黑潮区台风域海-气热输送量的计算

根据1972和1974年经过黑潮区的两个台风个例,计算和分析了台风各部位在不同的海气条件下热量输送的垂直分布特点。表明,在台风前部信风带中,热量垂直输送限于700hPa以下,在1000hPa处有约167.47—209.34J/(cm~2·h)的最大值,700hPa以上热量向下输送;在台风中心区,热量输送量最大,在1000hPa处接近420J/(cm~2·h),在850hPa附近可能有热输送量的最大值,其上随高度减小;在台风后部偏南气流中,向上热输送量较小;各层最大值不超过84J/(cm~2·h)。     

Variation in Water Masses on Shelf of Northern Bering Sea in September 2016-2018

Abstract

Based on hydrological data obtained during the 7th to 9th Chinese National Arctic Research Expeditions in the summers of 2016–2018, the main water structure on the shelf of the northern Bering Sea and the volume and heat fluxes of the Bering Strait throughflow were analyzed. Distinct variability was identified in the three Pacific water masses feeding the strait - Anadyr Water (AW), Bering Shelf Water (BSW) and Alaskan coastal water (ACW). Overall, the temperature and salinity of the entire section increased each year, with 2018 showing significant anomalies, i.e., a temperature anomaly of up to 1?°C and a maximum salinity anomaly of 2. From 2016 to 2018, the extent of the ACW gradually narrowed in the eastern part of this section, while the AW expanded eastward each year. The net volume transport through each of the three sections increased poleward from 1.65?Sv to 2.76?Sv, with the AW increasing from 0?Sv to 1.03?Sv, the BSW varying between 0.52–1.65?Sv, and the ACW gradually decreasing from 1.04?Sv to disappearing completely. The net heat fluxes were also poleward, varying between 25.77 TW and 61.50 TW, and showing a significant increase. Significant variations in magnitude and extent were observed in each water mass of the Bering Strait throughflow, which could produce widespread effects in the Arctic Ocean and the global ocean beyond.     

Sources and hydrothermal alteration of organic matter in Quaternary sediments: A synthesis of studies from the Central Gulf of California

Deep sea drilling in the Central Gulf of California, a young and active spreading centre, shows that the high heat flow typical of these regions causes extensive alteration of sediment organic matter, especially near sills and above magma chambers where hydrothermal activity is concentrated. Even on the nearby passive margin, where there are no sills, heat flow is moderately high and hydrocarbon generation has begun in immature sequences. Migrating light hydrocarbons are detected especially where hydrothermal activity is concentrated. Thermogenic methane is more widespread, though not in the passive margin bordering the spreading centre. Despite the incidence of hydrocarbon generation and migration, the amounts of hydrocarbons involved are relatively small and apparently do not lead to commercially significant accumulations of petroleum.The organic matter in these sediments is mostly marine because the Gulf of California generally has low runoff from land and highly productive surface waters. Turbidites rich in terrigenous organic material are locally abundant in the mainly pelagic section in the Guaymas Basin. The highest concentrations of organic matter are found in laminated diatomites deposited on the Guaymas passive margin within the oxygen minimum zone.     

Parabolic Wave Propagation Modelling in Orthogonal Coordinate Systems

This paper presents a numerical model study of the propagation of water waves using the parabolic approximation of the mild-slope equation in the orthogonal coordinate system. Two types of coordinate systems are studied: (a) a general form of orthogonal coordinate system and (b) the conformal system, a special form of orthogonal coordinate system. Two typical examples, namely, expanded breakwaters and a circular channel, are studied to validate the model. First, the examples are studied by use of the general orthogonal coordinates. Then the same examples are computed by use of the confonnal system. The computational results show that the confonnal coordinate system generally gives better predictions than the general orthogonal system. A numerical technique for generating the conformal grid is combined with the numerical model to improve the practicability of the model. The comparison between the result from the numerical grid system and that from the analytical grid system shows that reliable computational results can be obtained by use of the numerical confonnal grid system.     

Spatial and temporal variability of heat content above the thermocline in the tropical Pacific Ocean

Abstract-Heat content of the upper layer above the 20℃ isotherm in the tropical Pacific Ocean isestimated by using the sea temperature data set with a resolution 2°latitude×5°longitude (1980～1993)for the water depths (every 10 m) from 0 m to 400 m, and its temporal and spatial variabilities are an-alyzed. (1) The temporal variability indicates that the total heat in the upper layer of the equatorial Pa-cific Ocean is charcterized by the interannual variability. The time series of the equatorial heat anomaly5 months lead that of the El Nino index at the best positive lag correlation between the two, and theformer 13 months lag behind the latter at their best negative lag correlation. Therefore the equatorialheat content can be used as a better predictor than the El Nino index for a warm or cold event. In addi-tion, it is also found that less heat anomaly in the equator corresponds to the stronger warm events inthe period (1980～1993) and much more heat was accumulated in the 4 years including 1992/1     

一种带自由面的三维船体贴体网络的数值生成

本文提出了一个生成自由面的三维船体贴体网格的数值方法。文中以静水面以上的船体型线作为描述非定常自由面的计算网格域，进一步完善了我们以往开发的无法考虑兴波与静水面以上的船体型线相互作用对船舶粘性流动影响的网格生成方法。静水面以上的初始自由面网格分别沿船面法线η及切线ζ方向的曲线长的指数进行分布，即可极方便地调节自由面在船面及静水面附近的网格间距，也保证了在数值离散三维Ｐｏｉｓｓｏｎ方程时具有相当好的收敛性。这种方法的特点是计算量相当小，尤其能极方便地控制网格在船面簿粘性层中及静水面附近的分布。以Ｓｅｒｉｅｓ６０船模作为计算算例，带自由面的网格分布是相当满意的     

冲绳海槽热流机制浅析

冲绳海槽是一个高热流区，平均热流值极高，但不均匀，实测最小值与最大值相差三个数量级以上，结合海槽地区的构造和地球物理特征，探讨了导致这一高而分散热流特征的多种因素。包括异常壳幔结构。海底热液循环以及地下水对流等，并分析了相应的控制机制。     

用样条函数计算结果研究冲绳海槽热源机制

对冲绳海槽１９８４－１９９０年的实测热流值，利用数字滤波方法计算，得到反映该区深部地壳热状态的区域热流值为８０－１６０ｍＷ／ｍ＾２，用Ｂ样条函数法对其作数值模拟，计算出海槽地温场模式，并以此研究冲绳海槽海底高热流的形成机制，得出冲绳海槽热流值的区域性变化与綦中地质构造格局呈正相关，高热流是该区现代构造活动所致，其明显特征是地壳减薄，地幔上拱等结论。     

Effect of dispersion on impulsive waves

The generation and propagation of surface waves resulting from suddenly created disturbances over water surfaces is investigated. The initial boundary conditions defining the disturbance are given either by a velocity of the free surface, an initial elevation of the free surface or a pressure impulsively applied on the free surface. It is shown that the corresponding three forms of solutions are related by a simple time derivative. Linear solutions are obtained in the cases where the wave motion is assumed to be nondispersive, mildly dispersive and fully dispersive, as well as in the case where the motion is given by the method of stationary phase. Criteria are established to indicate the limit of validity of each method.