The first magnetic chart

Almost 300 years to the day since Edmond Halley's first magnetic chart, the RAS held a Discussion Meeting to commemorate this achievement and to consider Halley's work in navigation and geophysics. David Barraclough and Toby Clark report on the "300th anniversary of the first magnetic chart: Edmond Halley's work in geophysics and navigation".     

A new model on bidirectional reflectance surface-atmospheric coupled radiation

An exact and available model on bidirectional reflectance surface-atmospheric coupled radiation is of great significance for spaceborne remote sensing application. Based on the physical process of interaction of solar radiation with the surface and the atmosphere, a new model on bidirectional reflectance surface-atmospheric coupled radiation is developed in this paper. As shown in numerical simulation, this model is evidently better than the 6S model. The standard error among 110112 sets of upward radiance data calculated by this new model is only 0.49%, which is about one fourth of the one by 6S. In the condition of the solar zenith angle θ_s⩽75° and the viewing angle θ _v⩽ 60°, the error by the new model is usually smaller than 2.5%.     

The circum-global radiation in dublin

Summary The note presents results of five years measurements of circum-global radiation in Dublin with two Bellani spherical pyranometers constructed and supplied by the Physikalisch-Meteorologische Observatorium in Davos. It was found that the agreement of these remarkably simple instruments is very good over the whole period and that they are most suitable and convenient for climatological stations.

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Zusammenfassung Es werden die Resultate von fünfjährigen Messungen der Zirkumglobalstrahlung in Dublin mit zwei Kugelpyranometern des Physikalisch-Meteorologischen Observatoriums in Davos mitgeteilt. Die Übereinstimmung dieser bemerkenswert einfachen Instrumente während der ganzen Periode ist sehr gut und diese Pyranometer wurden als sehr geeignet und bequem für klimatologische Stationen gefunden.

     

2003年Hallowe’en磁暴后新质子带形成和损失机制的研究

本文利用低高度极轨卫星NOAA/POES的观测数据,对2003年Hallowe'en磁暴期间新质子带的形成和损失机制做了细致的研究和分析.结果表明新质子带的形成是诸多因素共同作用的结果.包括强太阳质子事件(Solar Proton Events,SPEs)、大的地磁暴和行星际激波.所有这些因素构成了新质子带形成的前提条件,尤其是行星际激波是形成新质子带不可缺少的因素.此外本文提出了磁暴主相对高能质子注入磁层稳定捕获区起到重要贡献.本文还运用绝热捕获判据分析了新质子带的损失机制,证明了由于磁暴期间环电流积累造成磁场大的扰动,破坏绝热不变量的守恒,导致新质子带粒子的损失.     

岩石物理模版在储层定量解释中的应用

岩石物理模板采用测井解释的各类岩性矿物骨架点值,选取适合该地区的岩石物理模型,模拟在不同储层组合、不同孔隙及不同饱和度情况下,储层岩石物理参数变化引起的储层测井参数及地球物理响应特征的变化,定量地建立起储层参数同地球物理弹性参数间的解释关系模版.本文根据新场JS42气藏储层参数分析结果,尝试性地将岩石物理解释模板应用于储层定量解释中,对储层高产气区、含水区域进行定量解释,并预测了该气藏的气水界面,该预测结果与实钻井测试情况吻合,证实了该方法的科学性.     

A new method to calculate near-field radiation excited by heterogeneous fault rupture

This paper derives from the representation theory the formula for calculating the radiation excited by heterogene- ous fault rupture based on box-like discretization scheme. Preliminary validation indicates that our algorithm has very high computation precision and efficiency; therefore, it is a very practical tool to investigate strong ground motion problems. Additionally, the equations given in this study can also be used to invert the fault rupture proc- ess.     

A new natural gamma radiation measurement system for marine sediment and rock analysis

A new high-efficiency and low-background system for the measurement of natural gamma radioactivity in marine sediment and rock cores retrieved from beneath the seabed was designed, built, and installed on the JOIDES Resolution research vessel. The system includes eight large NaI(Tl) detectors that measure adjacent intervals of the core simultaneously, maximizing counting times and minimizing statistical error for the limited measurement times available during drilling expeditions. Effect to background ratio is maximized with passive lead shielding, including both ordinary and low-activity lead. Large-area plastic scintillator active shielding filters background associated with the high-energy part of cosmic radiation. The new system has at least an order of magnitude higher statistical reliability and significantly enhances data quality compared to other offshore natural gamma radiation (NGR) systems designed to measure geological core samples. Reliable correlations and interpretations of cored intervals are possible at rates of a few counts per second.     

The radiation of sound from vibrating composite membranes

Summary In this paper, the sound radiated by vibrating composite circular and annular membranes have been discussed.     

The generation of condensation nuclei by ionising radiation

Summary The production of condensation nuclei by the irradiation of filtered nuclei-free air by X-rays, alpha particles and beta particles is described. It is found that nuclei are created in large numbers by such irradiation and that there appears to be a threshold radiation dose at which the nucleus concentration is increased by a factor of more than a hundred.The effect of varying sulphur dioxide content of the irradiated air has been investigated and for concentrations of between one and ten milligrams per cubic metre of air there is some proportionality between the sulphur dioxide content of the air and the nucleus concentration produced by a given radiation dose.It is shown, however, that sulphur dioxide cannot be exclusively responsible for the generation of condensation nuclei by irradiation of filtered air and other possible agents and mechanisms are suggested.     

Coupling SEBAL with a new radiation module and MODIS products for better estimation of evapotranspiration

ABSTRACT

Evapotranspiration (ET) is an important ecohydrological process especially in arid and semi-arid regions. In this study, a new radiation module based on MODIS data has been coupled with the Surface Energy Balance Algorithms for Land (SEBAL) to better estimate ET. The accuracies of the coupled model for estimating available energy and sensible heat (H) were improved significantly compared with the outputs from the original SEBAL which was based on empirical equations. The coupled SEBAL modelled instantaneous λET agreed much better with observations in the arid land of Central Asia than the original SEBAL, with a bias of ?2.86 W m^-2, root mean square error (RMSE) of 9.75 W m^-2, and normalized RMSE (NRMSE) of 0.13. The accuracy was blurred when scaling ET to a daily or monthly scale, mainly due to the uncertainties associated with temporal upscaling methods that were applied. Sensitivity analysis, which was conducted using numerical variance-based techniques, indicated that the estimated ET is sensitive to the available energy, suggesting the importance of obtaining accurate estimates of net radiation when applying the coupled SEBAL to estimate ET. This study provides a simple and reliable way to utilize MODIS products and contains sensitivity analysis for helping to correctly interpret the outputs, which are both important for large-scale ET estimation.     

The new X-ray universe

Phil Charles and Andy Fabian review the changes brought to X-ray astronomy by the two orbiting observatories, XMM-Newton and Chandra.
We describe here the changes to X-ray astronomy that are being brought about by the two new orbiting X-ray observatories, NASA's Chandra and ESA's XMM-Newton. Between them they bring a dramatic gain in sensitivity, spatial resolution (now comparable to ground-based optical and infrared telescopes) and spectral resolution. The superb Chandra mirrors rapidly resolved the diffuse X-ray background and have produced stunning detailed images of a wide variety of cosmic objects. Large gains have been made by both missions in spectroscopic performance, with individual X-ray emission lines now detectable in hot stellar coronae, supernova remnants, X-ray binaries, active galactic nuclei and galaxy clusters.     

The observation and research on pre-earthquake electromagnetic radiation information

By use of the specialized under ground electrodes as the sensor, the Experimental Multi-station Network observed Seismic Electromagnetic radiationsprior to the moderately strong earthquake. From the great number of electromagnetic anomalies recorded by the network continuously for about 10 years, it can be sure that the anomalies are related to earthquakes aboveM _s 5 within 300 km. The stronger the magnitude of the earthquake is, the better the relation is. The abnormal electromagnetic radiation information appears in a short-time before the moderately strong earthquake. The continuous automatic pen recording shows that the electromagnetic information is the waveform of the paroxysmal wave group, and has the features of undulating enhancement, amplitude in inversely proportion to epicentral distance, frequency increase, regional similarity of wave froms and directivity, etc.. It also contains some quantitative elements related to the parameters of the earthquake. The above characteristics and correlative elements can provide important bases for predicting the three elements of the earthquake. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 83–90, 1993. Associate Professor Da-Yuan CHANG and Teacher Feng CHEN have gave us a lot of help during the study.     

Molchan图表法在云南地区地震异常预测统计中的应用

近年来,全球地震可预测性合作研究CSEP计划( Collaboratory for the Study of Earthquake Predictability)取得较好的应用和发展,中国是该计划的主要参与国.该计划采用可比较的数据,使用统一的计算规则及严格的统计检验,获取地震异常的可预测性.其中Molchan图表统计...     

福州地震台电磁辐射观测资料映震效能分析

利用福州地震台电磁辐射1999年以来观测资料,研究福建省内4级以上地震,中国台湾6级以上地震电磁辐射接收的异常信息,找出震前有震异常次数及有震无异常次数,从而得出福州电磁辐射观测资料的映震效能。     

北京市局部地区电磁辐射监测结果分析

随着我国经济和社会的不断发展,人们对生态环境质量的要求也越来越高.电磁辐射污染对人类可能造成的危害,也引起了越来越多的重视.2004年８月至2005年6月,我们对北京市局部地区进行电磁辐射监测,通过手持式GPS定位选点,使用国产H-2A型非选频式全向智能场强仪测量4个地区的电磁辐射水平.对测量结果的分析表明,城市不同地区的电磁辐射水平与人类的活动、区域内的人文环境关系密切.广播电视发射系统、城市交通道路、输变电系统和人类的活动对区域的电磁辐射污染水平有很大的影响.