Distribution of suspended particulate matter in the northern Bohai Bay in summer and its relation with thermocline

Field observations of suspended particulate matter (SPM) in the Bohai Bay, China have not been widely reported. The aim of this paper is to describe the horizontal and vertical distribution of mass and volume concentrations of SPM, respectively, based on observed data at 312 stations in the northern Bohai Bay during summer of 2006. A numerical model ECOMSED coupled with a sediment transport module was also established to further discuss the mechanism of the thermocline effect on the vertical distribution of SPM. The mass concentrations of SPM exhibited high inshore values and low offshore values in the horizontal distribution; while in the vertical direction, characteristics of the volume concentration of SPM can be divided into two types: one with a sharp peak at depth of 10–15 m and another without. The peak value at the depth of the thermocline was resulted from concentrated phytoplankton. A numerical experiment further displayed that the thermocline can also prevent particles from being resuspended upward.     

Correction of the temperature effect in calibration of a solar radio telescope

This work analyzes the annual fluctuation of the observation data of the Mingantu Solar radio Telescope(MST) in S, C and X bands. It is found that the data vary with local air temperature as the logarithmic attenuation of equipment increases with temperature and frequency. A simplified and effective calibration method is proposed, which is used to calibrate the MST data in 2018–2020, while the correction coefficients are calculated from data in 2018–2019. For S, C and X bands, the root mean square errors of one polarization are 2.7, 5.7 and 20 sfu, and the relative errors are 4%, 6% and 8% respectively. The calibration of MUSER and SBRS spectra is also performed. The relative errors of MUSER at 1700 MHz,SBRS at 2800 MHz, 3050 MHz and 3350 MHz are 8%, 8%, 11% and 10% respectively. We found that several factors may affect the calibration accuracy, especially at X-band. The method is expected to work for other radio telescopes with similar design.     

应用卫星资料分析苏州夏季城市热岛效应

利用苏州2004-2007年自动气象站资料以及购自中国科学院对地观测与数字地球科学中心的Landsat 5卫星(25 m分辨率)资料,分析研究苏州地区城市热岛总体特点以及分布规律,并对可能变化做一些探讨.分析认为,由于城市热岛效应,苏州地区气温呈中间高两侧低的分布特征,气温高值中心呈西北-东南走向,沿太湖及沿江地区气温相对较低;苏州城市地表温度呈明显的放射型分布,以市区中心向四周呈放射状分布.     

江西赣县区牛角龙钨多金属矿床的发现及其特征

江西赣县区牛角龙钨多金属矿床是根据中国地质调查局在赣南老区实施精准扶贫工作总体部署,由南京地质调查中心"南岭东段重要矿种成矿要素调查"项目组通过1∶5万矿产地质调查、大比例尺填图、地表槽探揭露和深部钻探验证等技术手段发现的具有大型成矿远景的钨多金属矿床.最新研究成果显示,该矿床为石英细脉-网脉带型黑钨矿多金属矿床,地表已圈定南、北2个矿脉带,其中呈近SN向展布的北脉带( Ⅰ)是矿区的主矿脉,以石英细脉-网脉型黑钨多金属矿为主,宽10~30 m,南北延伸1 500 m以上,验证实施的ZK001钻孔和ZK002钻孔中分别发现含矿石英脉157条和249条,已圈定了4个钨矿体、2个银矿体和8个含矿细脉带.该矿床的发现不仅实现了赣南找矿空白区的新突破,为该区脱贫致富提供新的钨多金属矿资源基地,也为赣南及相邻地区钨多金属矿找矿勘查提供了理论依据和成功示范.     

多元门限回归模型的一种建模方法

本文根据门限自回归模型的基本思想[1]，提出一种多元门限回归模型的建模方法。其特点是充分考虑了预报系统中某些特殊预报因子突变点对预报关系的改变作用。数值实例表明，该模型在模拟和预报精度上比一般线性逐步回归模型有一定程度的提高。     

天津滨海地区浅层剪切波速与基底构造关系研究

Shear wave velocity is one of the important dynamic characteristics of soil layers and applied widely in aseismic engineering. In this paper, 500 drill logging data are used to make a linear interpolation based on 0.01°×0.01°×1m grid. A shallow 3-D shear wave velocity structure of Tianjin coastal area is obtained. According to the data and geological background, we selected two typical velocity profiles to try to introduce and explain its relationship to basement structure. The results show that the shear wave velocity structure clearly presents the characteristic of stratification and lateral inhomogeneity. Furthermore, the difference of the shear wave structure between tectonic elements is clear and the velocity structure between the two sides of the local or border fault in the Quaternary is disturbed or affected significantly. It intuitively shows that the basement structure and fault activity of this region had good control of sedimentation development and strata formation in the Quaternary period which would have an important effect on engineering seismic and geological condition evaluation.     

永清MS 4.3地震前永清井水温异常分析

2017年12月永清井观测温度急剧下降,采用该井水温、水位多年观测数据,从仪器测量原理及精细温度梯度测量出发,结合井孔资料,认为该变化为永清M_S 4.3地震（井震距<30 km）发生前的异常信息。利用正弦累加模型计算温度异常持续时间和幅度,发现该异常变化存在2个周期：①周期42天,温度变化幅度为0.042 12℃;②周期16.77天,温度变化幅度为0.018 62℃。分析认为,区域应力状态发生变化,使含水层渗透性受到影响,从而间接影响到井下温度传感器安放处水温。地震发生后近距离观测到水温异常变化尚属首次,利用模型对变化时间与幅度进行量化提取,可为经验预报、统计预报提供经典震例。     

地震前兆异常时间分布非线性特征的初步探讨——以海城地震和唐山地震为例

震源系统是一个与外界既有物质交换又有能量交换的耗散系统,在其发展演化过程中会经历一系列的分岔突变。作者运用非线性动力学的方法,分析了海城地震和唐山地震的前兆资料。研究结果表明,前兆异常活动具有阶段性,相邻两个异常阶段的持续时间的比值为一常量(5左右)。这种前兆时间分布规律可用震源体内应变能密度随孕震时间的增加发生倍周期分岔进行解析。它可用于预测主震的发生时间     

世界海洋油气资源与勘探模式概述

描述了全球海洋油气储量的总体情况、海洋油气资源的地域分布以及海洋油气产量的状况与增长趋势。简略阐述了海洋油气勘探的阶段划分、海洋地质调查、海洋地球化学勘探、海洋非地震地球物理勘探以及海洋地震勘探各方法的基本特点、关键技术和常用手段等。对海洋油气勘探的前景,尤其是深水区和天然气水合物的勘探前景作了展望。