Emulating the OPAL equation of state     

Hsiao-Hsuan Lin  Werner Däppen 《Astrophysics and Space Science》2010,328(1-2):175-178

The equation of state for the structure of the Sun and stars has to be precise to allow comparisons with observations, i.e., helioseismic inversions of thermodynamic quantities. Among the two of the most popular formalisms are (1) the OPAL equation of state developed at Livermore and (2) the Mihalas-Hummer-Däppen (MHD) equation of state. While OPAL has a solid theoretical foundation, and matches the observational data better, the MHD formalism is more intuitive, easy to realize, and has the possibility of adjustable parameters. Furthermore, it an open-source product in contrast to the proprietary OPAL. Recently a version of MHD has been obtained by including the so-called “Plank-Larkin partition function” and by adding scattering-state terms. The resulting formalism matches OPAL rather well. Here, we report on the next logical step, the implementation of this MHD upgrade into the simple and popular CEFF equation of state. Such an implementation will make it a flexible and convenient tool, allowing an approximative on-line implementation of OPAL in solar and stellar models.  相似文献   

北太平洋海表面高度(SSH) 与风应力变化的关系     

黄琳  孙佳  杨逸秋  袁逸凡 《海洋与湖沼》2013,44(1):111-119

利用1958-2008年的北太平洋海表面高度和风应力资料,并与ENSO和PDO指数进行相关分析.结果发现,风应力及其经向分量主要通过季节振动影响海表面高度(SSH)的年周期变化,纬向风应力主要通过多年振动影响SSH的ENSO和PDO周期.纬向风应力和SSH均以黑潮延伸体主轴为界,两侧呈现出相反的升降趋势,SSH为北降南升,纬向风应力南降北升.风应力和SSH升降趋势相同,均表现为“上升—下降—上升”的变化特征.在地形变化剧烈、等深线南北分布的海区,西风增强会导致SSH升高,且西侧升高较为明显.北风增强将导致北太平洋西岸SSH升高,东岸SSH降低.  相似文献   

A dual site study of the rainwater chemistry within the Western Pacific region     

K. M. Wai  S. H. Wang  P. A. Tanner  N. H. Lin 《Journal of Atmospheric Chemistry》2007,57(1):85-103

The two-year (1999–2000) rainwater chemistry at two monitoring sites in nearby coastal areas [Taiwan (TW) and Hong Kong (HK)] within the Western Pacific region has been studied. The volume weighted average pH values for the entire sampling period in TW and HK were 4.6 and 4.2, respectively. Sea salt Na⁺ and Cl⁻ were the most abundant species in the TW samples but and H⁺ were the most abundant in the HK samples. The sea salt and concentrations at TW were higher than those at HK both in the cold and warm seasons. Chloride depletion was minimal in the rainwater samples at both sites. Non seasalt- was associated with . Under the influence of the East Asian Winter Monsoon, the back-trajectory studies revealed that elevated anthropogenic species concentrations were associated with trajectories (1) very near to the continental boundary layer of Mainland China; or (2) along the coastline of Eastern China where large cities/industrial areas are located or (3) passing through the region of stagnant air over Northern/Eastern China. The lowest anthropogenic and crustal species concentrations measured in HK are associated with the summer monsoon and are attributed not only to the clean marine air masses but also to the relatively low SO₂, NO _x and NH₃ emissions from the South/ South East Asian countries, as well as infrequent biomass burning activities and wet scavenging at sources during the summer months. Approaching tropical cyclones led to the lowest pH values (4.2 in TW and 3.8 in HK) amongst the other weather categories. The findings here have been compared with other studies within East Asia and elsewhere.  相似文献   

南海热带气旋频数的气候预测方法     

梁健  林永堂  谢定升  林镇国  林少冰 《气象科技》2007,35(5):626-630

利用前期北半球500 hPa高度场格点资料、海温场(SST)格点资料,计算与后期热带气旋(TC)发生频数的相关系数,分析两个相关场显著相关区的统计特征,进一步分析其天气气候学意义和物理意义。选取若干相关系数高的格点,组成组合因子,建立二项式曲线方程,对影响南海以及登陆或影响广东的热带气旋,做年、月频数预测。预测试验和检验表明,二项式曲线预测模型有较高的拟合能力,在影响南海以及登陆或影响广东的热带气旋年、月频数预测中,有较好的效果。  相似文献   

建立天空场景的模拟算法   总被引：1，自引：0，他引：1  

顾大权  范茵  许屏  龚琳 《气象科技》2007,35(2):292-294

建立真实感的天空场景,在环境仿真和气象现象模拟中,有着极其重要的应用价值,也是计算机可视化研究中的难题。首先通过确定色彩层次模型,改进基于中点的变位方法生成基本云图,然后使用基于图像的方法进行云图映射,最后融合气象信息要素等过程生成天空背景,并采用光照叠加、背景合成及色彩调整等方法,产生千姿百态、形象逼真的天空场景图。可在多种气象现象的模拟仿真,纹理贴图的产生以及气象信息可视化系统的开发等方面发挥重要的作用。  相似文献   

陕北植被变化遥感监测及对径流的影响   总被引：5，自引：0，他引：5  

孙智辉  罗琳  苏锋  李新亚 《气象科技》2007,35(2):282-285

陕北北部是我国水土流失最为严重的地区,年输入黄河的泥沙量占全河的38%。1999年实施退耕还林草工程后,退耕还林草面积达9617.2 km2。利用1998-2004年NOAA卫星遥感资料,计算陕北北部地区归一化植被指数,发现陕北植被指数增幅在50%-200%之间,其中吴旗县增幅最大。对延安北部及榆林市1998-2004年降水量资料分析,得出植被指数增加是退耕还林草工程初见成效,不是由于降水变化引起的。利用1980-2004年吴旗县气象站观测的降水量和水文站所测径流量进行时间序列相关分析、典型年对比分析,得出该县植被变化对年径流量产生了影响,年径流量和泥沙量减少近一半,对保持水土有积极意义。  相似文献   

Spatial distribution and species composition of PAHs in surface sediments from the Bohai Sea   总被引：1，自引：0，他引：1  

Liu WX  Chen JL  Lin XM  Tao S 《Marine pollution bulletin》2007,54(1):113-116

  相似文献   

SAMHO BROTHER benzene ship accident     

Lin CL  Hu JH 《Marine pollution bulletin》2007,54(8):1285-1286

  相似文献   

A trophic model for the Danshuei River Estuary, a hypoxic estuary in northern Taiwan   总被引：1，自引：0，他引：1  

Lin HJ  Shao KT  Jan RQ  Hsieh HL  Chen CP  Hsieh LY  Hsiao YT 《Marine pollution bulletin》2007,54(11):1789-1800

The estuary of the Danshuei River, a hypoxic subtropical estuary, receives a high rate of untreated sewage effluent. The Ecopath with Ecosim software system was used to construct a mass-balanced trophic model for the estuary, and network analysis was used to characterize the structure and matter flow in the food web. The estuary model was comprised of 16 compartments, and the trophic levels varied from 1.0 for primary producers and detritus to 3.0 for carnivorous and piscivorous fishes. The large organic nutrient loading from the upper reaches has resulted in detritivory being more important than herbivory in the food web. The food-chain length of the estuary was relatively short when compared with other tropical/subtropical coastal systems. The shortness of food-chain length in the estuary could be attributed to the low biomass of the top predators. Consequently, the trophic efficiencies declined sharply for higher trophic levels due to low fractions of flows to the top predators and then high fractions to detritus. The low biomass of the top predators in the estuary was likely subject to over-exploitation and/or hypoxic water. Summation of individual rate measurements for primary production and respiration yielded an estimate of −1791 g WW m⁻² year⁻¹, or −95 g C m⁻² year⁻¹, suggesting a heterotrophic ecosystem, which implies that more organic matter was consumed than was produced in the estuary.  相似文献   

鄂尔多斯盆地直罗组—安定组沉积期原始边界恢复   总被引：3，自引：1，他引：2  

赵俊峰  刘池洋  梁积伟  王晓梅  喻林  黄雷  刘永涛 《地质学报》2010,84(4)

有关中生代鄂尔多斯盆地各时期原始沉积面貌的探讨,长期以来深受关注但认识和研究程度不一,其中对于直罗组—安定组沉积期的研究尤为薄弱。本文针对鄂尔多斯克拉通内大型坳陷型盆地的属性及其演化-改造特点,从今盆地及邻区残存沉积建造、现今构造格局两方面出发,在大量野外露头观测、钻井与测井资料分析及实验测试基础上,通过系统的地层划分与对比、沉积相分析、物源综合分析和对周邻构造单元形成演化史的分析,认为直罗组—安定组沉积期盆地的原始沉积边界大致为:东在今太行山脉以西;北在今河套盆地一带;西北部边界在狼山—巴彦浩特盆地—科学山一带;西南部边界在今六盘山西缘;南部边界在今渭河盆地一带。自盆地周缘向湖盆中心有大致7个方向的物源供给,沉积中心位于原始盆地中心偏南。该期盆地的演化记录了华北克拉通西部由印支期的南北分异向燕山期东西分异的转变过程与时限。该研究对于构建完整的中生代鄂尔多斯盆地演化时空坐标和铀矿、石油等能源矿产勘探评价具有理论和实际意义。  相似文献