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.     

Heavy metal contamination of cultivated wetland soils along a typical plateau lake from southwest China

Topsoil (0–20 cm) samples were collected from four cultivated wetlands including Northern and Western Fields (about 30-year tillage), and Southern and Western Fields (about 20-year tillage) along the Yilong Lake of China in October, 2005. Total concentrations of As, Cr, Cu, Pb, and Zn were determined using the inductively coupled plasma atomic absorption spectrometry in order to assess contamination status in four sampling plots. Results showed that the average concentrations of these heavy metals in Northern and Western Fields were significantly (P < 0.01) higher than those in reference soils, while they were generally lower in Southern and Eastern Fields. All the mean concentrations of heavy metals were lower, except that the average concentrations of As and Cr in Northern Field slightly exceeded the soil quality guidelines. The contamination indices showed low-contamination levels for As, Cu, Pb, and Zn in Northern and Western Fields, while no contamination levels could be observed in Southern and Eastern Fields. As for Cr, they showed moderate-contamination levels in Northern Field, but low or no contamination levels in other three Fields. The integrated contamination index values indicated Northern and Western Fields were moderately contaminated, while Southern and Eastern Fields were less contaminated. The same contamination sources of these heavy metals were identified in these fields using factor- and cluster analysis.     

HY-1C/D卫星中国海洋水色水温扫描仪几何定位方法

海洋一号C/D（HY-1C/D）卫星中国海洋水色水温扫描仪（Chinese Ocean Color and Temperature Scanner,COCTS）主要用于探测海洋水色、水温等要素,这些要素需要经过卫星资料处理才能获取,而几何定位是预处理的核心,直接影响这些要素的质量。COCTS具有114°视场角和四元逐点摆扫的特征,据此研究出一套完整的几何定位方法。从0级数据中提取卫星星历,利用插值法从中获取采样时间对应的卫星位置和速度,进而得到轨道（ORB）坐标系到地心旋转（ECR）坐标系的转换矩阵。基于四元逐点摆扫的特征,中心视矢量分别绕X轴、Y轴旋转相应角度,获得扫描行各采样点ORB视矢量,建立视矢量与地球交叉点关系模型,从而对根据波段数据绘制的遥感图像进行地理定位。本文使用插值法替代了传统需要6个轨道根数来计算卫星位置的复杂方法,同时直接计算ORB到ECR的转换矩阵,而不采用传统的两步转换方法。经过多组数据计算及定性定量验证,HY-1C/D COCTS几何定位结果一致;采样像元尺度效应导致从星下点到两侧边缘、从赤道到两极,误差逐渐增大,约在两个像元内。该方法满足一定的定位精度要求,可以用于COCTS的几何定位。     

陶诗言先生在中国暴雨发生条件和机制研究中的贡献

作者在1998年庆贺陶诗言先生八十华诞的文集中曾专题阐述和评价了陶先生对中国暴雨研究的贡献。 至今十五年过去了,陶诗言先生虽已于2012年仙逝,但其深邃的科学思想依然闪烁着智慧的火花。他在中国暴雨研究中留下的宝贵遗产不但深刻影响过去和现代两代人的暴雨研究和业务发展,而且也将继续影响将来的中国暴雨研究。本文是对陶诗言先生在中国暴雨的研究中所作的贡献并结合现代研究的成果作进一步介绍和评价。主要集中在暴雨发生的动力和热力条件与机理方面。全文内容包括六个方面:（1）季节突变对中国梅雨爆发的影响;（2）暴雨发生的多尺度相互作用;（3）暖湿季风输送带对北方大暴雨的影响;（4）高空急流对暴雨的作用;（5）暴雨和强对流发生的物理条件;（6）地形对暴雨的作用     

Effects of corridor networks on plant species composition and diversity in an intensive agriculture landscape

The development of modern agriculture has resulted in much homogenization of the landscape consisting of large patches of farmland,so small remnant non-crop habitats especially linear corridors play an important role in the conservation of species and the maintenance of ecosystem functions.However,little attention has been paid to the effects of corridors structural characteristics on the plant species restricted to such habitats.In this study,we selected three types of corridors including ditch,hedgerow and road,and ana-lyzed their structural characteristics.The plant species presented in these corridors were investigated,and the species diversity,abun-dance and frequency were estimated.Moreover,spatial arrangements of corridors were classified into different types to discuss whether there were significant effects of corridor network on plant distribution.The results show that three types of corridors have different ef-fects on plant species composition and diversity.The one-one combined corridor networks and total network associated by three corri-dors have more complex structural features than each single type of corridor.However,there is no strong correlation between the corri-dor networks with their plant species.We suggest that carrying out a pointed vegetation survey at corridor intersections to further test the relationships between structural features of corridor and plants is necessary.     

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Dynamic response analysis of a floating mooring system

An innovative floating mooring system with two or more independent floating mooring platforms in the middle and one rigid platform on each side is proposed for improving efficiency and safety in shallow water. For this new system, most of collision energy is absorbed through the displacement of floating platforms. In order to illustrate the validity of the system, a series of model tests were conducted at a scale of 1:40. The coupled motion characteristics of the floating mooring platforms were discussed under regular and irregular waves, and the influences of wave direction and other characteristics on dynamic response of the system were analyzed. The results show that the mooring system is safest at 0° of wave incident angle, whereas the most dangerous mooring state occurs at 90° of wave incident angle. Motion responses increase with the increase of wave height, but are not linearly related to changes in wave height.     

Nonlinear optimization method of ship floating condition calculation in wave based on vector

Ship floating condition in regular waves is calculated. New equations controlling any ship＇s floating condition are proposed by use of the vector operation. This form is a nonlinear optimization problem which can be solved using the penalty function method with constant coefficients. And the solving process is accelerated by dichotomy. During the solving process, the ship＇s displacement and buoyant centre have been calculated by the integration of the ship surface according to the waterline. The ship surface is described using an accumulative chord length theory in order to determine the displacement, the buoyancy center and the waterline. The draught forming the waterline at each station can be found out by calculating the intersection of the ship surface and the wave surface. The results of an example indicate that this method is exact and efficient. It can calculate the ship floating condition in regular waves as well as simplify the calculation and improve the computational efficiency and the precision of results.     

The variability of the East Asian summer monsoon and its relationship to ENSO in a partially coupled climate model

The variability of the East Asian summer monsoon (EASM) is studied using a partially coupled climate model (PCCM) in which the ocean component is driven by observed monthly mean wind stress anomalies added to the monthly mean wind stress climatology from a fully coupled control run. The thermodynamic coupling between the atmospheric and oceanic components is the same as in the fully coupled model and, in particular, sea surface temperature (SST) is a fully prognostic variable. The results show that the PCCM simulates the observed SST variability remarkably well in the tropical and North Pacific and Indian Oceans. Analysis of the rainfall-SST and rainfall-SST tendency correlation shows that the PCCM exhibits local air-sea coupling as in the fully coupled model and closer to what is seen in observations than is found in an atmospheric model driven by observed SST. An ensemble of experiments using the PCCM is analysed using a multivariate EOF analysis to identify the two major modes of variability of the EASM. The PCCM simulates the spatial pattern of the first two modes seen in the ERA40 reanalysis as well as part of the variability of the first principal component (correlation up to 0.5 for the model ensemble mean). Different from previous studies, the link between the first principal component and ENSO in the previous winter is found to be robust for the ensemble mean throughout the whole period of 1958–2001. Individual ensemble members nevertheless show the breakdown in the relationship before the 1980’s as seen in the observations.     

模糊综合评判模型在宝坻水源地地下水水质评价中的应用

运用模糊综合评判模型,对中石化天津分公司宝坻水源地奥陶系灰岩地下水水质行综合评价。评价结果表明,研究区采样点水质总体评判级别为I级,说明该区地下水水质较好,而氟离子含量超标是由于地区背景值造成的,这一结论与该区其它研究成果评价结果一致。说明模糊综合评判模型是一种较实用的地下水水质评判方法。