共查询到20条相似文献，搜索用时 31 毫秒
1.
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
2.
Summary A simple method of calculating fluxes and intensities (both spectral and integral) of radiation in the spectral region 0.29–4 in troposphere and lower stratosphere is proposed. This method allows to calculate with satisfactory accuracy the mean radiative regime of real atmosphere and to solve a wide range of problems both atmosphere-optical and thermal with arbitrary receivers of radiation. ( ) 0.29–4 . , . 相似文献
3.
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
4.
Stefan L. Hastenrath 《Pure and Applied Geophysics》1967,66(1):140-155
Summary Computations of solar heating and infrared cooling for clear sky conditions in the area of the Central American Seas are presented, as based on conventional radiosondes in 1960. Results are discussed with regard to latitude mean data available in the literature.Both solar heating and infrared cooling display the most pronounced latitudinal variation in winter, while the distribution is rather uniform in summer. Large heating rates are found in the lower layers over the Caribbean Sea. The infrared cooling shows maxima around 700 mb and below the 950 mb level, in both summer and winter. This contrasts withLondon's result, but agrees with a more recent study byDavis. Infrared cooling rates computed for clear sky conditions up to 500 mb are somewhat larger than the results form radiometer soundings in fall 1960 as reported byRiehl. Discrepancies betweenRiehl's data andLondon's latitude mean values appear to result essentially from different cloud conditions. The pattern of net cooling is in general consistent withLondon's latitude mean cross-sections for average cloudiness.Effective outgoing radiation in winter displays a decrease from the Caribbean Sea towards the cold interior of the North American Continent, while latitudinal contrasts vanish during the summer season. Computations compare well withBudyko's table andRiehl's estimate for fall 1960, while they are substantially lower thanLondon's data and estimates fromSverdrup's graph.
Zusammenfassung Absorption von Sonnenstrahlung und langwellige Ausstrahlung für wolkenfreien Himmel wurden für den Bereich des Amerikanischen Mittelmeers berechnet, auf Grund herkömmlicher Radiosondenaufstiege im Jahre 1960. Die Ergebnisse werden mit Hinblick auf die in der Literatur verfügbaren Breitenkreismittelwerte diskutiert.Absorption von Sonnenstrahlung und langwellige Ausstrahlung ändern sich mit der geographischen Breite besonders stark im Winter, wogegen horizontale Unterschiede im Sommer weniger ausgeprägt sind. Eine relativ starke Absorption von Sonnenstrahlung scheint in den unteren Schichten über der Karibischen See stattzufinden. Die langwellige Ausstrahlung ist besonders stark um 700 mb und unterhalb des 950 mb-Niveaus, und zwar sowohl im Sommer wie im Winter. Das steht im Gegensatz zu den Ergebnissen vonLondon, stimmt aber mit einer neueren Studie vonDavis überein. Die für wolkenfreien Himmel berechnete langwellige Ausstrahlung bis hinauf zum 500 mb-Niveau ist etwas grösser als die aus Aufstiegen von Radiometersonden im Herbst 1960 gewonnenen Werte vonRiehl. Unterschiede zwischen den Daten vonRiehl und den Breitenkreismittelwerten vonLondon scheinen im wesentlichen aus unterschiedlichen Bewölkungsverhältnissen herzurühren. Die aus Absorption und langwelliger Ausstrahlung resultierenden Abkühlungsbeträge entsprechen im allgemeinen den vonLondon für mittlere Bewölkungsverhältnisse mitgeteilten mittleren Vertikalschnitten.Die effektive Ausstrahlung der Erdoberfläche zeigt im Winter eine Abnahme von der Karibischen See auf den dann kalten Nordamerikanischen Kontinent hin; Unterschiede mit der geographischen Breite verschwinden hingegen im Sommer. Die Berechnungen entsprechen den Tabellenwerten vonBudyko und den Abschätzungen vonRiehl für den Herbst 1960;London's Daten sowie Abschätzungen nach dem Nomogramm vonSverdrup hingegen sind deutlich höher.相似文献
5.
Paula Chadwick 《Astronomy& Geophysics》2005,46(6):6.12-6.15
Very-high-energy gamma-ray astronomy from the surface of the Earth is now a reality, with the HESS collaboration starting to map the sky and track down these elusive and mysterious sources. Paula Chadwick reports on the story so far. 相似文献
6.
《Astronomy& Geophysics》2000,41(2):2.17-2.18
Derek McNally was a member of the organizing committee of IAU Symposium 196. Jacqueline Mitton is RAS Press Officer.
Derek McNally and Jacqueline Mitton report on an out-of-the-ordinary IAU Symposium, no. 196, held on 12–16 July 1999. 相似文献
Derek McNally and Jacqueline Mitton report on an out-of-the-ordinary IAU Symposium, no. 196, held on 12–16 July 1999. 相似文献
7.
Sky radiation,polarization and twilight radiation in Greenland 总被引：1，自引：0，他引：1
8.
Studia Geophysica et Geodaetica - 相似文献
9.
10.
Glenn E. Shaw 《Pure and Applied Geophysics》1980,119(2):231-247
Layers of stratospheric aerosol with optical thicknesses as small as 10–4 cause noticeable perturbations in the monochromatic logarithmic brightness gradient,G, and the color ratio,C, of the twilight sky. Modeling of the twilight's radiant properties shows that definite single-valued relationships exist between maxima inC or minima inG and optical thickness, , physical thickness h, and mean altitude,
, of stratospheric layers. It is therefore possible to determine , h and
and monitor their variations by performing either single wavelength measurements ofG or two-wavelength spectrophotometric measurements ofC. The presence of haze in the lower troposphere and the occurrence of multiple scattering both have relatively minor influences on the recovery of the stratospheric dust properties, provided that 10<
<30 km.Formal mathematical inversions of the single-scattering twilight equations are possible in principle, but difficult in practice because of non-linearities. Inversions incorporating an iterative linearization process with constrained smoothing, successfully recovered the features of the haze layer, but tended to oversmooth the vertical profile and underestimate the mean altitude of the haze layer. 相似文献
11.
Ground-based observations of the spectral sky radiance within the totality region during a total solar eclipse are of significant interest because the contribution from direct and single scattered light from the solar disk is eliminated. In the present paper, we develop a numerical model of the spectral sky radiance during totality, evaluate the contribution of double scattered sunlight to the sky radiance at totality and compare it to solar corona emissions. The results show that the single scattered coronal light is the major contaminant in ground-based observations of the corona, opposite to what was believed before. For observation directions outside the corona the double scattered sun radiation dominates over the single scattered coronal light. 相似文献
12.
Summary A comparison of the results of visual observations and objective colorimetry of the twilight aureole is made. It is shown that the color picture of the aureole is informative with regard to the composition of the atmosphere. 相似文献
13.
Kinetic shear resistance,fluid pressures and radiation efficiency during seismic faulting 总被引：1，自引：0，他引：1
Richard H. Sibson 《Pure and Applied Geophysics》1977,115(1-2):387-400
Summary During earthquake faulting, radiation efficiency and the degree stress relief are critically dependent on the kinetic shear resistance. This is often assumed to stay constant during slip, but geological evidence suggests that for moderate or large shallow earthquakes it may decrease dramatically to near-zero values once slip is initiated, either by melt formation or by transient increases in fluid pressure on the fault plane. The latter, probably more common process may arise partly through an interaction between temperature and water pressure, and partly through dilatancy recovery as shear stress is relieved. If the fault remains undrained, stress relief should be absolute with seismic efficiency reaching high values, so that stress drops give a measure of the level of tectonic shear stress in fault zones. Supporting evidence comes from the observation that apparent stress is generally about half the stress drop. 相似文献
14.
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
15.
16.
With recent advances in downscaling methodologies, soil moisture (SM) estimation using microwave remote sensing has become feasible for local application. However, disaggregation of SM under all sky conditions remains challenging. This study suggests a new downscaling approach under all sky conditions based on support vector regression (SVR) using microwave and optical/infrared data and geolocation information. Optically derived estimates of land surface temperature and normalized difference vegetation index from MODerate Resolution Imaging Spectroradiometer land and atmosphere products were utilized to obtain a continuous spatio-temporal input datasets to disaggregate SM observation from Advanced SCATterometer in South Korea during 2015 growing season. SVR model was compared to synergistic downscaling approach (SDA), which is based on physical relationship between SM and hydrometeorological factors. Evaluation against in situ observations showed that the SVR model under all sky conditions (R: 0.57 to 0.81, ubRMSE: 0.0292 m3 m?3 to 0.0398 m3 m?3) outperformed coarse ASCAT SM (R: 0.55 to 0.77, ubRMSE: 0.0300 m3 m?3 to 0.0408 m3 m?3) and SDA model (mean R: 0.56 to 0.78, ubRMSE: 0.0324 m3 m?3 to 0.0436 m3 m?3) in terms of statistical results as well as sensitivity with precipitation. This study suggests that the spatial downscaling technique based on remote sensing has the potential to derive high resolution SM regardless of weather conditions without relying on data from other sources. It offers an insight for analyzing hydrological, climate, and agricultural conditions at regional to local scale. 相似文献
17.
Ionospheric conductivity is not very easily measured directly. Incoherent scatter radars perhaps offer the best method but can only measure at one point in the sky at any one time and are limited in their time resolution. Statistical models of average conductivity are available but these may not be applied to individual case studies such as substorms. There are many instances where a real-time estimate of ionospheric conductivity over a large field-of-view is highly desirable at a high temporal and spatial resolution. We show that it is possible to make a reasonable estimate of the noctural height-integrated Pedersen conductivity, or conductance, with a single all-sky TV camera operating at 557.7 nm. This is not so in the case of the Hall conductance where at least two auroral wavelengths should be imaged in order to estimate additionally the energy of the precipitating particles. 相似文献
18.
《地震学报(英文版)》1996,9(3):447-454
In order to investigate the physical mechanism of seismo-electromagnetic signals, many scholars from China and other countries
have carried out laboratory and field experiments of rock samples by loading them up to fracture in recent ten-odd years.
In each of these experiments, the phenomenon of electromagnetic radiation was observed during the process of rock sample fracture.
However, the experimental results can not explain the non-synchronous electromagnetic radiation in actual observation records.
In these records, some stations displayed anomalies but some others did not, and the signals of different frequency bands
observed by the same station did not occur simultaneously. This has brought about many difficulties to the application of
electromagnetic radiation in earthquake prediction. The experimental result of this paper can explain the phenomenon of non-synchronous
electromagnetic radiation. In the experiment of this paper, rock samples are uniaxially compressed up to fracture. The antennas
of different frequency bands are installed two meters away from the rock sample in different directions. The electromagnetic
signals during the whole process of rock sample fracture are recorded synchronously by a 14-channel tape recorder. The experimental
results are as follows: (1) signals of the four frequency bands: VLF, MF, HF and VHF, are all recorded during the main fracturing
process of rock samples, but signals of different frequencies may somtimes occur non-synchronously; (2) the intensity of electromagnetic
radiation is the highest at the moment when the main fracture occurs, but signals in different directions are of different
intensities. The above results are consistent with the non-synchronous electromagnetic radiation observed in real earthquakes.
It seems possible to predict the orientation of future seismic source by the electromagnetic method of the LF or VLF frequency
bands.
Contribution No. 95A0075, Institute of Geophysics, SSB, China.
The paper is translated by Prof.Jie-Fan HUANG, Peking University from the Chinese into English version. 相似文献
19.
Wave radiation stress 总被引：2，自引：1，他引：1
George Mellor 《Ocean Dynamics》2011,61(5):563-568
There are differences in the literature concerning the vertically dependent equations that couple currents and waves. In this
paper, currents are purposely omitted until the end. Isolating waves from currents allows one to focus on two main topics:
an explanation of Stokes drift with apparent mean vorticity obtained from an otherwise irrotational flow and the determination
of vertically dependent wave radiation stress which, when vertically integrated, conforms to that obtained by Longuet-Higgins
and Stewart (1964) and Phillips (1977) nearly 50 years ago and, more recently, by Smith (2006). Discussion begins with the simple case of nonlinear flow beneath a stationary wavy wall. 相似文献
20.
Lisa Shevenell 《水文研究》1999,13(4):577-596
Values of evapotranspiration are required for a variety of water planning activities in arid and semi‐arid climates, yet data requirements are often large, and it is costly to obtain this information. This work presents a method where a few, readily available data (temperature, elevation) are required to estimate potential evapotranspiration (PET). A method using measured temperature and the calculated ratio of total to vertical radiation (after the work of Behnke and Maxey, 1969) to estimate monthly PET was applied for the months of April–October and compared with pan evaporation measurements. The test area used in this work was in Nevada, which has 124 weather stations that record sufficient amounts of temperature data. The calculated PET values were found to be well correlated (R2=0·940–0·983, slopes near 1·0) with mean monthly pan evaporation measurements at eight weather stations.In order to extrapolate these calculated PET values to areas without temperature measurements and to sites at differing elevations, the state was divided into five regions based on latitude, and linear regressions of PET versus elevation were calculated for each of these regions. These extrapolated PET values generally compare well with the pan evaporation measurements (R2=0·926–0·988, slopes near 1·0). The estimated values are generally somewhat lower than the pan measurements, in part because the effects of wind are not explicitly considered in the calculations, and near‐freezing temperatures result in a calculated PET of zero at higher elevations in the spring months. The calculated PET values for April–October are 84–100% of the measured pan evaporation values. Using digital elevation models in a geographical information system, calculated values were adjusted for slope and aspect, and the data were used to construct a series of maps of monthly PET. The resultant maps show a realistic distribution of regional variations in PET throughout Nevada which inversely mimics topography. The general methods described here could be used to estimate regional PET in other arid western states (e.g. New Mexico, Arizona, Utah) and arid regions world‐wide (e.g. parts of Africa). Copyright © 1999 John Wiley & Sons, Ltd. 相似文献