Numerical Modeling of Suspended Sediment Transport in the Gulf of Kachchh Including Kandla Creek, West Coast of India

A depth-averaged numerical model has been developed to study tidal circulation and suspended sediment transport in the Gulf of Kachchh including Kandla creek, west coast of India. The resolution of the model is taken as 750 m × 750 m, which is found to be adequate for the gulf region. However, this resolution could not produce the realistic circulation pattern and suspended sediment concentration in the Kandla creek region. There is a major seaport at Kandla which serves as the sea gate to northwest India. Therefore, a 2-D fine resolution (75 m × 75 m) model for Kandla creek has been developed and coupled with the coarser gulf model to compute the flow features in the creek region. The model dynamics and basic formulation remain the same for both the gulf model and the creek model. The models are barotropic, based on shallow water equations, and neglect horizontal diffusion and wind stress terms in the momentum equations. The models are fully nonlinear and use a semiexplicit finite difference scheme to solve mass, momentum, and advection-diffusion equations in a horizontal plane. The tide in the gulf is represented in the model by the semidiurnal M₂ constituent mainly. In this study, no fresh water discharge conditions have been considered so the results are appropriate for the dry season. Numerical experiments are carried out to study the circulation and suspended sediment concentrations in the gulf and the creek regions. The computed results are validated with the available observations.     

A First Generation Stochastic Bioeconomic Analysis of Algal Bloom Control in a Coastal Lagoon (Sacca di Goro, Po River Delta)

Abstract. In this work we have developed a very simple stochastic mathematical model of Ulva spp. growth to quantitatively evaluate the economic costs of algal harvesting and the related benefits in terms of avoided'economic loss'of clam production due to an effective prevention of algal blooms and the consequent anoxic crises. Algal growth was simulated by means of a discrete time difference equation of Ulva biomass where the finite growth rate depends only upon water temperature. In order to explicitly include environmental variability, a seasonal autoregressive model calibrated on available data was used to simulate water temperature. Different harvesting scenarios were analysed in terms of the number of harvesting vessels employed and the threshold biomass of Ulva at which vessels start to operate. Costs of algal harvesting and disposal, as well as monetary damages resulting from the collapse of clam production as a consequence of algal blooms, were assessed by interviewing the managers of the Clam Fishermen's Union of Goro. A Monte Carlo approach was used to estimate the mean and total statistical distribution of costs and benefits of different harvesting strategies. Our analysis shows that the most cost-effective management policy is attained with 4–6 vessels operating at low algal density able to harvest as much Ulva as possible with intensive and short interventions at the beginning of the seasonal growth.     

复杂多通道带乘性噪声系统的最优固定域平滑算法

研究 1种在更弱的乘性噪声限制条件下系统的状态最优估计算法。在最优滤波算法的基础上 ,进一步给出了在线性最小方差意义下最优的固定域平滑算法。针对该算法所进行的仿真研究已表明该算法的有效性     

Least-Squares Estimation of Bottom Topography Using Horizontal Velocity Measurements in the Tsushima/Korea Straits

Several bathymetric data sets are compared and assessed with constraints of an ocean current model and velocity observations. The root-mean-square (rms) differences among the data sets reach 20 m in the shallow Tsushima/Korea Straits. The numerical experiments to simulate the Tsushima Warm Current are performed using four different topography data sets. The JTOPO1 data (MIRC, 2003) give the smallest rms difference to long-term horizontal velocity observations. Several least-squares combinations of the topography data sets are then sought to minimize the rms difference between the observed and modeled barotropic velocities. Most of the data sets reveal a large bias of 30–60 m at the Western Channel compared to independent sounding depths     

Near-shore swell estimation from a global wind-wave model: Spectral process,linear, and artificial neural network models

Estimation of swell conditions in coastal regions is important for a variety of public, government, and research applications. Driving a model of the near-shore wave transformation from an offshore global swell model such as NOAA WaveWatch3 is an economical means to arrive at swell size estimates at particular locations of interest. Recently, some work (e.g. Browne et al. [Browne, M., Strauss, D., Castelle, B., Blumenstein, M., Tomlinson, R., 2006. Local swell estimation and prediction from a global wind-wave model. IEEE Geoscience and Remote Sensing Letters 3 (4), 462–466.]) has examined an artificial neural network (ANN) based, empirical approach to wave estimation. Here, we provide a comprehensive evaluation of two data driven approaches to estimating waves near-shore (linear and ANN), and also contrast these with a more traditional spectral wave simulation model (SWAN). Performance was assessed on data gathered from a total of 17 near-shore locations, with heterogenous geography and bathymetry, around the continent of Australia over a 7 month period. It was found that the ANNs out-performed SWAN and the non-linear architecture consistently out-performed the linear method. Variability in performance and differential performance with regard to geographical location could largely be explained in terms of the underlying complexity of the local wave transformation.     

Effects of vehicle,diet and gender on the expression of PMP70- and CYP2K1/2M1-like proteins in the mummichog

The mummichog (Fundulus heteroclitus) has been shown to be responsive to peroxisome proliferating agents (PPAs). Peroxisomes function as important sites for fatty acid beta-oxidation. Peroxisome proliferation by PPAs or starvation can lead to changes in the size and number of peroxisomes and the expression of omega-hydroxylases (CYP2K1/2M1 in rainbow trout). Mummichogs were subjected to 96 h fasting or 96 h recovery from fasting. Expression of PMP70- and CYP2K1/2M1-like proteins in vehicle-treated or non-treated controls was compared in both males and females. Fasting and vehicle produced decreases in PMP70- and CYP2K1/2M1-like proteins in both males and females. In reproductive females, decreases due to fasting and vehicle treatment were greater than in female fish that were not gravid. Recovery from fasting resulted in levels of CYP2K1/2M1 near control levels in males while in recovered females, about 2-fold higher levels compared to controls were noted. These results indicate that gender, reproductive status and diet can produce changes in the expressed levels of peroxisomal PMP70 and microsomal CYP2K1/2M1-like proteins in the mummichog.     

球上最小二乘问题向后误差的估计

A.N.Malyshev给出了球上最小二乘问题计算解的最佳向后扰动量表达式。从该表达式出发计算最佳向后扰动量却是很困难的。本文给出 1种有效的估算方法 ,所得结果对检验计算解的向后稳定性是有用的。并用几个简单的数值例子验证了所给算法的有效性。