A study of the attachment of radon daughter atoms to aerosol particles

Previous studies of the attachment of radon daughter atoms to aerosol particles in the atmospheric air have given varying results, a few of which did not conform to the diffusion theory developed byLassen andRau (1960). Our studies suggest that the radiolytic aerosols formed by gas-phase reactions in the presence of ionizing radiations interfere in the studies carried out with known aerosols. Radiolytic aerosols are formed spontaneously in the system, depending on the concentrations of aerosol-forming gases in the atmospheric air. It is shown that, under experimental conditions which suppressed the formation of radiolytic aerosols, the attachment rates of Ra-A atoms to aerosol particles in the range of 0.2 to 1.0 m in diameter agree with the diffusion theory developed byLassen andRau (1960). Such investigations of the interactions between atoms, molecules, ions, and aerosol particles are highly useful in atmospheric tracer studies.     

Ground and indoor radon measurements in a geothermal area

Geothermally active sites compared to a relatively passive site (no geothermal activity) contain much higher radon in the soil. As expected, the maximum soil radon content is at or near the major fracture zone where hot water emanates to the surface. Thus, buildings in geothermal sites nearby or at top of cracks that facilitate hot-water transfer to the surface may be extremely dangerous in terms of high radon concentrations and this situation may pose a big threat for the inhabitants. Controlled aeration of such high-risk buildings must be carefully and continuously conducted.     

A comparison of concentrations of fission products,radon 222, and cloud condensation nuclei over the North Atlantic

The concentrations of airborne fission products were observed to be air mass dependent during a cruise of the USNSHayes from Norfolk, Va to Athens, Greece in May–June 1977. Minimum concentrations of fission products, radon, and CCN (cloud condensation nuclei) were measured in maritime air which had previously transited northern North America. Higher fission products, radon, and CCN concentrations were measured in recent, continental air traceable to mid North America or central Europe. These data are consistent with either entrainment by strong winds of previously precipitated fission products (the continental effect) or greater transfer of fission products from the stratosphere to low levels by tropospheric folding.     

Determination of characteristics of steam reservoirs by Radon-222 measurements in geothermal fluids

The authors conducted a Rn²²² survey in wells of the Larderello geothermal field (Italy) and observed considerable variations in concentrations. Simple models show that flow-rate plays an important part in the Rn²²² content of each well, as it directly affects the fluid transit time in the reservoirs. Rn²²² has been sampled from two wells of the Serrazzano area during flow-rate drawdown tests. The apparent volume of the steam reservoir of each of these two wells has been estimated from the Rn²²² concentration versus flow-rate curves.List of symbols Q Flow-rate (kg h^–1) - Decay constant of Rn²²² (=7.553×10^–3 h^–1) - Porosity of the reservoir (volume of fluid/volume of rock) - ₁ Density of the fluid in the reservoir (kg m^–3) - ₂ Density of the rock in the reservoir (kg m^–3) - M Stationary mass of fluid filling the reservoir (kg). - E Emanating power of the rock in the reservoir (nCi kg _rock ^–1 h^–1). - P Production rate of Rn²²² in the reservoir: number of atoms of Rn²²² (divided by 1.764×10⁷) transferred by the rock to the mass unit of fluid per unit time (nCi kg _fluid ^–1 h^–1). - N Specific concentration of Rn²²² in the fluid (nCi kg^–1) - Characteristic time of the steam reservoir at maximum flow-rate (=M/Q)     

地下热水开采对水氡的影响与对策

阐述了漳州水氡因地下水过量开采而引起的趋势性变化,提出了一些降低干扰的对策,如严格执行观测规范,加大采样深度,提高观测质量,在分析资料时应用一些数理统计方法等。     

高分辨率Radon变换方法及其在地震信号处理中的应用

Radon变换方法在地震资料处理中广泛采用,在地震同相轴识别和估计方面具有良好效果．无论是倾斜叠加,还是广义Radon变换方法,一般采用最小二乘反演方法实现．目前,在提高反演算法的效率和分辨率方面仍值得研究．本文从倾斜叠加的定义出发,阐明Radon变换分辨率问题的来源和解决办法．采用最小二乘反演方法研究高分辨率抛物线Radon变换和双曲Radon变换时,给出稀疏约束预条件共轭梯度法求解的高分辨率Radon变换的实现方法,同阻尼最小二乘方法相比,分辨率和精度明显提高,文中给出了模型算例．根据有效波和多次波NMO后剩余时差不同,采用高分辨率抛物线和双曲Radon变换可以压制多次波,分别给出了方法原理,最后给出应用实例．研究表明,稀疏约束预条件共轭梯度法可以有效实现高分辨率Radon变换;数值算例表明,算法计算效率和精度较高,可以更好地实现多次波压制．     

Validation of temperature measurements from MIPAS-ENVISAT with balloon observations obtained by MIPAS-B

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), a limb sounding Fourier transform interferometer in the mid-infrared band, on board the polar-orbiting ENVIronmental SATellite (ENVISAT) was launched in March 2002 by the European Space Agency (ESA). For the MIPAS data validation, three balloon flights with MIPAS-B, a balloon version of MIPAS, were carried out on the 24th and 25th of September 2002 from Aire sur l’Adour (France 44°N, 0°E), on the 20th and 21th of March, and on the 2nd and 3rd of July 2003 from Esrange, Kiruna (Sweden 68°N, 21°E). The MIPAS operational data version 4.61 for the temperature vertical profiles were compared with the correlative MIPAS-B measurements via the coincident comparison and the trajectory comparison approaches, respectively. The precision of the MIPAS temperature was estimated to be 1.04–2.48 K in the region 123–8 hPa (15–33 km) and beyond the expectation. The systematic difference shows that the absolute accuracy of the MIPAS temperature is within the total combined errors between 356 and 3 hPa (8–39 km). The agreements in the middle stratosphere are better than in the lower stratosphere and upper troposphere. The maximum difference of 1.9 K (0.9%) was found at 228 hPa (11 km). The biases of MIPAS measurements are ?0.39 K (?0.19%) and +0.25 K (+0.12%) (“+” positive bias, “?” negative bias) corresponding to the altitude regions 143–31 hPa (14–24 km) and 31–5 hPa (24–37 km), respectively.     

Ground variation of radon 222 for location of hidden structural features. Example of the south of France (Alpes Maritimes)

We report two examples from the south of the French Alps, showing that radon emanation monitored by alpha-sensitive film may be used to locate certain discrete structural features revealed in data collected by remote sensing from a satellite. The variations observed in our data, over a period of several months, are in accordance with atmospheric changes and might correlate with local seismic activity when the detectors are located directly above structural fractures and the magnitude of the seismic event is greater than 2.     

Mapping groundwater discharge to a coastal lagoon using combined spatial airborne thermal imaging,radon (222Rn) and multiple physicochemical variables

Coastal lagoons are significant wetland environments found on coastlines throughout the world. Groundwater seepage may be a key component of lagoon water balances, though only a few studies have investigated large (>100 km²) coastal lagoons. In this study, we combined airborne thermal infrared imagery with continuous measurements of radon (²²²Rn—a natural groundwater tracer), conductivity, water temperature and dissolved oxygen to map groundwater seepage to a large coastal lagoon in New Zealand. We found evidence of seepage along the margins of the lagoon but not away from the margins. Our findings confirmed previously known seepage zones and identified new potential locations of groundwater inflow. Both point source and diffuse seepage occurred on the western and northwestern margins of the lagoon and parallel to the barrier between the lagoon and sea. These observations imply geologic controls on seepage. The combination of remote sensing and in-situ radon measurements allowed us to effectively map groundwater discharge areas across the entire lagoon. Combined, broad-scale qualitative methods built confidence in our interpretation of groundwater discharge locations in a large, dynamic coastal lagoon.     

水氡与气氡动态的对比分析

首先介绍了模拟和数字化方法观测地下水氡浓度所使用的仪器及其工作原理,然后对昌黎井、怀来4号井和矾山井的模拟(水氡)和数字(气氡)资料动态特征进行了对比分析。分析认为仪器工作原理和观测步骤基本相同,但采样(集气)环节有所不同。模拟方法是取一定量的水样,人工采集水样中的气体,然后观测;数字化方法是自流井(泉)的水流经脱气装置自动采集气体,气体样品自动进入观测装置。取样方法的不同,对观测资料的短周期变化特征有影响,但两者的趋势变化特征基本一致。     

嘉峪关断层带土壤气氡的影响因素及映震效能分析

本文利用嘉峪关断层带土壤气氡1998～2009年的观测数据,结合周边地区的ML≥5.0地震,提取氡在年尺度上的变化,系统分析了嘉峪关断层带土壤气氡与气温、地温和降雨等因素的关系以及氡浓度变化与周边地震活动的关系。研究结果表明,嘉峪关断层氡的年变化周期主要受气温控制,该台对祁连山西段和德令哈附近地区中等以上强度的地震响应较为灵敏,当氡值年变起伏较大时,附近地区地震活动性较强;反之,则地震活动性较弱。     

定襄泉水氡正常和异常动态特征及其相互关系的研究

系统分析了定襄泉水氡的正常与异常的动态变化。 定襄水氡具有“正弓型”年变化; 依据其主要的影响因素, 一个水文年内可分出气温影响期和降水-径流影响期; 水氡还有季节性短期变化和多年周期变化。 采用“改进从属函数法”, 其定襄水氡异常与华北多次强震有明显对应关系; 前兆异常变化具有破年变、 相关关系改变及多年周期性等特点, 可作为震兆性质的动态判断标志; 正常与异常动态有着相同与不同点, 表明两者间具有一定的成因联系。     

数字化测逸出氡替代模拟测水氡的理论与实践

模拟测水氡方法已有40年历史, 氡浓度异常变化预测地震取得了较好的效果, 在地震短临预报中发挥了重要作用。80年代中期, 人们逐渐认识到自流井中逸出气氡的信息量和异常量远远大于溶解氡, 随即开始对逸出气氡的微动态进行研究, 并在“九五”期间研制出目前国内功能、技术性能指标最佳的数字化测氡仪。然而数字化观测逸出氡能否代替模拟观测水氡存在不同意见, 通过理论上的分析和观测气氡实际震例的研究, 阐明模拟测水氡和测逸出氡的差异和一致性, 认为有逸出氡的井、泉测逸出氡完全可以代替模拟测水氡, 其效果更佳。     

The concentration of negative ions of oxygen and its combinations in the ionosphere

Summary There are some processes in the ionosphere which were or could be explained by means of negative ions, such as sunrise effects, echo duration anomalies of meteor train radar observations and others. Therefore the concentration of negative ions was computed in this paper for some electron density distributions in a stationary quasineutral model of the undisturbed ionosphere. Such an investigation seems necessary because in the last few years laboratory experiments and theoretical calculations give some improved values of attachment and detachment coefficients. The density of negative ions at 12 00 local time and at 00 00 local time in dependence on height was calculated. A discussion of these values shows that negative ions must be considered only in the lower ionosphere at most up to 130 km. This agrees well with the conclusions derived from the observations. By using the values derived in this paper it seems possible to explain some results of ionosphere measurements such as those concerning sunrise effects and others.Mitteilung Nr. 124.     

Determination of groundwater discharge rates and water residence time of groundwater‐fed lakes by stable isotopes of water (18O, 2H) and radon (222Rn) mass balances

Lacustrine groundwater discharge (LGD) and the related water residence time are crucial parameters for quantifying lake matter budgets and assessing its vulnerability to contaminant input. Our approach utilizes the stable isotopes of water (δ¹⁸O, δ²H) and the radioisotope radon (²²²Rn) for determining long‐term average and short‐term snapshots in LGD. We conducted isotope balances for the 0.5‐km² Lake Ammelshainer See (Germany) based on measurements of lake isotope inventories and groundwater composition accompanied by good quality and comprehensive long‐term meteorological and isotopic data (precipitation) from nearby monitoring stations. The results from the steady‐state annual isotope balances that rely on only two sampling campaigns are consistent for both δ¹⁸O and δ²H and suggested an overall long‐term average LGD rate that was used to infer the water residence time of the lake. These findings were supported by the good agreement of the simulated LGD‐driven annual cycles of δ¹⁸O and δ²H lake inventories with the observed lake isotope inventories. However, radon mass balances revealed lower values that might be the result of seasonal LGD variability. For obtaining further insights into possible seasonal variability of groundwater–lake interaction, stable water isotope and radon mass balances could be conducted more frequently (e.g., monthly) in order to use the derived groundwater discharge rates as input for time‐variant isotope balances.     

GDK-1型自动测氡仪的研制和应用

简要介绍了采用电离法原理研制的一种静电计型检测氡气的测氡仪,达到了智能化的程度,并于1995年6月开始至1996年1月在北京太平庄自流井进行试验,后于2003年10月至今在该台站进行断层气的观测,并与SD-3型数字化测氡仪进行同步观测,从台站的试验结果可见,该仪器观测的数据稳定性较好,无需人工操作和没有人为操作引起的误差。     

Origin of energetic ions in the polar cusp inferred from ion composition measurements by the Viking satellite

The magnetospheric ion composition spectrometer MICS on the Swedish Viking satellite provided measurements of the ion composition in the energy range 10.1 keV/e\leqE/Q\leq326.0 keV/e. Data obtained during orbit 842 were used to investigate the ion distribution in the northern polar cusp and its vicinity. The satellite traversed the outer ring current, boundary region, cusp proper and plasma mantle during its poleward movement. H⁺ and He⁺⁺ ions were encountered in all of these regions. He⁺ ions were present only in the ring current. The number of O⁺ and O⁺⁺ ions was very small. Heavy high-charge state ions typical for the solar wind were observed for the first time, most of them in the poleward part of the boundary region and in the cusp proper. The H⁺ ions exhibited two periods with high intensities. One of them, called the BR/CP event, appeared at energies up to 50 keV. It started at the equatorward limit of the boundary region and continued into the cusp proper. Energy spectra indicate a ring current origin for the BR/CP event. Pitch angle distributions show downward streaming of H⁺ ions at its equatorward limit and upward streaming on the poleward side. This event is interpreted as the result of pitch angle scattering of ring current ions by fluctuations in the magnetopause current layer in combination with poleward convection. The other of the two periods with high H⁺ ion intensities, called the accelerated ion event, was superimposed on the BR/CP event. It was restricted to energies \leq15 keV and occurred in the poleward part of the boundary region. This event is regarded as the high-energy tail of magnetosheath ions that were accelerated while penetrating into the magnetosphere. The cusp region thus contains ions of magnetospheric as well as of magnetosheath origin. The appearance of the ions depends, in addition to the ion source, on the magnetic field configuration and dynamic processes inside and close to the cusp.     

Determination of averaging period parameter and its effects analysis for eddy covariance measurements

It is more and more popular to estimate the exchange of water vapor, heat and CO2fluxes between the land surface and the atmosphere using the eddy covariance technique. To get believable fluxes, it is necessary to correct the observations based on the different surface conditions and to determine relevant techinical parameters. The raw 10 Hz eddy covariance data observed in the Yucheng and Changbai Mountains stations were recalculated by various averaging periods (from 1 to 720 min) respectively, and the recalculated results were compared with the results calculated by the averaging period of 30 mins. Meanwhile, the distinctions of fluxes calculated by different averaging periods were analyzed. The continuous 15 days observations over wheat fields in the Yucheng station were mainly analyzed. The results are shown that: (i) In the Yucheng station, compared with the observations by 30 min, when the averaging period changes from 10 to 60 min, the variations of the eddy-covariance estimates of fluxes were less than 2%; when the averaging period changes less than 10 min, the estimate of fluxes reduced obviously with the reduction of the averaging period (the max relative error was -12%); and when the averaging period exceeds 120 min, the eddy covariance estimates of fluxes will be increased and become unsteady (the max relative error is over 10%); (ii) the eddy covariance estimates of fluxes over wheat field in the Yucheng station suggusted that it is much better to take 10 min as an averaging period in studying diurnal change of fluxes, and take 30min for a long-term flux observation; and (iii) normalized ratio was put forward to determine the range of averaging period of eddy covariance measurements. By comparing the observations over farmlands and those over forests, it is indicated that the increase of eddy covariance estimates over tall forest was more than that over short vegetation when the averaging period increased.     

模拟水氡仪与数字化水氡仪对比观测实验

在相同观测条件下,选用平凉地震台北山2号泉水样作为实验目标,用 FD-125型模拟水氡仪与 SD-3B 型数字水氡仪进行对比观测实验;搜集全国用相同方法观测的5个地震台的观测资料进行对比分析,结果表明：FD-125型模拟水氡仪性能明显优于 SD-3B 型数字水氡仪。