南海北部湾表层悬浮体分布规律

受实测数据海域位置的限制,目前基于遥感手段对北部湾表层悬浮体的研究,在部分海域如海湾西部精度不高,且缺乏对悬浮体浓度（suspended sediment concentration,SSC）季节变化的研究。基于2003—2017年MODIS-Aqua卫星L1B数据,结合海南岛西部、广西沿岸和越南沿岸实测数据,建立表层SSC的反演模型,获得北部湾海域2003—2017年月均表层SSC分布,并对其影响因素进行初步探讨。结果显示：北部湾表层SSC存在3个终年高值区,包括广西沿岸、海南岛西侧和红河三角洲沿岸;受河流输沙和海洋动力季节变化影响,SSC表现为冬季和夏季较高、春季最低的季节变化特征;热带气旋过境导致北部湾海域SSC增高,其中热带风暴“贝碧嘉”过境时位于路径右侧的雷州半岛西部SSC较多年平均值增幅达75%。     

同步辐射技术在高分辨率古气候、古环境变化中的应用

随着古全球变化研究的深入,理解快速古气候变化的过程及机制正成为学术界关注的关键问题。同步辐射Ⅹ射线荧光原位无损分析是近年来发展起来的新方法。本文简单介绍了同步辐射技术,指出在分辨率和分析灵敏度方面,同步辐射Ⅹ射线荧光分析比其他方法更具有优势。以北极斯瓦尔巴德群岛Bolterskardet湖年纹层为例,介绍同步辐射技术在年纹层沉积物中的应用。初步研究结果表明,同步辐射Ⅹ射线荧光分析数据能够揭示元素含量变化的季节规律。在季节变化层面上,Rb/Sr比值的旋回变化与每个年纹层序列中夏季正粒序层逐渐过度为暗色的冬季粘土微层对应,甚至 Rb/Sr 比值变化亦能够反映夏季纹层内的次一级波动。因此,沉积物的粒度变化可能是决定 Rb/Sr 比值季节波动的主要因素。其他元素(As和Ti)含量的变化受沉积物粒度影响较小,Ti含量的变化可能主要受物理风化作用以及区域降水量变化的影响。     

单台地磁夜均值资料研究半年周期变化的电磁响应

用地磁夜均值资料研究半年周期变化的电磁响应 (地磁内外场比值 Q1) ,如夜均值半年周期变化的源场分布符合 P01分布模式 ,则可用单台资料进行计算 ,有利于进行地区性深地磁测深的研究 .本文选择了质量较好的 5个台约 2 6年的连续资料 ,又搜集了可用的全球分布的台站资料进行分析计算 .结果表明 ,从夜均值估算的半年周期变化的 Q1更为可靠 .原因可能是源场模式不同 .一般的日均值资料不符合 P01模式 ,而夜均值资料则比较符合 P01模式 .本文对此作了源场分布的研究 .     

Space-time analysis of the relative local secular variations of the geomagnetic field (1966–2005) along the Zgorzelec-Wiżajny profile

The Zgorzelec-Wiżajny profile cuts through the main European geotectonic units of the Palaeozoic Western and Central European Platform and the East European Craton, including the connecting Trans-European Suture Zone. The paper summarises 40 years of research on geomagnetic secular variations along the Zgorzelec-Wiżajny profile since 1966. It discusses methods of processing measurement records and presenting their results. The latter are presented against the background of the local geology and the crustal deep magnetic structure data. The hitherto method of variation analysis was modified to address a new trend in the geomagnetic secular variations that has emerged in the East European Craton during the last five years (2001–2005).     

塔里木盆地西北缘前陆冲断带构造分段特征及勘探方向

通过12条典型地质剖面的综合构造建模,系统建立了塔里木盆地西北缘不同构造部位的地质模型,经过平衡恢复求取了变形量,探讨了前陆冲断带的构造分段特征、转换方式及其控制因素,进而指出塔里木盆地西北缘的有利勘探方向和领域。研究发现塔里木盆地与南天山造山带边界断裂系呈东、西两段不连续展布,整体控制前陆冲断带的构造展布格局。根据构造特征的差异性,将塔里木盆地西北缘前陆冲断带划分为7段,不同构造部位变形量差异巨大,向前陆不均一推覆扩展,最小水平缩短量约8.7～64.5km。中部温宿-乌什地区是前陆冲断系统构造转换过渡的关键地区,在该区构造样式由邻区盖层滑脱突变为基底卷入,缩短量也由邻区30～60km突降至9.8～25km。研究表明塔里木盆地西北缘前陆冲断带构造分段和不均一推覆扩展特征受先期构造、地层结构和动力学条件等因素控制,构造样式和变形量侧向变化主要靠走滑断裂和基底断裂调节。     

Characteristics of intraseasonal variations in the mixed layer of “warm pool” areas

Observational data obtained during the TOGA-COARE IOP in the “warm pool” area of the Western Tropical Pacific were used to analyze some characteristics of the intraseasonal variations in the mixed layer. The influence of westerly burst and rainfall on SST, salinity and mixed layer depth are discussed. There are two pairs of counteracting processes in the “warm pool” mixed layer: (1) The increase of mixed layer depth caused by local westerly bursts and the decrease of mixed layer depth caused by larger scale easterly relaxation; (2) the vertical mixing by local wind and the strong stratification due to rainfall in the mixed layer. Some possible mechanisms through the interactions between the intraseasonal time scale variations of the oceanic mixed layer and atmospheric low frequency oscillations are revealed. Supported by National Natural Science Foundation of China (49276250) and LASG of Beijing.     

Temporal Variations in the Second-Degree Stokes Tesseral Geopotential Coefficients from Topex/Poseidon Altimetry

The TOPEX/POSEIDON (T/P) altimetry data set covering the periodof January 1, 1993 to January 3, 2001 was used to derive monthlyseries of the second-degree tesseral geopotential coefficients.To account for the sea water temperature variations, rathersimple models have been devised and discussed, describinglocalized as well as areal variations of sea water temperatureand heights. The second-degree tesseral coefficients have alsobeen shown to be proportional to the pressureportions of the oceanic equatorial effective excitation functions,used in Ocean Angular Momentum (OAM) data. OAM datatogether with Atmospheric Angular Momentum (AAM) data canbe used to study observed polar motion (PM) series.The excess PM rates, derived from the T/P effective excitationfunctions, were compared to the corresponding observed PM rates,derived from the International Earth Rotation Service (IERS)Bulletin A and corrected with AAM also obtainedfrom IERS. The noise of the T/P derived PM rate series was foundto be significantly larger than the corresponding Bulletin A/AAMPM rate residuals as well as the PM rates derived from anindependent OAM series that was also available for the1993–2000 period.     

Influence of the Convection over the South China Sea on the Summer Precipitation of Shandong Province

1　Introduction　ShandongProvince ,whichislocatedintheeastofChina ,consistspartlyofpeninsulaandpartlyofinlandwithatotalareaofabout 1 5 0 0 0 0km2 .Lyingfrom34°2 0′Nto 38°2 0′Nandfrom 1 1 4°4 0′Eto 1 2 2°4 0′E ,alltheareabelongstothemoderateregionandtothetypicalAsianmonsoonclimate .SoShandong’ssum merprecipitationaccountsforover 6 0 %oftheannualrainfall,andaccordinglyflood droughtdisastersmain lyoccurinsummer.Moreover,becauseitisgeographi callylocatedinthetransitionalareabetweenthe…     

Glacier variations in Breheimen,southern Norway: dating Little Ice Age moraine sequences at seven low‐altitude glaciers

Moraine sequences in front of seven relatively low‐altitude glaciers in the Breheimen region of central southern Norway are described and dated using a ‘multi‐proxy’ approach to moraine stratigraphy. Lichenometric dating, based on the Rhizocarpon subgenus, is used to construct a composite moraine chronology, which indicates eight phases of synchronous moraine formation: AD 1793–1799, 1807–1813, 1845–1852, 1859–1862, 1879–1885, 1897–1898, 1906–1908 and 1931–1933. Although the existence of a few cases of older moraines, possibly dating from earlier in the eighteenth or late in the seventeenth centuries cannot be ruled out by lichenometry, Schmidt hammer R‐values from boulders on outermost moraine ridges suggest an absence of Holocene moraines older than the Little Ice Age. Twenty‐three radiocarbon dates from buried soils and peat associated with outermost moraines at three glaciers—Tverreggibreen, Storegrovbreen and Greinbreen—also indicate that the ‘Little Ice Age’ glacier maximum was the Neoglacial maximum at most if not all glaciers. Several maximum age estimates for the Little Ice Age glacier maximum range between the fifteenth and seventeenth centuries, with the youngest from a buried soil being AD 1693. A pre‐Little Ice Age maximum cannot be ruled out at Greinbreen, however, where the age of buried peat suggests the outermost moraine dates from AD 981–1399 (at variance with the lichenometric evidence). Glaciofluvial stratigraphy at Tverreggibreen provides evidence for minor glacier advances about AD 655–963 and AD 1277–1396, respectively. Copyright © 2003 John Wiley & Sons, Ltd.