GGR Biennial Review: Reference Materials in Geoanalytical and Environmental Research – Review for 2008 and 2009

This review gives an overview of the literature on reference materials of geochemical and environmental interest for the two-year period 2008–2009. Reference materials play an increasingly important role in all fields of geoanalytical research. This is demonstrated by the large number of publications containing data on reference materials. Although many reference materials exist, there is still a great need for certified samples, so-called delta zero materials for stable isotopic work and homogeneous microanalytical reference materials. This review focuses on six topics: developments of certification processes of reference materials mainly postulated in ISO guidelines and the IAG protocol, new developments of the GeoReM database, investigations of powdered rock reference materials, Chinese reference materials published in Chinese journals, microanalytical reference materials and isotopic reference materials.     

越赤道气流ISO特征在台风季节预报中的可行性研究

越赤道气流作为南北半球物质、能量和水汽的输送通道,它的季节内变化引起台风水汽源变化,影响台风的生成频数和路径。该文研究了越赤道气流ISO特征在台风季节预报中的可行性。台风路径在传统的分类基础上细分为7种,对不同路径的台风所对应的低频流场进行超前和滞后合成,发现不同台风路径对应着不同的低频越赤道气流通道,低层20°N附近的低频气旋外围气流总是预示着台风路径未来的走向。低层低频流场的演变表明,越赤道气流的振荡周期为准40 d,它的ISO特征影响低纬地区的低频气旋的位置和强度,进而影响台风路径。高层低频流场刚好与低层反向,越赤道气流不再是以通道出现而是呈现区域特征。越赤道气流ISO特征可以作为台风季节预报的参考量之一。     

西北太平洋台风活动与大气季节内振荡

本文综合介绍了大气季节内振荡与西北太平洋台风活动关系的最新研究结果。主要内容是:大气MJO的活动对西北太平洋台风的生成有比较明显的调制作用,在MJO的活跃期与非活跃期西北太平洋生成台风数的比例为2:1;而在MJO活跃期,对流中心位于赤道东印度洋(即MJO第2～3位相)与对流中心在西太平洋地区(即MJO第5～6位相)时的比例也为2:1。在MJO的不同位相,西太平洋地区的动力因子和热源分布形势有很明显不同。在第2～3位相,各种因子均呈现出抑制西太平洋地区对流及台风发展的态势;而在第5～6位相则明显促进对流的发生发展。这说明MJO在不断东移的过程中,将影响和改变大气环流形势,最终影响台风的生成。对多台风年与少台风年850 hPa的30～60 d低频动能距平合成分析表明,在多台风年有两个低频动能的大值区,其中最显著的是低频动能正异常位于菲律宾以东15°N以南的西北太平洋地区,此区域正好为季风槽所在的位置。而少台风年的情况与多台风年相反,从阿拉伯海东部经印度半岛、孟加拉湾一直到我国南海地区,都是低频动能的大值区,最大的低频动能中心位于印度半岛和我国南海南部;而菲律宾以东的西北太平洋是低频动能的负距平区,季风槽偏弱,对台风生成发展不利。200 hPa速度势场清楚表明,多台风年(少台风年)在菲律宾以东的西北太平洋上表现为高层辐散(辐合),增强(减弱)该地区的上升气流,有利于(不利于)台风的生成。大气季节内振荡(ISO)对西北太平洋台风路径影响的研究表明,大气ISO)流场对台风路径预报有重要参考意义。其结果表明,台风生成时850 hPa低频气旋(LFC)的正涡度带(特别是最大正涡度线)走向往往预示着台风的未来走向;200 hPa的低频环流形势对台风的路径也有一定的指示作用,与200 hPa低频反气旋(LFAC)相联系的200 hPa强低频气流对台风起着引导气流的作用。     

Causes of the Intraseasonal SST Variability in the Tropical Indian Ocean

Satellite observations reveal a much stronger intraseasonal sea surface temperature (SST) variability in the southern Indian Ocean along 5-10oS in boreal winter than in boreal summer. The cause of this seasonal dependence is studied using a 2?-layer ocean model forced by ERA-40 reanalysis products during 1987-2001. The simulated winter-summer asymmetry of the SST variability is consistent with the observed. A mixed-layer heat budget is analyzed. Mean surface westerlies along the ITCZ (5-10oS) in December-January-February (DJF) leads to an increased (decreased) evaporation in the westerly (easterly) phase of the intraseasonal oscillation (ISO), during which convection is also enhanced (suppressed). Thus the anomalous shortwave radiation, latent heat flux and entrainment effects are all in phase and produce strong SST signals. During June-July-August (JJA), mean easterlies prevail south of the equator. Anomalies of the shortwave radiation tend to be out of phase to those of the latent heat flux and ocean entrainment. This mutual cancellation leads to a weak SST response in boreal summer. The resultant SST tendency is further diminished by a deeper mixed layer in JJA compared to that in DJF. The strong intraseasonal SST response in boreal winter may exert a delayed feedback to the subsequent opposite phase of ISO, implying a two-way air-sea interaction scenario on the intraseasonal timescale. Citation: Li, T., F. Tam, X. Fu, et al., 2008: Causes of the intraseasonal SST variability in the tropical Indian ocean, Atmos. Oceanic Sci. Lett., 1, 18-23     

渤海西部表层沉积物中重金属的环境地球化学特征

为探讨渤海西部在多重环境因素变化下沉积物中重金属的环境地球化学行为,分析了渤海西部44个站位表层沉积物样品中8种重金属元素含量,研究了重金属元素的分布特征、环境影响因素及其生态风险。结果表明,渤海西部表层沉积物中As、Cu、Cd、Cr、Hg、Ni、Pb、Zn的平均含量分别为117 mg/kg、255 mg/kg、014 mg/kg、689 mg/kg、0037 mg/kg、303 mg/kg、223 mg/kg、757 mg/kg;Cu、Cr、Ni、Zn含量与有机碳含量、小于63 μm细粒沉积物呈显著正相关,其在表层沉积物中的分布明显受到有机质含量和沉积物粒径的控制,而As、Hg分布没有明显受到有机质含量的影响。富集系数显示,Cr、Ni、Pb和Zn为无富集,Cu、As为轻度富集,Cd和Hg为中度富集。与多种背景值和一致性沉积物质量基准相比较,渤海西部表层沉积物Pb、Cd的含量超出背景值,而Cu、Zn、Ni、Cr、As、Hg含量也存在一定的异常,但其含量水平引发有害生物效应的可能性不大,尽管重金属元素含量偏高,但生态风险较小。     

Reference Values Following ISO Guidelines for Frequently Requested Rock Reference Materials

We present new reference values for nineteen USGS, GSJ and GIT‐IWG rock reference materials that belong to the most accessed samples of the GeoReM database. The determination of the reference values and their uncertainties at the 95% confidence level follows as closely as possible ISO guidelines and the Certification Protocol of the International Association of Geoanalysts. We used analytical data obtained by the state‐of‐the‐art techniques published mainly in the last 20 years and available in GeoReM. The data are grouped into four categories of different levels of metrological confidence, starting with isotope dilution mass spectrometry as a primary method. Data quality was checked by careful investigation of analytical procedures and by the application of the Horwitz function. As a result, we assign a new and more reliable set of reference values and respective uncertainties for major, minor and a large group of trace elements of the nineteen investigated rock reference materials.