Comparison of coupled and uncoupled models in simulating Monsoon Intraseasonal Oscillation from CMIP6     

Baosheng Li  Dake Chen  Tao Lian  Jianhuang Qin 《海洋学报(英文版)》2022,41(10):100-108

The monsoon intraseasonal oscillation (MISO) is the dominant variability over the Indian Ocean during the Indian summer monsoon (ISM) season and is characterized by pronounced northward propagation. Previous studies have shown that general circulation models (GCMs) still have difficulty in simulating the northward-propagating MISO, and that the role of air-sea interaction in MISO is unclear. In this study, 14 atmosphere-ocean coupled GCMs (CGCMs) and the corresponding atmosphere-only GCMs (AGCMs) are selected from Phase 6 of the Coupled Model Intercomparison Project (CMIP6) to assess their performance in reproducing MISO and the associated vortex tilting mechanism. The results show that both CGCMs and AGCMs are able to well simulate the significant relationship between MISO and vortex tilting. However, 80% of CGCMs show better simulation skills for MISO than AGCMs in CMIP6. In AGCMs, the poor model fidelity in MISO is due to the failure simulation of vortex tilting. Moreover, it is found that failure to simulate the downward motion to the north of convection is responsible for the poor simulation of vortex tilting in AGCMs. In addition, it is observed that there is a significant relationship between the simulated sea surface temperature gradient and simulated vertical velocity shear in the meridional direction. These findings indicate that air-sea interaction may play a vital role in simulating vertical motions in tilting and MISO processes. This work offers us a specific target to improve the MISO simulation and further studies are needed to elucidate the physical processes of this air-sea interaction coupling with vortex tilting.  相似文献   

壳聚糖/纳米铜复合微球的制备及其对刚果红染料的脱色性能     

李瑞明  李瑾  钟莲  朱巧雅 《中国海洋大学学报(自然科学版)》2022,52(2):77-86

以壳聚糖和CuCl₂·2H₂O为原料,分别采用直接负载法和吸附法成功制备了壳聚糖/纳米铜复合微球,运用傅里叶变换红外光谱(FT-IR)、X-射线衍射(XDR)和扫描电镜(SEM)对催化剂结构进行了表征。以刚果红(CR)染料为目标污染物,评价了催化剂的制备方法、制备条件及氢转移催化反应条件对其催化性能的影响。结果表明,由直接负载法(CS/CuNPs)和吸附法(CS/CuNPs-X)制备的壳聚糖/纳米铜复合微球在CR染料浓度为100 mg/L,催化剂投加量为0.05 g,供氢体浓度为0.05 mol/L的氢转移催化反应条件下,催化反应进行180和60 min时CR脱色率可分别达95.8%和96.8%。CS/CuNPs-X比CS/CuNPs表现了更高的对CR氢转移催化反应的催化速率。两种催化剂催化还原CR染料的反应均符合准一级动力学模型。在连续循环使用10次后,CS/CuNPs和CS/CuNPs-X对CR的脱色率分别为93.9%和89.4%,表明催化剂具有良好的重复使用性能。  相似文献   

Ecological risk assessment and ecological security pattern optimization in the middle reaches of the Yellow River based on ERI+MCR model     

YANG Lian'an  LI Yali  JIA Lujing  JI Yongfan  HU Guigui 《地理学报(英文版)》2023,33(4):823-844

The middle reaches of the Yellow River represent an important area for the protection and development of the Yellow River Basin. Most of the area of the river basin is within the Loess Plateau, which establishes it as a fragile ecological environment. Firstly, using high-resolution data of land use in the watershed from the past 30 years, landscape ecological risk(LER) sample units are defined and an ecological risk index(ERI) model is constructed. Kriging interpolation is used to display the LE...  相似文献   

Molecularly imprinted polymers for selective extraction of crystal violet from natural seawater coupled with high-performance liquid chromatographic determination     

LIAN Ziru  and WANG Jiangtao 《中国海洋大学学报(英文版)》2014,13(2):236-242

Molecularly imprinted polymers(MIPs) were prepared by the bulk polymerization using crystal violet as the template molecule, and the methacrylic acid and ethylene glycol dimetheacrylate as functional monomer and cross-linker, respectively. Systematic investigations of synthetic conditions were conducted. The surface morphology and recognition mechanism of the obtained polymers were studied using scanning electron microscope and spectrophotometric analysis. MIPs showed high affinity to template molecule and were successfully applied as special solid-phase extraction sorbent for selective extraction of crystal violet from natural seawater. An off-line molecularly imprinted solid-phase extraction(MISPE) method followed by high-performance liquid chromatography with diodearray detection for the analysis of crystal violet was also established. MISPE columns have good recoveries for crystal violet standard solutions and good linearity was obtained over the concentration range of 0-200 μg L-1(R2 0.99). Finally, two natural seawater samples were investigated. The recoveries of spiked seawater on the MISPE columns were from 44.47% to 62.34%, the relative standard deviation(n=3) being in the range of 2.89%-5.96%.  相似文献   

Effects of different operational modes on the flood‐induced turbidity current of a canyon‐shaped reservoir: case study on Liuxihe Reservoir,South China     

Sheng Wang  Xin Qian  Bo‐Ping Han  Lian‐Cong Luo  Rui Ye  Wen Xiong 《水文研究》2013,27(26):4004-4016

Suspended matter is an important indicator of water quality in freshwater systems. The flood‐induced turbidity current plays a dominant role in the seasonal dynamic of suspended matter in the Liuxihe Reservoir (23°45′50″N; 113°46′52″E), a large, stratified reservoir at the Tropic of Cancer in southern China. Field measurements show that loading and distribution of suspended matter in the reservoir differ in typical wet, dry and medium years, as a result of different discharge volumes and water level variation patterns. Using historical data and the practical demand for water supply and flood control, we generalized two feasible reservoir operational modes: flood impounding mode (drawing down the reservoir to a low level before flood events to impound inflow during the flooding season) and moderate level change mode (drawing down the reservoir to a moderate level before flood events, then keeping the level within the flood control level during runoff events). To examine the effects of different operational modes and outlet depths on the reservoir's flood‐induced turbidity current, a numerical simulation model was applied in three types of hydrological conditions. The results show that the mode with moderate drawdown and recharge processes can decrease loading of suspended matter in spring and promote turbidity current release during flood events, and upper withdrawal can improve the effects of turbid water release. We suggest that more attention should be focused on water quality management in the reservoir operation stage, severe artificial water level fluctuation being avoided and selective withdrawal becoming an optional management measure. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Till‐forming processes beneath parts of the Cordilleran Ice Sheet,British Columbia,Canada: macroscale and microscale evidence and a new statistical technique for analysing microstructure data     

Christina M. Neudorf  Tracy A. Brennand  Olav B. Lian 《Boreas: An International Journal of Quaternary Research》2013,42(4):848-875

This paper presents the first integrated macroscale and microscale examination of subglacial till associated with the last‐glacial (Fraser Glaciation) Cordilleran Ice Sheet (CIS). A new statistical approach to quantifying till micromorphology (multivariate hierarchical cluster analysis for compositional data) is also described and implemented. Till macrostructures, macrofabrics and microstructures support previous assertions that primary till in this region formed through a combination of lodgement and deformation processes in a temperate subglacial environment. Macroscale observations suggest that subglacial environments below the CIS were probably influenced by topography, whereby poor drainage of the substrate in topographically constricted areas, or on slopes adverse to the ice‐flow direction at glacial maximum, facilitated ductile deformation of the glacier bed. Microscale observations suggest that subglacial till below the CIS experienced both ductile and brittle deformation, including grain rotation and squeeze flow of sediment between grains under moist conditions, and microshearing, grain stacking and grain fracturing under well‐drained conditions. Macroscale observations suggest that ductile deformation events were probably followed by brittle deformation events as the substrate subsequently drained. The prevalence of ductile‐type microstructures in most till exposures investigated in this study suggests that ductile deformation signatures can be preserved at the microscale after brittle deformation events that result in larger‐scale fractures and shear structures. It is likely that microscale ductile deformation can also occur within distributed shear zones during lodgement processes. Cluster analysis of microstructure data and qualitative observations made from thin sections suggest that the relative frequency of countable microstructures in this till is influenced by topography in relation to ice‐flow direction (bed drainage conditions) as well as by the frequency and distribution of voids in the till matrix and skeletal grain shapes.  相似文献   

大坂山含“铬矿物”石英闪长岩岩石特征     

韩英善  陆海莲 《青海国土经略》2001,(2)

大坂山“铬矿物”产出于灰绿色中细粒石英闪长岩中,笔者从区域地质特征、岩石学、岩石化学、地球化学、同位素等方面对石英闪长岩进行了较全面的研究后认为,该套岩石成因为壳幔混合型,构造环境为北祁连加里东洋盆收缩阶段板块俯冲作用下形成的火山弧,岩石成岩时代为早奥陶世,铬矿物形成深度约30km,受区域性岩石圈断裂带控制。  相似文献   

波吉卵囊藻的固定化培养及利用   总被引：3，自引：0，他引：3  

郑莲  黄翔鹄  刘楚吾 《广东海洋大学学报》2005,25(1):17-20

以褐藻酸钙为固定化载体,探讨了胶球直径、不同接种量、CaCl2溶液浓度、褐藻酸钠浓度等条件对波吉卵囊藻(Oocystisborgei)固定化培养及对养殖水体水质的影响。结果表明:波吉卵囊藻固定化培养的最好条件是微藻接种量为1×106 mL-1,CaCl2溶液的质量浓度为30g/L,褐藻酸钠溶液的质量浓度为20g/L。在此条件下制备的固定化藻珠,波吉卵囊藻的生物量从1 83×10-2 mg/粒增加到17. 46×10-2 mg/粒,增加了近10倍,生长率相对较高,证明了它的生理活性不会因固定化而受干扰。引入固定化的波吉卵囊藻不但可以降低养殖水体中氨氮、亚硝酸氮等有害因子的浓度,还能提高水中溶解氧含量,使水体环境长时间处于良好的动态平衡状态。  相似文献   

桂北376铀矿床烃气地球化学研究     

莫连 《地质与勘探》2023,59(5):1027-1042

烃气测量法在锡、金、铜、铅锌等金属矿床找矿中得到了广泛应用,而该技术在花岗岩型铀矿找矿中的应用鲜有报道。本文对桂北376铀矿床已知矿体开展了烃气测量试验,结果显示：相较于其他金属矿,该铀矿区花岗岩和土壤中总烃含量极低,而且花岗岩总烃含量(平均19.42μL/kg)高于上覆土壤(平均6.32μL/kg)。花岗岩中U与多数烃气组分呈负相关,与重烃呈正相关,重烃在U迁移过程中作用强于轻烃;花岗岩烃气标准化配分模式以C₁、iC₄和C₂^-正异常为特征;铀矿化程度与iC₄/nC₄、(C₁+iC₄+C₂^-)/(C₂+C₃+nC₄)及C₂^-/C₃^-比值呈正相关,与C₂₊/∑C比值呈负相关等可为寻找铀矿提供依据。3...  相似文献   

多源数据在甘肃山羊坝地区找矿勘查中的应用     

连琛芹  姚佛军  封志明  杨建民  贾祥祥 《现代地质》2022,36(6):1605-1612

针对单一遥感数据已难以满足地质找矿工作需求的问题,本次研究综合使用雷达数据、光学数据及其他非遥感数据共同服务于地质找矿。以甘肃山羊坝地区为研究区,选择ASTER多光谱遥感数据,采用植被抑制法+特征向量主成分分析法,提取研究区的蚀变信息;选择PALSAR雷达数据,采用聚焦、多视、滤波、辐射定标、地理编码和增强处理等一系列处理方法制作雷达强度图,提取研究区构造信息。最后利用GIS平台进行遥感、地质及化探等信息的集成与综合分析,最终圈定了具有找矿前景的矿产资源靶区,野外查证发现一处金矿点。此次研究获得了良好的找矿效果,表明同时使用雷达数据、光学数据及其他非遥感数据的综合找矿方法,对本地区金矿找矿勘查具有重要的指导作用。  相似文献