共查询到20条相似文献，搜索用时 327 毫秒
1.
S. M. Khaykin V. A. Yushkov L. I. Korshunov A. N. Luk’yanov J. -P. Pommereau J. Nielsen H. Vömel 《Izvestiya Atmospheric and Oceanic Physics》2010,46(1):76-84
The results of measurements of water-vapor vertical profiles in the upper troposphere and stratosphere on board a meteorological
balloon with a FLASH-B optical fluorescent hygrometer (Russia) are presented. These data were obtained during two international
field campaigns in West Africa (August 2006) and Central America (August 2007). Eleven high-resolution water-vapor vertical
profiles measured in the course of these works make it possible to characterize the processes controlling humidity in the
tropical tropopause region. Layers with increased humidity are detected in the lower stratosphere over West Africa to the
level of the potential temperature 450 K. An analysis of satellite maps of the brightness temperature, balloon ozone measurements,
and aerosol scattering, as well as trajectory modeling, display the relation between the observed layers with increased humidity
and the phenomena of convective overshooting of the tropopause, as a result of which cold and ozone-depleted air penetrates
into the lower stratosphere together with ice particles, which, rapidly sublimating, locally increase the water-vapor concentration.
A comparison of the humidity data obtained in West Africa in 2006 and in Central America in 2007 reveals substantial distinctions
in values and vertical structures of water vapor, both in the tropopause region and in the middle stratosphere. 相似文献
2.
The optical coefficients of soot particles are measured in a flow-through optical cell at the wavelength 635 nm in a dry atmosphere and in an atmosphere saturated with water vapor. Two types of systems modeling atmospheric soot aerosols and differing in the degree of hygroscopicity of their particles are investigated and compared. One of the systems contains hydrophobic acetylene soot, and the other contains hydrophilic soot obtained through modification of the initial soot by vapors of glutaric acid. The results show that the optical properties of hydrophobic soot depend only slightly on the conditions of moistening, whereas the optical properties of hydrophilic soot change abruptly upon its moistening because of the formation of a hydrate shell. In the atmosphere saturated with water-vapor, the monomolecular layer of a hydrophilic organic substance leads to the watering of particles and an abrupt (more than twofold) increase in the cross section of light scattering. A further growth of the hydrophilic component of soot particles initiates the formation of micron drops on them, thus resulting not only in the natural effect of light scattering enhancement but also in a noticeable light absorption increase. In particular, a light absorption enhancement by a factor of 3.5 is characteristic of particles of enriched hydrophilic soot. 相似文献
3.
Mitsuhiro Toratani Hajime Fukushima Hiroshi Murakami Akihiko Tanaka 《Journal of Oceanography》2007,63(3):525-532
The present study proposes an atmospheric correction scheme for Advanced Earth Observation Satellite II (ADEOS-II)/Global
Imager (GLI) ocean color retrieval that corrects for the atmospheric absorptive aerosol effect. Radiative transfer simulations
were conducted assuming a non-absorptive model aerosol with a soot-type aerosol at various mixture ratios. The results indicate
that while the spectral dependency of aerosol reflectance does not change in the longer (>550 nm) wavelength region, the reflectance
at shorter wavelengths is highly variable and depends on the mixture ratio. The influence of aerosol absorption was also investigated
using GLI data from ocean areas adjacent to Japan in the presence of absorptive Siberian fire smoke aerosol in the spring
of 2003. The spectral curvature of the aerosol was estimated from the data obtained. An empirical, iterative scheme that detects
and evaluates the influence of absorptive aerosols was developed by comparing 380 nm GLI-observed aerosol reflectance with
predicted reflectances derived using an in-water optical model. To evaluate the performance of this scheme, satellite-derived
normalized water-leaving radiances were compared with those measured from a ferry servicing Nagasaki and Fukue. The results
of data acquired on March 20, 2003, indicate that this absorption correction scheme improved root mean square estimation error
for normalized water-leaving radiance by approximately 40% in the 380, 400, and 412 nm bands. This atmospheric correction
algorithm was used as a part of the second version of the GLI standard ocean color data process system at Japan Aerospace
Exploration Agency (JAXA). 相似文献
4.
我国海区SeaWiFS资料大气校正 总被引：13，自引：1，他引：13
利用光谱辐射传输理论，结合海上同步实测资料，开发出我国海区SeaWiFS资料大气校正模型。经卫星资料处理结果比对，本模型在一类水体，基本消除了412nm和443nm波段离水辐射率小于0的现象；在二类水体，利用临近一类水体的大气条件进行了有效的大气校正；同时建立了670nm,765nm,865nm波段的大气校正模型，这三个面适用于高浓度悬浮泥沙的信息提取。本模型用于处理我国海区的SeaWiFS资料比美国NASA模型更适合我国海区特定的大气和海洋环境，为SeaWiFS资料海洋水色信息提取和我国海洋一号（HY－1）及风云一号（FY－1C）卫星资料的大气校正研究提供了技术基础。 相似文献
5.
S. P. Smyshlyaev V. Ya. Galin P. A. Zimenko A. P. Kudryavtsev A. A. Malykh 《Izvestiya Atmospheric and Oceanic Physics》2006,42(2):171-183
New prognostic estimates are obtained for the potential variability of the atmospheric ozone content in the first half of the 21st century. The calculations are based on models of gas composition and general circulation in the lower and middle atmosphere and on the scenarios of the World Meteorological Organization (WMO). It is shown that the rate of ozone content increase will be controlled to a considerable extent by variations in stratospheric temperature. Even though the contents of atmospheric chlorine and bromine are not reduced, contrary to the WMO prediction, and remain at the present-day levels, the continuation of stratospheric cooling will lead to a rapid recovery of the ozone content to its level characteristic of the 1980s. Model experiments on variations in the stratospheric aerosol content have shown that an increase in the aerosol concentration will not affect the rate of ozone recovery in the atmosphere during reduced emissions of chlorine and bromine gases if the stratospheric temperature remains lowered. Numerical experiments have also shown that the simultaneous anthropogenic action on the contents of halogen gases and on the lower-stratosphere temperature can reduce the adverse effects of Freons and halons on the ozone layer. 相似文献
6.
A review of contemporary methods for determining integrated parameters of the water content in the atmosphere―atmospheric water-vapor content and cloud liquid-water content―is presented. Fields of these parameters can only be mapped spatially on the basis of using data of satellite measurements. The least errors of the retrieval of atmospheric water-vapor content and cloud liquid-water content is provided by methods based on using measurements of the satellite-borne scanning multichannel microwave radiometers over the ice-free ocean areas in the absence of precipitation. Most methods for retrieving the atmospheric water-vapor content and cloud liquid-water content from the data of microwave radiometers are based on results of numerical simulation of brightness temperatures of the upwelling microwave radiation of the ocean–atmosphere system. The evolution of satellite-borne microwave radiometers and methods for the retrieval of integrated parameters of water content is presented. 相似文献
7.
G. I. Gorchakov A. V. Karpov N. V. Pankratova E. G. Semoutnikova A. V. Vasiliev I. A. Gorchakova 《Izvestiya Atmospheric and Oceanic Physics》2017,53(9):875-884
We have investigated the variability of smoke aerosol absorbing ability with variations in the content of brown carbon (BrC) and black carbon (BC). Using monitoring data on radiative characteristics of smoke aerosol at AERONET stations and the spatial distribution of aerosol optical depth (AOD) obtained by the MODIS spectrometer (Terra satellite), we have detected large-scale smokes during boreal forest fires in Russia and Canada (1995–2012). The spatial distribution (50°–70° N, 95°–125° W) and temporal variability (at AERONET station Fort McMurray) of AOD during the smoking of a part of Canada in July 2012 have been analyzed. AOD probability distributions for July 14–18, 2012, and an estimate of aerosol radiative forcing of smoke aerosol at the upper boundary of the atmosphere have been obtained. We have proposed a technique for the diagnostics of BrC and BC in smoke aerosol particles from the spectral dependence of the imaginary part of the refractive index. At a wavelength of 440 nm, the contributions of BrC and BC to the smokeaerosol absorbing abitity can be comparable in magnitude. In many cases, the absorption spectra of smoke aerosol can be adequately approximated by either power or exponential functions. The presence of BrC in smoke-aerosol particles highly extends the variety of observed absorption spectra in a smoky atmosphere and spectral dependences of single scattering albedo. In the spectral range of 440–1020 nm, the radiative characteristics of smoke aerosol are largely contributed by its fine mode. 相似文献
8.
L. G. Bolshakova 《Izvestiya Atmospheric and Oceanic Physics》2009,45(6):770-778
The requirements imposed on the spectral characteristics of optical filters for portable optical ozonometers are analyzed;
when satisfied, they make it possible to determine the total atmospheric ozone to an accuracy no lower than the accuracy achieved
by complex spectral slit instruments. Considered is the dependence of the calculated ozone absorption coefficients on the
spectral characteristic of the filters and total ozone for the nonmonochromatic radiation measured with two optical filters.
Estimates of the role of contrast and permissible values of the background transmittance of filters in the range of 294.8–400
nm are presented. With these estimates taken into account, it is recommended in two-filter ozonometers to use interference
filters with a transmission maxima at 305.5–307 and 326–330 nm with a spectral width of their bands at half of the height
of the maximum transmission of 2–5 nm. 相似文献
9.
Besides ozone, oxygen and water vapour should be considered for their absorptive effects on ＂HY--1A＂ CZI data processing. First ,gaseous transmittances under various conditions are computed and analyzed for the band settings of this sensor. Second, transmittances under six standard atmospheres are approximated as functions of zenith angle, the water vapour transmittance is approximated as a function of water vapour content and zenith angle, and the ozone transmittance is approximated as a function of ozone content and zenith angle. Finally, taking Rayleigh scattering as an example, the influence of ignoring gaseous absorption when calculating TOA reflectance is analyzed, and the effect of applying the presented transmittance approximations to gaseous absorption correction for Rayleigh scattering in ＂HY--1A＂ CZI data processing is evaluated. 相似文献
10.
A. E. Aloyan 《Izvestiya Atmospheric and Oceanic Physics》2009,45(1):55-68
A hydrodynamic model is used to reproduce the atmospheric circulation during forest fires. The dynamics is simulated with an improved model of free convection with allowance for heat flux emission from the fire area. Against the background of the atmospheric circulation patterns obtained, the problem of aerosol evolution and size distribution due to the forest’s combustible materials from the fire area was solved. The evolution of soot particles is described by solving the kinetic equations of condensation and coagulation. The results of numerical experiments to develop a process that considers water-vapor condensation in a moist atmosphere are presented. 相似文献
11.
水色遥感大气校正方程的研究进展 总被引：1，自引：0，他引：1
大气校正是水色遥感研究中必不可少的一步,文中概括总结了对于一类水体、二类水体的大气校正以及在每类水体中对气溶胶单散射、复散射两种情况下的大气校正方法,列出了比较实用的计算流程。 相似文献
12.
I. A. Gorchakova T. A. Tarasova M. A. Sviridenkov P. P. Anikin E. V. Romashova 《Izvestiya Atmospheric and Oceanic Physics》2009,45(4):467-477
The solar radiation flux incident on the land surface and aerosol radiative forcing are calculated from measurements carried
out under clear skies during the summers of 2004 and 2005 at the Zvenigorod Scientific Station (ZSS) of the A.M. Obukhov Institute
of Atmospheric Physics, Russian Academy of Sciences. In these calculations, the following five models of aerosol optical parameters
are used: a standard model of continental aerosol, a semiempirical model based on measurement data, and three models obtained
from calculations on the basis of the Mie scattering theory for the mean size distribution of aerosol particles (which is
retrieved from aureole measurements). A study of the sensitivity of the flux and forcing to the choice of aerosol model has
shown that the relative error related to the model choice is not large (<5%) for the incident radiation flux and reaches 120%
for aerosol forcing at the atmospheric upper boundary. The aerosol radiative forcing at the atmospheric upper boundary is
also estimated and, according to our calculations, varies from −15 to −2 W/m2. The use (in calculations) of the values of the albedo of single-scattering and the factor of scattering-indicatrix asymmetry
at a wavelength of 550 nm, which were obtained for each of the observation periods, has made it possible to significantly
refine the value of aerosol radiative forcing (compared to that calculated for the means of these parameters over all the
periods). An even more accurate determination of aerosol radiative forcing is possible only when data on the size-distribution
of aerosol particles and their chemical composition for a certain situation under analysis are available. As a result of this
study, two models of the optical parameters of background aerosol have been proposed for use in radiation calculations: a
semiempirical model and a mean model obtained from the calculations based on the theory of scattering. Both models use the
values of the albedo of single scattering and the factor of asymmetry (at a wavelength of 550 nm) retrieved from the measurements
for each of the observation periods. 相似文献
13.
V. N. Aref’ev F. V. Kashin V. K. Semenov R. M. Akimenko N. E. Kamenogradskii N. I. Sizov V. P. Sinyakov L. B. Upenek V. P. Ustinov 《Izvestiya Atmospheric and Oceanic Physics》2006,42(6):739-751
Refined data of systematic measurements of total water vapor in the atmosphere from May 1980 to April 2005 are presented. The data were obtained at the Issyk Kul atmospheric-monitoring station by the method of solar molecular-absorption spectroscopy. Over 25 years, the annual mean water-vapor content in the atmosphere increased by 4.5% at a mean rate of increase of 0.18% per year. However, the water-vapor content decreased in the last five years. The results of statistical processing of experimental data (general statistical characteristics, correlation coefficients, composite oscillations) are described. A refined model is proposed for forecasts of temporal variations in the monthly mean and annual mean water-vapor contents for the coming years. The model includes a linear trend and the sum of oscillations with periods close to the periods of a number of well-known geophysical phenomena. Regression equations are proposed to relate the water-vapor content in the atmospheric column to the surface temperature and absolute humidity. 相似文献
14.
Development of atmospheric correction algorithm for Geostationary Ocean Color Imager (GOCI) 总被引：2，自引：0，他引：2
Jae-Hyun Ahn Young-Je Park Joo-Hyung Ryu Boram Lee Im Sang Oh 《Ocean Science Journal》2012,47(3):247-259
This paper describes an atmospheric correction algorithm for Geostationary Ocean Color Imager (GOCI) and its early phase evaluation. This algorithm was implemented in GOCI Data Processing System (GDPS) version 1.1. The algorithm is based on the standard SeaWiFS method, which accounts for multiple scattering effects and partially updated in terms of turbid case-2 water correction, optimized aerosol models, and solar angle correction per slot. For turbid water correction, we used a regional empirical relationship between water reflectance at the red (660 nm) and near infrared bands (745 nm and 865 nm). The relationship was derived from turbid pixels in satellite images after atmospheric correction, and processed using aerosol properties derived for neighboring non-turbid waters. For validation of the GOCI atmospheric correction, we compared our results with in situ measurements of normalized water leaving radiance (nL w ) spectra that were obtained during several cruises in 2011 around Korean peninsula. The match up showed an acceptable result with mean ratio of the GOCI to in situ nL w (??), 1.17, 1.24, 1.26, 1.15, 0.86 and 0.99 at 412 nm, 443 nm, 490 nm, 555 nm, 660 nm and 680 nm, respectively. It is speculated that part of the deviation arose from a lack of vicarious calibration and uncertainties in the above water nLw measurements. 相似文献
15.
Ultraviolet(UV) radiation has a significant influence on marine biological processes and primary productivity;however, the existing ocean color satellite sensors seldom contain UV bands. A look-up table of wavelengthintegrated UV irradiance(280–400 nm) on the sea surface is established using the coupled ocean atmosphere radiative transfer(COART) model. On the basis of the look-up table, the distributions of the UV irradiance at middle and low latitudes are inversed by using the satellite-derived atmospheric products from the Aqua satellite,including aerosol optical thickness at 550 nm, ozone content, liquid water path, and the total precipitable water.The validation results show that the mean relative difference of the 10 d rolling averaged UV irradiance between the satellite retrieval and field observations is 8.20% at the time of satellite passing and 13.95% for the daily dose of UV. The monthly-averaged UV irradiance and daily dose of UV retrieved by satellite data show a good correlation with the in situ data, with mean relative differences of 6.87% and 8.43%, respectively. The sensitivity analysis of satellite inputs is conducted. The liquid water path representing the condition of cloud has the highest effect on the retrieval of the UV irradiance, while ozone and aerosol have relatively lesser effect. The influence of the total precipitable water is not significant. On the basis of the satellite-derived UV irradiance on the sea surface, a preliminary simple estimation of ultraviolet radiation's effects on the global marine primary productivity is presented, and the results reveal that ultraviolet radiation has a non-negligible effect on the estimation of the marine primary productivity. 相似文献
16.
太湖水中可溶性有机质,悬浮质和浮游藻类色素的光学特性的测定 总被引：1，自引：0，他引：1
本文着重分析了分光光度计测定的太湖水体中悬浮质、可溶性有机质和浮游藻类色素在可见光波段(400nm—700nm)的吸收;讨论了对池塘及两种高等植物色素吸收的对比测定;并利用迭代回归方法对测试样品的散射效应进行了订正。结果表明:(1)可溶性有机质吸收在短波部分较强;并且随着入射波长的增大,吸收几乎呈指数律减小,减小速率比国外海洋中的测量结果小。(2)水中悬浮质对光具有较强的散射作用,散射系数约按入射波长呈倒数变化。(3)不同植物中的色素的吸收光谱有明显差异。此外,利用所测数据,本文还对冬季太湖水体的反射光谱和向下光照衰减系数进行了数值计算,表明该水体对入射光照的反射和衰减与纯净水情况有很大差别,目此,太湖水光学特性研究中必须考虑水中物质的影响。 相似文献
17.
18.
D.G. Bowers K.M. Braithwaite W.A.M. Nimmo-Smith G.W. Graham 《Estuarine, Coastal and Shelf Science》2011,91(3):341-350
A correct understanding of the way in which light interacts with suspended particles is essential for quantitative interpretation of satellite visible band imagery of turbid shelf seas and estuaries. In this paper we describe new optical observations at 90 stations in the tidally energetic waters along the south and west coasts of Britain. The cross sectional area of the particles in suspension has been measured with a LISST laser diffraction instrument. Light scattering and absorption coefficients have been determined by applying Kirk’s method to radiometric measurements at 6 wavelengths. Results show that the scattering coefficient increases linearly with particle cross sectional area A per unit volume of water with a slope (scattering efficiency) of 1.96 (standard error 0.08) at 665 nm. Particle absorption coefficients aP also increase with particle cross sectional area but at the most turbid stations, particle absorption per unit area (aP/A) is observed to increase with the mean size of the particles in suspension. The particles are mostly mineral flocs which become more opaque as they grow larger and the photon path length through them increases. The implication of these results for remote sensing is that reflectance in the red part of the spectrum, which mainly depends on light scattering, is proportional to the cross sectional area of particles in suspension. Reflectance measurements in the green and blue parts of the spectrum, where particle absorption becomes more important, depend on the diameter of the particles as well as their cross sectional area. We show that simultaneous measurements of reflectance in the red and green parts of the spectrum can be used to derive both the area and size of the particles in suspension. 相似文献
19.
We study examples of surveys of the Black Sea performed with the help of a SeaWiFS satellite instrument. It is shown that the results of measurements carried out in spectral channels of 510 and 555nm give information on the basic specific features of the space and time variability of the characteristics of absorption and scattering of light in seawater. The use of a spectral channel of 412nm is inefficient due to the low reliability of the results of the procedure of atmospheric correction performed according to standard algorithms. The results of model calculations demonstrate that the predominant contribution to the absorption of light in the Black Sea in summer is made by the yellow substance. 相似文献
20.
气象条件对青岛地区气溶胶光学特性的影响 总被引：8，自引：0，他引：8
利用 2 0 0 2年 4月至 2 0 0 3年 10月多波段太阳光度计资料和同期的气象观测资料 ,分析了不同气象条件下青岛气溶胶光学特性的变化。气象条件的转变与青岛地区气溶胶光学特性之间具有很好的响应关系 :南风盛行时会加大光学厚度 ,并增强气溶胶对 >5 0 0nm波段太阳辐射的散射能力 ;轻雾和霾在青岛气溶胶光学厚度中占有较大比重 ,而霾对 <5 0 0nm波段辐射的散射能力较强。 相似文献