新疆西准噶尔蛇绿岩形成时代和环境的探讨

西准噶尔位于西伯利亚,哈萨克斯坦和塔里木3个大陆板块的交汇处,其间存在着不同时代的洋壳残片,有晚寒武世—中奥陶世(523.2±7.2—489±53Ma)形成的夏坦河—唐巴勒蛇绿岩带,有志留纪和泥盆纪—早石炭世(395±1.2Ma)形成的玛依拉和达拉布特蛇绿岩带,有奥陶纪(444±27Ma)形成的洪古勒楞蛇绿岩带。按其岩石组合及地球化学特征可分为两种类型,即唐巴勒和洪古勒楞两类。前着代表弧后盆地拉张的产物,后者是在洋脊环境下形成的。从其分布大致可以反映出西准噶尔古生代洋盆不断向大陆俯冲的痕迹。     

沙质海岸沿岸输沙率计算方法研究进展

准确预测波浪作用下沿岸输沙率是沙质海岸研究领域的重要科学问题。根据数十年来国内外沿岸输沙率公式的研究进展,按研究方法对各项成果进行分类,并兼顾时间逻辑,回顾了各研究方法的发展历程及其代表性成果。对各项成果的理论基础、考虑因素、资料来源等方面进行了探讨,并采用现场原型沙、室内原型沙和室内轻质沙等实测资料,对国内外常用公式的预测准确性进行了检验。结果表明,孙林云公式与各项实测资料的吻合程度最高,在众多沿岸输沙率公式中具有明显的先进性。在此基础上,对未来可进一步深化研究的方向作出了展望。     

Bending localization of nitrous oxide under anharmonicity and Fermi coupling: the dynamical potential approach

This paper studies the vibrational nonlinear dynamics of nitrous oxide with Fermi coupling between the symmetric stretching and bending coordinates by classical dynamical potential approach. This is a global approach in the sense that the overall dynamics is evidenced by the classical nonlinear variables such as the fixed points and the focus are on a set of levels instead of individual ones. The dynamics of nitrous oxide is demonstrated to be not so much dependent on the excitation energy. Moreover, the localized bending mode is shown to be ubiquitous in all the energy range studied.     

利用深度学习预报美国东北部日降水分布

现阶段降水预报主要依靠数值天气预报模式。但受物理参数化、计算资源等因素的影响,基于数值模式的降水预报还存在非常大的不确定性。近年来,深度学习在天气预报领域显示出巨大优势和潜力。本文通过构建神经网络预报美国东北部日降水分布,探讨神经网络模型基于低分辨率气象场(ERA-Interim, 0.7°)预报高分辨率降水(CPC,0.25°)的能力,并比较3种主流网络框架(VGG,ResNet, GoogleNet)在该任务中的表现。结果表明,3种网络框架都对美国东北部日降水分布具有一定的预报能力(VGG框架表现最优),但三者的均方根误差(RMSE)均高于ERA-Interim 24-h(ERA24)的降水预报。3种神经网络的集合预报结果优于ERA24预报,且这三者与ERA24预报结果的集合平均能够显著提高ERA24对不同季节、不同强度降水的预报。     

东黄海星康吉鳗渔业生物学特性研究

Whitespotted conger Conger myriaster is a commercially important species in the seas around China, Korea and Japan. The coastal waters of China serve as an important feeding ground for congers, but the spatio-temporal variations in the fishery and biological characteristics of the population have been rarely evaluated and less well understood in this area. We studied the growth, spawning and feeding characteristics of C. myriaster on the basis of samples collected from October 2016 to April 2017 in the Yellow Sea and East China Sea. A total of 529 specimens were collected, with ages ranging from 1 to 6 years and total length ranging from 132 mm to 834 mm.The parameters of von Bertalanffy growth equation L_∞ and k were 1 026 mm and 0.226 a~(–1), respectively; the sex ratio was 88:0(female: male) in the East China Sea and 2.67:1 in the South Yellow Sea; the development stage of ovary ranged from peri-nucleolus stage to secondary yolk globule stage, and the testis of two males was at midmeiotic stage; Crustacean was the major prey for conger of small length, and food source shift to fish with somatic growth. The results showed substantial differences from previous studies in Japan and Korean waters, as well as from China seas in the 1980 s, suggesting potential spatiotemporal changes in the biological characteristics of C.myriaster. This study may improve current understanding of the fishery biology of C. myriaster in the Yellow Sea and East China Sea.     

顾及空间与光谱差异的单幅遥感影像自适应云雾去除方法

光学遥感影像经常受到云雾的干扰而导致数据质量下降。在暗原色先验理论和云雾影像模型的基础上,提出了一种顾及空间和光谱差异的单幅遥感影像自适应云雾去除方法,较好地解决了传统暗原色先验在高亮地物校正过度和部分波段云雾校正不足的问题,有效地实现了影像云雾去除。首先通过高亮地物的光谱特征构建高亮地物判别指数,辅以密度分割对其进行提取分类,在此基础上引入自适应校正函数对该区域透射率进行修正;其次在对多幅云雾遥感影像实验分析的基础上,提出了符合大气散射机制的波段透射率校正系数,实现了波段间处理强度的自适应调整。实验结果表明,该方法能有效去除不同波段的云雾干扰,并避免高亮地物的过度校正,可取得较好的复原结果。     

初始场与云微物理参数方案在飑线数值模拟中的对比研究

采用CM1模式以200 m的高精度水平网格距对一次东北冷涡下的飑线过程进行模拟,采用1 km的水平网格距进行对比试验探究网格距的影响,并通过探空资料的替换与修改研究不稳定能量和垂直风切变对飑线发展的影响。研究表明,水平网格距增大主要使系统演变减缓,强度也有一定的减弱;初始场的不稳定能量减小会使飑线减弱明显,直至无法生成;垂直风切变对飑线的形成影响较小,主要改变了飑线的结构,没有垂直风切变时形成的飑线更为松散。最后的敏感性试验研究了7种云微物理参数方案对飑线内水粒子分布的影响,发现不同的云微物理参数方案会使水粒子的含量和分布出现变化,进一步影响固、液态的降水,飑线模拟采用的NA方案高层冰和雪含量最高,但由于雨和降落到地表的雹、霰含量低,使得累计降水量最小。     

黏土矿物—水界面的量子力学模拟研究

黏土矿物广泛分布于自然界中,其对地质和地球化学过程有重要意义,也是工业、环境等领域中的重要矿物材料。黏土矿物的众多物化性质均与其表界面结构和性质有关。作为实验研究方法的重要补充,量子力学模拟被广泛用于黏土表界面性质的研究。本文回顾了利用量子分子动力学模拟对黏土矿物-水界面性质的研究,包括表界面结构、表面酸度和离子络合等方面。     

车牛山岛铠平鲉繁殖群体生物学研究

利用2009年12月在海州湾车牛山岛调查采集的60尾标本,初步研究该海域铠平鲉群体的繁殖群体生物学特征。铠平鲉繁殖群体体长范围64～119mm,体质量范围6.4～60.2g,年龄组成Ⅱ～Ⅷ龄,性比1.5∶1,以Ⅳ龄和Ⅴ龄组占优势,成熟个体最低年龄为Ⅱ龄,最高年龄为Ⅷ龄。绝对怀卵量变动于327～7 706粒之间,平均3 387粒;相对怀卵量变动于29～204粒/g,均值126粒/g。绝对怀卵量与纯质量的关系为E=126 W-326.27,与体长的关系为E=6×10-7 L4.352。以矢耳石切片为材料鉴定年龄并用Von Bertallanffy方程描述其生长,结果显示雌雄生长差异显著,生长方程分别为雌性Lt=135.5×(1-e-0.158×(t+3.578)),雄性Lt=136.9×(1-e-0.148×(t+3.289))。根据生态参数判断,铠平鲉属于偏k-选择型鱼类。     

Comparison of turbulence schemes for prediction of wave-induced near-bed sediment suspension above a plane bed

Based on a wave bottom boundary layer model and a sediment advection-diffusion model, seven turbulence schemes are compared regarding their performances in prediction of near-bed sediment suspension beneath waves above a plane bed. These turbulence algorithms include six empirical eddy viscosity schemes and one standard two-equation k-ε model. In particular, different combinations of typical empirical formulas for the eddy viscosity profile and for the wave friction factor are examined. Numerical results are compared with four laboratory data sets, consisting of one wave boundary layer hydrodynamics experiment and three sediment suspension experiments under linear waves and the Stokes second-order waves. It is shown that predictions of near-bed sediment suspension are very sensitive to the choices of the empirical formulas in turbulence schemes. Simple empirical turbulence schemes are possible to perform equally well as the two-equation k-ε model. Among the empirical schemes, the turbulence scheme, combining the exponential formula for eddy viscosity and Swart formula for wave friction factor, is the most accurate. It maintains the simplicity and yields identically good predictions as the k-ε model does in terms of the wave-averaged sediment concentration.