安徽濉溪杨桥孜铜金矿金的赋存状态及富集规律     

产思维  张顺林  张家嘉 《江苏地质》2016,40(1):64-69

安徽濉溪杨桥孜铜金矿是皖北地区中型规模的矽卡岩型金矿床,矿体产于燕山期石英二长闪长玢岩与中寒武统徐庄组、毛庄组接触带上。矿床自西向东分为刘楼村、小任家、栆孤堆和杨桥孜4个矿段,其中杨桥孜矿段为主要矿段,该矿段金矿体多与铜矿体共生,极少数为独立金矿体。该矿段共圈定矿体39个,其中Ⅱ4、Ⅲ1、Ⅳ5和Ⅳ6为主要矿体。以分析测试为基础,结合野外工作,系统总结杨桥孜金的矿石类型、矿石矿物成分、金的分布、赋存状态等特征,并对金的富集规律进行了初步研究。  相似文献   

Importance of Air-Sea Coupling in Simulating Tropical Cyclone Intensity at Landfall     

Charlie C. F. LOK  Johnny C. L. CHAN  Ralf TOUMI 《大气科学进展》2022,39(10):1777-1786

An atmosphere-only model system for making seasonal prediction and projecting future intensities of landfalling tropical cyclones (TCs) along the South China coast is upgraded by including ocean and wave models. A total of 642 TCs have been re-simulated using the new system to produce a climatology of TC intensity in the South China Sea. Detailed comparisons of the simulations from the atmosphere-only and the fully coupled systems reveal that the inclusion of the additional ocean and wave models enable differential sea surface temperature responses to various TC characteristics such as translational speed and size. In particular, interaction with the ocean does not necessarily imply a weakening of the TC, with the coastal bathymetry possibly playing a role in causing a near-shore intensification of the TC. These results suggest that to simulate the evolution of TC structure more accurately, it is essential to use an air-sea coupled model instead of an atmosphere-only model.  相似文献   

Recent Decrease in the Difference in Tropical Cyclone Occurrence between the Atlantic and the Western North Pacific     

Johnny C. L. CHAN  Kin Sik LIU 《大气科学进展》2022,39(9):1387-1397

Climatologically, among all ocean basins, the western North Pacific (WNP) has the largest annual number of tropical cyclones (TCs) of around 26 while the Atlantic has around 13, yielding a difference of 13. However, the difference is –7 in 2020, with 30 TCs in the Atlantic and 23 in the WNP, which is the most negative difference within the last 46 years. In fact, during the last 26 years, the difference in TC number is below 10 in ten years, with four years being negative. Such a decreasing difference in TC number can be attributed to the natural multidecadal variation of the Atlantic Multidecadal Oscillation and Interdecadal Pacific Oscillation, as well as other external forcings such as anthropogenic aerosol forcing and increased greenhouse gases, with the additional impact from the La Ni?a condition. This result has significant implications on climate model projections of future TC activity in the two ocean basins.  相似文献   

Variational Quality Control of Non-Gaussian Innovations in the GRAPES m3DVAR System: Mass Field Evaluation of Assimilation Experiments     

Jie HE  Xulin MA  Xuyang GE  Juanjuan LIU  Wei CHENG  Man-Yau CHAN  Ziniu XIAO 《大气科学进展》2021,38(9):1510-1524

The existence of outliers can seriously influence the analysis of variational data assimilation. Quality control allows us to effectively eliminate or absorb these outliers to produce better analysis fields. In particular, variational quality control(VarQC) can process gray zone outliers and is thus broadly used in variational data assimilation systems. In this study,governing equations are derived for two VarQC algorithms that utilize different contaminated Gaussian distributions(CGDs): Gaussian plus flat distribution and Huber norm distribution. As such, these VarQC algorithms can handle outliers that have non-Gaussian innovations. Then, these VarQC algorithms are implemented in the Global/Regional Assimilation and PrEdiction System(GRAPES) model-level three-dimensional variational data assimilation(m3 DVAR) system. Tests using artificial observations indicate that the VarQC method using the Huber distribution has stronger robustness for including outliers to improve posterior analysis than the VarQC method using the Gaussian plus flat distribution. Furthermore,real observation experiments show that the distribution of observation analysis weights conform well with theory,indicating that the application of VarQC is effective in the GRAPES m3 DVAR system. Subsequent case study and longperiod data assimilation experiments show that the spatial distribution and amplitude of the observation analysis weights are related to the analysis increments of the mass field(geopotential height and temperature). Compared to the control experiment, VarQC experiments have noticeably better posterior mass fields. Finally, the VarQC method using the Huber distribution is superior to the VarQC method using the Gaussian plus flat distribution, especially at the middle and lower levels.  相似文献   

厚覆盖区找矿“循环渐近式勘查技术体系”与应用     

汪青松  张金会  张顺林  张家嘉  产思维  程培生  崔先文  张凯 《地质论评》2021,67(3):67040004-67040004

覆盖区找矿难度不仅与覆盖层厚度有关,还与覆盖层物性、水文地质条件以及矿体特征关系密切。覆盖区找矿突破是一个系统过程,需要经历选区—圈靶—定位—验证评价4个阶段,存在勘查选区、地质信息探测和多学科有效融合难题。前人较少研究覆盖区找矿突破过程与勘查技术体系,笔者等基于“现有技术+结合实际创新”思路,总结提出了厚覆盖区找矿“循环渐近式勘查技术体系”,在实际应用中,能够提高找矿成功率,入选自然资源部《矿产资源节约和综合利用先进适用技术目录(2019年版）》。  相似文献   

Influence of South China Sea SST and the ENSO on Winter Rainfall over South China   总被引：7，自引：0，他引：7  

ZHOU Lian-Tong  Chi-Yung TAM  ZHOU Wen  Johnny C. L. CHAN 《大气科学进展》2010,27(4):832-844

The present study investigates the influence of South China Sea (SCS) SST and ENSO on winter (January--February--March; JFM) rainfall over South China and its dynamic processes by using station observations for the period 1951--2003, Met Office Hadley Center SST data for the period 1900--2008, and ERA-40 reanalysis data for the period 1958--2002. It is found that JFM rainfall over South China has a significant correlation with Nino-3 and SCS SST. Analyses show that in El Nino or positive SCS SST anomaly years, southwesterly anomalies at 700 hPa dominate over the South China Sea, which in turn transports more moisture into South China and favors increased rainfall. A partial regression analysis indicates that the independent ENSO influence on winter rainfall occurs mainly over South China, whereas SCS SST has a larger independent influence on winter rainfall in northern part of South China. The temperature over South China shows an obvious decrease at 300 hPa and an increase near the surface, with the former induced by Nino-3 and the latter SCS SST anomalies. This enhances the convective instability and weakens the potential vorticity (PV), which explains the strengthening of ascending motion and the increase of JFM rainfall over South China.  相似文献   

Local Climate Change Induced by Urbanization on a South China Sea Island     

郝宇  李磊  陈柏纬  孙伟  戴永久 《热带气象学报(英文版)》2024,30(1):11-19

The South China Sea is a hotspot for regional climate research. Over the past 40 years, considerable im provement has been made in the development and utilization of the islands in the South China Sea, leading to a substantialchange in the land-use of the islands. However, research on the impact of human development on the local climate of theseislands is lacking. This study analyzed the characteristics of local climate changes on the islands in the South China Seabased on data from the Yongxing Island Observation Station and ERA5 re-analysis. Furthermore, the influence of urba nization on the local climate of the South China Sea islands was explored in this study. The findings revealed that the 10-year average temperature in Yongxing Island increased by approximately 1.11 °C from 1961 to 2020, and the contributionof island development and urbanization to the local warming rate over 60 years was approximately 36.2%. The linearincreasing trend of the annual hot days from 1961–2020 was approximately 14.84 days per decade. The diurnal tem perature range exhibited an increasing trend of 0.05 °C per decade, whereas the number of cold days decreased by 1.06days per decade. The rapid increase in construction on Yongxing Island from 2005 to 2021 led to a decrease in observedsurface wind speed by 0.32 m s –1 per decade. Consequently, the number of days with strong winds decreased, whereas thenumber of days with weak winds increased. Additionally, relative humidity exhibited a rapid decline from 2001 to 2016and then rebounded. The study also found substantial differences between the ERA5 re-analysis and observation data,particularly in wind speed and relative humidity, indicating that the use of re-analysis data for climate resource assessmentand climate change evaluation on island areas may not be feasible.  相似文献   

SURFACE IMBALANCE ENERGY CALCULATED AND ANALYZED WITH THE DATA OF EBEX-2000^*          下载免费PDF全文

LI Jie  LIU Shuhu  LIU Heping  Johnny CHAN  Andrew Y. S CHENG  HU Fei  LIU Huizhi 《Acta Meteorologica Sinica》2003,17(4):448-464

Mainly.three methods have been developed to calculate turbulence heat flux.They are eddy covariance method,Bowen ratio/energy balance method and aerodynamic method.In this paper, all the three methods have been used to calculate sensible heat flux,latent heat flux and imbalance energy near the surface with the experiment data of EBEX-2000.Then comparisons of the three methods and some possible explanations of the surface imbalance energy are given.  相似文献   

油气藏全空间磁学、地球化学与矿物学结构及意义--检验"烟筒效应"的形成机理   总被引：2，自引：0，他引：2  

刘庆生  李海侠  王芳  田志  王艾红  陈龙生  张双喜  夏响华  程同锦 《地球科学》2002,27(5):637-644

位于松辽盆地南部某油气田边缘一个油气显示井的磁性测量结果表明,岩石具有明显的磁性变异结构特征.以磁化率(κ)为例,在低缓的背景磁性上主要呈现高强度与中等强度的2类异常:大于400×10-5为强磁性,100×10-5～150×10-5为中等强度磁性.结合录井资料与地球化学分析解释可知,强磁性异常主要位于取样间隔的底部干层区,少数样品位于浅部油气显示层;中等强度异常主要位于2 700 m附近的油气显示层.岩石磁性与地球化学成分对应分析表明,油气显示层岩石的C1和C2成分与磁化率 (κ)、饱和磁化强度 (Js) 和饱和等温剩余磁化强度(SIRM)之间呈明显的正相关,与内禀矫顽力(Hc)为逆相关,而干层岩石相关性不明显.矿物成分分析显示,岩石中主要含铁矿物为磁铁矿、磁赤铁矿、赤铁矿、黄铁矿和菱铁矿.其中磁赤铁矿主要分布在具有中等磁性强度的油气显示层,而高含量(最高含量达12.5%)的磁铁矿主要位于底部干层.磁赤铁矿与赤铁矿、黄铁矿及菱铁矿含量之间相关特征初步表明,自生磁赤铁矿可能主要来源于原地赤铁矿与黄铁矿.推测油气显示层岩石中磁性偏软的磁赤铁矿属于烃蚀变的产物,为烃微渗漏效应(或烟筒效应)的全空间形成机理提供了新证据.  相似文献   

香港青马大桥在交通荷载作用下的疲劳评估     

周太全  郭力  陈鸿天 《地震工程与工程振动》2002,22(5):24-29

在全桥三维有限元模型基础上 ,进行了车载响应分析 ,得到全桥的动力响应 ,并与实测结果进行了分析对比 ;对疲劳危险部位建立局部有限元模型 ,并进行了局部应力分析。在结构健康安全监测系统实测数据基础上 ,得到应变循环标准块 ,用基于热点应力疲劳评估方法对危险部位进行了疲劳寿命评估。  相似文献