Study of red tide prediction model for the Changjiang Estuary

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Cosmic‐ray rejection for single spectroscopic CCD images by means of template matching

This article describes a novel algorithm for cosmic‐ray rejection in single spectroscopic CCD images. This algorithm is based on a variation of template matching. It focuses on identifying those pixels belong to spectra, while other conventional algorithms tried to locate the cosmic‐ray hits directly. The main principle is applying template matching to find suspicious blocks, which is followed by surface patching to locate the legitimate pixels accurately. Therefore, the rest pixels are the ones corrupted by cosmic‐ray hits. Meanwhile, almost all the parameters are automatically extracted from the images. Examples of its performance are given for both simulated and observed images. It shows an advantage of significantly low false alarm rate with relatively high detection rate (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Tests and applications of an approach to absorbing reflected waves towards incident boundary

If the upstream boundary conditions are prescribed based on the incident wave only, the time-dependent numerical models cannot effectively simulate the wave field when the physical or spurious reflected waves become significant. This paper describes carefully an approach to specifying the incident wave boundary conditions combined with a set sponge layer to absorb the reflected waves towards the incident boundary. Incorporated into a time-dependent numerical model, whose governing equations are the Boussinesq-type ones, the effectiveness of the approach is studied in detail. The general boundary conditions, describing the down-wave boundary conditions are also generalized to the case of random waves. The numerical model is in detail examined. The test cases include both the normal one-dimensional incident regular or random waves and the two-dimensional oblique incident regular waves. The calculated results show that the present approach is effective on damping the reflected waves towards the incident wave boundary.     

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基于北斗卫星的预警信息发布技术研究及实现

利用北斗卫星短报文通信功能,以广播方式发布预警信息,可提高预警信息的覆盖范围和时效性, 填补我国海洋及陆地边远地区预警信息发布空白。但北斗卫星预警信息发布存在传输速率低、冗余信息量大、长预警信息发布成功率低的问题。该文对北斗卫星预警信息发布系统的系统结构、协议体系和关键问题开展研究,通过指挥机并联、预警信息编码、影响区域识别、联合补包等方法,解决了北斗卫星预警信息发布系统建设的关键问题。在此基础上,该文设计了预警信息网络发布协议、预警信息北斗发布协议和预警信息北斗传输协议,并开发了原型系统。     

Relation between temperature changes of the mid-upper troposphere over Eurasian mid-high latitudes and solar irradiance in the twentieth century

The δ¹⁸O data obtained from an 18.7 m ice core drilled in Chongce Ice Cap at an elevation of 6,530 m a.s.l. in the West Kunlun Mountains on the northern Tibetan Plateau show a strong correlation with the summer temperature of the middle to upper troposphere over the mid-high latitudes of Eurasia. Based on this, the δ¹⁸O record can be used as a proxy of the June–September mean temperature of the mid-upper troposphere (MUT) from 1903 to 1992. The time span of the ice core record is much longer than the meteorological data available only after 1948. Using the empirical mode decomposition method (EMD), the δ¹⁸O record is decomposed into various frequency components and compared with the solar irradiance variations of the same period. The results show that (1) The June–September mean temperature of the MUT over Eurasian mid-high latitudes is completely decomposed into four IMF (intrinsic mode function) components and an increasing trend. (2) Solar irradiance is decomposed into the Schwabe cycle, the Hale cycle, the Gleissberg cycle, and an increasing trend. (3) The correlation coefficients between the June and September mean temperatures of the MUT over Eurasian mid-high latitudes and solar irradiance on the longer timescales (at least more than 11-year) show the significant correlations; their phase changes are basically identical in general, and (4) the 11-year Schwabe cycle exists in the June–September mean temperature of the MUT over Eurasian mid-high latitudes during most of the time from 1903 to 1992, and only in the two high-temperature phases (1929–1944 and from 1975 to the present) may global warming disturb this relation. A full understanding of this phenomenon would shed insight into the potential consequence of global warming on the MUT.     

A 16 ka climate record deduced from δ^13C and C/N ratio in Qinghai Lake sediments, northeastern Tibetan Plateau

1 INTRODUCTION δ13C in organic matters from lacustrine sedi- ments varies with several factors including aquatic plants, vegetation type in the catchment, atmos- pheric CO2 concentration, climate (temperature and precipitation), and properties of water, …     

海洋声信道R-ω平面"纹理"特征与形成机理

采用数值模拟给出水平均匀波导环境下的声场强度在R-ω平面上的"纹理"图案,根据相位及任2号简正波之间的水平相干距离[1]随频率的变化,分析了平面中存在的"分裂"和"孤立的干涉线"2种干涉"纹理"的形成机理.     

The hydrothermal karstification and its effect on Ordovician carbonate reservoir in Tazhong uplift of Tarim Basin,Northwest China

With a detailed study on petrology, mineralogy and geochemistry of some important Ordovician carbonate well core samples in Tazhong uplift of Tarim Basin, the distinguishing symbols of hydrothermal karstification are first put forward as the phenomena of rock hot depigmentation, hot cataclasm and the appearance of typical hydrothermal minerals such as fluorite, barite, pyrite, quartz and sphalerite. The main homogenization temperatures of primary fluid inclusions in fluorite are from 260 to 310°C, indicating the temperature of hydrothermal fluid. The fluid affected the dissolved rocks and showed typical geochemistry features with low contents of Na and Mg, and high contents of Fe, Mn and Si. The ratio of ³He/⁴He is 0.02R _a, indicating the fluid from the typical continental crust. The hydrothermal fluid karstification pattern may be described as follows: the hot fluid is from the Permian magma, containing dissolving ingredients of CO₂ and H₂S, and shifts along fault, ruptures and unconformity, and dissolves the surrounding carbonates while it flows. The mechanism of hydrothermal karstification is that the mixture of two or more fluids, which have different ion intensity and pH values, becomes a new unsaturated fluid to carbonates. The hydrothermal karstification is an important process to form hypo-dissolved pinholes in Ordovician carbonates of Tazhong uplift of Tarim Basin, and the forming of hydrothermal minerals also has favorable influence on carbonate reservoirs.

     

GIS工作流系统的长事务处理研究

分析了Sagas事务模型及空间数据版本树技术,设计了一种灵活的长事务补偿控制方案,为集成GIS,MIS及OA的工作流系统提供了有力的事务处理技术支持。