The mean oceanic residence time     

Chen-Ping Chang  Lian-Sen Liu  Chen-Tung Chen 《Marine Chemistry》1982,11(3):293-295

In this note the significance of heat of hydration and electronegativity in the study of oceanic residence times of elements is discussed.  相似文献   

VLF input impedance of a loop antenna embedded in the magnetosphere     

T.N.C. Wang  C.D. Chang 《Planetary and Space Science》1973,21(10):1810-1815

An analysis is made to calculate input impedance of a loop antenna for radiation of the VLF whistler mode in the magnetosphere. The magnetosphere is assumed to be represented by a cold, uniform and collisionless magnetoplasma medium. Assuming a uniform current distribution of a circular loop, oriented at an arbitrary angle with respect to the Earth's magnetic field line, several closed-form expressions for the loop impedance have been derived. It is found that the loop input reactance is in substantial agreement with the self-inductance of a loop in free space and that the radiation resistance for a small loop can be as large as ～10 ² Ω. It is also found that a second order quasi-static theory is quite valid for determining the input impedance for small loops radiating VLF whistlers in the magnetosphere.  相似文献   

反向断阶构造样式与砂质沉积体发育     

程日辉  郑和荣  林畅松 《吉林大学学报(地球科学版)》2001,31(2):146-148

孤南洼陷是一个复合的半地堑盆地 ,洼陷斜坡发育由断层和断块构成的断阶构造样式 ,其中一种为反断阶。反断阶的发育使得盆地斜坡的沉积地形复杂化 ,因此发育其上的砂质沉积体具有特殊的分布型式 ,包括展布方向、几何形态和水流特征。孤南凸起东南斜坡的反向断阶是由一正断层和倾向相反的斜坡构成。斜坡总体向盆内倾斜 ,但在断层处形成一个次级隆起。沙河街组二段的砂体是在这样的复合地形上沉积并赋存下来。在平面上该砂体一方面沿沉积斜坡方向延伸至断层 ,一方面沿断层走向延伸或越过断层 ,呈不规则的丁字形。砂体在越过孤南洼陷与孤岛凸起的分界断层后在远端发散 ,形成扇体。  相似文献   

泡塑-地电联用法找金研究   总被引：2，自引：0，他引：2  

伍岳  常桂兰  吴慧山  白云生  张书成  辛至秀  林玉飞 《铀矿地质》2000,16(5):297-304

本文介绍了一种新的找金方法－泡塑－地电联用法。该用法将泡沫塑料吸附和地电化学离子提取等两种找金方法融为一体。通过综合研究联用法找金机理,改进提取器材料、结构及仪器设备,并结合研究金的地坏化学规律,使该联用法成为寻找隐伏型金矿的新方法。该联用法既发挥了上述两种方法的优点,又克服了二者的缺点,具有灵敏度高、探测深度大和使用安全可靠的特点。  相似文献   

自适应网格技术在数值模式中的应用研究Ⅰ.一维问题   总被引：4，自引：0，他引：4  

康红文  王鹏云  徐祥德 《大气科学》2000,24(5):615-624

利用变分原理的自适应网格技术被应用到三个有解析解的问题上,它能根据问题的求解,在解的大梯度区自动加密网格,从而非常成功地算出了激波.通过分析发现自适应网格技术在提高精度、减少运行时间方面显示了优良的性能.  相似文献   

地面电场资料在雷电预警技术中的应用   总被引：37，自引：0，他引：37  

孟青  吕伟涛  姚雯  何平  张义军  刘强  李林  张曼  常晨 《气象》2005,31(9):30-33

论述利用地面电场仪的探测资料对雷电预警预报的技术方法，以大气电场测量为基础，利用地面电场仪的组网，实现自动、连续、实时监测雷雨云中强雷电活动中心在地面产生的电场强度、极性以及闪电数等，提供监测范围内雷暴强电荷活动中心的发生发展演变特征和整个雷暴过程中雷电活动位置和发展信息。同时结合闪电定位系统的观测，为雷电的监测和预报提供更充分的信息。  相似文献   

Dynamics of the boreal summer African monsoon in the NSIPP1 atmospheric model   总被引：1，自引：0，他引：1  

Alessandra Giannini  R. Saravanan  Ping Chang 《Climate Dynamics》2005,25(5):517-535

A nine-member ensemble of simulations with a state-of-the-art atmospheric model forced only by the observed record of sea surface temperature (SST) over 1930–2000 is shown to capture the dominant patterns of variability of boreal summer African rainfall. One pattern represents variability along the Gulf of Guinea, between the equator and 10°N. It connects rainfall over Africa to the Atlantic marine Intertropical Convergence Zone, is controlled by local, i.e., eastern equatorial Atlantic, SSTs, and is interannual in time scale. The other represents variability in the semi-arid Sahel, between 10°N and 20°N. It is a continental pattern, capturing the essence of the African summer monsoon, while at the same time displaying high sensitivity to SSTs in the global tropics. A land–atmosphere feedback associated with this pattern translates precipitation anomalies into coherent surface temperature and evaporation anomalies, as highlighted by a simulation where soil moisture is held fixed to climatology. As a consequence of such feedback, it is shown that the recent positive trend in surface temperature is consistent with the ocean-forced negative trend in precipitation, without the need to invoke the direct effect of the observed increase in anthropogenic greenhouse gases. We advance plausible mechanisms by which the balance between land–ocean temperature contrast and moisture availability that defines the monsoon could have been altered in recent decades, resulting in persistent drought. This discussion also serves to illustrate ways in which the monsoon may be perturbed, or may already have been perturbed, by anthropogenic climate change.  相似文献   

复数矢量球谐函数在形变场中的应用     

张捍卫  郑勇 《测绘学院学报》2000,17(2):79-81

研究了复知球函数的理论性质,给出了一般向量场的复数矢量球函数表达及其有关公式。对潮汐形变位移和形状进行了讨论。  相似文献   

应用TOVS资料变分分析技术增加青藏高原地区摸式初始场信息   总被引：12，自引：1，他引：11  

翁永辉  徐祥德  柏晶瑜  董超华 《气象学报》2000,58(6):679-691

首次在测站稀少的高原地区引入经变分技术处理的 TOVS卫星资料 ,通过动力诊断探讨了解决高原地区测站少、数值预报模式初始场信息误差大的技术关键问题 ,提出了采用TOVS反演资料在高原地区增加模式初始场信息的构思 ,并应用变分法处理 TOVS反演资料 ,显著地提高了高原初始场信息的可靠性 ;并从动力诊断分析角度 ,进一步证实了 TOVS反演资料的应用有利于提高高原动力系统特征的描述能力 ,并显著改善水汽输送通道分布及其层结稳定度等有关初始场信息的客观性  相似文献   

THE IMPACT OF MID-LATITUDE CIRCULATION OVER THE TIBETAN PLATEAU ON THE TRACK OF TYPHOON OVER THE NORTHWEST PACIFIC          下载免费PDF全文

徐晶  陈联寿  徐祥德 《Acta Meteorologica Sinica》2000,(3)

There is a close relationship between variation of middle latitude synoptic system over theTibetan Plateau and movement of typhoon over the Northwest Pacific.This paper tries to discussthe mechanism of it through the numerical simulation and dynamic diagnosis.25-year statistical results during the period from 1970 to 1995 indicate that the relationshipbetween middle latitude circulation over the Plateau and the track of typhoon over the NorthwestPacific are as follows.When longwave trough in 500 hPa isobaric surface over the Plateau.it isfavourable to typhoon's westward movement:on the contrary,large scale anticyclone over thePlateau is favourable to typhoon's recurvature.We simulated the typhoon under these two flowpatterns with MM5 model.Numerical simulation results showed that:(a)Longwave trough on500 hPa surface over the Plateau makes subtropical high extended westward so as to typhoon southto high moves westward in easterly steering flow.(b)Anticyclone over the Plateau will bringabout the longwave trough developing along the east coast of Asia,it'will usually cause typhoonrecurring in front of the developed trough.In addition,the results of dynamic diagnosis show the physical mechanism on impact ofsynoptic system over the Plateau on the downstream synoptic system,that is,the transport ofdisturbance kinetic energy over the upstream Plateau makes the downstream trough developed.And then it affects the steering flow of typhoon.Because of existence of the high ridge over thePlateau.the energy transport channel moves to north.On the contrary,the trough exists over thePlateau,the energy transport channel moves to south.The southerly in front of trough over thePlateau and the southerly in the east part of typhoon transport low potential vorticity of lowlatitude into subtropical high.That is beneficial to development of subtropical high and affectstyphoon's movement.These results fully reflect the impact of interaction between mid-latitude andlow latitude on synoptic system.  相似文献