Objective array design for three-dimensional temperature and salinity observation: Application to the South China Sea

In this study, a moored array optimization tool (MAOT) was developed and applied to the South China Sea (SCS) with a focus on three-dimensional temperature and salinity observations. Application of the MAOT involves two steps: (1) deriving a set of optimal arrays that are independent of each other for different variables at different depths based on an empirical orthogonal function method, and (2) consolidating these arrays using a K-center clustering algorithm. Compared with the assumed initial array consisting of 17 mooring sites located on a 3°×3° horizontal grid, the consolidated array improved the observing ability for three-dimensional temperature and salinity in the SCS with optimization efficiencies of 19.03% and 21.38%, respectively. Experiments with an increased number of moored sites showed that the most cost-effective option is a total of 20 moorings, improving the observing ability with optimization efficiencies up to 26.54% for temperature and 27.25% for salinity. The design of an objective array relies on the ocean phenomenon of interest and its spatial and temporal scales. In this study, we focus on basin-scale variations in temperature and salinity in the SCS, and thus our consolidated array may not well resolve mesoscale processes. The MAOT can be extended to include other variables and multi-scale variability and can be applied to other regions.     

S波段相控阵天气雷达与新一代多普勒天气雷达定量对比方法及其初步应用

受外场试验条件的限制,相控阵天气雷达在测试过程中难以与用于对比的多普勒天气雷达保持相同位置,造成不同雷达之间的观测资料无法直接对比。为了较全面地分析该情况下相控阵天气雷达的探测能力,提出了针对不同地理位置不同分辨率的雷达反射率因子匹配方法和观测资料的定量对比方法。初步使用该方法对2010年5月21日的S波段相控阵天气雷达（S-PAR）与相距54 km的南京新一代多普勒天气雷达（CINRAD/SA）观测资料进行了结构的对比及数值的分析。结果表明：（1）S-PAR的回波结构与位置均较为合理,与CINRAD/SA相比反射率因子测量偏差很小,未受地物影响的径向速度较为接近,同时单波束发射4波束同时接收的扫描方式大大节约了扫描时间;（2）S-PAR受宽波束的影响,100 km外的回波出现了明显的平滑现象,难以探测到细微结构;（3）S-PAR的灵敏度比CINRAD/SA差,100 km处的最小可测反射率因子偏高16 dBz,通过相同灵敏度的模拟后发现S-PAR较差的灵敏度是造成回波结构差异的主要原因;（4）提出的经纬度匹配方法较好地将不同位置下的雷达资料对应起来,经纬度匹配后在垂直方向的不同处理方式得到的结果存在细微差异,基于采样体积的平均方法取得的效果最佳。     

Tandem repeat arrays in the mitochondrial genome as a tool for detecting genetic differences among the ark shell Scapharca broughtonii

We found that tandem repeat (TR) arrays were present in the ark shell Scapharca broughtonii mitochondrial genome, and we demonstrated the efficiency of using this TR region as a tool for the detection of genetic differentiation. In samples collected from seven populations off the Japanese, Chinese, Russian and Korean coasts, five TR types with length ranging from 481 to 601 bp (base pairs) were found, as were 18 haplotypes (n = 155). All the Japanese samples from SD, IK, AM and KG, which represented four geographically distinct populations, had the same type of tandem repeat array, 481‐TR. All the samples from China and all but one sample from Russia had the same TR type, 511‐TR; these finding may be strong evidence that the ark shell populations in China and Russia are very similar. Based on a neighbor‐joining dendrogram of haplotypes, the Korean population was divided into two groups as follows: samples with haplotype H481‐3 and samples with haplotypes H601‐1, H601‐2, H601‐3 or H541‐1. Based on the haplotype diversity and nucleotide diversity, the Chinese, Russian and Korean populations showed a higher diversity than Japanese populations (P < 0.05).     

P波极性揭示的甘东南地区构造应力场特征

通过分析甘东南宽频带流动台阵以及周边固定台站2010年11月1日-2011年11月30日记录的大量近震资料,对区域地震进行了重新定位.根据P波极性数据推断了甘东南地区主应力轴方向,给出了0.25°×0.25°的构造应力场方向.结果显示,甘东南地区最大主压应力轴表现出旋转特性.最大主压应力轴由北部的NEE向逐渐向南部偏转为近EW向和SEE向.结合该区域其它结果讨论了本区域应力场的成因机制.     

时域激电单极～偶极测深数据转换为施伦贝格尔测深数据及其二维反演

这里简述并图示了单极～偶极和对称四极装置测深原理及野外布极方式。根据单极～偶极装置视电阻率与施伦贝格尔装置视电阻率存在的内在关系,以及"等效电阻率法",给出了施伦贝格尔装置视极化率与单极～偶极装置视极化率的数学式,即时域激电单极～偶极装置测得的电性参数数据,可以转换为施伦贝格尔装置电性参数的数据,并对这两种测深装置视电阻率、视充电率分别进行二维反演、成图及对比,结合测区简单的地质特征,显示出两种装置测深具有相同的地质勘探效果。     

光伏屋顶项目发电系统设计与分析

基于建筑屋顶面积大、无遮阳等具有可利用光伏屋顶发电的有利条件,本文以山西某市职中校区内的建筑物为例,从气象条件、系统运行方式、光伏电池方阵设计及并网电气设计等方面提出了综合优化设计方案。     

声学光学法泥沙浓度观测的对比研究

根据光学后散射传感器(Optical Backscatter Sensor,OBS)和声学后散射传感器(Acoustic Backscatting Sensor,ABS)估算悬浮沉积物质量浓度(Suspended sediment concentration,SSC)的原理,在水槽实验室不同波况产生较高悬浮沉积物质量浓度的条件下运用OBS仪器ASM-IV(激光边界层泥沙剖面仪)和ABS仪器AQUAscat1000(多频声学悬沙剖面仪)观测并记录数据。然后用水槽实验抽取的水样标定光学和声学仪器,反演得到高精度的垂向泥沙浓度分布剖面。结果表明,OBS仪器ASM-IV上的不同光学探头测得的浊度与SSC可以用同一个线性关系描述,相关系数高达0.996,进而能够高精度(垂向间距1cm)地反演垂向的SSC剖面;对于本组水槽实验的粉土底质和不同的波况而言,声学仪器比光学仪器的量测精度低;不同频率声学仪器换能器的量测值可相差几个数量级,不同波况条件下的声学仪器反演值与实测SSC的相关性系数在0.716~0.974变化。     

起伏地表地震波场定向照明方法

基于惠更斯-菲涅尔原理和组合震源理论,提出了起伏地表情况下地震波场定向照明分析方法。该方法根据地表起伏形态和给定的照明方向进行坐标系变换,在新坐标系中计算组合震源的激发延时并模拟起伏地表定向的地震波场,从而得出地震波场源-检定向照明度。简单的二维起伏速度模型和起伏的Marmousi模型数值试验验证了该方法的有效性,表明通过坐标变换进行地震波场定向照明分析在地表起伏的勘探区域具有较大的适用性和灵活性,可以用来分析地下复杂构造对照明能量分布的贡献。     

利用密集台阵研究滇西北地区地震活动性

采用双差定位方法对2018-04~2020-09滇西北密集台阵记录到的15 816个地震进行重定位,得到14 110个重定位事件,获得滇西北地区精确的地震空间分布。结果表明：1）研究区地震活动分布不均匀,多数地震沿着深大断裂呈条带状分布,充分展示了断裂在地表的展布形态;2）研究区内地震的震源优势深度范围为7~11 km,说明本区地震多发生在中上地壳内;3）地震在各个剖面深度的分布特征显示出断裂在深部的构造特征。     

Ambient Noise Vertical Directionality and Reflection Loss Estimates for a Shallow Tropical Site with a Fast Sound Speed Bottom

Abstract

For high frequency ocean acoustic modeling applications, seabed reflection loss is a useful alternative input compared to conventional geoacoustic model parameters. Reflection loss can be estimated by comparing the noise intensity of the up and down components of the ambient noise vertical directionality pattern. The potential of this method is demonstrated with experimental data spanning one week, collected off shallow east coast of India using a 21 element vertical hydrophone array. The compact and easily operable vertical array has been designed for high frequency directionality estimation in the band 2–10?kHz. The ambient noise data are beam formed to arrive at the vertical directionality pattern. Further reflection loss values as a function of frequency and grazing angle have been estimated for 1/3 octave bands for a sandy sea bed in warm tropical waters. This has been compared with modeled reflection loss estimates using OASR reflection loss module of OASES. This will serve as inputs to propagation models for applications such as inverse techniques, ambient noise modelling, and sonar system performance prediction.