为了实现高精度连续探测对流层和平流层大气风场，搭建了一台直接测风激光雷达系统对对流层和平流层大气风场进行探测。该系统基于双边缘法布里-珀罗标准具的瑞利散射多普勒测风原理，使用转台式探测结构，通过频率跟踪的手段对频率漂移进行跟踪，确保测风的精度。实验结果表明，该系统对对流层和平流层大气风场探测效果良好，频率跟踪的范围为±50 MHz，可以大大减小频率漂移带来的风速误差。经过系统的稳定运行和长时间的观测，在40 km处测得的径向风速随机误差为8 m/s。径向风速合成为水平风速后，随机误差在38 km处最大为10 m/s左右。该系统白天探测高度为25 km，夜晚探测高度为38 km。与探空数据对比，风速误差均小于10 m/s，其中风速误差在±5 m/s的范围内的数据量约占75.8%，探测的风向误差与探空气球的趋势基本一致，误差范围在10°～20°之间，在15°范围内的数据量约占58.6%。将实测数据与探空数据进行统计分析，结果具有良好的一致性。该系统可以为对流层和平流层大气风场的探测提供数据支撑。

激光雷达作为大气探测的有效手段之一,逐渐向小型化、轻量化的趋势发展.针对激光雷达的功能专用性,基于现场可编程门阵列(FPGA)对探测、采集系统进行了集成优化设计.逻辑中各模块之间通过握手协议和同步有限状态机有序配合完成数据链路的构建和传递.系统以FIFO作为ADC的数据存储器,通过AXI总线协议配合Xilinx MIG IP有序将FIFO的数据突发缓存到DDR中,并且通过千兆以太网完成对采集数据的传输.该激光雷达数据采集卡集成光电倍增管增益控制和回波信号采集功能,并采用兼容性硬件和逻辑设计,具有集成度高、增益调节便捷且精度高、采集快速方便以及快速适配等诸多优点.

Lageos卫星是专用地球动力学卫星,其卫星激光测距数据质量的提升对地球动力学研究具有重要意义.基于Lageos卫星激光角反射器分布,推导了不同层级角反射器回波与反射深度的关系,建立了Lageos卫星前沿回波数据提取模型,并将其应用于上海天文台卫星激光测距数据预处理,验证了该提取模型生成标准点的数据质量改善情况:内符合实验结果表明采用前沿数据提取模型生成的标准点距离参考线的标准差由3.37 mm减小为0.50 mm;外符合实验结果表明前沿数据提取模型处理结果经过快速精密定轨后反馈的距离偏差均值由28 mm减小为21 mm.因此,前沿回波数据提取模型所得标准点数据的稳定性和准确性有一定提升,为获得高质量Lageos卫星激光测距数据提供了一种有效的方法.

针对目前国际激光服务(ILRS)不同分析中心提供的卫星激光测距(SLR)卫星精密轨道综合问题,该文利用几何加权平均法对各分析中心提供的精密轨道进行综合生成综合轨道,其中各分析中心权重采用方差分量法进行估计,通过各分析中心精密轨道与综合轨道的比较,及该文综合轨道与ILRSA和ILRSB综合轨道对比,评价该文综合轨道精度.结果表明:不同分析中心卫星轨道权重不同,其中德国联邦制图和大地测量局(BKG)和欧空局(ESA)的轨道总体精度较好;通过各分析中心相对综合解的尺度因子的比较分析,发现其尺度因子存在长期的线性项变化;各个分析中心的轨道相对于综合解,对Lageos1/2卫星来说RMS均在2 cm左右,速度RMS为(1.5～3)×10-5 m/s,Etalon1/2卫星的位置和速度的RMS变化较大,但总体和权重分布相一致;与ILRSA和ILRSB综合轨道相比,该文的综合轨道在位置上和ILRSA具有较好的一致性,在速度上3种综合轨道的RMS差异大致相同.

Abundant Early-Middle Triassic foraminiferal fossils were collected from the limestones of the Xiejiacao section,Guan'an,Sichuan,China of which 34 species in 12 genera have been identified and described systematically.According to the distribution characteristics of the foraminiferal assemblages on this section,4 foraminiferal assemblage zones are recognized from the bottom up as follows:(1) Rectocornuspira kalhori-Cornuspira mahajeri Zone;(2) Glomospirella vulgaris-Arenovidalina chialingchiangensis Zone;(3) Meandrospira pusilla-Glomospirella irregulariformis Zone;(4) Glomospira sinensis Arenovidalina amylovoluta Zone.These foraminiferal zones provide very important fossil evidence for the precise biostratigraphical sub-division and correlation of the marine Triassic strata in this region.

17 ichnogenera are described as Arenicolites, Bifungites,Chondrites,Didymaulichnus,Isopodichnus,?Monocraterion,Palaeophycus,Phycodes, Planolites, Psammichnites, Skolithos, Taenidium,Teichichnus,Thalassinoides,Treptichnus,Uchirites and Star-like trace fossils.They are assigned to the Cruzianaichnofacies reflecting shallow water environments with soft substrates. Some special taxa are known to have occurred in the storm-generated sediments. Skolithos are mainly yielded from the storm layers and Planolites and Palaeophycus from warning storm deposition layers respectively.The opportunistic taxa such as Chondrtes, Treptichnus gathering in stripped limestones are indicative to dysaerobic environments.This paper also probes into the relationship between the spatial and anachronistic distribution of the trace fossils in the Early Triassic and ocean biotic recovery after the Permian/Triassic mass extinction.

A dolomite unit near the Permian-Triassic boundary has long been used as the boundary marker in northwestern Sichuan but no biostratigraphically diagnostic fossils have been found in this units.Here we report the discovery of the conodont Hindeodus parvus and foraminifer disaster species from a microbiate bed in the dolomite unit above Permian coral beds at the Yudongzi section in Jiangyou of Sichuan Province.This discovery allows us to determinate the Permian-Triassic boundary in northwestern Sichuan and to understand the ecological and environmental changes across the boundary.We also present a detailed sedimentological analysis of the uppermost Changxing Formation and the lower-middle Feixianguan Formation