区域冷锋降水微物理机制研究

20世纪利用一维层状云模式对2002年4月4~5日河南省冷锋降水过程进行了模拟。数值模拟结果显示,此次冷锋降水属于冷云降水过程,冷锋前后云中主要以冰相粒子为主,云中水质粒自上而下的空间分布依次为冰晶、雪、云水、霰、雨水。冷锋前后,各种水质粒有着不同的含量及数密度,但形成水质粒的主要微物理过程都表现为:冰晶数密度的增加主要依靠核化、繁生,大部分雪主要靠凝华、撞冻过冷云水和冰晶增长,霰的质量增加主要靠撞冻雪、过冷云水和雪自动转化而来,大部分的雨水是由霰融化而来,因而此次冷锋降水机制表现为“水汽—雪—霰—雨水”。     

What Mineral Resources will China Need to Discover by the Mid-21st Century?

正In the past 40 years of China's reform and opening up,China's economy has been developing rapidly,and industrialization and urbanization have begun to take shape.At present,China is heading towards an information society.Mineral resources have played a great supporting role during this process.During the whole of2017,China consumed 2.344 billion tons of iron ore,2.4billion tons of cement and 3.65 billion tons of raw coal     

2013 Production of China’s Shale Gas Reaches 200 Million Cubic Meters and the First Transportation Pipeline Constructed

Results of the global shale gas resources show that minable resources of global shale gas are 187 trillion cubic meters(tcm),of which China accounts for 36 tcm(about 20%of the total amount),which is mainly distributed in the Sichuan Basin,Yangtze Terrace,and Ordos Basin.From 2009 to 2012,China completed an accumulative number of 129 drilling wells related to shale gas,including 46 investigated vertical wells,55 exploration wells and     

China’s Technologies for Exploration and Mining of Uranium Deposits Have Stepped into the World’s Top Team

On June 2011, the Beijing Research Institute of Uranium Geology, an Institute within the China National Nuclear Corporation （CNNC）, and the Department of Geology ＆ Mining CNNC carried out a project Scientific Drilling.for Deep Metallogenic Research in the Xiangshan Large Uranium Ore Field. A year later on June 21, the project, representing the first scientific drilling of China＇s uranium, was officially launched, and successfully completed on June 17, 2013. A 2818.88 m of drilling depth has broken the previous record 1200 m of exploration depth.     

Joint land-sea seismic survey and research on the deep structures of the Bohai Sea areas

This paper presents the survey and research work of two land-sea profiles in the Bohai Sea, China, carried out in 2010-2011, including the seismic sources on land and in the sea, the ocean bottom seismographs （OBS） and their recovery, the coupling of OBS and the environment noise in sea area, the data quality of OBSs, and the result of data analysis. We focused on the investigation of crustal structures revealed by the two NE／EW-trending joint land-sea profiles. In combination with the Pn-velocity distribution and gravity- magnetic inversion results in the North China Craton, we propose that the undulation of the Moho interface in the Bohai and surrounding areas is not strong, and the lithospheric thinning is mainly caused by the thinning of its mantle part. The research result indicates that obvious lateral variations of Moho depth and seismic velocity appear nearby all the large-scale faults in Bohai Sea, and there is evidence of underplating and reforming of the lower crust by mantle material in the Bohai area. However, geophysical evidence does not appear to support the ＂mantle plume＂ or ＂delamination＂ model for the North China Craton destruction. The crustal structure of the Bohai Sea revealed ＂a relatively normal crust and obviously thinned mantle lid＂, local velocity anomalies and instability phenomena in the crust. These features may represent a combined effect of North China-Yangtze collision at an early stage and the remote action of Pacific plate subduction at a late stage.     

一次河南省春季层状云降水的地面雨滴谱特征

2002年4月4-5日河南省出现了层状云降水天气，临颖、孟津两站进行了地面雨滴谱观测。通过对降水过程中两站的雨滴微物理参量和雨滴谱的对比分析，指出河南层状云降水的雨滴平均直径为10～mm，雨滴数密度为10^2个／m ^3，占雨滴总数较小的大雨滴对雨强的贡献较大。锋前暖区雨滴的平均直径比锋后冷区雨滴平均直径小，雨滴数密度比锋后冷区大，但冷区降水强度大于暖区。在层状云降水过程中，暖区雨滴谱型由宽谱双峰型演变为窄谱单峰型，冷区雨滴谱型由宽谱单峰型演变为窄谱单峰型。雨滴平均直径的起伏暖区要大于冷区，这与暖区中云系结构不均匀及云中对流有关。     

General characteristics of climate changes during the past 2000 years in China

The general characteristics of climate changes over the past 2000 years in China,regional differences and uncertainties were analyzed based on the recently peer-reviewed high time-resolution climatic reconstructions.The results showed that there exists four warm periods of the temperature variation in China since the Qin Dynasty,including the western and eastern Han Dynasties(200 BC-AD 180),the Sui and Tang dynasties(541-810),the Song and Yuan dynasties(931-1320),and the 20th century,and three cold phases involving the Wei,Jin,and North-South Dynasties(181-540),the late Tang Dynasty(811-930),and the Ming and Qing dynasties(1321-1920).The Song and Yuan warm period is consistent with the Medieval Warm Period over the Northern Hemisphere,and the cold phases of the North-South Dynasties and the Ming and Qing dynasties are paralleled to the Dark Ages Cold Period and the Little Ice Age,respectively.The 13th-15th century could be a shift to the wet condition of the climate,and the low precipitation variability is exhibited in western China prior to 1500.In the context of the climate warming,the pattern of the drought in north and flood in south is prevalent over the eastern China.In addition,the published reconstructions have a high level of confidence for the past 500 years,but large uncertainties exist prior to the 16th century.     

川西米亚罗林区云杉天然林与人工林的群落特征比较

云杉林是四川西部山区重要的群落类型,为了解云杉天然林和人工林在物种组成、物种多样性以及群落结构等方面的差异,促进该区域植被的恢复与重建,我们设置典型样地对两种林型进行了详细调查,通过比较分析表明:在川西米亚罗林区,林龄在30 a左右的云杉林,其天然林乔木层、灌木层的物种数以及其所属科、属数均明显比人工林多一些,而草本层物种数相差不大;但从物种多样性指数方面看,除天然林乔木层物种多样性要明显高于人工林外,二者在灌木层和草本层上无显著差异.天然林和人工林乔木层的生长状况无显著差异,天然林灌木层物种的平均密度和平均高度要显著大于人工林,平均盖度则没有显著差异;草本层各群落特征指标在两种林型之间没有显著差异.但是天然林乔木层、灌木层和草本层的物种个体数在不同样地之间的变幅均要比人工林小.物种相似性指数的比较表明,天然林与人工林内物种组成较为一致,没有显著差异.     

New species of Saurichthys (Actinopterygii: Saurichthyidae) from Middle Triassic (Anisian) of Yunnan Province, China

Abstract: Saurichthys dawaziensis sp. nov., from the third member of the Gejiu Formation (Anisian of Middle Triassic) in the vicinity of Luoping, Yunnan Province, is a small to medium- sized saurichthyid fish. It is characterized by the efferent pseudobranchial arteries penetrating on the parasphenoid and the mandible sensory canal with a branch in the angular. The new species is more derived than the Lower Triassic species in having a relatively narrow postorbital region, short preopercular, single ossification of the sclerotic ring, small haemal arches between the pelvic fins and the anal fin without ossified spines, and in the absence of quadratojugal. It is more primitive than the Middle and Upper Triassic Saurichthys in having fringing fulcra and numerous segments in the unpaired fins, and the presence of both prae- and post-zygapophyses in the neural arches. Some anatomic changes related to the vertebral column and unpaired fins of the genus are also discussed.