Toxic contaminants and their biological effects in coastal waters of Xiamen,China. II. Biomarkers and embryo malformation rates as indicators of pollution stress in fish

Baseline information is presented on embryo malformation rate and biomarkers in fish as indicators of sub-lethal stress caused by pollution in coastal waters of Xiamen, PR China. Fish and eggs were sampled from several areas in Xiamen coastal waters (Xiamen Harbour, Maluan and Tongan Bays and East Channel), where varying levels of pollutant input have been documented. Comparative sampling was done at a "cleaner" reference site at Dongshan Island. Embryonic malformation rates, which indicate general water quality, varied with location and species of fish, and exceeded background levels for unpolluted waters (assumed approximately 5%) by up to eightfold at some sites. Generally, sites around Xiamen Harbour show signs of poor water quality having highest mean levels of embryo deformity (20-30%) and these decreased towards open waters (Tongan Bay, Eastern Channel) where abnormalities approached background levels. An indication that toxic contaminants may be having a localised effect in the region, particularly in the harbour was reinforced by the biomarker assays. However, activities of the biomarkers ethoxyresorufin O-deethylase (EROD) and glutathione S-transferase in fish livers indicate no clear pattern, and there is no evidence that fish from the four sampling areas have been more or less exposed to PAHs and other compounds that induce these biomarkers. Antioxidant biomarkers (glutathione peroxidase, catalase, superoxide dismutase, and reduced glutathione) suggest that exposure to xenobiotics appears to be lowest in Dongshan and Maluan and highest in the harbour and Tongan. Inhibition of acetylcholinesterase in fish muscle indicated possible effects by organophosphate and carbamate pesticides in Xiamen waters and these effects may be greatest in the area of the harbour.     

Ionospheric measurements of relative coronal brightness during the total solar eclipses of 11 August, 1999 and 9 July, 1945

Swept-frequency (1/10 MHz) ionosonde measurements were made at Helston, Cornwall (50°06N, 5°18W) during the total solar eclipse on August 11, 1999. Soundings were made every three minutes. We present a method for estimating the percentage of the ionising solar radiation which remains unobscured at any time during the eclipse by comparing the variation of the ionospheric E-layer with the behaviour of the layer during a control day. Application to the ionosonde date for 11 August, 1999, shows that the flux of solar ionising radiation fell to a minimum of 25±2% of the value before and after the eclipse. For comparison, the same technique was also applied to measurements made during the total solar eclipse of 9 July, 1945, at Sörmjöle (63°68N, 20°20E) and yielded a corresponding minimum of 16 ± 2%. Therefore the method can detect variations in the fraction of solar emissions that originate from the unobscured corona and chromosphere. We discuss the differences between these two eclipses in terms of the nature of the eclipse, short-term fluctuations, the sunspot cycle and the recently-discovered long-term change in the coronal magnetic field.     

Modelling peak accelerations from earthquakes

This paper deals with the prediction of peak horizontal accelerations with emphasis on seismic risk and insurance concerns. Non‐linear mixed effects models are used to analyse well‐known earthquake data and the consequences of mis‐specifying assumptions on the error term are quantified. A robust fit of the usual model, using recently developed robust weighted maximum likelihood estimators, is presented. Outlying data are automatically identified and subsequently investigated. A more appropriate model accounting for the extreme value nature of the responses, is also developed and implemented. The implication on acceleration predictions is demonstrated. Copyright © 2006 John Wiley & Sons, Ltd.     

Improvement of Nakamura technique by singular spectrum analysis

In this work we investigate the application of the Singular Spectrum Analysis to improve Nakamura Technique. The SSA has a wide and multidisciplinary range of applications; it allows a time series to be decomposed into different components, e.g. the signal itself, as well as various noise components, which can be subsequently removed from the data. Removal of the minor component of the data can lead to significant improvements in the identification of the system. In this paper the use of SSA Technique allows to optimize the signal to noise ratio before computing the classical Nakamura spectral ratios. A number of typical applications are also presented.     

遥感地面辐射观测中的视场效应问题研究

以典型的垄行作物玉米为研究对象，提出了一种新的视场效应分析方法：网格模型法。该方法将目标空间和测量空间网格化，然后在网格空间计算观测视场内的组分比例，进而确定组合信号值。本文采用网格模型法分析了垄行作物亮叶、暗叶、亮土、暗土四分量在传感器视场中面积权重变化、空隙率的变化、方向亮温的变化、红波段反射率的变化、红外波段反射率的变化以及植被指数NDVI的变化率，研究了不同观测角度情况下视场效应的变化。     

建筑群对城市冠层动力、热力效应的数值试验研究

利用中尺度模式MM5,分别耦合传统的边界层参数化方案和城市冠层参数化方案,模拟了2001年冬季北京冠层大气的动力、热力特征,并和观测资料进行了对比分析.分析结果表明,城市冠层参数化方案更能细致描述建筑群对城市冠层大气的动力、热力作用.由于建筑群的动力、热力作用,使北京城区的温度升高,风速减小,湍流动能增强,形成了明显的增温区、阻风区和湍能增强区,中心均位于城区高大建筑群附近,并向郊区递减.     

A preliminary investigation of strong-motion data from the French Antilles

Strong-motion networks have been operating in the Caribbean region since the 1970s, however, until the mid-1990s only a few analogue stations were operational and the quantity of data recorded was very low. Since the mid-1990s, digital accelerometric networks have been established on islands within the region. At present there are thought to be about 160 stations operating in this region with a handful on Cuba, 65 on the French Antilles (mainly Guadeloupe and Martinique), eight on Jamaica, 78 on Puerto Rico (plus others on adjacent islands) and four on Trinidad.After briefly summarising the available data from the Caribbean islands, this article is mainly concerned with analysing the data that has been recorded by the networks operating on the French Antilles in terms of their distribution with respect to magnitude, source-to-site distance, focal depth and event type; site effects at certain stations; and also with respect to their predictability by ground motion estimation equations developed using data from different regions of the world. More than 300 good quality triaxial acceleration time-histories have been recorded on Guadeloupe and Martinique at a large number of stations from earthquakes with magnitudes larger than 4.8, however, most of the records are from considerable source-to-site distances. From the data available it is found that many of the commonly-used ground motion estimation equations for shallow crustal earthquakes poorly estimate the observed ground motions on the two islands; ground motions on Guadeloupe and Martinique have smaller amplitudes and are more variable than expected. This difference could be due to regional dependence of ground motions because of, for example, differing tectonics or crustal structures or because the ground motions so far recorded are, in general, from smaller earthquakes and greater distances than the range of applicability of the investigated equations.     

Comments on: ‘The Neutral, Barotropic Planetary Boundary Layer, Capped by a Low-Level Inversion’ by G. D. Hess, Boundary-Layer Meteorology (2004) 110, pp. 319–355

Precision measurements indicate that the stability capping of the neutral planetary boundary layer (PBL) that leads to a reduced PBL height is caused by the very stable upper part of the PBL, rather than by an overlying inversion. Radiative processes related to liquid water in boundary-layer clouds seem to play the key role for the formation of the stable upper PBL. The famous Leipzig Profile – generally considered as an example of a neutral PBL – has been included in Hess’s analysis because its PBL height is considerably lower than the ca. 3000 m to be expected by numerical models in truly neutral conditions. An analysis of the original observations reveals that the Leipzig PBL was stable and that it can be consistently treated as a ‘normal’ stable PBL with a height of ca. 700 m. A further finding is that the super-geostrophic PBL wind speed maxima predicted by almost all models are not observed in near-steady-state conditions. For the ‘ranking’ of analytical models versus numerical models, the comparisons with measurements show that the analytical models perform comparably well and even partially better than the numerical models.     

Saturation of the Large Aperture Scintillometer

The saturation aspects of a large aperture (0.3 m) scintillometer operating over a 10-km path were investigated. Measurements were made over mainly forested, hilly terrain with typical maximum sensible heat fluxes of 300–400 W m ⁻², and over flat terrain with mainly grass, and typical maximum heat fluxes of 100–150 W m⁻². Scintillometer-based fluxes were compared with eddy-correlation observations. Two different schemes for calculating the reduction of scintillation caused by saturation were applied: one based on the work of Hill and Clifford, the other based on Frehlich and Ochs. Without saturation correction, the scintillation fluxes were lower than the eddy-correlation fluxes; the saturation correction according to Frehlich and Ochs increased the scintillometer fluxes to an unrealistic level. Correcting the fluxes after the theory of the Hill and Clifford gave satisfying results     

A three-dimensional finite-element model of wind effects upon higher harmonics of the internal tide

A non-linear three-dimensional unstructured grid model of the M₂ tide in the shelf edge area off the west coast of Scotland is used to examine the spatial distribution of the M₂ internal tide and its higher harmonics in the region. In addition, the spatial variability of the tidally induced turbulent kinetic energy and associated mixing in the area are considered. Initial calculations involve only tidal forcing, although subsequent calculations are performed with up-welling and down-welling favourable winds to examine how these influence the tidal distribution (particularly the higher harmonics) and mixing in the region. Both short- and long-duration winds are used in these calculations. Tidal calculations show that there is significant small-scale spatial variability particularly in the higher harmonics of the internal tide in the region. In addition, turbulence energy and mixing exhibit appreciable spatial variability in regions of rapidly changing topography, with increased mixing occurring above seamounts. Wind effects significantly change the distribution of the M₂ internal tide and its higher harmonics, with appreciable differences found between up- and down-welling winds and long- and short-duration winds because of differences in mixing and the presence of wind-induced flows. The implications for model validation, particularly in terms of energy transfer to higher harmonics, and mixing are briefly discussed.