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1.
K. V. S. Badarinath Shailesh Kumar Kharol V. Krishna Prasad Anu Rani Sharma E. U. B. Reddi H. D. Kambezidis D. G. Kaskaoutis 《Journal of Atmospheric Chemistry》2008,59(3):219-236
Measurements of total ozone column and solar UV radiation under different atmospheric conditions are needed to define variations
of both UV and ozone and to study the impact of ozone depletion at the Earth’s surface. In this study, spectral and broadband
measurements of UV-B irradiance were obtained along with total ozone observations and aerosol optical depth measurements in
the tropical urban region of Hyderabad, south India. We specifically used an Ultra-Violet Multifilter Rotating Shadow band
Radiometer (UVMFR-SR), to measure UV irradiance in time and space. To assess the aerosol and O3 effects on ground-reaching UV irradiance, we used measurements from a Microtops II sun photometer in addition to the Tropospheric
Ultraviolet Visible radiation (TUV) model. We also assessed the Defense Meteorological Satellite Program – Operational Line
Scanner (DMSP-OLS) night time satellite data for inferring biomass burning fires during the study period. Results clearly
suggested a negative correlation between the DMSP-OLS satellite derived fire count data and UVMFR-SR data suggesting that
aerosols from biomass burning are directly attenuating UV irradiance in the study region. Also, correlation analysis between
UV index and ozone measurements from sun photometer and TOMS-Ozone Mapping Instrument (OMI) indicated a clear decrease in
ground reaching UV-B irradiance during higher ozone conditions. The higher levels are attributed to photochemical production
of O3 during the oxidation of trace gases emitted from biomass burning. Results also suggested a relatively high attenuation in
UV irradiance (~6% higher) from smoke particles than dust. We also found a relatively good agreement between the modeled (TUV)
and measured UV irradiance spectra for different atmospheric conditions. Our results highlight the factors affecting UV irradiance
in a tropical urban environment, south India. 相似文献
2.
比较分析了2017年南极中山站3种仪器测量地面太阳紫外B（UVB）波段和紫外A（UVA）波段的辐照度。以Brewer光谱仪测值为参考,国产宽波段FSUVB日射表在UVB（波段280~315 nm）的辐照度相对误差为（55±75）%,误差随大气臭氧总量的增加呈上升趋势,但在南极“臭氧洞”期间偏低。Yankee UVB宽波段日射表在UVB（波段280~320 nm）的辐照度相对误差为（-31±22）%;国产宽波段FSUVA日射表在UVA（波段315~400 nm）的辐照度相对误差为（23±5.9）%。太阳天顶角低于80°的晴天以Tropospheric Ultraviolet Visible（TUV）辐射模式计算结果为参考时,FSUVB,Yankee UVB和FSUVA辐照度的平均相对误差分别为（30±37）%,（-22±19）%和（27±6.4）%,而Brewer相对误差未超过3.5%。国产宽波段UV日射表测值偏高,反映出波长较长的杂散光对太阳辐照度测值影响明显。 相似文献
3.
卫星遥感地面紫外辐射的参数化方法 总被引：6，自引：2，他引：6
提出了一个从卫星观测推算地面UVB辐射通量密度和红斑生物紫外辐射剂量的新的参数化方法。该方法基于一个简单的模式:大气辐射传输介质被简化成三个等效层:臭氧单独构成的吸收层，空气分子、云和气溶胶粒子组成的散射层，以及地面反射层。地面紫外辐射通量密度和生物紫外辐射剂量可以由臭氧层的等效透过率、散射层和地面的联合反射率计算。臭氧层的等效透过率可由大气臭氧总量计算。散射层和地面的联合反射率可由不存在臭氧吸收的紫外或可见光通道的反射辐射强度测量得到。该反演算法形式简单，只包含很少几个可从卫星测量获得的参数。它通过了一个可靠而相对复杂的基于DISORT的紫外辐射传输模式的检验。在广泛的计算条件下，包括晴天、云天、以及混浊大气，用这个简单算法计算的地面紫外辐射通量密度和红斑生物紫外辐射剂量与精确算法的结果相差无几。另外，还实际运用这个算法利用卫星观测资料反演地面紫外辐射通量密度，与地面实际观测资料做了比较，符合较好。 相似文献
4.
晴空或少云状况下紫外辐射强度及指数预报模式 总被引：4，自引：0，他引：4
在大气辐射传输理论的基础上，利用中分辨率大气辐射传输系统，应用可测得的实际大气物理参数，建立睛空或少云天气状况下石家庄市紫外波段（280-400nm)辐射强度及指数预报模式，考虑了臭氧的两个吸收带。晴空条件下的散射主要考虑了分子和气溶胶的多次散射，少云时还考虑了云对紫外辐射的影响。其中多次散射的计算采用子离散坐标法。且对由于臭氧实时资料的短缺造成的误差进行了系统订正，并将订正结果与实况资料进行了对比。结果表明，由模式客观预报紫外辐射强度是可行的。 相似文献
5.
6.
Spectroradiometers using photodiode array detectors (PDAs) are increasingly applied for airborne and ground-based atmospheric measurements of spectral actinic flux densities due to their high time resolution (less than one second). However they have limited sensitivity of ultraviolet (UV) radiation for wavelengths less than about 305 nm. This results in uncertainties of ozone photolysis frequencies derived from spectral actinic flux density measurements using PDA spectrometers. To overcome this limitation a parameterization method is introduced which extrapolates the data towards the wavelength range of limited sensitivity of the PDA spectrometers (less than about 305 nm). The parameterization is based on radiative transfer simulations and is valid for measurements in the lower troposphere. The components of the suggested parameterization are the lower threshold wavelength of the PDA spectrometer, the slant ozone column (ratio of the total ozone column and the cosine of the solar zenith angle), and the ambient temperature. Tests of the parameterization with simulated actinic flux density spectra have revealed an uncertainty of the derived ozone photolysis frequency of ±5%. Field comparisons of the parameterization results with independent measurements of the ozone photolysis frequency were within ±10% for solar zenith angles less than 70^∘. Finally the parameterization was applied to airborne measurements to emphasize the advantage of high time resolution of PDA spectrometers to study ozone photolysis frequency fields in inhomogeneous cloud condtitions. 相似文献
7.
采用1979—2013年6—8月欧洲中期数值预报中心ERA-Interim逐月再分析资料和2004—2010年6—8月美国国家大气和海洋管理局太阳光谱辐照度资料,利用北京气候中心大气辐射模式,计算了北半球平流层夏季臭氧加热率(Ozone Heating Rate,OHR)和净加热率(Net Heating Rate,NHR),分析了太阳准11 a变化中太阳活动强年与弱年纬向平均OHR(NHR)的差异,并讨论了差异形成的原因。结果表明:太阳活动强年比弱年的紫外辐射明显要强,导致OHR、NHR整层增强,且随高度增加而增加;臭氧浓度在平流层下层较小,在平流层上层较大,该变化导致OHR、NHR有类似的变化型,且稍向高处偏移;OHR、NHR在平流层上层的变化,由紫外辐射和臭氧共同作用,其他地区均为臭氧起主要作用。 相似文献
8.
Francisco P. J. Valero Thomas P. Ackerman Warren J. Y. Gore 《Journal of Atmospheric Chemistry》1989,9(1-3):225-244
The interaction of the Aretic winter aerosol (Arctic haze) with solar radiation produces changes in the radiation field that result in the enhancement of scattering and absorption processes which alter the energy balance and solar energy distribution in the Arctic atmosphere-surface system. During the second Arctic Gas and Aerosols Sampling Project (AGASP II) field experiment, we measured radiation parameters using the NOAA WP-3D research aircraft as a platform. State-of-the-art instrumentation was used to measure in situ the absorption of solar radiation by the Arctic atmosphere during severe haze events. Simultaneously with the absorption measurements, we determined optical depths, and total, direct, and scattered radiation fields. All optical measurements were made at spectral bands centered at 412, 500, 675, and 778 nm and with a bandpass of 10 nm. With this selection of spectral regions we concentrated on the measurement of the radiative effects of the aerosol excluding most of the contributions by the gaseous components of the atmosphere. An additional measurement performed during these experiments was the determination of total solar spectrum fluxes. The experimentally determined parameters were used to define an aerosol model that was employed to deduce the absorption by the aerosols over the full solar spectrum and to calculate atmospheric heating rate profiles. The analyses summarized above allowed us to deduce the magnitude of the change in some important parameters. For example, we found changes in instantaneous heating rate of up to about 0.6 K/day. Besides the increased absorption (30 to 40%) and scattering of radiation by the atmosphere, the haze reduces the surface absorption of solar energy by 6 to 10% and the effective planetary albedo over ice surfaces by 3 to 6%. The vertical distribution of the absorbing aerosol is inferred from the flux measurements. Values for the specific absorption of carbon are found to be around 6 m2/g for externally mixed aerosol and about 11.7 m2/g for internally mixed aerosol. A complete study of the radiative effects of the Arctic haze should include infrared measurements and calculations as well as physics of the ice, snow, and water surfaces. 相似文献
9.
《大气科学进展》2017,34(7):805-815
Ultraviolet(UV) radiation has significant effects on ecosystems, environments, and human health, as well as atmospheric processes and climate change. Two ultraviolet radiation datasets are described in this paper. One contains hourly observations of UV radiation measured at 40 Chinese Ecosystem Research Network stations from 2005 to 2015. CUV3 broadband radiometers were used to observe the UV radiation, with an accuracy of 5%, which meets the World Meteorology Organization's measurement standards. The extremum method was used to control the quality of the measured datasets. The other dataset contains daily cumulative UV radiation estimates that were calculated using an all-sky estimation model combined with a hybrid model. The reconstructed daily UV radiation data span from 1961 to 2014. The mean absolute bias error and root-mean-square error are smaller than 30% at most stations, and most of the mean bias error values are negative, which indicates underestimation of the UV radiation intensity. These datasets can improve our basic knowledge of the spatial and temporal variations in UV radiation. Additionally, these datasets can be used in studies of potential ozone formation and atmospheric oxidation, as well as simulations of ecological processes. 相似文献
10.
为确定新疆博斯腾湖地区气溶胶主要组分,减小辐射传输计算和卫星遥感应用中由于气溶胶模型误判造成的误差,分别取大陆型、背景沙漠型、体积百分比自定义模型和两种动态气溶胶模型,用6S辐射传输算法计算出对应于太阳光度计测量时段的各波段大气气溶胶光学厚度。将模式计算值与测量值进行比较,确定测量地区的大气气溶胶模型。将该方法用于2010年在新疆博斯腾湖地区测量的太阳光度计数据,结果显示该地区在测量时段较为符合体积百分比自定义模型,沙尘性粒子体积百分比均在88%上,符合当地靠近沙尘源地和测量时段浮尘天气频发的实际情况。 相似文献
11.
利用Morlet小波变换方法分析了近56a来华东地区降水、气温变化以及ENSO的变化,结果表明,华东地区的降水、温度、海温(ΔSST)以及南方涛动指数(ΔSOI)的月距平序列中都存在多时间层次结构,并且各时间尺度周期分量的强度是不同的。同时又采用交叉小波变换方法,分别分析研究了ΔR、ΔT与ΔSST、ΔSOI相关关系,发现华东地区降水与ENSO在准2～4a周期变化上呈正相关关系,在年代际和8a以上年际间呈正负有规律交替且以正相关为主,而气温与ENSO存在多时间尺度特征。 相似文献
12.
以较为精确的大气辐射传输模式为基础,研制出晴天地表总辐射和净辐射瞬时值的计算方案。与以往的经验计算方法不同,该方案将辐射传输带模式的思路引入地面太阳辐射计算,并尽可能将大气中吸收和散射物质对太阳辐射的影响考虑进去,从而使该方法具有较好的精确性和普适性。在此基础上采用了Kokhanovsky等人提出的大气气溶胶反射率和透过率参数化方案,使得气溶胶对地面总辐射和净辐射的影响得到较好的处理。采用的自变量都是数值预报模式或卫星观测能提供的气象要素,因此该方案即可用于数值预报模式或陆面过程模式计算地表辐射平衡,又可以利用卫星观测或再分析资料估算地面太阳能资源分布。利用美国能源部三个大气辐射观测站点2005年全年的观测资料及欧洲宇航局提供的卫星反演气溶胶资料对计算方案进行了检验。结果表明,该方法十分精确,所有点的平均相对误差都小于6%,误差的均方差都小于0.3 W•m-2。 相似文献
13.
14.
Summary It is investigated how long-term UV trends can be assessed by analysing the longest time series of measured spectral UV irradiance in Europe, which have been started in the early 1990s in Thessaloniki, Greece and Sodankylä, Finland. It can be concluded that both time series do not yet show an unambiguous yearly trend in UV irradiance. The regression lines show no uniform behaviour and vary irregularly in strength and from one solar zenith angle to the next if all sky conditions are analysed. It is emphasised that these findings do not disagree with previous studies, that significant changes in UV irradiance have been observed over Europe especially in spring.Our study introduces a new method to estimate the required time series length for trend detection using the measured time series in combination with model calculations. At Sodankylä, a reduction of the total ozone column of –5.7% per decade has been observed from 1979 to 1998. A positive UV trend due to such conditions may be detected after 12 years at the earliest. For Thessalonki, a decrease in total ozone of –4.5% per decade has been observed. A corresponding increase of UV irradiance should be detectable after 15 years. It should be noted that a constant ozone trend over the whole period had to be assumed for this analysis.Since 1990 there has been a considerable variability of total ozone, but no steady decrease could be observed. Consequently, no general UV increase could be expected due to ozone changes. Even if there was a constant ozone trend over that period it is shown that even the longest European time series of UV irradiance are still too short to show distinct trends. However, this does not imply that no changes have occurred, it only shows that the large natural variability of UV irradiance has so far hindered the identification of unambiguous trends. The only way to find significant and consistent UV trends is the continuation of high-quality long-term measurements of spectral UV irradiance. 相似文献
15.
Dongchul Kim Christopher P. Loughner Melanie A. Wetzel Wendy S. Goliff William R. Stockwell 《Journal of Atmospheric Chemistry》2007,57(1):59-71
Photolysis rate parameters depend upon solar actinic flux and chemical species dependent quantum yields and cross sections.
Spectrally resolved measurements of actinic flux should be preferred over flux derived from models for the analysis of field
observations. Actinic flux can be difficult to derive from the irradiance measurements of flat-plate radiometers. It is also
difficult to estimate from models due to uncertainties in the ozone column, aerosol concentrations and distributions, cloud
cover, optical depth and surface albedo. A series of actinic flux measurements were performed at Storm Peak Laboratory (3,210 m
above sea level), Colorado, United States with spectroradiometers during the wintertime (January 07–10, 2004). The site is
relatively remote with a clean atmosphere and during the wintertime the ground is generally covered by fresh snow with a high
albedo. The actinic flux measurements were used to estimate the photolysis rate parameters of ozone, nitrogen dioxide and
formaldehyde. The measured actinic flux and the photolysis rate parameters derived from the flux were compared to calculations
using the Tropospheric Ultraviolet-Visible Model (TUV), version 4.2 (Madronich and Flocke, 1998). The TUV modeled actinic
flux, the measured flux and the photolysis rate parameters derived from them had similar temporal patterns. However there
were significant differences in their magnitude due to uncertainties in the data available to initialize the TUV model and
the calibration of the spectroradiometer. 相似文献
16.
The role of atmospheric ozone to protect the living organisms and vegetation from the harmful effects of ultraviolet irradiation is well known. Depletion of the ozone layer is a great threat to the human society. In this paper we have discussed the lethal effects of ozone depletion and have presented the ozone and UV-B scenarios from 1979 to 2005 at different Indian latitudes using satellite data. The erythemal UV irradiance data obtained from Nimbus-7 and Earth probe total ozone mapping spectrometer (TOMS) and the tropospheric and stratospheric ozone data obtained from the convective cloud differential (CCD) method have been used to study the variability of erythemal UV irradiance and the stratospheric and tropospheric column ozone, respectively, over a period from 1979 to 2005. The observed results along with the expected upper and lower tolerance limits for tropospheric and stratospheric ozone, respectively, for different Indian latitudes, which have been estimated statistically using monthly mean CCD ozone data from 1979 to 2005 have been discussed in detail. 相似文献
17.
Eugenia Paulescu Nicoleta Stefu Paul Gravila Remus Stefan Boata Nicolina Pop Marius Paulescu 《Theoretical and Applied Climatology》2012,109(3-4):323-332
In order to perform calculations of biologically effective irradiance, the usual procedure is to modulate the ground-measured spectral solar irradiance with a specific biological action function. The inconvenience is that only a few meteorological stations worldwide are equipped to measure the spectral solar irradiance in the ultraviolet range. This motivates the search for a numerical substitute, which constitutes the subject of this report. An innovative approach based on generalized mean is used to infer the effective atmospheric transmittance. Its illustration resulted in a new parametric model for computing the biological dose under clear sky. The action spectrum for the growth response of plants, as a carrier of biological effects, is encapsulated into the atmospheric transmittance, leading to the calculation of the effective irradiance by simple algebra. The overall results indicate that the new parametric model performs accurately enough to be routinely used in practice. The procedure is general; therefore, it is described in detail to guide potential users in developing similar models incorporating other biological action spectra as needed. For speed-intensive applications, an executable file intended to run on any PC, which computes the effective irradiance with the proposed model, is provided. 相似文献
18.
Sinnhuber B.-M. Müller R. Langer J. Bovensmann H. Eyring V. Klein U. Trentmann J. Burrows J. P. Künzi K. F. 《Journal of Atmospheric Chemistry》1999,34(3):281-290
In this study measurements of mid-stratospheric Arctic ozone are compared with model simulations. The measurements obtained at Spitsbergen (79°N, 12°E) by ground based millimeter-wave radiometry exhibit large day to day variabilities as well as periods with low ozone. To interpret these measurements, calculations were made using the new photochemical box-trajectory model BRAPHO, with air parcel trajectories calculated from analyzed wind fields. Using a relatively simple approach, the model reproduces the observed ozone variability well, including inter-annual variations. The explanation for the observed ozone behavior is that at these altitudes ozone is determined by what we call dynamically controlled photochemistry. This means that the photochemical evolution of the ozone volume mixing ratio is mainly controlled by the atmospheric dynamics, in particular the solar zenith angle the air parcel has experienced. 相似文献
19.
Summary The diffuse sky radiation component in the ultraviolet wavelengths is often at least 50% of the global irradiance under clear skies, and is the dominant component of ultraviolet global radiation under translucent overcast skies. The distribution of sky radiance was measured in a rural area and modeled for wavelength bands of ultraviolet-B (UVB, 280–320 nm) and ultraviolet-A (UVA, 320–400 nm). Sky radiance measurements were made during the summer of 1993 over a wide range of solar zenith angles using radiance sensors mounted on a hand-operated hemispherical rotation mount. UVB irradiance measurements were also made during each scan. Since the ratio of measured irradiance under overcast skies and that predicted for clear skies was not correlated with cloud base height, opaque cloud fraction, or solar zenith angle, it was concluded that the scattering from the clouds dominated the global irradiance, and this scattering was relatively unaffected by the scattering off opaque clouds in the translucent atmosphere.Analysis of the translucent overcast sky UVA and UVB radiance measurements using a semi-empirical distribution model showed that the spectral influences on multiple scattering, single scattering, and horizon brightening components of the distributions agreed with basic atmospheric radiation theory. The best model used solar zenith, the sky zenith, and the scattering angle with resultant coefficient of determination values of 0.62 and 0.25 for the UVA and UVB respectively. The developed equations can be applied directly to the diffuse sky irradiance on the horizontal to provide radiance distributions for the sky.With 6 Figures 相似文献
20.
Precipitable water measurements made coincident in time and space with direct broadband solar irradiance measurements are used in conjunction with an atmospheric transmission model to derive a parameter whose major dependence is on total aerosol extinction. Irradiance measurements are used to calculate an atmospheric transmission factor (ATF) that is independent of the instrument calibration and the extraterrestrial solar constant. The dependency of the ATF on precipitable water is determined using LOWTRAN5, an atmospheric transmission model with high spectral resolution. Precipitable water measurements are then used to adjust the measured ATF to correspond to an ATF value obtained for a constant precipitable water amount. The remaining variability in the adjusted ATF is due mostly to aerosol extinction. The technique is applied to a 6-year period (1978–1983) for clear-sky mornings at Mauna Loa, Hawaii (MLO). MLO ATF aerosol residuals are compared with independently measured monochromatic aerosol optical depth. Results show that the ATF aerosol residual is nearly equal to the 500 nm aerosol optical depth prior to the eruption of E1 Chichon, at which time a nonlinear time-dependent relationship between the two quantities is evident. ATF aerosol residuals reflect the spectrally integrated aerosol influence on transmission and, therefore, could indicate better than monochromatic optical depth the radiation balance perturbations due to aerosols. The 6-year precipitable water record for MLO, determined from a dual-channel sunphotometer, has a mean value of 0.3 cm. An annual cycle in precipitable water is evident, as is a 4-month 5-standard-deviation drought from December 1982 through March 1983. 相似文献