965 resultados para Sst


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This report presents the results of a two-year investigation and summary of oceanographic satellite data obtained from multiple operational data providers and sources, spanning years of operational data collection. Long-term summaries of Sea Surface Temperature (SST) and SST fronts, Sea Surface Height Anomalies (SSHA), surface currents, ocean color chlorophyll and turbidity, and winds are provided. Merged satellite oceanographic data revealed information on: (1) seasonal cycles and timing of transition periods; (2) linkages between seasonal effects (warming and cooling), upwelling processes and transport; and (3) nutrient/sediment sources, sinks, and physical limiting factors controlling surface response for Olympic Coast marine environments. These data and information can be used for building relevant hind cast models, ecological forecasts, and regional environmental indices (e.g. upwelling, climate, “hot spot”) on biological distribution and/or response in the PNW.

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As sea turtles migrate along the Atlantic coast of the USA, their incidental capture in fisheries is a significant source of mortality. Because distribution of marine cheloniid turtles appears to be related, in part, to sea surface temperature (SST), the ability to predict water temperature over the continental shelf could be useful in minimizing turtle–fishery interactions. We analyzed 10 yr of advanced very high resolution radiometer (AVHRR) SST imagery to estimate the proportion of 18 spatial zones, nearshore and offshore of Hatteras, North Carolina, USA (35° N), to north of Cape Sable, Nova Scotia (44° N), at temperatures >10 to 15°C, by week. Detailed examples for 11°C, the temperature employed by some management actions in the study area, and for 14°C, the lowest temperature at which turtles were sighted by some studies in the area, demonstrate a predictable pattern of rapid warming in March and April, followed by rapid cooling in October and November, with nearshore waters warming more rapidly than those offshore. Of those loggerhead turtles Caretta caretta that stranded, were sighted, or were incidentally captured between Cape Hatteras, North Carolina, and Cape Cod, Massachusetts, those at lower latitudes occurred when 25% or more of the area reached a water temperature of 11°C, while those in the northern zones did not occur until 50% or more of the area had reached a water temperature of 14°C. This analysis provides a means of predicting marine cheloniid turtle presence, which can be helpful in regulating fisheries that seasonally interact with turtles.

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Annual mean fork length (FL) of the Pacific stock of chub mackerel (Scomber japonicus) was examined for the period of 1970–97. Fork length at age 0 (6 months old) was negatively correlated with year-class strength which fluctuated between 0.2 and 14 billion in number for age-0 fish. Total stock biomass was correlated with FL at age but was not a significant factor. Sea surface temperature (SST) between 38–40°N and 141–143°E during April–June was also negatively correlated with FL at age 0. A modified von Bertalanffy growth model that incorporated the effects of population density and SST on growth was well fitted to the observed FL at ages. The relative FL at age 0 for any given year class was maintained throughout the life span. The variability in size at age in the Pacific stock of chub mackerel is largely attributable to growth during the first six months after hatching.

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We present a method to integrate environmental time series into stock assessment models and to test the significance of correlations between population processes and the environmental time series. Parameters that relate the environmental time series to population processes are included in the stock assessment model, and likelihood ratio tests are used to determine if the parameters improve the fit to the data significantly. Two approaches are considered to integrate the environmental relationship. In the environmental model, the population dynamics process (e.g. recruitment) is proportional to the environmental variable, whereas in the environmental model with process error it is proportional to the environmental variable, but the model allows an additional temporal variation (process error) constrained by a log-normal distribution. The methods are tested by using simulation analysis and compared to the traditional method of correlating model estimates with environmental variables outside the estimation procedure. In the traditional method, the estimates of recruitment were provided by a model that allowed the recruitment only to have a temporal variation constrained by a log-normal distribution. We illustrate the methods by applying them to test the statistical significance of the correlation between sea-surface temperature (SST) and recruitment to the snapper (Pagrus auratus) stock in the Hauraki Gulf–Bay of Plenty, New Zealand. Simulation analyses indicated that the integrated approach with additional process error is superior to the traditional method of correlating model estimates with environmental variables outside the estimation procedure. The results suggest that, for the snapper stock, recruitment is positively correlated with SST at the time of spawning.

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Pacific sea surface temperatures (SSTs) are examined for their associations with (1) summer rainfall, and (2) the latitude location of the mid-tropospheric subtropical high pressure ridge (STR) in the southwestern United States during 1945 to 1986. Extreme northward (southward) displacements of STR are associated with wet (dry) summers over Arizona and an enhanced (weakened) gradient of SST off the California and Baja coasts. These tend to follow winters marked by positive (negative) phases of the PNA, Pacific/North America, teleconnection pattern. Recent decadal variations of Arizona summer rainfall (1950s wet; 1970s dry) appear similarly related to southwestern United States synoptic circulation and eastern Pacific SSTs.

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Climate conditions in land areas of the Pacific Northwest are strongly influenced by atmosphere/ocean variability, including fluctuations in the Aleutian Low, Pacific-North American (PNA) atmospheric circulation modes, and the El Niño-Southern Oscillation (ENSO). It thus seems likely that climatically sensitive tree-ring data from these coastal land areas would likewise reflect such climatic parameters. In this paper, tree-ring width and maximum lakewood density chronologies from northwestern Washington State and near Vancouver Island, British Columbia, are compared to surface air temperature and precipitation from nearby coastal and near-coastal land stations and to monthly sea surface temperature (SST) and sea level pressure (SLP) data from the northeast Pacific sector. Results show much promise for eventual reconstruction of these parameters, potentially extending available instrumental records for the northeastern Pacific by several hundred years or more.

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EXTRACT (SEE PDF FOR FULL ABSTRACT): In this study we use ocean and atmosphere datasets from observations and from an ocean general circulation model integration to examine decadal time scale variability that is centered in the Pacific basin. We know that decadal variability is likely to have a strong expression in the Pacific basin; for example, a marked "shift" of cool season climate in the mid-1970s introduced major changes in Pacific SST and atmospheric circulation, along with many other physical and biological properties.

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EXTRACT (SEE PDF FOR FULL ABSTRACT): Selected hydrometeorological (HM) data for the Pacific Northwest and atmospheric and North Pacific sea-surface temperature (SST) data are examined for three successive periods that are subsets of the historical record to estimate if their characteristics have changed.

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海表面温度(Sea Surface Temperature, SST)是海洋生态环境变化的重要因子,也是海洋观测研究的最重要的因子之一。海表温度场表征了海洋热力、动力过程和海洋与大气相互作用的综合结果,是反映海气热量、动力和水汽交换的重要参量,也是气候变化及海洋营养盐浓度和初级生产力的重要影响因子。台风过后通常会在上层海洋引起冷迹,即台风路径附近的海表温度降低。海表温度的变化是台风与海洋之间能量交换的关键,对于台风的产生,演化和强度变化有非常重要的作用。因此,研究上层海洋对台风的响应,特别是海表温度对台风的响应过程有非常重要的科学意义。本研究主要利用微波SST逐日数据资料统计研究了海表面温度对南海台风的响应过程,并分析了中尺度涡(特别是气旋性涡)对台风所引起的降温幅度和降温位置的影响作用。在此研究基础上初步尝试提出了一种新的量化台风降温效应的方法。 首先,本研究以1998-2009年总共12年内经过中国南海的92个台风为研究对象,利用逐日连续的微波TMI及TMI-AMSER海表温度数据资料分析了92个台风所引起的最大降温幅度以及冷迹位置的分布特征。统计结果表明有64个(69.6%)台风引起了海表温度明显的降低(降温≥2oC),而对最大降温出现的位置进行分析发现:有超过半数(56个)的台风引起的最大降温位于台风路径的附近或路径右侧,同时还有8个(8.7%)台风引起的最大降温明显位于路径的左侧。文中选取了冷迹相对于台风路径出现在不同位置(左、右、附近)的4个台风为例来说明台风引起的降温特征。通过量化降温中心到台风路径的距离发现台风所引起的最大降温出现的位置主要集中分布在路径左右两侧100km范围内。另外,通过对比台风来之前的海平面高度距平发现先于台风之前处在于上层海洋环境的冷涡,特别是强冷涡,在台风引起的海表面降温幅度和位置分布中可能起着重要的作用,其中冷涡的位置与台风所引起的最大降温中心出现的位置有很好的相关性。 其次,本研究提出一个新的描述降温效应的指数。台风所经过的海域往往会出现海表温度的降低,而海表温度的变化对海洋生态系统有很重要的影响。台风的降温效应因台风、背景温度场和台风前的海洋环境条件而异。目前,海表温度对台风的响应效应主要是通过三个物理量来描述,降温幅度、冷迹范围、冷迹持续时间。但是还没有一个综合的量来对台风的降温效应进行定量的描述。本研究利用遥感微波SST数据尝试初步

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The objective of this paper is to test various available turbulent burning velocity models on an experimental version of Siemens small scale combustor using the commercial CFD code. Failure of burning velocity model with different expressions for turbulent burning velocity is observed with an unphysical flame flashback into the swirler. Eddy Dissipation Model/Finite Rate Chemistry is found to over-predict mean temperature and species concentrations. Solving for reaction progress equation with its variance using scalar dissipation rate modelling produced reasonably good agreement with the available experimental data. Two different turbulence models Shear Stress Transport (SST) and Scale Adaptive Simulation (SAS) SST are tested and results from transient SST simulations are observed to be predicting well. SAS-SST is found to under-predict with temperature and species distribution.

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Aerodynamic shape optimisation is being increasingly utilised as a design tool in the aerospace industry. In order to provide accurate results, design optimisation methods rely on the accuracy of the underlying CFD methods applied to obtain aerodynamic forces for a given configuration. Previous studies of the authors have highlighted that the variation of the order of accuracy of the CFD solver with a fixed turbulence model affects the resulting optimised airfoil shape for a single element airfoil. The accuracy of the underlying CFD model is even more relevant in the context of high-lift configurations where an accurate prediction of flow is challenging due to the complex flow physics involving transition and flow separation phenomena. This paper explores the effect of the fidelity of CFD results for a range of turbulence models within the context of the computational design of aircraft configurations. The NLR7301 multi-element airfoil (main wing and flap) is selected as the baseline configuration, because of the wealth of experimental an computational results available for this configuration. An initial validation study is conducted in order to establish optimal mesh parameters. A bi-objective shape optimisation problem is then formulated, by trying to reveal the trade-off between lift and drag coefficients at high angles of attack. Optimisation of the airfoil shape is performed with Spalart-Allmaras, k - ω SST and k - o realisable models. The results indicate that there is consistent and complementary impact to the optimum level achieved from all the three different turbulence models considered in the presented case study. Without identifying particular superiority of any of the turbu- lence models, we can say though that each of them expressed favourable influence towards different optimality routes. These observations lead to the exploration of new avenues for future research. © 2012 AIAA.

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Aerodynamic shape optimisation is being increasingly utilised as a design tool in the aerospace industry. In order to provide accurate results, design optimisation methods rely on the accuracy of the underlying CFD methods applied to obtain aerodynamic forces for a given configuration. Previous studies of the authors have highlighted that the variation of the order of accuracy of the CFD solver with a fixed turbulence model affects the resulting optimised airfoil shape for a single element airfoil. The accuracy of the underlying CFD model is even more relevant in the context of high-lift configurations where an accurate prediction of flow is challenging due to the complex flow physics involving transition and flow separation phenomena. This paper explores the effect of the fidelity of CFD results for a range of turbulence models within the context of the computational design of aircraft configurations. The NLR7301 multi-element airfoil (main wing and flap) is selected as the baseline configuration, because of the wealth of experimental an computational results available for this configuration. An initial validation study is conducted in order to establish optimal mesh parameters. A bi-objective shape optimisation problem is then formulated, by trying to reveal the trade-off between lift and drag coefficients at high angles of attack. Optimisation of the airfoil shape is performed with Spalart-Allmaras, k - ω SST and k - ε realisable models. The results indicate that there is consistent and complementary impact to the optimum level achieved from all the three different turbulence models considered in the presented case study. Without identifying particular superiority of any of the turbu- lence models, we can say though that each of them expressed favourable influence towards different optimality routes. These observations lead to the exploration of new avenues for future research. © 2012 by the authors.

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两栖动物是最原始的陆生脊椎动物,分布比较广泛。无尾目两栖动物现有3000 多种,它们皮肤裸露、光滑,为适应广泛的栖息地和生态条件,已进化出各种有效的皮肤防御系统。抗菌肽(Antimicrobial peptides,AMPs)作为两栖类先天防御系统的重要组成部分,在皮肤分泌液中含量异常丰富。我们以来源于云南省普洱市景东县的铃蟾科微蹼铃蟾(Bombina microdeladigitora)和楚雄州双柏县雨蛙科华西雨蛙(Hyla annectans)为实验材料,对其皮肤分泌液中抗菌肽的分子多样性并对其结构和功能进行研究。微蹼铃蟾皮肤抗菌肽多样性非常丰富,我们从单一个体中克隆得到了64 条编码不同抗菌肽的cDNA 序列,其中有两条序列只编码Maximin 一种抗菌肽,其余 62 条均编码Maximin 和Maximin H 两类抗菌肽。这64 条cDNA 序列共编码44 种Maximins 和30 种Maximin Hs,其中有32 种Maximins 和20 种Maximin Hs 为新鉴定的抗菌肽,其余和铃蟾属其它种中发现的抗菌肽具有相同的序列。除了皮肤外,两栖动物的脑也是抗菌肽的丰富资源库。我们分别从微蹼铃蟾和大蹼铃蟾(B. maxima)脑中得到了大量新的抗菌肽cDNA 序列。其中从微蹼铃蟾脑中克隆到21 条新的cDNA序列,共编码16 种Maximins 和10 种Maximin Hs,其中7 种Maximins 和4 种Maximin Hs 为新鉴定的抗菌肽。从大蹼铃蟾脑中克隆到39 条新的cDNA 序列,编码27 种Maximins 和20 种Maximin Hs,其中16 种 Maximins 和12 种Maximin Hs 为新鉴定的抗菌肽。在以上新鉴定的抗菌肽中,Maximins 均为阳离子抗菌肽,Maximin Hs 中除以前鉴定的Maximin H5 外,尚有十余种阴离子抗菌肽。抗菌肽碱基转换/颠换(R=s/v)分析表明,RMaximin<1 而RMaximin H>1,说明这两种抗菌肽碱基转换和颠换发生的几率并不相同,Maximin 间差异主要由碱基颠换引起,而Maximin H 则主要由碱基转换引起。种间进化分析表明,大蹼铃蟾和微蹼铃蟾的遗传距离较近,而它们与欧洲花铃蟾(B. variegata)的遗传距离均较远。种内各部分遗传距离差异较大。与信号肽和酸性间隔肽相比,成熟肽的遗传距离明显增大,其中Maximin 的进化速度比Maximin H 更快。抗菌肽Maximin 和Maximin H 种内、种间均存在正选择(ω>1),而信号肽和酸性间隔肽在分化过程中没有正选择(ω<1),说明Maximin 和Maximin H 经受着达尔文正选择驱动的快速进化,是抗菌肽多样性产生的根本原因。这与抗菌肽参与最终的生物防御功能,从而增加物种对环境的适应是一致的。功能研究发现,有些微蹼铃蟾Maximins 抗菌肽是多功能分子,不但对革兰氏阴性菌、革兰氏阳性菌和真菌起抗菌作用,而且还具有很强的抗氧化功能。脑中抗菌肽基因的大量表达也预示着抗菌肽可能在神经信号传导中起一定作用。用基因克隆方法我们从微蹼铃蟾皮肤得到大量缓激肽前体序列,由1-4 个拷贝的Bombinakinin 或1-4 个拷贝的Bombinakinin 和1 个拷贝的Bombinakinin-GAP 组成。这与大蹼铃蟾皮肤中缓激肽前体由1-8 个拷贝的Bombinakinin 或1-8 个拷贝的Bombinakinin 和1 个拷贝的Bombinakinin-GAP 组成有所不同。按同样方法,我们从大蹼铃蟾脑中也得到了三条缓激肽前体序列,其中两条含有6 个 Bombinakinin 拷贝,另一条含2 个Bombinakinin 拷贝。通过比较只含Bombinakinin 和同时含有Bombinakinin 和Bombinakinin-GAP 的前体cDNA 序列后发现, 前者序列中缺失了一段碱基序列TGCGGGTA, 从而导致移码突变, 终止了 Bombinakinin-GAP 的表达。通过生物化学的手段从微蹼铃蟾皮肤分泌液中分离到一种丝氨酸蛋白酶抑制剂BMSI1,与铃蟾属其它种中的胰蛋白酶抑制剂具有很高的相似性。根据已有铃蟾属丝氨酸蛋白酶抑制剂cDNA 序列设计引物,以皮肤cDNA 为模板,扩增丝氨酸蛋白酶抑制剂的基因序列,结果得到两条不同的序列。这两条前体序列与铃蟾属其它两栖动物皮肤中的丝氨酸蛋白酶抑制剂具有高度相似性(>70%),而且它们都含有10 个半胱氨酸残基。BMSI1 对五种丝氨酸蛋白水解发色底物的抑制活性测定表明,BMSI 1 能抑制胰蛋白酶和凝血酶的水解活性,其K(i)分别为0.02 μM 和0.15 μM。通过随机筛选cDNA 文库的方法,我们从大蹼铃蟾脑中得到了一条完整的 Somatostatin(SST)序列,根据该序列,我们在大蹼铃蟾和微蹼铃蟾脑cDNA 文库中筛选到两条变异体序列SST-L(Leu11-SST-14)和SST-R(Arg14-SST-14)。功能研究表明,这两种变异体具有和SST 相似的生物学功能,可抑制肿瘤细胞增殖、抑制细胞因子释放以及具有一定的镇痛作用。从大蹼铃蟾和微蹼铃蟾脑中得到了阿片肽前体POMC 和Proenkephalin 的 cDNA 序列,序列比对发现与东方铃蟾具有较高的同源性。从华西雨蛙皮肤cDNA 中克隆得到两类活性多肽,命名为Annins。其中一类为抗菌肽类似肽,共11 条序列,编码单一的成熟肽序列,其信号肽与雨蛙科信号肽具有很高的同源性,但酸性间隔肽和成熟肽相差较大。其成熟肽由15-17 个氨基酸残基组成,活性分析表明无抗菌和抗氧化作用,但在较高浓度时对部分细菌和多种细胞有促进生长作用,推测可能在使伤口快速愈合方面起重要作用;另一类编码具有2 个拷贝的成熟肽序列,成熟肽由5 个氨基酸残基组成,具有一定的镇痛活性,其镇痛机理可能是拮抗bradykinin 作用。

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利用近50年来西沙、南沙海域SST及全球温度资料,分析西沙、南沙海域SST

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采用基于Menter SST两方程湍流模型的DES方法, 数值模拟开式凹腔在跨声速条件下的非定常流动特性.计算凹腔底部和后壁面上的点的声压级频谱以及总声压级, 证明在第二噪声模态上的声压级最大