垂直切变基流中东西向地形对惯性重力波稳定性的影响

利用分层浅水波方程和小参数(WKB)方法，考虑具有垂直切变的基流和地形的作用，求得惯性重力波的局地频率方程，并根据此方程分析讨论了在多种环境条件下波动的稳定性情况。     

城市化对北京平均气温的影响

本文利用北京（观象台）及周围几个气象台站月平均气温资料，滑动平均后，采用主成分分析方法，再进行倾向性分析，探讨了北京城市化对气平均气温的影响，估算对北京（观象台）气温记录的影响约为０．２１℃／３３ａ推断市中心二环路以内强烈地影响。     

DYNAMIC VARIATIONS OF WATER QUALITY IN TAIHU LAKE AND MULTIVARIATE ANALYSIS OF ITS INFLUENTIAL FACTORS

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含金硫化物基岩区红土型金矿的成矿作用

实验表明，在含金硫化物基岩区，硫代硫酸金络阴离子团和硫酸金络阴离子团是金在表生条件下的主要迁移形式，它们的沉淀与铁、锰氢氧化物的形成有密切联系。金的表生迁移－沉淀条件除一般的表生地质条件外，还有特殊的物理化学－生物化学条件。络阴离子团的地球化学性质，控制着红土型金矿床的垂向分带与金的次生富集。     

多金属结核的沉积物地球化学场

远洋沉积物是多金属结核赖以生长的场所，本文系统地研究了沉积物中主要成矿元素水成组分在不同地球化学场和不同沉积阶段的地球化学特征，以及水成组分的含量比与成矿作用的相互关系。研究表明，Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ都是一些比较活泼的元素，它们共处于多金属结核、沉积物和大洋水的统一体系中，当结核形成时，Ｍｎ、Ｆｅ、Ｎｉ、Ｃｕ在结核与沉积物中的含量呈负相关，而Ｃｏ含量呈正相关。研究区东部结核以富含Ｍｎ、Ｎｉ、Ｃｕ贫Ｆｅ、Ｃｏ为特征，其伴生沉积物相对贫Ｍｎ、Ｎｉ、Ｃｕ、Ｃｏ，而富Ｆｅ，可称之为贫化的地球化学场。研究区西部结核富含Ｆｅ、Ｃｏ而贫Ｍｎ、Ｎｉ、Ｃｕ，其伴生沉积物则相应贫Ｆｅ，而富Ｍｎ、Ｎｉ、Ｃｕ、和Ｃｏ，可称之为富化的地球化学场。可以看出，贫化的沉积物地球化学场，恰恰是寻找富矿结核的最佳场所。早中新世以来的沉积物，根据水成组分的含量或含量比，也可相应于结核的形成分为三大沉积阶段，其中的第Ⅱ阶段具有贫化的地球化学特征，是多金属结核形成的最有利时期     

南极罗斯岛及泰勒谷地区火山岩的地球化学特征及成因讨论

利用微量元素和Ｓｒ，Ｎｄ，Ｐｂ同位素资料，得出了南极罗斯岛及泰勒谷地区火山岩来自于上地幔，五个地区火山岩具有相同的源区。岩石具有大洋岛屿玄武岩（ＯＩＢ）的特征。来自地幔的火山喷发的岩浆未遭受地壳物质的混染作用。地幔源区是具有高μ（＝２０６Ｐｂ／２０４Ｐｂ）比值的地幔组分ＨＩＭＵ与亏损地幔组分ＤＭＭ混合作用的结果，其中以ＨＩＭＵ组分为主，原生岩浆由具ＨＩＭＵ组分特征的深部地幔柱与浅部的ＤＭＭ混合而成。     

Site effects at a vertical accelerometer array near Paducah, Kentucky

The downhole vertical accelerometer array VSAP near Paducah, KY, consists of three-component accelerometers at the surface, the top of the McNairy Formation (−41 m), and the top of the Paleozoic bedrock (—99 m). The array is at the northern end of the Mississippi Embayment, and it was installed to verify the ground-motion modeling for the site, assuming a significant earthquake in the New Madrid Seismic Zone. Accelerograms from 4.2 and 2.0 m_b earthquakes were used to check aspects of the modeling pertaining to linear behavior of the soil column, and to review the soil column models derived by drilling and geotechnical methods and through the use of high-resolution P- and SH-wave seismic refraction in reflection techniques. Results of the study indicate that for the linear case the soil column models derived by the two techniques are equivalent, and that the most important boundary in the soil column, with respect to amplification of the ground motions, is the interface between the limestone bedrock and soil.     

The role of diapycnal mixing for the equilibrium response of thermohaline circulation

Using a zonally averaged, one-hemispheric numerical model of the thermohaline circulation, the dependence of the overturning strength on the surface equator-to-pole density difference is investigated. It is found that the qualitative behavior of the thermohaline circulation depends crucially on the nature of the small-scale vertical mixing in the interior of the ocean. Two different representations of this process are considered: constant vertical diffusivity and the case where the rate of mixing energy supply is taken to be a fixed quantity, implying that the vertical diffusivity decreases with increasing stability of the water column. When the stability-dependent diffusivity parameterization is applied, a weaker density difference is associated with a stronger circulation, contrary to the results for a fixed diffusivity. A counterintuitive consequence of the stability-dependent mixing is that the poleward atmospheric freshwater flux, which acts to reduce the thermally imposed density contrast, strengthens the thermally dominated circulation and its attendant poleward heat transport. However, for a critical value of the freshwater forcing, the thermally dominated branch of steady states becomes unstable, and is succeeded by strongly time-dependent states that oscillate between phases of forward and partly reversed circulation. When a constant vertical diffusivity is employed, on the other hand, the thermally dominated circulation is replaced by a steady salinity-dominated state with reversed flow. Thus in this model, the features of the vertical mixing are essential for the steady-state response to freshwater forcing as well as for the character of flow that is attained when the thermally dominated circulation becomes unstable.Responsible Editor: Jin-Song von Storch     

The pelagic community of a gravel pit lake: Significance of Coleps hirtus viridis (Prostomatida) and its role as a scavenger

Coleps hirtus viridis was the dominant species of the planktonic ciliate community of Lake Fühlinger See (Germany) during the study in 1999 and 2000. Total ciliate densities ranged from 120 to 42,000 ind. l⁻¹ in 1999 and up to 8,000 ind. l⁻¹ in 2000. Coleps contributed up to 98% to both total ciliate abundance and biomass and made up an average of 64% of the total ciliate biomass. Oligotrichs (Rimostrombidium, Strobilidium) dominated the epilimnetic zone, whereas peritrich ciliates (Pelagovorticella, Vorticella) were predominantly located in the hypolimnion. The population maximum of Coleps changed locations from the epilimnion in early summer to the hypolimnion (up to 40,000 ind. l⁻¹) during stratification. High growth rates in the hypolimnion, presence of endosymbiontic algae and the ability to ingest detritus seem to be important for the success.Growth rates of Coleps in June were determined by Landry-Hassett dilution experiments in both the epilimnion and the hypolimnion. The instantaneous growth rates were similar in both layers (0.6 d⁻¹), but a distinctly higher instantaneous mortality was estimated for the epilimnion. These high loss rates may be due to grazing pressure by cladocerans.The significance of the histophagous feeding of Coleps was evaluated through an experiment using killed zooplankton. Parts of Daphnia magna were incorporated at rates of about 1,100 μm³ ind.⁻¹ h⁻¹ by Coleps without endosymbiotic algae and at rates of 500 μm³ ind.⁻¹ h⁻¹ by Coleps with endosymbionts. These high feeding rates support the conclusion that Coleps can use dead organic matter as an additional food source.     

Integrated spatial sampling modeling of geospatial data

Sampling is to, by efficient selection of samples, acquire the accurate information about the population (the research object) at less cost. Spatial sampling is a kind of sampling toward geospatial objects or features with spatial correlation. The differences between effi-cient sampling and completely universal survey lie in quality, time and cost. Sampling provides a kind of economical, prompt and accurate survey[13]. Efficient spatial sampling can be regarded as the optimization of the sampl…