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1.
Comparison of different land-surface perturbation methods in short-range ensemble forecasts 下载免费PDF全文
Zhibo Gao Jiangshan Zhu Yan Guo Xiaodong Yan Xiujuan Wang Huoqing Li Shuwen Li 《大气和海洋科学快报》2021,14(3):60-65
为了比较不同陆面扰动方法对短时集合预报的影响,本研究设计了陆面模式扰动实验(LSMPE),初始土壤湿度扰动实验(ISMPE),陆面-大气耦合系数扰动实验(LCCPE)以及大气扰动对照实验(GEFSPE).结果表明,在三组陆面扰动实验中,LSMPE能代表最大的不确定性且误差最小;ISMPE的离散度要比LCCPE稍大,但是耦合系数的减弱能有效降低区域平均降水量.然而,所有陆面扰动实验产生的离散度均小于GEFSPE,这表明未来有必要将陆而扰动与大气扰动相结合,以使得模式能代表更多的不确定性. 相似文献
2.
The increasing use of pharmaceuticals has become a major environmental issue in China.The presence of antibiotics in water may have deleterious effects on non-target aquatic organisms such as microalgae.In this study,a cyanobacterium and an alga species in surface waters,Microcystis aeruginosa and Chlamydomonas microsphaera,were exposed to 0,0.1,0.5,1.0,2.0,5.0,10.0,and 20.0 mg/L of oxytetracycline dihydrate(OXY) and sulfamethoxazole(SMZ) for 96 h to determine the effects of these antibiotics on the growth and surface morphology.Moreover,the photosynthetic activity and the contents of superoxide dismutase(SOD),malondialdehyde(MDA),and protein were measured to examine the biochemical characteristics of M.aeruginosa and C.microsphaera under OXY and SMZ stress.The effects of both antibiotics on the growth of both species were concentration-dependent and characterized by low-dose stimulation and high-dose inhibition.C.microsphaera was more sensitive to both antibiotics than M.aeruginosa was.The algal cell membranes of both species disintegrated after exposure to a high concentration of OXY.All of the physiological parameters measured in this study were relatively stable at low concentrations of OXY and SMZ.After exposure to high concentrations of OXY and SMZ,photosynthetic activity decreased significantly,whereas lipid peroxidation and the abundance of SOD,MDA,and protein increased significantly.Thus,low-dose antibiotics may increase algal blooms in eutrophic waters. 相似文献
3.
Water flow velocity is an important hydraulic variable in hydrological and soil erosion models, and is greatly affected by freezing and thawing of the surface soil layer in cold high-altitude regions. The accurate measurement of rill flow velocity when impacted by the thawing process is critical to simulate runoff and sediment transport processes. In this study, an electrolyte tracer modelling method was used to measure rill flow velocity along a meadow soil slope at different thaw depths under simulated rainfall. Rill flow velocity was measured using four thawed soil depths (0, 1, 2 and 10 cm), four slope gradients (5°, 10°, 15° and 20°) and four rainfall intensities (30, 60, 90 and 120 mm·h−1). The results showed that the increase in thawed soil depth caused a decrease in rill flow velocity, whereby the rate of this decrease was also diminishing. Whilst the rill flow velocity was positively correlated with slope gradient and rainfall intensity, the response of rill flow velocity to these influencing factors varied with thawed soil depth. The mechanism by which thawed soil depth influenced rill flow velocity was attributed to the consumption of runoff energy, slope surface roughness, and the headcut effect. Rill flow velocity was modelled by thawed soil depth, slope gradient and rainfall intensity using an empirical function. This function predicted values that were in good agreement with the measured data. These results provide the foundation for a better understanding of the effect of thawed soil depth on slope hydrology, erosion and the parameterization scheme for hydrological and soil erosion models. 相似文献
4.
钪(Sc)是世界各国竞相争夺的关键金属矿产资源之一。滇中牟定大弯山变质玄武岩厚度>36.5m,出露面积0.5km^(2),形成时代为新元古代南华纪(781.3±1.9Ma)。本文对该变质玄武岩开展了全岩地球化学分析、全自动矿物分析(TESCAN TIMA)观测、NPPM薄片区域面扫和单矿物原位LA-ICPMS分析等研究,结果显示变质玄武岩全岩Sc含量为47.0×10^(-6)~97.9×10^(-6),平均含量为69.1×10^(-6),钪氧化物(Sc_(2)O_(3))平均含量为106×10^(-6),变质玄武岩空间Sc矿化特征稳定,具有形成钪矿资源的潜力。同时,变质玄武岩共伴生有钛和铁矿化,全岩TiO_(2)含量为2.57×10^(-2)~6.13×10^(-2),平均为4.25×10^(-2);TFe含量为13.3×10^(-2)~23.7×10^(-2),平均为17.7×10^(-2)。Sc可能存在类质同象和离子相两种赋存形式,类质同象形式Sc主要赋存于钛铁矿和金红石矿物中,钛铁矿中Sc含量为70.0×10^(-6)~168×10^(-6),平均值为108×10^(-6);金红石中Sc含量高达297×10^(-6);而磁铁矿、黑云母等矿物中Sc含量较低,均低于全岩Sc含量,对全岩Sc矿化贡献较小。牟定大弯山Sc矿化与以往报道侵入岩及其风化壳中Sc矿化在富集特征、赋存岩性和载体矿物等方面不同,是变质火山岩中新发现的Sc矿化信息,显示了较好的找矿潜力,对Sc资源勘查和研究具有重要指示意义。 相似文献
5.
隐爆角砾岩筒型金(铜)矿床作为重要的金矿床类型,常伴生关键金属碲的矿化,然而对于此类矿床中碲的分布、分配特征及沉淀机制研究仍较为薄弱。黄屯矿床是长江中下游成矿带近年来发现的最为典型的隐爆角砾岩筒型金铜矿床,伴生有大量的碲化物产出。本文在详细的野外地质工作和岩相学观察基础上,发现碲在矿床中发生了显著富集。通过对黄屯矿床不同蚀变类型矿石及主要富碲矿物开展全岩及微区地球化学分析,明确了碲的分布、分配特征以及初步讨论了碲的沉淀机制。黄屯矿床成矿阶段从早到晚可划分为钠钙硅酸盐、钾硅酸盐、绿泥石-碳酸盐和伊利石-蒙脱石阶段,在不同深度形成了相应的蚀变带,并发育有不同强度的金铜矿化。黄屯矿床伴生的碲储量约有118.71t,平均品位为5.3g/t,达到中型规模,具备重要的综合利用价值。钾硅酸盐蚀变带碲的分布比例最高,占总储量约92.37%,平均品位约为9.6g/t。钾硅酸盐蚀变带内约有89%~99%的碲呈独立矿物,主要以微米级、纳米级的碲铋矿包体的形式分布在黄铁矿中,剩余部分则以类质同象的形式赋存在黄铁矿和黄铜矿内。减压沸腾引起流体温度骤降导致硫化物沉淀,和沸腾过程中释放大量气相H_(2)S,共同导致流体的f(Te_(2))/f(S_(2))比值升高,可能是黄屯矿床中碲沉淀富集的主要机制。 相似文献
6.
Journal of Oceanology and Limnology - We present observations from deployments of turbulent microstructure instrument and CTD package in the northern South China Sea from April to May 2010. From... 相似文献
7.
Liang Zhou Xiaomei Xu Yaping Wang Jianjun Jia Yang Yang Gaocong Li Changliang Tong Shu Gao 《海洋学报(英文版)》2021,40(11):162-175
The relationship between storm activity and global warming remains uncertain. To better understand storm–climate relationships, coastal lagoon deposits are increasingly being investigated because they could provide high-resolution storm records long enough to cover past climate changes. However, site-specific sediment dynamics and high barriers may bias storm reconstructions. Here, we aimed to investigate these factors through the reconstruction of five distinct storm records (XCL-01, XC-03, XC-06, XC-07, XC-08) from different water depths in a lagoon with a high barrier (i.e., Xincun Lagoon of Hainan Island). Sediment cores were characterized using high-resolution grain size and XRF measurements, to identify storm events. These data were coupled with a numerical simulation to obtain bed shear stress data with high-spatial resolution to better understand storm-induced sediment transport mechanisms. 210Pb dating and Pb pollution chronostratigraphic markers indicated that the chronology of the storm deposit sequences of the cores span the period between 117 a and 348 a. The grain size and XRF results indicated numerous, highly variable and short-duration fluctuations, suggesting that storm-induced coarse-grained sediments were deposited at these core sites. The inconsistent storm events recorded in these cores suggest that these sites have different preservation potentials for storm deposits. However, the consistence between storm sediment records and historical documents for Core XCL-01 indicates that high-barrier lagoons could provide long-term storm event records with high preservation potential. 相似文献
8.
Yan Guo Herong Gui Jiuchuan Wei Zhi Zhang Mancong Hu Pei Fang Guangping Li Chuan Gao Xin Wang 《Ground water》2021,59(2):256-265
Permian coal measure sandstone fissure water (referred to as “coal measure water,” that is, water in coal measures) is one of the important water sources for industrial and agricultural activities in mining areas. However, the regional high-pressure grouting, one of the most widely used floor control methods, may affect the coal measure water which is connected with limestone aquifer. This study used Taoyuan mine, a typical coal mine in Huaibei coalfield, as the research area to study the influencing mechanism of a grouting treatment on the hydrogeochemical evolution of coal measure water. The hydrogeochemical characteristics and water-rock interaction mechanism of the coal measure water before and during the treatment were evaluated using a Piper trigram, ion combination ratio, and hydrogen-oxygen stable isotope. The anions and cations in the coal measure water before and during the treatment had the same trends at SO42− > HCO3− > Cl− and Na+ > Ca2+ > Mg2+, respectively. Hydrochemical types of coal measure water before treatment were mainly SO4·Cl-Ca·Mg, SO4·Cl-Na, and HCO3-Na, and during treatment they were mainly SO4·Cl-Na and HCO3-Na. The formation of chemical components of coal measure water before treatment was mainly caused by carbonate dissolution, sulfate dissolution, and pyrite oxidation. During the treatment, sulfate dissolution and pyrite oxidation were the main geochemical processes, and ion exchange was enhanced. Atmospheric precipitation was the source of all water samples, and all showed an obvious 18O drift. 相似文献
9.
山东省齐河县境内发育有矽卡岩型铁矿,近年来该区铁矿勘查和研究工作取得了较大进展。本文通过对研究区内铁矿勘查研究成果进行统计分析,旨在对其控矿特征和找矿标志进行探讨来促进该区铁矿找矿工作。研究区内铁矿控矿地层为奥陶纪碳酸盐岩和石炭纪-二叠纪碎屑岩地层,成矿地质体为燕山晚期中基性侵入岩体;铁矿体主要赋存于地层和岩体的接触带处,且在碳酸盐岩、碎屑岩地层中和侵入岩体中也赋存有部分铁矿体。区内铁矿体赋存类型多样,其中以接触带赋存式为主,且含有断裂充填式、层间充填式、裂隙贯入式、捕虏体构造式等。铁矿体形态复杂,呈层状、似层状、囊状、透镜状等;矿床典型蚀变分带特征为闪长岩带-蚀变闪长岩带-内矽卡岩带-铁矿体-外矽卡岩带-大理岩化带-灰岩带。该区成矿作用以接触扩散交代作用、接触渗滤交代作用为主,此外还有富矿热液充填作用等。研究区内铁矿找矿标志主要包括地层标志(奥陶纪碳酸盐岩和石炭纪-二叠纪碎屑岩地层)、岩体标志(中基性侵入岩体,且发育有钠长石化的蚀变闪长岩)、构造标志(地层与岩体接触带、构造交汇部位、层间滑脱部位、脆性裂隙部位等)、围岩蚀变标志(磁铁矿化、矽卡岩化、钠长石化、蛇纹石化、金云母化等与成矿关系密切)、地球物理标志(明显的高值磁异常和化极磁异常部位、重力异常梯度带和高-低电阻转换带)。在今后铁矿勘查过程中,需要在综合研究该区控矿特征的基础上,可利用多种找矿标志进行相互配合、互为补充和综合研究,以期达到预期勘查效果。 相似文献
10.
Hydrologic separation and their contributions to N loss in an agricultural catchment in hilly red soil region 总被引:1,自引:0,他引:1
The impacts of hydrological processes on N loss is of great value to understand the N transport at catchment scale,which is far from clear. Rainfall, soil water, groundwater and stream water and their N concentrations were monitored from March 2017 to February 2018 in Sunjia agricultural catchment of the red soil critical zone. Objectives of this study were:(1) to determine the dynamics of N concentration of different waters and their N loads;(2) to assess their contributions to N load of streamflow in the paddy and upland mixed agricultural catchment. Our results showed that the N concentrations of soil water(4.8 mg L~(-1)) and groundwater(6.0 mg L~(-1)) were the highest, approximately 2 to 5 times higher than those of stream water(2.7 mg L~(-1)), rain water(1.7 mg L~(-1)) and irrigation water(1.2 mg L~(-1)). The N net loss of the catchment(38.2 kg ha~(-1) yr~(-1))accounted for 15% of the total fertilizer N input. Rainy season(April–June) was a high-risk period of N loss, contributing to more than one third of the total annual loss amount. Using end-member mixing analysis model(EMMA), we found groundwater(whose discharge accounted for 25% of the catchment streamflow) was an important source for the N loss in the agricultural catchment. Even in this catchment with coexisting upland and paddy field ecosystems, identified end-members could be used to predict the N load well(R~20.87, p0.001). These results can deepen our understanding of the relationship between hydrological process and N transport in the red soil critical zone and are also helpful to improve the water and fertilizer management in subtropical agricultural catchment. 相似文献