Unusual Behavior of the Kuroshio Current System from Winter 1996 to Summer 1997 Revealed by ADEOS-OCTS and Other Data (Continued): A Study from Broad External Conditions with Bottom Topography

In the previous paper (Toba and Murakami, 1998) we reported on an unusual path of the Kuroshio Current System, which occurred in April 1997 (April 1997 event), using the Ocean Color and Temperature Scanner (OCTS) data of the Advanced Earth Observing Satellite (ADEOS). The April 1997 event was characterized by the flow of the Kuroshio along the western slope (northward) and the eastern slope (southward) of the Izu-Ogasawara Ridge, a very southerly turning point at about 32°N, followed by a straight northward path up to 37°N of the Kuroshio Extension along the eastern flank of the Izu-Ogasawara and the Japan Trenches. Overlaying of depth contours on ADEOS-OCTS chlorophyll-a images at the April 1997 event demonstrates the bottom topography effects on the current paths. A new finding based on TOPEX/Poseidon altimeter data is that the sea-surface gradient across the Kuroshio/Kuroshio Extension diminished greatly in the sea area southeast of the central Japan, as a very temporary phenomenon prior to this event. This temporary diminishing of the upper-ocean current velocity might have caused a stronger bottom effect along the Izu-Ogasawara Ridge, and over the Izu-Ogasawara Trench disclosed a weak background, barotropic trench-flank current pattern, which existed otherwise independently of the Kuroshio Extension. The very southerly path of the Kuroshio Extension from winter 1996 to autumn 1998 corresponded, with a time lag of about 1.5 years, to the previous La Niña tendency with weaker North Equatorial Current. The April 1997 event occurred in accordance with its extreme condition.     

Heat content change in the surface isothermal layer of a warm core ring in the sea east of Japan

Heat content change in the surface isothermal layer of a typical warm core ring in the sea east of Japan is described based on approximately 90 CTD profiles obtained by one profiling float. Erosion of the seasonal thermocline and development of a surface isothermal layer from the mid-summer to the early winter of 1999 are clearly seen. While heat content change between two consecutive profiles with a 35-hour time interval is much noisier, its 10-day running mean is consistent with net surface heat flux, indicating that surface heat flux dominates the temporal heat content change in the surface isothermal layer in the warm core ring.     

2000—2014年东北高纬度地区霾环境参数分析

利用探空观测资料及NCEP再分析资料,统计2000-2014年东北高纬度地区霾发生时的环境气象条件,并进行对比分析。结果表明：风垂直切变、地表风速、假相当位温垂直差、逆温强度、混合层高度、K指数、A指数、理查森数和扩散系数等指标和霾发生与维持关系密切。对于东北高纬度地区而言,500hPa与850hPa水平风垂直切变低于21m/s,地表风速在6m/s以下,理查森数大于0.3,逆温强度大于-0.9℃/100m,假相当位温垂直差大于-3K,混合层高度低于1000m,K指数和A指数低于对流天气发生时的经验阈值的情况下,大气垂直和水平方向都不利于污染物扩散,有利于霾的产生与维持。探空资料与再分析资料对应各统计指标在数值上具有较高一致性,特别是极值以外的部分,二种资料计算的指标具有显著的相关关系。对于东北高纬度地区,再分析资料可以代替探空观测资料进行环境参数分布和阈值的统计分析。     

滇东北地区中三叠统关岭组中发现爬行类足迹化石

滇东北地区中三叠统关岭组中首次发现的四足五趾爬行类动物足迹以大小足迹形式呈一条直线前后相伴出现,足迹形状与人手印非常相似,总体表现为第三趾最长,大拇指具有外翻弯曲特征,初步判断为"手兽"足迹,该发现对研究中生代爬行类生物种属、迁移、运动模式及古地理环境具有极其重要的意义。     

鲁迅与顾琅早期地质作品新论——《中国地质略论》与《中国矿产志》知识来源考

鲁迅在日本留学期间曾于1903年在《浙江潮》发表《中国地质略论》一文,1906年与同到日本留学的顾琅合作出版《中国矿产志》（附《中国矿产全图》）一书。它们在中国地质学史上均具有开创性并产生重要影响,特别是《中国矿产志》被认为是中国第一部地质矿产著作。本文从中日地质学交流的角度,结合新发现的史料,通过文本对比分析,指出《中国地质略论》和《中国矿产志》均是吸收当时日本的一些地学著作编写而成。《中国地质略论》的部分内容来源于佐藤传藏的《地质学》（1898）一书;《中国矿产志》的导言部分是在《中国地质略论》的基础上拓展而成,增补的内容则参考了矢津昌永的《高等地理清国地志》（1905）、横山又次郎的《地质学教科书》（1903）以及石川成章的《地球发达史》（1904）等著作,本言部分主要参考了日本地质调查所1902年发表的《清国及韩国主要矿产颁布图说明——附清国主要矿产地名表》;《中国矿产全图》则是顾琅依据日本《清国主要矿产分布图》绘制而成。《中国地质略论》和《中国矿产志》（附《中国矿产全图》）的编撰反映了20世纪初日本逐渐成为中国地质学知识的主要来源。     

滇东北茂租铅锌矿控矿因素及找矿方向

茂租铅锌矿位于扬子地块西南缘茂租断层和莲峰―巧家断裂交汇的三角带,是川滇黔铅锌多金属成矿域滇东北铅锌矿化集中区重要的铅锌矿床。矿区有上、下2个矿层,9个似层状矿体、2个脉状矿体。似层状矿体赋存于上震旦统灯影组白云岩中,顺层产出,矿体产状与地层产状一致;脉状矿体产于断裂破碎带中,矿体产状受断层控制。研究认为赋矿地层岩性、矿体围岩性质、矿区褶皱构造、区域性茂租断层的多次活动及其派生出的次一级NE向断层是区内铅锌矿形成的重要控制因素。根据成矿条件分析及化探异常显示,矿区南部深部及外围铅锌矿有较大找矿潜力。     

Sub‐Permil Interlaboratory Consistency for Solution‐Based Boron Isotope Analyses on Marine Carbonates

Boron isotopes in marine carbonates are increasingly used to reconstruct seawater pH and atmospheric pCO₂ through Earth’s history. While isotope ratio measurements from individual laboratories are often of high quality, it is important that records generated in different laboratories can equally be compared. Within this Boron Isotope Intercomparison Project (BIIP), we characterised the boron isotopic composition (commonly expressed in δ¹¹B) of two marine carbonates: Geological Survey of Japan carbonate reference materials JCp‐1 (coral Porites) and JCt‐1 (giant clam Tridacna gigas). Our study has three foci: (a) to assess the extent to which oxidative pre‐treatment, aimed at removing organic material from carbonate, can influence the resulting δ¹¹B; (b) to determine to what degree the chosen analytical approach may affect the resultant δ¹¹B; and (c) to provide well‐constrained consensus δ¹¹B values for JCp‐1 and JCt‐1. The resultant robust mean and associated robust standard deviation (s*) for un‐oxidised JCp‐1 is 24.36 ± 0.45‰ (2s*), compared with 24.25 ± 0.22‰ (2s*) for the same oxidised material. For un‐oxidised JCt‐1, respective compositions are 16.39 ± 0.60‰ (2s*; un‐oxidised) and 16.24 ± 0.38‰ (2s*; oxidised). The consistency between laboratories is generally better if carbonate powders were oxidatively cleaned prior to purification and measurement.     

Assimilation of TOPEX/POSEIDON Altimeter Data with a Reduced Gravity Model of the Japan Sea

Sea level data measured by TOPEX/POSEIDON over the Japan Sea from 1993 to 1994 is analyzed by assimilation using an approximate Kalman filter with a 1.5 layer (reduced-gravity) shallow water model. The study aims to extract signals associated with the first baroclinic mode and to determine the extent of its significance. The assimilation dramatically improves the model south of the Polar Front where as much as 20 cm² of the observed sea level variance can be accounted for. In comparison, little variability in the northern cold water region is found consistent with the model dynamics, possibly due to significant differences in stratification.     

Intermediate Waters in the East/Japan Sea

Properties of the intermediate layer in the East/Japan Sea are examined by using CREAMS data taken mainly in summer of 1995. Vertical profiles of potential temperature, salinity and dissolved oxygen and relationships between these physical and chemical properties show that the dissolved oxygen concentration of 250 μmol/l, roughly corresponding to 0.6°C at the depth of about 400 db, makes a boundary between intermediate and deep waters. Water colder than 0.6°C has a very stable relationship between potential temperature and salinity while salinity of the water warmer than 0.6°C is lower in the western Japan Basin than that in the eastern Japan Basin. The low salinity water with high oxygen corresponds to the East Sea Intermediate Water (ESIW; <34.06 psu, >250 μmol/l and >1.0°C) which was previously identified by Kim and Chung (1984) and the high salinity water with high oxygen found in eastern Japan Basin is named as the High Salinity Intermediate Water (HSIW; >34.07 psu, >250 μmol/l and >0.6°C). Spatial distribution of salinity and acceleration potential on the surface of σ_ϑ = 27.2 kg/m³ shows that the ESIW prevailing in the western Japan Basin is transported eastward by a zonal flow along the polar front near 40°N and a cyclonic gyre in the eastern Japan Basin is closely related to the HSIW. This revised version was published online in August 2006 with corrections to the Cover Date.