G-856质子磁力仪恒温系统的研制及应用

本文介绍了G-856质子磁力仪恒温系统的结构、特点、功能及其在野外工作中的应用效果。     

一种高分辨率温度传感器

介绍一种基于Pt1000惠斯通平衡电桥的高分辨率温度传感器。 实验测试表明, 该温度传感器具有精确、 稳定、 分辨率高的特点, 测试温度的分辨率可以达到1×10^-5℃。 其温度测试范围可调, 从而可以满足不同测试环境温度测试的需要, 具有较广泛的应用范围, 并可同通用数据采集器连接构成精密温度观测系统。     

大跨度连续梁CPⅢ点平面坐标修正方法探讨

使用大跨度连续梁上CPⅢ平面坐标时,应尽量与CPⅢ测量时环境条件一致。要满足环境条件尽量一致难以实现,为此需要探讨大跨度连续梁上CPⅢ点平面坐标受环境影响变化的规律,建立大跨度连续梁上CPⅢ点平面坐标受环境影响变化的数学模型,对平面坐标进行修正,从而减少测量次数。     

Temperature and emissivity separation and mineral mapping based on airborne TASI hyperspectral thermal infrared data

Thermal infrared remote sensing (8–12 μm) (TIR) has great potential for geologic remote sensing studies. TIR has been successfully used for terrestrial and planetary geologic studies to map surface materials. However, the complexity of the physics and the lack of hyperspectral data make the studies under-investigated. A new generation of commercial hyperspectral infrared sensors, known as Thermal Airborne Spectrographic Imager (TASI), was used for image analysis and mineral mapping in this study. In this paper, a combined method integrating normalized emissivity method (NEM), ratio algorithm (RATIO) and maximum–minimum apparent emissivity difference (MMD), being applied in multispectral data, has been modified and used to determine whether this method is suitable for retrieving emissivity from TASI hyperspectral data. MODTRAN 4 has been used for the atmospheric correction. The retrieved emissivity spectra matched well with the field measured spectra except for bands 1, 2, and 32. Quartz, calcite, diopside/hedenbergite, hornblende and microcline have been mapped by the emissivity image. Mineral mapping results agree with the dominant minerals identified by laboratory X-ray powder diffraction and spectroscopic analyses of field samples. Both of the results indicated that the atmospheric correction method and the combined temperature–emissivitiy method are suitable for TASI image. Carbonate skarnization was first found in the study area by the spatial extent of diopside. Chemical analyses of the skarn samples determined that the Au content was 0.32–1.74 g/t, with an average Au content of 0.73 g/t. This information provides an important resource for prospecting for skarn type gold deposits. It is also suggested that TASI is suitable for prospect and deposit scale exploration.     

近地大气层测线温度模型的试验研究

从湍流传导模型（TTM）理论出发，结合试验数据，探讨了近地大气层测线温度模型，进而得出了相应的折光改正公式，用此方法对试验数据进行折光改正，取得了良好的效果。     

Solar wind influence on atmospheric processes in winter Antarctica

Galactic cosmic rays (GCRs) altered by solar wind are traditionally regarded as the most plausible agent of solar activity influence on the Earth's atmosphere. However, it is well known that severe reductions in the GCRs flux, known as Forbush decreases (FDs), are caused by solar wind of high speed and density, which sweeps away the GCRs on its way. Since the FD beginnings are registered at the Earth's orbit simultaneously with dramatic disturbances in the solar wind, the atmospheric effects, assigned to FDs, can be, in reality, the results of the solar wind influence on the atmospheric processes. This paper presents a summary of the experimental results demonstrating the strong influence of the interplanetary electric field on atmospheric processes in central Antarctica, where the large-scale system of vertical circulation is formed during winter seasons. The influence is realized through acceleration of the air masses, descending into the lower atmosphere from the troposphere, and the formation of cloudiness above the Antarctic Ridge, where the descending air masses enter the surface layer. The acceleration is followed by a sharp increase of the atmospheric pressure near-pole region, which gives rise to the katabatic wind strengthening above the entire Antarctica. The cloudiness formation results in the sudden warmings in the surface atmosphere, since the cloud layer efficiently backscatters the long wavelength radiation from the ice sheet, but does not affect the adiabatic warming process of the descending tropospheric air masses. When the drainage flow strengthening the circumpolar vortex around the periphery of the Antarctic continent decays, the surface easterlies typical of the coast stations during the winter season are replaced by southerlies and the cold Antarctic air masses flow out to the Southern ocean.     

Geoenvironmental Testing

Geoenvironmental concerns involve unsaturated soils in problems like soil contamination, waste disposal and ground-atmosphere interactions. This paper deals with the two first points. To tackle geoenvironmental problems in unsaturated soils, it is necessary to identify experimentally the retention and transfer phenomena that govern the movements of fluids and chemical species in the unsaturated soil. Some of the experimental techniques used in unsaturated soils can be adapted to face these problems, but extensions accounting for the various physico-chemical processes involved in soil contamination and waste disposal are necessary, including temperature effects and the mechanical couplings resulting from the changes in temperature and chemical concentrations. After an introduction to the geoenvironmental problems that are related to unsaturated soils, the paper presents a series of experimental developments carried out in relation to retention and transfer properties of water (pure or with dissolved species), hydrocarbons and gas, also accounting for temperature effects and chemical effects. The techniques presented are applicable to soil contamination and waste disposal, with a special concern addressed to nuclear waste disposal, in which the effects of desaturation of the geological barrier together with the unsaturated nature of compacted engineered barriers appeared to be quite important.     

Enhancement of regional variations in salinity and temperature in a coral reef lagoon, New Caledonia

The variability in salinity and temperature in the southwest lagoon of New Caledonia (2100 km²) under non-storm conditions is analysed using a 4-year dataset (1997–2001). Seasonal and interannual variations in salinity are amplified nearshore. Temperature is larger in bays than in the open lagoon during summer, the reverse is true in winter. El Niño Southern Oscillation (ENSO) related nearshore temperature variations parallel those at regional scale, but with seasonal variations amplified. Haline stratification, if any, is enhanced in coastal areas. To cite this article: S. Ouillon et al., C. R. Geoscience 337 (2005).     

Circulation and teleconnection mechanisms of Northeast Brazil droughts

The Northern Nordeste of Brazil has its short rainy season narrowly concentrated around March–April, when the interhemispheric southward gradient of sea surface temperature (SST) is weakest and the Intertropical Convergence Zone (ITCZ), which is the main rainbearing system for the Nordeste, reaches its southernmost position in the course of the year. The recurrent Secas (droughts) have a severe socio-economic impact in this semi-arid region. In drought years, the pre-season (October–January) rainfall is scarce, the interhemispheric SST gradient weakened and the basin-wide southerly (northerly) wind component enhanced (reduced), all manifestations of an anomalously far northward ITCZ position. Apart from this ensemble of Atlantic indicators, the Secas also tend to be preceded by anomalously warm equatorial Pacific waters in January. During El Niño years, an upper-tropospheric wave train extends from the equatorial eastern Pacific to the northern tropical Atlantic, affecting the patterns of upper-tropospheric topography and divergence, and hence of vertical motion over the Atlantic. The altered vertical motion leads to a weaker meridional pressure gradient on the equatorward flank of the North Atlantic subtropical high, and thus weaker North Atlantic tradewinds. The concomitant reduction of evaporation and wind stirring allows for warmer surface waters in the tropical North Atlantic and thus steeper interhemispheric meridional thermal gradient. Consequently, the ITCZ stays anomalously far North and the Nordeste rainy season becomes deficient.     

Formation of the salinity minimum in the Mixed Water Region between the Oyashio and Kuroshio Fronts

The salinity minimum frequently occurring in the Mixed Water Region between the Oyashio and Kuroshio Fronts seems to originate from the salinity minimum at the density of 26.8σ_θ called the North Pacific Intermediate Water. We examined water exchange of this region with the Oyashio and the Kuroshio Extension using mixing ratio R_K defined as (θ - θ_OY)/(θ_K - θ_OY) × 100, where θ_OY, θ_K, and θ represent potential temperature of the Oyashio and Kuroshio Waters and their mixture on the isopycnal surfaces, respectively. CTD data were obtained by repeated observation from January 1990 to May 1991. R_K increases southward from the Oyashio Front to the Kuroshio Front with the range of −20 to 120%. The gradient of R_K on the isopycnal surfaces is large around the Oyashio Front above the 26.8σ_θ surface, while it is large around the Kuroshio Front below it. This agrees with the average R_K in the Mixed Water Region decreasing greatly with the increase of density at densities less dense than 26.8σ_θ. We calculated thickness and volume transport of the Oyashio between the isopycnal surfaces near the coast of Hokkaido. They increase largely with density at densities less dense than 26.8σ_θ. It is supposed that the salinity minimum in the Mixed Water Region is the upper limit of the water largely influenced by the Oyashio Water. Its density could depend only on the density structure of the Oyashio.