Effect of relative humidity on the angular distribution of scattered light intensity for rural and urban aerosols

The change in atmospheric relative humidity affects the physical and optical properties of aerosol particles. It would be interesting to study the effect of an increase in relative humidity on the angular scattering of light by aerosols (by incorporating the changes due to it as the complex refractive index and the parameters of the size distribution function). In the present paper we have computed the angular scattering function for rural and urban aerosols, for light of wavelength 0.55 μn. The results obtained for these two models, representative of different environments, are interesting and show some discriminating features.     

闾阳－海城－东沟剖面深地震波动力学特征初探

本文利用国内外有关深地震波动力学特征的研究方法，结合现有原始资料的实际条件，对闾阳－海城－东沟深地震测深剖面某些地段的主要波组的动力学特征进行了定性或半定量的分析与研究。在频谱分析，速度振幅的计算与相对理论振幅的对比等方面，获得了一些有益信息。为进一步合理解释深地震测深资料提供依据。     

Total precipitable water in the atmosphere over India

Electromagnetic radiation, in its passage through the atmosphere, is attenuated by absorption and scattering by atmospheric gases, dust and aerosols. The most important absorber is water vapour and the most significant parameter in atmospheric absorption studies is the total precipitable water in the atmosphere. The present paper summarises the results of a study made to compute the total precipitable water in the atmosphere over India using radiosonde and other data, as part of a programme for the computation of direct, global and diffuse solar radiation at the ground from the solar constant. Using values of air temperature and dew point from the ground up to 250 mb at 19 radiosonde stations and surface water vapour mixing ratio values at 105 surface observatories in India, precipitable water amounts have been computed for 124 stations, for each month and for the whole year. The paper describes the techniques used to extend the total precipitable water amounts derived from radiosonde data at 19 stations to 124 stations covering the major climatic zones in the country and presents the results in the form of 12 maps showing the spatial and temporal distribution of total precipitable water over India     

Regional variability in relationships between climate and dengue/DHF in Indonesia

Since 1970, the worldwide distribution, frequency and intensity of epidemics of dengue and dengue haemorrhagic fever (DHF) have increased dramatically. In Indonesia, as elsewhere, the geographic distribution and behaviour of the two main vectors – Aedes aegypti and Aedes albopictus – and the consequent transmission dynamics of the disease are strongly influenced by climate. Monthly incidence data were examined in relation to monthly data for temperature, rainfall, rainfall anomalies, humidity and the Southern Oscillation Index for 1992–2001. Focusing on eight provinces, significant Pearson correlations were observed between dengue/DHF incidence and at least one climate variable ( r  = ±0.2 to ±0.43; P  < 0.05). Multiple regression analyses showed that 12.9–24.5 per cent of variance in incidence was explained by two or three climate variables in each province ( P  < 0.1–0.01). Rainfall appears to be the principal climatic agent affecting the geographic distribution and temporal pattern of incidence while temperature appears to play a critical role in outbreak intensity. Wide regional and temporal variations in the strength and nature of the observed associations led to the identification of three groups of provinces where increases in dengue/DHF incidence were variously associated with increased rainfall, decreased rainfall and/or high susceptibility to climate variability. Although climatic factors play an important role in explaining the timing and intensity of dengue/DHF outbreaks, a wide range of other factors specific to local environments also appear to be involved – information that may assist in the prediction and mitigation of regional dengue/DHF outbreaks.     

Stochastic assessment of GPS carrier phase measurements for precise static relative positioning

 Global positioning system (GPS) carrier phase measurements are used in all precise static relative positioning applications. The GPS carrier phase measurements are generally processed using the least-squares method, for which both functional and stochastic models need to be carefully defined. Whilst the functional model for precise GPS positioning is well documented in the literature, realistic stochastic modelling for the GPS carrier phase measurements is still both a controversial topic and a difficult task to accomplish in practice. The common practice of assuming that the raw GPS measurements are statistically independent in space and time, and have the same accuracy, is certainly not realistic. Any mis-specification in the stochastic model will inevitably lead to unreliable positioning results. A stochastic assessment procedure has been developed to take into account the heteroscedastic, space- and time-correlated error structure of the GPS measurements. Test results indicate that the reliability of the estimated positioning results is improved by applying the developed stochastic assessment procedure. In addition, the quality of ambiguity resolution can be more realistically evaluated. Received: 13 February 2001 / Accepted: 3 September 2001     

南京城区夏季低层逆温对人体舒适状况影响初探

利用2000年夏季南京志区地面气象要素和低层探空资料，分析了该夏季南京城区早、晚低层逆温的频率、厚度和强度变化特征，着重从统计角度研究了逆温的厚度、强度与城区地面温度、相对湿度变化的关系及对人体舒适状况的影响。结果表明：低层逆温对城区地面温湿变化及其幅度影响较大，当07时有逆温层时，08时至14时的温度增加幅度变大，相对温度减小幅度也变大，人体不适指数增加幅度变大；当19时有逆温层时，20时至23时温度减小幅度变小，相对湿度增加幅度也变小，人体不适指数减小幅度变小，并通过相关分析建立了人体舒适度指数与逆温强度之间的回归方程。     

用地面湿度参量计算我国整层大气可降水量及有效水汽含量方法的研究

根据1993年我国28个台站地面及高空气象要素资料,拟合出这28个台站所在地区整层大气可降水量同地面湿度参量(地面水汽压、地面露点)关系的经验表达式,并且在此基础上,通过引进地理纬度ψ和海拔高度H两个参量,将经验系数参数化,建立起由地面湿度参量计算整层大气可降水量的经验计算模式.另外还拟合出这些地区整层大气有效水汽含量同可降水量关系的经验表达式,提出一个先由地面湿度参量计算整层大气可降水量,再由此计算出整层大气有效水汽含量的方法.     

THE IMPACT OF RELATIVE HUMIDITY ON THE RADIATIVE PROPERTY AND RADIATIVE FORCING OF SULFATE AEROSOL

With the data of complex refractive index of sulfate aerosol,the radiative properties of theaerosol under 8 relative humidity conditions are calculated in this paper.By using the concentrationdistribution from two CTM models and LASG GOALS/AGCM,the radiative forcing due tohygroscopic sulfate aerosol is simulated.The results show that:(1)With the increase of relativehumidity,the mass extinction coefficiency factor decreases in the shortwave spectrum;singlescattering albedo keeps unchanged except for a little increase in longwave spectrum,andasymmetry factor increases in whole spectrum.(2)Larger differences occur in radiative forcingsimulated by using two CTM data,and the global mean forcing is—0.268 and—0.816 W/m~2,respectively.(3)When the impact of relative humidity on radiative property is taken into account,the distribution pattern of radiative forcing due to the wet particles is very similar to that of drysulfate,but the forcing value decreases by 60%.     

DJM10湿度检定箱加湿不能自控的原因浅析

详细介绍了新型湿度检定箱内部气路原理及升降湿外围控制原理，并给出故障检修实例 ,供设备检定人员在维修工作中参考。     

Kriging方法在区域土壤水分估值中的应用

土壤水分的观测对于地表参数化的发展以及气候变化的研究有着重要的作用。本文对大尺度区域土壤水分的估值进行了尝试:采用1987年中国102个气象站点1米土层四个季节的土壤水分值作为样本,运用KRIGING方法,通过对半变异函数的计算和分析,得出了所研究7个采集日的拟合函数,发现均符合球状模型,对模型有关的参数进行了拟合。并将插值结果与距离反比法进行了对比性检验,同时给出了KRIGING方法的估值精度。检验结果表明平均相对误差和标准偏差均以距离反比法较小,以样本量较大的f时段为例对检验结果进行了深入分析。由此得出了KRIGING方法内插估值的优势和不足,简要给出了提高估值精度的可能方案。最后对中国东半部f时段的土壤水分值进行内插成图。