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1.
Summary Measurements of the total incoming solar radiation on a horizontal surface have been recorded since 1967 at a network of actinometric stations in Iraq. The instrument used at each of these stations is a bimetallic actinograph of the Robitzsch type. The stations at Mosul, Baghdad and Nasiriya have been selected, to represent respectively the northern, central and southern climatic zones of Iraq.This paper examines from the available records at these stations, until August 1973, the differnt aspects of radiation climatology which are important in solar energy utilizations. The mean annual, monthly and daily radiation; the number of days in which the radiation has exceeded certain given limits and the periods of successive days having radiation less than 100 and 250 cal cm–2 day–1 have been studied and presented in tabular and graphical forms suitable for direct application.To architects and engineers interested in the availability of solar radiation on vertical and inclined surfaces, the hourly radiation values for Baghdad have been studied for the different months of the year and the corresponding isopleths on the horizontal have been drawn. 相似文献
2.
《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
3.
月表太阳辐射是深入研究月表温度分布的关键问题之一. 本文根据月表有效太阳辐照度与太阳常数、太阳辐射入射角以及日月距离之间的关系,建立月表有效太阳辐照度的实时模型. 该模型在1950～2050年的100年内的理论误差百分比小于0.28％, 相对前人提出的模型在精度上有了很大程度的提高,能较为真实地反映月表有效太阳辐照度随时间的变化规律. 计算结果表明2007年月表太阳辐照度的年变化范围在1321.5～1416.6 W·m-2之间,平均为1368.0 W·m-2. 通过对月表太阳辐射入射角计算结果的分析,证实了月球的两极可能存在极昼极夜. 相似文献
4.
Dr. M. K. Elnesr 《Pure and Applied Geophysics》1958,40(1):247-251
Summary A study of the depletion of solar radiation at Helwan Observatory has shown, for Egypt, that:a) Diffuse reflexion and absorption by suspended particles in the atmosphere constitute about 20 percent of the total depletion;b) Absorption by water vapour is the only factor that should be evaluated at any place to give an estimation of the solar radiation received at that place. This can be obtained either from the mean values of the surface water vapour pressure which have been considered in detail, or, for individual cases, from spectroscopic measurements of the precipitable water content whose daily variations have been studied. 相似文献
5.
Summary Records of total solar radiation on a horizontal surface has been obtained at the Agro-meteorological Station at Giza continuously since December 1, 1955 by means of a Robitzsch actinograph. The difficulties in obtaining precise measurements were described. The results of the first three years of record were discussed and summarized in tabular and graphical form. To such few years of observations, a 15 days moving average was applied. The new data were plotted so as to obtain the solar radiation pattern, which has been compared with the radiation received at the outer limits of the atmosphere and with the maximum probable radiation expected at the Station. 相似文献
6.
The response of the thermobaric characteristics of the high-latitude troposphere to short-term events attributed to solar
activity (solar cosmic rays and geomagnetic storms) has been investigated. The spatial manifestation of these disturbances
in the troposphere is shown to be of a “focal” character. It is found that the manifestation is most evident in the cold period
and depends on the properties of the underlying surface (land, ocean). The properties of the variations of the troposphere
air temperature in the manifestation “foci” on the standard isobaric surfaces, as well as the variations of the altitude profile
of temperature and the long-wave radiation flux at the upper boundary of the atmosphere, have been considered. The variations
of the heat content of the high-latitude troposphere after solar flares have been analyzed. The variation of the thermobaric
field is shown to be accompanied by the rearrangement of circulation forms in moderate and polar latitudes. The revealed properties
are completely explained within the mechanism proposed here for the solar activity effect on the climatic characteristics
of the troposphere. 相似文献
7.
Summary This paper presents the study of variations of the solar radiation and the blueness of the sky during the eclipse of June 30, 1954 at Athens. The comparison of the solar radiation march during the eclipse day to that of the two preceding and the two following days of the eclipse-all five days were almost identical from the standpoint of weather—proved that the direct solar radiation and the total (sky and sun) radiation underwent a considerable decrease during the phenomenon. The blueness of the sky also underwent a significant change, especially at the maximum of the eclipse. 相似文献
8.
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
9.
《Journal of Atmospheric and Solar》1999,61(1-2):15-24
Total solar irradiance has been monitored from space for nearly two decades. These space-borne observations have established conclusively that total solar irradiance changes over a wide range of periodicities—from minutes to the 11-year solar cycle. Since the total energy flux of the Sun is the principal driver for all Earths atmospheric phenomena, the accurate knowledge of the solar radiation received by the Earth and its variations is an extremely important issue. In this paper we review the long-term variations of total solar irradiance during solar cycles 21 and 22. We conclude that, within the current accuracy and precision of the measurements, the minimum level of total solar irradiance is about the same for both solar cycles 21 and 22. 相似文献
10.
11.
《Journal of Atmospheric and Solar》2000,62(7):567-571
The relationships between the solar radiation input to the lower atmosphere at higher and middle latitudes and different phenomena related to solar activity have been studied at the network of actinometric stations of Russia. It was shown that the effects of galactic cosmic ray variations and solar flares on the half-yearly sums of global radiation strongly depend on latitude, with a negative correlation being observed in the high-latitudinal belt and a positive one at lower latitudes. The change of the correlation sign was found to take place at the latitude ∼57°. Auroral phenomena are likely to affect the radiation fluxes only in the high-latitude (auroral) region. The effects observed seem to be due to the latitudinal dependence of cloud cover variations associated with the helio/geophysical phenomena under study. 相似文献
12.
The analytical formulas for the solar radiation refraction angle and the times of the sunrise and sunset at altitudes of the
atmosphere, which make it possible to take into account the dependence of these parameters on the temperature, density, and
temperature vertical gradient in the atmosphere specified at the ground level, have been obtained. It has been indicated that
solar radiation refraction pronouncedly affects the times of the sunrise and sunset at altitudes of the atmosphere. 相似文献
13.
Hemispherical photographs of forest canopies can be used to develop sophisticated models that predict incident below canopy shortwave radiation on the surface of interest (i.e. soil and water). Hemispherical photographs were collected on eight dates over the course of a growing season to estimate leaf area index and to quantify solar radiation incident on the surface of two stream reaches based on output from Gap Light Analyser and Hemisfer software. Stream reaches were shaded by a mixed‐deciduous Ozark border forested riparian canopy. Hemispherical photo model results were compared to observed solar radiation sensed at climate stations adjacent to each stream reach for the entire 2010 water year. Modeled stream‐incident shortwave radiation was validated with above‐stream pyranometers for the month of September. On average, the best hemispherical photo models underestimated daily averages of solar radiation by approximately 14% and 12% for E–W and N–S flowing stream reaches, respectively (44.7 W/m2 measured vs 38.4 W/m2 modeled E–W, 46.8 W/m2 vs. 41.1 W/m2N–S). The best hemispherical photo models overestimated solar radiation relative to in–Stream pyranometers placed in the center of each stream reach by approximately 7% and 17% for E–W and N–S stream reaches respectively (31.3 W/m2 measured vs 33.5 W/m2 modeled E–W, 31.5 W/m2 vs. 37.1 W/m2N–S). The model provides a geographically transferable means for quantifying changes in the solar radiation regime at a stream surface due to changes in canopy density through a growing season, thus providing a relatively simple method for estimating surface and water heating in canopy altered environments (e.g. forest harvest). Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
14.
Summary Ground-based photometric measurements of spectral sky radiation have been made using a simple filter instrument. Sky radiation intensities measured in the solar vertical at =3200 Å and 3600 Å are compared to infer total ozone. A model of multiple scattering Rayleigh atmosphere serves as a primary reduction parameter. Spectral measurements of all-sky radiance distribution are used to study the effects of haze and clouds on the inference of total ozone. The brightness distribution of clear and overcast sky in ultraviolet is also described. 相似文献
15.
Partitioning transpiration (T) from evapotranspiration (ET) is a key process for understanding the interaction between land surfaces and the atmosphere. This paper reports daily partitioning results for a grassland over a 10-year period, obtained using the Community Land Model 3.5 (CLM3.5) land surface model. Hourly forcing data were collected from a long-term observation system located in the northeast of Japan ( http://doi.org/10.24575/0001.198108 ). To test the model behavior, total ET was validated using eddy correlation measurements combined with the energy balance method. The results were compared with previous research using an isotope approach for partitioning. The results demonstrate that our model can capture the dynamics of ET and its components at this location. Evaporation (E), originating from the ground and canopy, varied inter-annually, and from 2006 to 2015, average annual E was approximately 285 mm/year from the ground and 45 mm/year from the canopy. Average, T, was approximately 302 mm/year, accounting for approximately 48% of the total ET. Inter-annual results demonstrate that the water flux transported by vegetation ranges from 17 to 83% during the April–October period. A sensitivity test conducted with forcing data indicates air temperature, incident solar radiation, and longwave radiation exhibited a notable effect on all ET components. Relative humidity exhibited the only negative feedback to both evaporation and transpiration, contrary to the other forcing parameters. Our study reemphasized the effectiveness of CLM3.5 in partitioning T from ET and in understanding the complex interaction between land surfaces and the atmosphere. 相似文献
16.
Exchange flux of total gaseous mercury between air and natural water surfaces in summer season 总被引：5，自引：0，他引：5
The exchanges of mercury between surface and air are of significance in the biogeochemical cycling of Hg in the environment,
but there are still few reliable data on air/surface exchange in aquatic systems. Field measurement campaigns over seawater
surface at Kristineberg Marine Research Station (KMRS) and over Hovg?rds?n River surface at Knobesholm in southwestern Sweden
were conducted to measure mercury flux using a dynamic flux chamber technique coupled with automatic mercury vapor-phase analyzers.
Both sites show net emissions during summer time. Mercury fluxes measured over both river and seawater surfaces exhibit a
consistently diurnal pattern with maximum fluxes during the daytime period and minimum fluxes during the nighttime period.
At freshwater site, mercury flux is strongly correlated with the intensity of net solar radiation, and negatively correlated
with relative humidity. A typical exponential relationship between mercury flux and water temperature was observed at freshwater
measurement site. At seawater site, a strong correlation between mercury flux and intensity of solar radiation was obtained.
The driving force of mercury emission from water surface to air is the super-saturation of dissolved gaseous mercury in aqueous
phase. 相似文献
17.
Predicting the rate of snowmelt and intercepted snow sublimation in boreal forests requires an understanding of the effects of snow-covered conifers on the exchange of radiant energy. This study examined the amount of intercepted snow on a jack pine canopy in the boreal forest of central Saskatchewan and the shortwave and net radiation exchange with this canopy, to determine the effect of intercepted snow and canopy structure on shortwave radiation reflection and extinction and net radiation attenuation in a boreal forest. The study focused on clear sky conditions, which are common during winter in the continental boreal forest. Intercepted snow was found to have no influence on the clear-sky albedo of the canopy, the extinction of short wave radiation by the canopy or ratio of net radiation at the canopy top to that at the surface snow cover. Because of the low albedo of the snow-covered canopy, net radiation at the canopy top remains positive and a large potential source of energy for sublimation. The canopy albedo declines somewhat as the extinction efficiency of the underlying canopy increases. The extinction efficiency of short wave radiation in the canopy depends on solar angle because of the approximately horizontal orientation of pine branches. For low solar angles above the horizon, the extinction efficiency is quite low and short wave transmissivity through the canopy is relatively high. As the solar angle increases, extinction increases up to angles of about 50°, and then declines. Extinction of short wave radiation in the canopy strongly influences the attenuation of net radiation by the canopy. Short wave radiation that is extinguished by branches is radiated as long wave, partly downwards to the snow cover. The ratio of net radiation at the canopy top to that at the snow cover surface increases with the extinction of short wave radiation and is negative for low extinction efficiencies. For the pine canopy examined, the daily mean net radiation at the snow cover surface became positive when daily mean solar angles exceeded 22° in late March. Hence, canopy structure and solar angle control the net radiation at the snow cover surface during clear sky conditions and will govern the timing and rate of snowmelt. Models of intercepted snow sublimation and forest snowmelt could beneficially incorporate the canopy radiation balance, which can be extrapolated to stands of various canopy densities, coverage and heights in a physically based manner. Such models could hence avoid ‘empirical’ temperature index measures that cannot be extrapolated with confidence. 相似文献
18.
19.
T. A. Hariharan 《Pure and Applied Geophysics》1969,77(1):151-158
Summary Results of the measurements of the polarization of reffected solar radiation in the visible region over various land, sea and cloud surfaces carried out from a high altitude aircraft are presented. It is shown that the measurable polarization can be used as a sensitive parameter to determine atmospheric turbidity and the aerosol content. 相似文献
20.
准确的湿度垂直廓线对短期数值天气预报和中长期气候研究分析均具有重要参考价值,但太阳辐射与高空云雨等因素导致探空湿度测量精度较低.针对探空仪GTS1白天进行湿度测量时存在明显偏干误差的现象,本文建立了GTS1湿度测量结构模型,采用计算流体动力学方法重点研究了太阳辐射对GTS1湿度测量的影响,同时探讨了其防雨/防辐射罩的防雨效果.结合改进的太阳辐射计算模型,利用Fluent模拟分析了防雨/防辐射罩云雨滴轨迹和内部温度场分布,数值仿真结果表明:在垂直气流下防雨/防辐射罩基本保护湿度传感器免受高空云雨的影响,对太阳辐射也起到一定防护作用.但太阳辐射对GTS1湿度测量的偏干影响仍较显著,海拔30km左右相对误差甚至高达70%.通过与RS92及GTS1探空湿度测量中的太阳辐射偏干误差相对比,发现基于流体动力学数值计算的湿度相对误差随海拔高度的变化趋势与之基本吻合.本文也给出了理论计算与实验测量存在一定差异的原因,进而以南京探空站2014年不同季节的温度、气压、气球的上升速度等探空数据为计算参数,获取了太阳辐射误差与海拔及环境温度的关系,并对四组探空湿度廓线进行太阳辐射误差修正,提升了GTS1探空仪高空湿度测量的精度.本文研究结果为探空湿度测量太阳辐射偏干误差的有效修正提供了一定的参考. 相似文献