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491.
Banded structure of drifting macroalgae   总被引:3,自引:0,他引:3  
A massive bloom of macroalgae occurred in the western Yellow Sea at the end of May, 2008, and lasted for nearly 2 months. The surface-drifting macroalgae was observed to accumulate in a pattern dominated by linear bands. The maximum length of individual algal bands exceeded 10 km and the distance between neighboring bands ranged from hundreds of meters to 6 km. Seven satellite images were analyzed to determine the distances between neighboring bands. Proportions of about 24%, 38%, and 22% are responsible for the separation distances smaller than 1 km, between 1 and 2 km, and between 2 and 3 km, respectively. The separation of about five percent of the bands exceeds 4 km. The probability distribution of the separation distance is quite close to log-normal which is that found in Langmuir circulation. However, the observed algal band separation greatly exceeds the distances between convergence lines reported in Langmuir circulation.  相似文献   
492.
The hexagonal to orthorhombic phase transition in synthetic Mg-cordierite has been studied by (i) measuring the spontaneous strain associated with the transition using Synchrotron X-ray powder diffraction and (ii) measuring the degree of Al, Si order in terms of the number of Al-O-Al bonds per formula unit using solid state NMR spectroscopy. This defines the two order parametersQ andQ od respectively, and their relationship as a function of annealing temperature and time is used to define the structural states of cordierite during the ordering sequence. The formation of modulated hexagonal cordierite within which a high degree of Al, Si order can be attained, results in a strongly non-linear relationship betweenQ andQ od .The transition from modulated to orthorhombic cordierite is strongly first-order under all temperature conditions studied and involves a large step inQ, whileQ od changes continuously throughout the ordering sequence with no marked discontinuity at the phase transition. The lattice distortion, traditionally defined in cordierite by the Δ index provides no full information on the degree of Al, Si order in anhydrous Mg-cordierite, and both order parameters must be used to define its structural state. Transmission electron microscopy has been used to study the mechanism of the transformation from hexagonal to modulated to orthorhombic cordierite.  相似文献   
493.
A total of 95 surface water samples (6 m depth) was collected during a transect from the Bothnian Bay to Kiel between 28 August and 5 September 1982. This report presents the dissolved trace metal (<0.4 μm) and the associated hydrographic and nutrient data. Except for aluminium, all other metals determined (Zn, Cd, Cu, Ni, Fe, Mn) showed a rather homogeneous distribution within the subregions, with highest values in the Bothnian Bay (except for Mn) and net variations of the individual samples of about 20%. Cadmium, copper and nickel reveal conservative behaviour when values from this study and literature data from the Kattegat and North Sea area are plotted against salinity.  相似文献   
494.
The new scenario framework facilitates the coupling of multiple socioeconomic reference pathways with climate model products using the representative concentration pathways. This will allow for improved assessment of climate impacts, adaptation and mitigation. Assumptions about climate policy play a major role in linking socioeconomic futures with forcing and climate outcomes. The paper presents the concept of shared climate policy assumptions as an important element of the new scenario framework. Shared climate policy assumptions capture key policy attributes such as the goals, instruments and obstacles of mitigation and adaptation measures, and introduce an important additional dimension to the scenario matrix architecture. They can be used to improve the comparability of scenarios in the scenario matrix. Shared climate policy assumptions should be designed to be policy relevant, and as a set to be broad enough to allow a comprehensive exploration of the climate change scenario space.  相似文献   
495.
Anthropogenic disturbances influence plant regeneration and species diversity, which impact the conservation status of protected areas. A study was conducted in the Sitakund Botanical Garden and Eco-park (SBGE), Chittagong, Bangladesh to analyze the natural regeneration and tree species diversity in disturbed and less disturbed zones. Stratified and systematic random sampling was used to select 50 sample plots from each of the two zones. A total number of 109 plant species from 43 families were recorded in the study; of which 93 species were of natural origin while the rest were planted. From the species with natural origin 66 were tree species, 9 were shrub species and 28 were climbers. Species richness, density of regeneration and disturbance index in the height classes (0- 0.5 m) and {dbh 〉 6 cm) indicated significant differences between the zones. The study analyzed how disturbances affect species diversity in the area. It was found that species richness and basal area are negatively related with disturbances. Moreover, density (N/ha) of trees was more likely to decrease with increasing tree height that reflects the huge demand of local people to harvest large trees as part of their income generating activities. The study findings have implications for future managementdecisions of the SGBE. To restore these ecosystems, management should focus on both biodiversity eonservation and providing benefits to local people without hampering forest ecosystems.  相似文献   
496.
An enhanced strategy for GNSS data processing of massive networks   总被引:2,自引:1,他引:1  
Although the computational burden of global navigation satellite systems (GNSS) data processing is nowadays already a big challenge, especially for huge networks, integrated processing of denser networks with data of multi-GNSS and multi-frequency is desired in the expectation of more accurate and reliable products. Based on the concept of carrier range, in this study, the precise point positioning with integer ambiguity resolution is engaged to obtain the integer ambiguities for converting carrier phases to carrier ranges. With such carrier ranges and pseudo-ranges, rigorous integrated processing is realized computational efficiently for the orbit and clock estimation using massive networks. The strategy is validated in terms of computational efficiency and product quality using data of the IGS network with about 460 stations. The experimental validation shows that the computation time of the new strategy increases gradually with the number of stations. It takes about 14 min for precise orbit and clock determination with 460 stations, while the current strategy needs about 82 min. The overlapping orbit RMS is reduced from 27.6 mm with 100 stations to 24.8 mm using the proposed strategy, and the RMS could be further reduced to 23.2 mm by including all 460 stations. Therefore, the new strategy could be applied to massive networks of multi-GNSS and multi-frequency receivers and possibly to achieve GNSS data products of higher quality.  相似文献   
497.
The dynamics of the ultra‐long Rossby waves are studied with the aid of a primitive equation numerical model. The investigation is focused on a study of the breakdown of a high‐index circulation. Different idealized flow patterns are used as initial conditions and forecasts are made with the numerical model. The influences of oceans and mountains are studied by incorporating them into the model. The results indicate that barotropic and baroclinic instabilities as well as the structure of the earth's surface are of importance for the development, but the experiments do not clearly indicate which one of these factors is most important.  相似文献   
498.
Abstract

In the long term, any definition of adequacy consistent with UNFCCC Article 2 will require increased mitigation efforts from almost all countries. Therefore, an expansion of emission limitation commitments will form a central element of any future architecture of the climate regime. This expansion has two elements: deepening of quantitative commitments for Annex B countries and the adoption of commitments for those countries outside of the current limitation regime. This article seeks to provide a more analytical basis for further differentiation among non-Annex I countries. To be both fair and reflective of national circumstances, it is based on the criteria of responsibility, capability and potential to mitigate. Altogether, non-Annex I countries were differentiated in four groups, each including countries with similar national circumstances: newly industrialized countries (NICs), rapidly industrializing countries (RIDCs), ‘other developing countries’, and least developed countries (LDCs). Based on the same criteria that were used for differentiating among non-Annex I countries, a set of decision rules was developed to assign mitigation and financial transfer commitments to each group of countries (including Annex I countries). Applying these decision rules results in (strict) reduction commitments for Annex I countries, but also implies quantifiable mitigation obligations for NICs and RIDCs, assisted by financial transfers from the North. Other developing countries are obliged to take qualitative commitments, but quantifiable mitigation commitments for these countries and the LDC group would be not justifiable. As national circumstances in countries evolve over time, the composition of the groups will change according to agreed triggers.  相似文献   
499.
Equitable access to sustainable development (EASD) is crucial for the future of the climate regime as it applies to adaptation, mitigation, and the means of implementation. An approach to allocating effort and deriving carbon budgets is presented here based on the United Nations Framework Convention on Climate Change (UNFCCC) principles of responsibility, capability, and sustainable development. A transparent model to operationalize EASD is applied by applying quantitative proxies for these criteria, and results for selected countries and groups are presented. A robust result is that the mitigation burden calculated by the model is significantly greater for developed than developing countries. For individual countries the results vary depending on the parameters chosen. A middle value of the mitigation burden for South Africa of 15 GtCO2e over the first half of the 21st century is reported, with the greatest effort required when a starting year of 1970 is chosen and historical land-use, land-use change and forestry (LULUCF) emissions are excluded when accounting for responsibility. In a regime applicable to all, it is clear that although all countries must do more, some must do more than others.

Policy relevance

Equitable access to sustainable development is crucial to the climate negotiations. Quantified allocations are presented for South Africa and other countries, based on the UNFCCC principles of responsibility, capability, and sustainable development. It is shown that the mitigation burden given these principles must be significantly greater for developed than developing countries. The results are relevant to, inter alia, the upcoming 2013–2015 review and the negotiations under the Durban Platform.  相似文献   
500.
Schw.  RG 《地学前缘》2000,7(2):485-497
纤磷钙铝石类化合物系由自纤磷钙铝石CaAl3 (OH) 6(HPO4) (PO4)本身、经磷钙铝石CaAl3 (OH) 6(SO4) (PO4)到钾明矾石KAl3 (OH ) 6(SO4) 2 等的天然矿物族所组成的。它们表现出具有很大范围的阳离子置换系列 ,其中以Sr2 +和Ba2 +置换Ca2 +,REEs3 +置换Ca2 +和H+,As5 +置换P5 +,S6+/Se6+置换H+P5 +最为重要。随着置换的进行 ,其热动力学稳定性也逐渐增加。由此 ,纤磷钙铝石类化合物成为很能抗风化的矿物 ,在红土中尤其如此。厚的纤磷钙铝石层形成在闪长岩 (富Sr) ,碳酸盐岩 (富REEs)和含金石英脉 (富As)之上 ,从而保护整个磷酸盐红土 ,使之免受风化。以此方式 ,形成了桌状山脉或岛屿 ,他们具有未受覆盖的表面。这些“纤磷钙铝”石化合物为上述及其它元素形成一有效的地球化学障。“纤磷钙铝石”的这种天然地球化学固定作用可以用适当的母体或人工合成晶体来进行模拟 ,即通过金属阳离子交换或就地反应来模拟。这种固定作用还可用于处理天然和人造的放射性裂变产物、有毒的重金属元素、砷酸盐和硒酸盐、硫酸盐等。  相似文献   
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