胶州湾北部水层生态动力学模型与模拟 Ⅱ.胶州湾北部水层生态动力学的模拟研究

利用建立起的浅海水层生态动力学箱式模型,模拟了胶州湾北部１９９５年的浮游植物、浮游动物、无机氮、无机磷、溶解氧以及ＤＯＣ和ＰＯＣ年变化特征。结果是合理的。通过模型参数敏感性实验分析,揭示了该模型系统的一些动力学特征     

ISO14000环境管理系列国际标准简介

本文概述ＩＳＯ１４０００环境管理系列国际标准的产生背景、国际环境管理标准化技术委员会、已发布的五项环境管理国际标准以及宣传贯彻该系列标准的建议。     

A baroclinic typhoon model with a moving multi-nested grid and variational adjustment initialization Ⅱ. Forecast experiments

INTRODUCTIONBeingoneofthemestdisastrousweathersystemsinfluencingthesoutheaStcoastofChinainsurnmerandautumn,typhoonsalsocausestrongstormsUrgeSandseawavesI'eSultinginsevereoceandisasters,whichthreaten~theasternChina'sagriculture,navigation,offshoreoila...     

1997年日本短期降水数值预报效果的检验

对1997年青岛市降水分布进行了初步统计,并对日本数值预报产品在青岛市天气预报中的应用效果进行了检验分析。结果显示,晴雨和小雨预报在青岛市的短期降水预报中有较好的参考价值。     

A remote sensing environmental study of Haiko Bay——Ⅰ Tidal influx and its changes

Through the water areas extracted from remote sensing images and the combination of the methods for establishing the formula for calculating tidal influx with tidal data, the tidal influx of the Haikou Bay, Hainan Province was found to be 5.14×10⁷m³ in 1990, 5.80×10⁷m³ in 1984 and 5.05×10⁷m³ in 1965, respectively.After the analysis of the morphological and tidal range factors which determine tidal influx, this paper presents the trend of the changes in tidal influx caused by the changes in the morphological factors of the Haikou Bay.It is found that a decreasing trend was shown with a depressive rate of 2×10^-3during the period from 1965 to 1984, and an increasing trend with an incremental rate of 1×10^-3 during the period of 1984-1990.The main reason for the appearance of the decreasing trend before 1984 is the natural deposition and silting-up of the bay sediments; after 1984, the dredging and expansion of the Haikou Port and the Haikou New Port which caused an increase in water area at the mean low tide are the leading factor which causes the increase in tidal influx.     

An experimental method for determining the frequency-dependent added mass and added mass moment of inertia for a floating body in heave and pitch motions

Most of the existing relevant materials have been obtained from experiments, in which evaluating the added mass at the resonant frequency corresponding to the peak of a frequency-response curve obtained from the “forced” vibration analysis is the most popular technique. In this paper, a simple experimental method was presented where the “free” vibration responses instead of the “forced” ones were used to determine the values of m_ah and I_ap. The main part of the experimental system is composed of a floating body (model) and a spring–shaft shaker. The “free” vibration of this main part was induced by imposing on it an initial displacement (and/or an initial velocity), and from the time histories of displacements information such as the “damped” natural frequencies, damping ratios, sectional added mass coefficients (C_V and C_P) were obtained. Since the displacements of the spring–shaft shaker are “translational” and those of the floating body due to pitch motions are “angular”, a technique for the transformation between the associated parameters of the two components of the main part was presented.     

Efficient Modeling of Gravity Fields Caused by Sources with Arbitrary Geometry and Arbitrary Density Distribution

We present a brief review of gravity forward algorithms in Cartesian coordinate system, including both space-domain and Fourier-domain approaches, after which we introduce a truly general and efficient algorithm, namely the convolution-type Gauss fast Fourier transform (Conv-Gauss-FFT) algorithm, for 2D and 3D modeling of gravity potential and its derivatives due to sources with arbitrary geometry and arbitrary density distribution which are defined either by discrete or by continuous functions. The Conv-Gauss-FFT algorithm is based on the combined use of a hybrid rectangle-Gaussian grid and the fast Fourier transform (FFT) algorithm. Since the gravity forward problem in Cartesian coordinate system can be expressed as continuous convolution-type integrals, we first approximate the continuous convolution by a weighted sum of a series of shifted discrete convolutions, and then each shifted discrete convolution, which is essentially a Toeplitz system, is calculated efficiently and accurately by combining circulant embedding with the FFT algorithm. Synthetic and real model tests show that the Conv-Gauss-FFT algorithm can obtain high-precision forward results very efficiently for almost any practical model, and it works especially well for complex 3D models when gravity fields on large 3D regular grids are needed.     

Mass Balance Study on Phosphorus Removal in Constructed Wetland Microcosms Treating Polluted River Water

A number of studies have showed that the mass removal rates of phosphorus (P) in different constructed wetlands (CWs) varied significantly, and it is essential to quantify the contributions of major P removal processes in order to improve system design. The objective of this study was to investigate the effects of vegetation, hydraulic retention time (HRT), and water temperature on P removal from polluted river water and to quantify the contributions of different P removal pathways in surface CWs. Results showed that the average total P removal rates ranged between 2.69 and 20.84 mg/(m² day) in different seasons and were influenced significantly by vegetation, HRT, and water temperature. According to the mass balance approach, plant uptake removed 4.81–22.33% of P input, while media storage contributed 36.16–49.66%. Other P removal processes such as microbiota uptake removed around 0.26–4.13%. Media storage and plant uptake were identified as the main P removal processes in surface CWs treating polluted river water. This illustrated the importance of selecting media and plants in CWs for future practical application.     

郯庐断裂带南段及邻区地震b值的空间分布特征

The Tanlu( Tancheng-Lujiang) fault is one of the major structures in eastern China,which cuts across different blocks and controls the tectonic activity. Using the seismic data from the China Earthquake Networks Center,we investigate the spatial variations of the b-value in the Dabie-Sulu( Jiangsu-Shandong) organic belt by calculating the b-value of each grid( 1°×1°) from 1970 to 2010. The study shows that: the b-value is smaller in the Tanlu fault and its adjacent area,which might suggest that the major earthquake recurrence period is relatively long due to the lower frequency of small earthquake activity. In both sides of Tanlu fault,the b-value is higher at the edge of Sulu block and the eastern part of Dabie orogenic belt. The b values are higher in North China central orogenic belt,and small earthquake activity which occurred along the central orogenic belt is frequent. Additionally,combined with geological and geophysical study,we find that the b-value has a certain correspondence relationship with the lithologic distribution,which informs us that seismic activity features are closely related to the inhomogeneous media in the crust.     

Effects of rotation motions on strong-motion data

Rotation motion and its effects on strong-motion data, in most cases, are much smaller than that of translational motion and have been ignored in most analyses of strong-motion data. However, recent observations from near-fault and/or extreme large ground motions suggest that these effects might be underestimated and quantitative analyses seem to be necessary for improving our understating of these effects. Rotation motion-related effects include centrifugal acceleration, the effects of gravity and effects of the rotation frame. Detailed analyses of these effects based on the observed data are unavailable in the literature. In this study, we develop a numerical algorithm for estimating the effects of rotational motion on the strong-motion data using a set of six-component ground motions and apply it to a set of rotation rate-strong motion velocity data. The data were recorded during a magnitude 6.9 earthquake. The peak value of the derived acceleration and rotation rate of this dataset are about 186 cm/s/s and 0.0026 rad/s. Numerical analyses of data gives time histories of these rotational motion-related effects. Our results show that all the rotation angles are less than 0.01°. The maximum centrifugal acceleration, effect from gravity and effect of the rotation frame are about 0.03 and 0.14 cm/s/s, respectively. Both these two effects are much smaller than the peak acceleration 186 cm/s/s. This result might have been expected because our data are not near-field and wave motions are expected to be nearly plane waves. However, it is worth noticing that the centrifugal acceleration is underestimated and a small rotational effect can cause large waveform difference in acceleration data. The waveform difference before and after the correction for rotational motion can reach 16 cm/s/s (about 10 %).