the original and control (CK) samples, the 14 other groups of soil samples were treated with different combinations of 1% or 3% alfalfa powder, 1% or 3% ammonia (NH₃) water, and 1% or 3% acetic acid. The soil samples were placed inside size-five self-styled plastic bags and incubated in a constant-temperature biochemical incubator at 35°C for 14 days after blending, flooding, and sealing. Seven groups of soil samples were designed for the pot experiments based on the laboratory test results. Each group consisted of 30 parallel samples of 3 kg (dry soil weight). These samples were incubated outdoors for 4 months after mixing with alfalfa powder and/or NH₃ and/or acetic acid according to the experimental design, blending, flooding, and sealing. Watermelon seedlings were planted in the air-dried soil samples from May to July in 2017. The results showed that the pH of the soil samples treated by RSD were elevated except for those samples with acetic acid. In addition, the electrical conductivities of the soil samples treated by RSD were effectively adjusted. The presence of soil-borne pathogenic Fusarium oxysporum f.sp. niveum was significantly suppressed (p < 0.05) in soil samples treated by RSD, and the incidence and mortality rate of watermelons planted in these samples were remarkably lower than those planted in the CK and flooded CK soil samples. Therefore, continuous cropping obstacle of watermelon can be controlled by RSD.  相似文献   

T639和EC模式对内蒙古主要天气系统的预报性能检验   总被引：2，自引：0，他引：2  

荀学义  孟雪峰  王学强  胡英华  金迎春  赵斐  拓彦军  张旭 《气象科技》2014,42(5):832-838

利用2012年T639和EC模式500hPa高度场预报产品及ECMWF客观再分析资料,采用天气学检验方法,对内蒙古主要天气影响系统之西风槽、贝加尔湖冷涡、蒙古冷涡和东北冷涡数值产品的预报性能进行检验。检验结果表明:T639和EC模式产品对内蒙古影响系统具有较好的预报性能,36h内的预报性能更为显著。EC模式产品预报准确率优于T639模式产品,但对内蒙古东部地区影响系统的预报稳定性相对较差。T639模式产品在36h的预报能力比较高,对影响系统的生成时间、槽线位置、移动速度及中心强度4项检验指标预报准确率均在80%以上。EC模式预报产品,48h内对影响系统4项检验指标预报准确率均在80%以上。随着预报时效延长,T639和EC模式产品预报能力均有所下降。两套模式产品与实况相关系数空间分布在各时效均具有显著的相关关系,并且对应相关系数空间分布,T639和EC模式产品标准差的大值中心与相关系数的低值中心基本一致。  相似文献   

北京城市通量足迹及源区分布特征分析   总被引：2，自引：1，他引：1  

刘郁珏  胡非  程雪玲  宋宗朋 《大气科学》2014,38(6):1044-1054

城市下垫面具有不同于其他下垫面的特殊复杂性,通量的源汇分布十分不均,导致直接测量以及定量的描述城市中水汽、二氧化碳等通量变得非常困难。涡动观测系统在城市通量观测中得到广泛应用,但由于涡动协方差观测系统传感器都架设在一定的高度上,其测量结果只反映特定点下垫面或某部分下垫面的物理过程,不能说明观测结果是否具有下垫面属性的代表性,无法反映观测通量的空间变异性。足迹函数(Footprint)的产生就是为了解决这一问题,其又称源权重函数,是描述近地面层表面源或汇的空间分布和仪器观测通量值之间关系的函数。本文采用北京325 m气象塔近1年7层涡动协方差观测数据、超声数据,分析了不同风向、不同稳定度、不同高度下足迹函数所表达的通量贡献区域范围的变化规律。结果表明,在大气稳定条件下时,通量贡献区范围的大小与主风向无显著差异,而不稳定条件下计算结果与主风向无关。在不同高度下所有稳定条件下通量贡献区范围要大于不稳定条件,中性条件则介于两者之间。8 m、16 m高度上的观测结果不能完全代表城市下垫面通量贡献区,47 m以上能够代表城市下垫面通量贡献区,280 m则已经包含了郊区和城区的权重平均。同一大气稳定度条件下,高度越高通量贡献区范围越大,90%通量贡献区范围与观测高度成线性关系,这种线性关系可以预测没有观测高度或者更高处的通量贡献区范围。  相似文献