共查询到20条相似文献，搜索用时 31 毫秒
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M. P. Petrov A. Yu. Terzhevik N. I. Palshin R. E. Zdorovennov G. E. Zdorovennova 《Water Resources》2005,32(5):496-504
Based on the analysis of data of many-year actinometric observations, a considerable temporal (interannual, seasonal, synoptic, and diurnal) and spatial variability of the albedo of the snow-and-ice cover of a shallow lake is shown. The ranges of variations in the albedo of snow and ice for a wide spectrum of the state of surface and weather conditions are presented. The variability of the thickness and structure of snow-and-ice cover is analyzed for different periods in winter. The results of field experiments aimed to determine the degree of absorption of solar radiation by snow and ice are presented. The effective coefficients of absorption of solar radiation by snow and ice are determined. The comparison of the observed and calculated values of the under-ice radiation has shown that the determined coefficients adequately describe the absorption of solar radiation by snow-and-ice cover. 相似文献
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B. G. Verma 《Pure and Applied Geophysics》1970,83(1):46-48
Summary The paper considers a shock wave to be reflected from a wall in the presence of a transverse magnetic field when the radiation pressure and radiation energy are taken into account. It has been shown that under certain physical conditions, the velocity of the reflected radiative shock would be greater than the corresponding velocity when the magnetic field and radiation effects are neglected. 相似文献
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针对天文、大气、宏观地理与局地地形等因子对起伏地形下太阳散射辐射的复杂作用,将影响起伏地形下太阳散射辐射的天空因素与地面因素分开处理.通过基于数字高程模型（DEM）数据的起伏地形下天文辐射模型和地形开阔度模型,综合考虑地面因素对散射辐射的影响;基于常规地面气象站观测资料建立的水平面散射辐射模型考虑天空因素对散射辐射的影响;依据各向异性散射机理,建立了起伏地形下太阳散射辐射分布式计算模型,探索出一条利用DEM数据和常规气象观测资料实现山区太阳散射辐射定量模拟的技术路线.以1 km×1 km分辨率的DEM数据作为地形的综合反映,实现了起伏地形下黄河流域1 km×1 km分辨率的太阳散射辐射分布式模拟. 相似文献
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利用反射声场探测井外地质构造的声波远探测方法已逐渐成为石油测井的一门重要应用技术.在远探测测井中声源常采用单极、偶极和四极等.为了考察各种声学辐射器的辐射性能,本文从辐射声场和井孔声场的能流密度出发,提出了一种利用辐射器向井外辐射的能量与沿井筒传播的能量比的大小来评价其辐射效率的方法,考察了不同声源激发的沿井传播的导波能流、地层辐射波能流及声源辐射效率随频率的变化规律.计算结果表明:不同声源的辐射效率和优势激发频段各不相同.单极声源在低频下的辐射效率很低,因为此时声源激发的能量几乎全部被斯通利波带走,相比之下,偶极声源在低频时的辐射效率远大于单极声源.本文的结果说明了偶极声源作为低频远探测声源要优于单极声源. 相似文献
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Erythemal ultraviolet (UVER; 280–400 nm) and total shortwave (SW; 305–2800 nm) solar irradiances were recorded from 2000 to 2009 in Valladolid, Spain. UVER and SW values under cloudless conditions are simulated by radiative transfer (TUV 4.6) and empirical models. These model estimations are tested with experimental measurements showing a great agreement (root mean square error around 7%). The aerosol effect on UVER irradiance is determined through a model study. UVER radiation and total ozone column (TOC) temporal evolutions show a negative relationship. TOC accounts for 80% of UVER variance and its radiation amplification factor is 1.1 at zenith of 65°. Cloud effects on solar radiation are shown and quantified by the cloud modification factor. Moreover the enhancement effect cases are analysed. SW radiation proves more sensitive to clouds than UVER. Clouds are seen to attenuate and enhance solar radiation by up to 93% and 22% in the UVER range, respectively. 相似文献
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Y. Viswanadham 《Pure and Applied Geophysics》1972,97(1):183-213
Summary Studies of various radiation fluxes, namely solar radiation, albedo (reflection coefficient), long-wave radiation of the earth and the atmosphere and net radiation observed at a tropical station are presented in this paper. The time variation of these fluxes are examined in relation to various meteorological parameters and atmospheric conditions.The constants of the general radiation balance equation are determined. The calculated radiation balance equation with new constants for the station isR=0.86 (1–)S–4.2. A high correlation coefficient 0.99 is obtained between net short-wave radiation (1–)S and net radiationR. The radiation balance at a tropical station is evaluated. It is found over a year there is a net surplus of 94 kilo-langleys. 相似文献
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《中国科学:地球科学(英文版)》2015,(3)
The warming over the Tibetan Plateau(TP) is very significant during last 30 years,but the thermal forcing has been weakened.The thermal weakening is attributed mainly to the enhancement of the TOA(top of atmosphere) outgoing radiation.This enhancement is opposite to the greenhouse-gas-induced weakening of the global mean TOA outgoing radiation and is also unable to be explained by the observed decrease of total cloud cover.This study presents the importance of cloud height change and the warming over the TP in modulating the TOA radiation budget and thus the thermal forcing during spring and summer.On the basis of surface observations and satellite radiation data,we found that both the TOA outgoing shortwave radiation and longwave radiation were enhanced during this period.The former enhancement is due mainly to the increase of low-level cloud cover,which has a strong reflection to shortwave radiation,especially in summer.The latter enhancement is caused mainly by the planetary warming,and it is further enhanced by the decrease of total cloud cover in spring,as clouds extinguish outgoing longwave radiation emitted from the land surface.Therefore,the radiative cooling enhancement and thus the thermal weakening over the TP is a response of the earth-atmosphere system to the unique change of cloud cover configuration and the rapid warming of the land surface.However,these trends in cloud cover and TOA outgoing radiation are not well represented in four reanalyses. 相似文献
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近年来城市化和大气污染对辐射收支的影响日益显著.本研究利用2013—2014年中国科学院大气物理研究所325m铁塔、南郊观象台、密云气象塔、上甸子区域大气本底站四个观测站点的辐射及自动站气象要素数据,采用南郊观象台的能见度资料将观测数据分为清洁天和污染天,并进行类比分析,以1月份为例,研究了北京地区大气污染和城郊差异对辐射收支的影响.结果表明:(1)从月平均值来看,各站污染天入射短波辐射均小于清洁天,衰减最大可达55.8W·m~(-2),直接辐射亦然,衰减最大可达161.1W·m~(-2),散射辐射相反,增加最大值为72.2W·m~(-2);长波辐射污染天大于清洁天,向下向上长波辐射增加最大值分别为85.0 W·m~2和70.0 W·m~(-2),且长波辐射的衰减与污染物浓度和大气温度相关;净辐射白天污染天小于清洁天,夜间相反.(2)从各站的对比可知,大气污染对入射短波辐射的衰减,南部郊区(13.2%)大于北部城区(7.4%),与北京地区"南北两重天"的污染物分布特征一致;且污染物对长短波辐射的影响呈现了从城区到郊区衰减率依次减小的现象.本研究为大气污染与气象条件的相互作用研究提供了观测基础. 相似文献
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安徽石台大山地区分布着较为广泛的下寒武统荷塘组石煤层,而石煤出露地区即是富硒区也是放射性水平含量较高区。根据本次调查在下寒武统荷塘组含煤岩系分布区的地方,其天然γ射线水平较高,不适宜人类在此居住。而调查区内的居民村庄大多远离含煤岩系分布区的地方,对当地的居民接收天然γ辐射照射人均年有效剂量估算,该地区居民居住的村庄和学校的人年均天然贯穿辐射有效剂量当量为0.32~0.43 m Sv。因此,可以确定认为该地区居民居住γ射线辐射水平对人居环境影响不大,天然γ射线辐射环境对当地居民健康是安全的。 相似文献
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《Journal of Atmospheric and Solar》1999,61(7):521-529
The influence of helio/geophysical factors on the solar energy input to the lower atmosphere has been studied at the network of actinometric stations of Russia in different latitudinal belts. It was found that there are appreciable changes in the half-yearly values of total radiation associated with galactic cosmic ray (GCR) variations in the 11-yr solar cycle, the increase of GCR flux being accompanied by a decrease of the total radiation at higher latitudes and by its increase at lower latitudes. Auroral phenomena and solar flare activity are likely to affect the solar radiation input to the high-latitudinal belt together with GCR variations, the increase of both these factors resulting in the decrease of total radiation. The changes found in the total radiation fluxes in the lower atmosphere seem to be related to the cloud cover variations associated with the solar and geophysical phenomena under study. The variations of the solar radiation input in the 11-yr-cycle amounting to ±4–6% may be an important factor affecting tropospheric dynamics. 相似文献
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The basic principles of calculations of direct and diffuse radiation onto slope surfaces during the snowmelt period are discussed. An approximate scheme for the calculation of daily sums of radiation is presented for a wide spectrum of geographical, meteorological, and slope characteristics. 相似文献
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Solar diffuse radiation data including global radiation, shortwave and longwave balances, net radiation and sunshine hours have been extensively analyzed to study the variation of diffuse radiation with turbidity and cloud discharges appearing in the form of atmospherics over the tropics. Results of surface radiation measurements at Calcutta, Poona, Delhi and Madras are presented together with some meteorological parameters. The monthly values of diffuse radiation and the monthly ratios of diffuse to global solar radiation have been examined, with a special emphasis in relation to the noise level of atmospherics at Calcutta in the very low frequency band. The results exhibit some definite seasonal changes which appear to be in close agreement with one another. 相似文献
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Geomagnetism and Aeronomy - The extreme ultraviolet radiation (EUV radiation) of the Sun is studied. The time series of daily values of the radiation fluxes outside flares in the EUV range are... 相似文献
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The problems of frequency spectrum generation, radiation, and reception of signals at high power line (PL) harmonics of 50/60 Hz, and high PL harmonics caused by the use of thyristor power controllers in control circuits of large electricity consumers are discussed. The PL for frequencies of 2–8 kHz is considered a sufficiently effective traveling-wave antenna (the so-called Beverage antenna). The response of the spectrometer to a periodic sequence of PL radiation broadband pulses is discussed. The effects of a slow signal frequency drift at high PL harmonics and the occurrence of pulse components with fast frequency drift on the dynamic spectra, which in the literature is often associated with the magnetospheric trigger radiation, are considered. 相似文献
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A critical analysis is given for various methods for recovery of the ozone layer of the Earth: the emission of alkane gases, the destruction of freons by laser IR radiation and with microwave discharge, exposure to laser UV radiation and electric discharge in the atmosphere, the use of solar radiation, laser infrared radiation, and gamma rays, and the creation of an artificial formation at high altitudes that shields the solar radiation dissociating ozone. The optimal methods are discussed in terms of their effectiveness, economic costs, and environmental consequences. These include the use of gamma rays sources, electric discharge in the atmosphere, and microwave breakdown. 相似文献
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The problem of the observed fast damping of longitudinal waves in solar coronal magnetic loops is studied. According to some data, the radiation effect, which plays a key role in the cooling of coronal loops that are observed in the extreme UV wavelength range, is used to explain this phenomenon. The dispersion relation for slow magnetosonic modes of a cylindrical magnetic tube has been obtained with regard to the radiation effect. It has been indicated that the radiation actually results in the fast damping of the slow magnetosonic modes of coronal magnetic loops. 相似文献