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741.
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We analyze the data of investigation of the intrusive structure of the Gulf-Stream frontal zone obtained in making frequent drift sections with the help of an MGI-8102 probing complex, study the regularities of variation of temperature, salinity, and density along separate intrusions, and present a series of results connected with the specific features of initiation and development of intrusions and the types of exchange processes determining their transformations. It is shown that the T-diagrams of all intrusions are well separated into segments with different slopes. Moreover, by comparing the slopes and locations of these segments with each other and with the T-diagrams of the Gulf Stream and slope waters, we can fairly reliably attribute the corresponding segments of intrusions to one of the following four types: initial dynamic folds of the frontal zone, layers of domestic water separating the intrusive segments of foreign water from each other, intrusive segments characterized by the penetration of ambient water, and segments not intrusive initially but getting the required slope as a result of interaction with upper and lower intrusive segments. For segments of the last two types, it is possible to specify the predominant type of exchange. 相似文献
746.
Estimation of Contamination of ERS-2 and POSEIDON Satellite Radar Altimetry Close to the Coasts of Australia 总被引:4,自引:0,他引:4
It is broadly acknowledged that the precision of satellite-altimeter-measured instantaneous sea surface heights (SSH) is lower in coastal regions than in open oceans, due partly to contamination of the radar return from the coastal sea-surface state and from land topography. This study investigates the behavior of ERS-2 and POSEIDON altimeter waveform data in coastal regions and estimates a boundary around Australia's coasts in which the altimeter range may be poorly estimated by on-satellite tracking software. Over one million 20 Hz ERS-2 (March to April 1999) and POSEIDON (January 1998 to January 1999) radar altimeter waveform data were used over an area extending 350 km offshore Australia. The DS759.2 (5'resolution) ocean depth model and the GSHHS (0.2 km resolution) shoreline model were used together to define the coastal regions. Using the 50% threshold retracking points as the estimates of expected tracking gate, we determined that the sea surface height is contaminated out to maximum distance of between about 8 km and 22 km from the Australian shoreline for ERS-2, depending partly on coastal topography. Using the standard deviation of the mean waveforms as an indication of the general variability of the altimeter returns in the Australian coastal region shows obvious coastal contamination out to about 4 km for both altimeters, and less obvious contamination out to about 8 km for POSEIDON and 10 km for ERS-2. Therefore, ERS-2 and POSEIDON satellite altimeter data should be treated with some caution for distances less than about 22 km from the Australian coast and probably ignored altogether for distances less than 4 km. 相似文献
747.
We study the problem of reconstruction (interpolation and extrapolation) of the vertical profiles of hydrochemical and hydrobiological elements according to incomplete sets of data with simultaneous filtration of short-period components based on expansions in empirical orthogonal functions. The genetic algorithm is used to compute the coefficients of expansion of profiles with missing data. We present the results of processing the data arrays on oxygen, chlorophyll A, and biogenic elements collected in the Black Sea in 1982–1993. The mean error of reconstruction of the profiles enables us to conclude that the proposed method has considerable advantages over the conventional approaches. 相似文献
748.
格陵兰东南部和相邻大洋表层气温时序中记录了一个急剧的事件。这一事件大约出现在3100a(模拟年) ,持续约40a ,以温度降低3°C为特征。由于其峰值比平均值高6个标准偏差(σ)以上 ,可以认为降温是急剧的。如果该区域年平均表层气温时序正常排布 ,那么这种异常可能每数亿年出现一次,如此大幅度降温持续那么久的概率极小。如果将不足40a的变化从时序中去掉 ,那么事件高峰期表层气温低于平均值10~11σ。大气层较低层位的这种急剧降温源于海面温度急剧下降。大约3086a开始 ,格陵兰东海岸中部滨外发育了约0.5°C… 相似文献
749.
We consider the problem of stable development of natural economical complexes from the viewpoint of basic balances in an ecological
economical system. We construct a basic dynamical model of the complex capable of predicting various scenarios of the industrial
development, consumption of natural resources, and pollution of the environment and propose a mechanism of control over the
process of development by introducing rent payments for the use of natural resources and ecological fines for the pollution
of the environment. The efficiency of the applied model is demonstrated by analysing the process of control over the concentration
of biological resources in marine media as an example. We describe the results of numerical experiments performed to show
the possibility of creation of the information technology of control over marine bioresources.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
750.
A. J. O'Neill T. S. Galloway M. A. Browne A. Dissanayake M. H. Depledge 《Marine environmental research》2004,58(2-5):327
Increasing numbers of industrial, agricultural and natural chemicals are present in sewage effluent and are known to elicit toxic effects in laboratory exposures, but little is known of their combined sub-lethal effect in the field. In this study, a combination of esterase activity and ventilation rate assays was performed to determine the neurological and physiological function of the freshwater crustacean Asellus aquaticus (L.) at sites above and below a sewage treatment works (STW). Cholinesterase and carboxylesterase activities were significantly inhibited (n=8, P<0.05) and ventilation rates increased (n=8, P=0.0001) in A. aquaticus at STW sites compared to those from reference sites, indicating a decrease in neurological and physiological function. The ecological relevance of these findings for the population dynamics of the organisms in the field is discussed. 相似文献