Spatial-temporal characteristics of the “cumulative effect” of torrential rain over South China

To expand torrential rain, which is a meso- and microscale weather process, to a meso- and long-scale weather process, in this paper, we choose South China as a sample region and propose the conception of the “Cumulative Effect” of torrential rain (CETR) by using daily precipitation observational data from 740 stations. Through a statistical analysis of the observations, three indexes—continuous time (L _d), control area (A _r), and precipitation contribution rate (Q _s)—are used to define the CETR and indicate the torrential rain processes. The relationships between the CETR and simultaneous total precipitation over South China are analyzed in the pre-flooding and latter flooding seasons. This analysis shows that on both interannual and interdecadal scales, the three indexes are highly correlated with simultaneous total precipitation over South China in the pre-flooding season and latter flooding season. Moreover, an empirical orthogonal function (EOF) analysis is performed to classify the spatial distribution of the CETR. In both the pre-flooding season and the latter flooding season, the four major spatial models of torrential rain are similar to those of total precipitation over South China. With regard to the amount of precipitation caused by the CETR, the latter flooding season is affected more significantly than the pre-flooding season. Regarding the geographical distribution of precipitation, the opposite result occurs. In conclusion, in both the pre-flooding season and the latter flooding season, the CETR influences and even determines the amount and distribution of precipitation over South China.

     

Platinum-group Mineral (PGM) and Base-metal Sulphide (BMS) Inclusions in Chromitites of the Zedang Ophiolite, Southern Tibet, China and their Petrogenetic Significance

Voluminous platinum-group mineral(PGM) inclusions including erlichmanite(Os,Ru)S_2, laurite(Ru,Os)S_2, and irarsite(Ir,Os,Ru,Rh)As S, as well as native osmium Os(Ir) and inclusions of base metal sulphides(BMS), including millerite(NiS), heazlewoodite(Ni_3S_2), covellite(CuS) and digenite(Cu_3S_2), accompanied by native iron, have been identified in chromitites of the Zedang ophiolite, Tibet. The PGMs occur as both inclusions in magnesiochromite grains and as small interstitial granules between them; most are less than 10 μm in size and vary in shape from euhedral to anhedral. They occur either as single or composite(biphase or polyphase) grains composed solely of PGM, or PGM associated with silicate grains. Os-, Ir-, and Ru-rich PGMs are the common species and Pt-, Pd-, and Rh-rich varieties have not been identified. Sulfur fugacity and temperature appear to be the main factors that controlled the PGE mineralogy during crystallization of the host chromitite in the upper mantle. If the activity of chalcogenides(such as S, and As) is low, PGE clusters will remain suspended in the silicate melt until they can coalesce to form alloys. Under appropriate conditions of ?S_2 and ?O_2, PGE alloys might react with the melt to form sulfides-sulfarsenides. Thus, we suggest that the Os, Ir and Ru metallic clusters and alloys in the Zedang chromitites crystallized first under high temperature and low ?S_2, followed by crystallization of sulphides of the laurite-erlichmanite, solid-solution series as the magma cooled and ?S_2 increased. The abundance of primary BMS in the chromitites suggests that ?S_2 reached relatively high values during the final stages of magnesiochromite crystallization. The diversity of the PGE minerals, in combination with differences in the petrological characteristics of the magnesiochromites, suggest different degrees of partial melting, perhaps at different depths in the mantle. The estimated parental magma composition suggests formation in a suprasubduction zone environment, perhaps in a forearc.     

A total error-based multiquadric method for surface modeling of digital elevation models

Digital elevation model (DEM) source data are subject to both horizontal and vertical errors owing to improper instrument operation, physical limitations of sensors, and bad weather conditions. These factors may bring a negative effect on some DEM-based applications requiring low levels of positional errors. Although classical smoothing interpolation methods have the ability to handle vertical errors, they are prone to omit horizontal errors. Based on the statistical concept of the total least squares method, a total error-based multiquadric (MQ-T) method is proposed in this paper to reduce the effects of both horizontal and vertical errors in the context of DEM construction. In nature, the classical multiquadric (MQ) method is a vertical error regression procedure, whereas MQ-T is an orthogonal error regression model. Two examples, including a numerical test and a real-world example, are employed in a comparative performance analysis of MQ-T for surface modeling of DEMs. The numerical test indicates that MQ-T performs better than the classical MQ in terms of root mean square error. The real-world example of DEM construction with sample points derived from a total station instrument demonstrates that regardless of the sample interval and DEM resolution, MQ-T is more accurate than classical interpolation methods including inverse distance weighting, ordinary kriging, and Australian National University DEM. Therefore, MQ-T can be considered as an alternative interpolator for surface modeling with sample points subject to both horizontal and vertical errors.     

浅论东海盆地海礁凸起的含油气性

勘探资料证实 ,西湖凹陷内生成的油气由生烃深凹向西部和南部的古斜坡带运移。凹陷内的局部构造大多形成于中新世末期的龙井运动 幕 ,圈闭形成期晚于油气主运移期 ,致使油气运移到比斜坡带更高的海礁凸起上保存或散失了。作者利用现有东海地震资料及西湖凹陷钻井、测井及油气资源评价结果从油气运移、聚集、保存等方面探讨东海陆架盆地海礁凸起油气勘探的良好前景     

论东海陆架盆地玉泉运动

据地质及地球物理勘探资料，并结合周围邻近盆地的对比研究后提出：（１）目前确定的新玉泉运动，其影响比前人描述的轻微得多；（２）以前所确定的原（老）玉泉运动的活动强度比新玉泉运动强烈得多，不应将原（老）玉泉运动取消，而应将新、老玉泉运动的间隔期视为构造变革过渡期。     

温度破纪录事件预测理论研究

分析中国740个常规观测站1960-2005年日最高、最低温度器测资料,揭示了46年来中国日最高、最低温度破纪录事件的强度特征.利用历史观测资料验证了日温度极值服从高斯分布,并将历史资料中已知的高、低温破纪录事件作为初始条件,经冗长的理论推导得到破纪录温度的期望值,与用纯极值理论进行迭代获得的结果相比,前者更符合观测事实,预测效果更好.在此基础上对中国未来可能发生的高、低温破纪录事件进行了预测评估,给出了各地区高、低温破纪录事件强度理论上所能达到的最大、最小值分布.结果表明中国各地区极端温度变化幅度差异明显,具有明显的区域特征,西南地区的极端高温事件强度未来处于较大上升期,西部相对较小;而极端低温事件强度降幅最大的区域位于东北和西北部地区,华中及西南地区处于相对平稳期.     

合肥遥测台网限幅时间震级公式

为了满足遥测地震台网地震速报的需要，本文利用地震限幅时间拟合给出了合肥遥测台网确定限幅地震震级的经验公式，给出了精度分析结果，认为在近震范围内利用地震限幅时间确定遥测台网内外多台限幅情况下的地震震级，是一种可行的方法，与地震持续时间方法比较，具有速度快、精度高的优点     

双轨道差分干涉测量技术在地面沉降监测中的应用

介绍了双轨道差分干涉测量监测地面沉降的基本原理,应用了具体的 RADARSAT数据,提取出Belridge油田因石油开采所造成的地表形变,并阐述了数据处理的主要步骤,实现了差分干涉结果的解译和分析.     

一种利用NDVI辅助提取植被信息的改进方法

为提高遥感影像中不同覆盖度植被信息由栅格到矢量的转化效率和准确度,改进了常用的NDVI辅助提取植被信息方法,即根据NDVI与植被覆盖度之间的关系自动提取不同覆盖度的植被信息.为检验该方法的效果,利用试验区一组TM影像进行植被信息的提取试验.结果表明,该方法与常用方法相比能有效地增强不同覆盖度植被边缘信息,提高了植被边缘信息栅格矢量化的效率和准确度.     

化学絮凝法对钛白废水的处理

详述了硫酸铝钾－聚丙烯酰胺体系处理钛白废水的研究,较全面地分析了江西赣东化工厂钛白废水的物质组成和污染负荷,对该处理体系的工艺条件进行了系统研究,确定了最佳工艺条件。结果表明,该体系处理钛白废水,能有效降低废水中污染物质,值得作进一步研究。