Rainfall intensity affects runoff responses in a semi-arid catchment     

Ze Tao  Min Li  Bingcheng Si  Dyan Pratt 《水文研究》2021,35(4):e14100

The source and hydrochemical makeup of a stream reflects the connectivity between rainfall, groundwater, the stream, and is reflected to water quantity and quality of the catchment. However, in a semi-arid, thick, loess covered catchment, temporal variation of stream source and event associated behaviours are lesser known. Thus, the isotopic and chemical hydrographs in a widely distributed, deep loess, semi-arid catchment of the northern Chinese Loess Plateau were characterized to determine the source and hydrochemical behaviours of the stream during intra-rainfall events. Rainfall and streamflow were sampled during six hydrologic events coupled with measurements of stream baseflow and groundwater. The deuterium isotope (²H), major ions (Cl⁻, SO₄²⁻, NO₃⁻, Ca²⁺, K⁺, Mg²⁺, and Na⁺) were evaluated in water samples obtained during rainfall events. Temporal variation of ²H and Cl⁻ measured in the groundwater and stream baseflow prior to rainfall was similar; however, the isotope compositions of the streamflow fluctuated significantly and responded quickly to rainfall events, likely due to an infiltration excess, overland dominated surface runoff during torrential rainfall events. Time source separation using ²H demonstrated greater than 72% on average, the stream composition was event water during torrential rainfall events, with the proportion increasing with rainfall intensity. Solutes concentrations in the stream had loglinear relationships with stream discharge, with an outling anomaly with an example of an intra-rainfall event on Oct. 24, 2015. Stream Cl⁻ behaved nonconservative during rainfall events, temporal variation of Cl⁻ indicated a flush and washout at the onset of small rainfall events, a dilution but still high concentration pattern in high discharge and old water dominated in regression flow period. This study indicates rainfall intensity affects runoff responses in a semi-arid catchment, and the stored water in the thick, loess covered areas was less connected with stream runoff. Solute transport may threaten water quality in the area, requiring further analysis of the performance of the eco-restoration project.  相似文献   

Bacterial productivity in the Prydz Bay and its adjacent waters,Antarctic     

邱雨生  黄奕普  陈敏  刘广山 《极地研究(英文版)》2004,15(1):14-27

1　IntroductionBacteriaandtheiractivitiesplayanimportantroleintheelementalbiogeochemicalcyclesandenergytransformingintheocean (Zhenetal.1 997) .DortchandPackard(1 989) proposedthatfoodwebsintheeutrophicwatersaredominatedbythebiomassofprimaryproducerswhilefoodwebsintheoligotrophicwatersaredominatedbythebiomassofmicrobes.Heterotrophicbacteriahadbeenshowntoplayanimportantroleinthedecompositionoflarge ,rapidlysinkingorganicparticleswithinandbelowtheeuphot iczone ,andfurthertoaffecttheelementaldyn…  相似文献   

Fluid Inclusion Feature of Gold-Bearing Quartz Veins from the Jinniushan Gold Deposit, Shandong, China     

Shen Ping  Shen Yuanchao  Li Guangming  LIU Tiebing  ZENG Qingdong 《世界地质(英文版)》2002,5(2)

The auriferous veins at Jinniushan occurs within the Jinniushan faulted zone in the Kunyushan Granite. Optical observation reveals that gold ore body formed during the main stage of hydrothermal activity. Detailed geothermometric studies of fluid inclusions from the veins show that the forming temperature ranges between 130℃ and 370℃ and the salinity is from 4.01 to 15.21 wvt percent NaCl. The ore-forming fluid is featured by low to moderate salinity, and low to moderate temperature. According to investigations of the values of vapor/liquid and temperatures of the ore-forming fluids, we propose that the boiling fluid inclusions exist in the main mineralization stages. Fluid boiling is suggested as a mechanism for the precipitation of gold from the hydrothermal fluid in the Jinniushan gold deposit.  相似文献   

GPS/LEO掩星观测的变分同化技术   总被引：6，自引：0，他引：6  

刘敏  郭鹏 《天文学进展》2006,24(1):27-42

在简单介绍GPS/LEO掩星探测大气的发展历史和科学意义之后,详细阐述了反演的基本原理;分析了标准反演中存在的问题,并说明一维变分同化(1DVAR)在反演方法中的重要性;给出了一维变分同化中价值函数的求解,以及各种同化因子;简单介绍了对当前气象学中普遍使用的四维变分同化(4DVAR);重点讨论了各种同化方法,以及使用各种同化因子的优缺点。最后,通过CHAMP卫星的观测实例分析,验证了GPS数据在数值天气预报(NWP)中的作用,以及相对于标准反演法一维变分对气象要素的改进。  相似文献   

Observational evidence for solar coronal decimetric radio pulsations with very short periods     

Xie Rui-xiang  Wang Min  Shi Shuo-biao  Xu Chun  Li Wei-hua  Yan Yi-hua 《Chinese Astronomy and Astrophysics》2003,27(4):426-434

Using the decimetric (700–1500 MHz) radio spectrometer and the synchronous observational system with high temporal resolution at four frequencies (1420, 2130, 2840 and 4260 MHz) of Yunnan Observatory, two rare events were observed on 2001 June 24 and 1990 July 30. The former was a small radio burst exhibiting pulsations with short periods (about 29, 40 and 100 ms) in the impulsive phase. The latter was a large radio burst, which at 2840 MHz produced radio pulsations with period of about 30 ms. This paper focuses on pulsations with very short periods in the range of 29–40 ms. The mechanism of generation of such pulsations may be modulation of radio radiation by the periodic trains of whistler packets originating in unstable regions of the corona. Alternatively, these pulsations can be attributed to wave-wave non-linear interactions of electrostatic upper hybrid waves driven by beams of precipitating electrons in flaring loops.  相似文献   

Tanlu Fault Zone and Gold Ore Metallogenesis     

SHEN Yuanchao  ZENG Qingdong  LIU Tiebing 《东北亚地学研究》2002,(1)

Tanlu Fault Zone (TFZ) is a large NE trending deep fracture system in East China and is about 2500 km long. It extends from the south of Lujiang to Tancheng, and passes through the Bohai Sea and continues to the north, where it branches into Yilan ?Shulan Fault and Dunhua ?Mishan Fault. TFZ is a long lasting huge deep - rooted lithospherical fault system with different characteristics in different parts and at different periods of its evolution. TFZ also controls the distribution and occur-rences of many superlarge, large, middle and small sized gold ore deposits, e. g. Jiapigou, Haigou, Xiaoxihancha and Ciwei-gou gold deposits in Northeast China; Linglong, Jiaojia, Sanshandao, Taishang, Xincheng, Rushan, and Pengjiakuang gold deposits in Jiaodong Peninsula of Shandong Province; and Guilaizhuang and Yinan in Western Shandong Province.  相似文献   

APPLICATION OF MAP AND FILE INFORMATIONVISUALIZATION SYSTEM TO COMPREHENSIVEDIVISION OF NATURAL DISASTERS- Takingthe ChangjiangValleg as an Example     

HU Bao-qing    JIANG Mei-xin  JUN Su-lan  ZENG Qiao-song 《中国地理科学(英文版)》2001,(4)

In recent years，scholars at home and abroad have method，and that vanous disasters would be analyzed assynthetically studied natural dlsaste‘theoretically and an Integral．SHI Peilun（1991）putforwad a scientificmethodologlcally，as well as its cases analys。s（CND，term—regional disaster system，which Indicates that1987； MA et al，1990； MARBLE，1990； NE et al，the situation of a disaster（calamity loss）results from1999； PATAK et al，1982； SHI，1991；VAN et al，h…  相似文献   

能量色散X射线荧光光谱法测定钼矿石中钼铅铁铜   总被引：1，自引：1，他引：0  

田文辉  王中岐  张敏 《岩矿测试》2008,27(3):235-236

建立了能量色散X射线荧光光谱法测定钼矿石中钼、铅、铁、铜的方法,讨论了粒度效应、矿物效应的影响因素,确定了采取粉末样品,用系列标准样品建立工作曲线,通过元素间相互校正消除基体效应,用内控标准样品考察了方法的精密度(RSD,n=11)为0.44%～15.4%。实际样品的测定结果和化学法相符,可满足日常分析工作需要。  相似文献   

多接收器电感耦合等离子体质谱法测定镉标准溶液中镉的同位素组成   总被引：1，自引：1，他引：0  

高博  梁细荣  刘颖  胡光黔  曾文  涂湘林 《岩矿测试》2008,27(5):321-324

建立了多接收器电感耦合等离子体质谱仪对Cd标准溶液同位素组成进行分析的实验方法。仪器的质量分馏校正采用Standard-Sample Bracketing法。实验结果用δ114/110Cd来表达。在此研究基础上,以SPEX Cd标准溶液为参考标准,对国外4种Cd标准溶液进行了测定。结果表明,实验测定的精度在0.07‰~0.13‰(δ114/110Cd),与目前文献报道的结果具有相似的精度。以最新SPEX Cd标准样品(δ114/110Cd=0)为基准,计算的δ114/110CdJMC、δ114/110CdSPEX-1、δ114/110CdBAM1012和δ114/110CdM櫣nster的值分别为0.55‰、0.56‰、-0.65‰和5.14‰,说明不同批次SPEX标准溶液的Cd同位素组成是明显不同的,最新的SPEX Cd标准溶液与SPEX-1 Cd的δ114/110Cd值存在着0.56‰的差别。将以SPEX Cd为参考标准的δ114/110CdBAM1012和δ114/110CdM櫣nster转化为以SPEX-1或JMC为参考标准后,得到的结果与文献报道的结果在误差范围内一致。  相似文献   

赣南崇义—大余—上犹矿集区不同类型含矿石英中白云母40Ar/39Ar年龄及其地质意义   总被引：14，自引：0，他引：14  

刘善宝  王登红  陈毓川  李建康  应立娟  许建祥  曾载淋 《地质学报》2008,82(7):932-2008-01-30

崇义—大余—上犹矿集区是世界著名的黑钨矿床集中区,本文选择钨锡多金属硫化物石英脉型（柯树岭和漂塘矿床）和锡钨石英脉型（仙鹅塘矿床）3个矿床石英中的白云母开展40Ar/39Ar年代学研究,测得坪年龄分别是：钨锡多金属硫化物石英脉型是 158.9 ± 1.4 Ma（漂塘）、158.8 ± 1.2 Ma（柯树岭）;钨锡石英脉型的是231.4 ± 2.4 Ma（仙鹅塘）,在反等时线图上,其对应的截距年龄分别是158.8 ± 1.6 Ma、158.7 ± 1.9Ma和232.5 ± 2.4 Ma。由此表明,在崇余犹矿集区内存在两个不同成矿时期,即以黑钨矿为主的多金属硫化物石英脉型矿床形成于中侏罗世,集中于160~150Ma之间,与南岭地区钨锡矿床的主成矿期是一致的;而以锡石为主的,并含有大量白钨矿的石英脉型矿床可形成于印支期  相似文献