兰州九州台黄土剖面元素地球化学研究   总被引：6，自引：2，他引：6  

张虎才 Maha.  WC 《地球化学》1991,(1):79-86

本文着重对兰州九州台黄土剖面上部的马兰黄土及全新世黄土3个样品及其下部的古土壤层(9层)共21个样品进行了系统的化学元素分析。结果表明,九州台黄土剖面中仅有微弱的元素分异现象;REE分布模式揭示,兰州九州台不同时代的黄土具有相同的物源区并与洛川黄土物源相似。在过去百万年时间尺度内,兰州九州台黄土形成于干旱、半干旱生物气候环境下的弱碱性介质条件和氧化环境中。  相似文献   

7月无台风     

申敏夏  王美丽  黄彬 《气象知识》2021,(1):40-41

往年7月在天气舞台上常见的台风,却在2020年“缺席”了!2020年7月成为有台风历史记录以来的首个“空台”7月。历史罕见!7月无台风打破历史纪录从常年来看,7月属于台风活跃期(常年7月平均生成台风4.1个),甚至有不少台风登陆我国。  相似文献   

弱消减岩石板的形变和地震活动性随深度的变化     

Tao  WC 关伟沂 《地壳构造与地壳应力》1994,(4):20-23

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北太平洋冬季船舶西行航线的对比分析   总被引：2，自引：0，他引：2  

尹尽勇  黄彬 《气象科技》1999,(2):59-64

文章根据船舶气象导航的原理、气象航线的设计技术以及影响航线选择的因素，通过对北太平洋冬季气候、洋流、天气形势的分析，指出了加－中高纬度航线在其经向型环流天气形势下，比中纬度航线更有利于西行船舶航行。船舶应结合自身性能及天气形势分析，尽量选择高纬度航线，以达到安全和经济的目的  相似文献   

南太平洋上的副热带急流     

Vinc.  DG 黄彬 《气象科技》1998,(3):17-24

文章的主要目的是要对存半年澳大利亚－南太平洋区域副热带对流层上层的西风最大区有一个更好的了解，过去的论文表明它的出现具有１－２周的周期性。该文的重点在于对前面提到的西风最大区的加速阶段中热带和温带强迫的相对重要性作一个定量分析。向外长波辐射，风数据以及分解为旋转和辐射分量的动能收支平衡，被用来探讨１９８５－１９８９年 夏季时段中强迫机制的重要性，制定了判据，用来判定纬向风的强加速阶段。总共找出４０  相似文献   

The influence of underwater data transmission sounds on the displacement behaviour of captive harbour seals (Phoca vitulina)     

Kastelein RA  van der Heul S  Verboom WC  Triesscheijn RJ  Jennings NV 《Marine environmental research》2006,61(1):19-39

To prevent grounding of ships and collisions between ships in shallow coastal waters, an underwater data collection and communication network (ACME) using underwater sounds to encode and transmit data is currently under development. Marine mammals might be affected by ACME sounds since they may use sound of a similar frequency (around 12 kHz) for communication, orientation, and prey location. If marine mammals tend to avoid the vicinity of the acoustic transmitters, they may be kept away from ecologically important areas by ACME sounds. One marine mammal species that may be affected in the North Sea is the harbour seal (Phoca vitulina). No information is available on the effects of ACME-like sounds on harbour seals, so this study was carried out as part of an environmental impact assessment program. Nine captive harbour seals were subjected to four sound types, three of which may be used in the underwater acoustic data communication network. The effect of each sound was judged by comparing the animals' location in a pool during test periods to that during baseline periods, during which no sound was produced. Each of the four sounds could be made into a deterrent by increasing its amplitude. The seals reacted by swimming away from the sound source. The sound pressure level (SPL) at the acoustic discomfort threshold was established for each of the four sounds. The acoustic discomfort threshold is defined as the boundary between the areas that the animals generally occupied during the transmission of the sounds and the areas that they generally did not enter during transmission. The SPLs at the acoustic discomfort thresholds were similar for each of the sounds (107 dB re 1 microPa). Based on this discomfort threshold SPL, discomfort zones at sea for several source levels (130-180 dB re 1 microPa) of the sounds were calculated, using a guideline sound propagation model for shallow water. The discomfort zone is defined as the area around a sound source that harbour seals are expected to avoid. The definition of the discomfort zone is based on behavioural discomfort, and does not necessarily coincide with the physical discomfort zone. Based on these results, source levels can be selected that have an acceptable effect on harbour seals in particular areas. The discomfort zone of a communication sound depends on the sound, the source level, and the propagation characteristics of the area in which the sound system is operational. The source level of the communication system should be adapted to each area (taking into account the width of a sea arm, the local sound propagation, and the importance of an area to the affected species). The discomfort zone should not coincide with ecologically important areas (for instance resting, breeding, suckling, and feeding areas), or routes between these areas.  相似文献   

DEPOSITIONAL SEQUENCES AROUND J/K BOUNDARY IN THE QOMOLONGMA AREA, SOUTH TIBET     

Shi Xiaoying  Nicol Morton 《地学前缘》2000,(Z1)

DEPOSITIONAL SEQUENCES AROUND J/K BOUNDARY IN THE QOMOLONGMA AREA, SOUTH TIBET1　ShiX ,YinJ ,JiaC ,MesozoicandCenozoicsequencestratigraphyandsea levelchangesintheNorthernHimalayas,SouthTibet,China[J].NewslStratigr ,1996 ,33(1) :15～ 6 1. 2　LiuG ,WangS ,AdvancesintheUpperJurassictoLowerCretaceousstudyoftheTebetanHimalayas.PapStratigrPale ontol[M ].Beijing :GeologicalPress ,1987,17:143～ 16 6 .theNationalNaturalScienceFoundationofChina (No ..4982 5 …  相似文献   

一次雷达回波图像缓慢变坏的故障   总被引：4，自引：4，他引：0  

贺汉清  黄彬 《广东气象》2007,29(3):60-61

分析新一代天气雷达出现故障报警,并且伴随有回波图像变坏的现象。通过数据、图像分析,发现雷达回波图像变化与雷达性能参数如系统噪声温度、线性标定等数据的变坏有关。硬件检查结果表明,由于下光纤板电路故障,接收机保护器响应信号无法发送,影响保护器的正常工作及测试信号对雷达功率的正确测量,导致雷达性能参数变坏及回波图象变坏。  相似文献   

2018年6月上合组织青岛峰会期间海雾大气边界层特征及能见度分析     

黄彬  侯淑梅  吴振玲  渠鸿宇 《海洋预报》2021,38(6):73-81

利用常规观测、地面加密自动站及NCEP再分析资料,对2018年6月9-10日上合组织青岛峰会期间海雾发展和消散过程进行了分析,总结了大气能见度预报的着眼点.结果 表明:低纬暖湿气流在向岸风的作用下,在青岛沿海附近形成风速辐合和水汽辐合生成海雾,水汽辐合散度增大,海雾处于发展阶段;当切断来自低纬暖湿的水汽输送,水汽辐合减...  相似文献   

热带风暴莲花外围特大暴雨的成因分析   总被引：1，自引：1，他引：0  

张清华  吴建成  刘蕾  黄彬 《气象》2012,38(5):543-551

利用1°×1°的NCEP再分析资料计算螺旋度、湿位涡及各种基本物理量,并结合多普勒雷达资料,对0903号热带风暴莲花外围环流在粤东引发特大暴雨过程进行追踪和诊断分析,探讨此次特大暴雨天气发生、发展的热力学和动力学机制以及雷达回波特征。分析结果表明：台风低槽外围的西南急流为特大暴雨提供了充沛的水汽条件和热力条件;暴雨区上空中低层（）θ_（se）/（）p〉0,存在明显的等θ_（se）陡立面,同时该区上空低层MPV为高负值区,两者结合可见特大暴雨区上空存在强对流性不稳定层结;而低空强辐合、高空强辐散的高低空形势配置、中尺度次级环流以及强烈的旋转上升运动为此次特大暴雨提供了重要的动力机制。分析还表明：高θ_（se）舌和MPV低舌出现叠加的区域和时间与特大暴雨落区和发生时段有很好的一致性;垂直螺旋度中低层正值中心和高层负值中心与特大暴雨中心区域对应较好;强降水最易发生在旋转上升运动迅速加强发展的时间段里;天气雷达在暴洪预报中的运用,有利地追踪了暴雨系统的演变过程,回波特征显示此次特大暴雨是由高降水率配合较长降水持续时间产生。  相似文献