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首页> 外文会议>International symposium on the measurement of toxic and related air pollutants >Surface Levels of Ultraviolet-B Under Variable Conditions of Tropospheric Air Quality and Cloudiness: Recent Results
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Surface Levels of Ultraviolet-B Under Variable Conditions of Tropospheric Air Quality and Cloudiness: Recent Results

机译：紫外线-B的表面水平在对流层空气质量和浑浊的可变条件下：最近的结果

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The impact of cloud cover and tropospheric aerosols on surface levels of UV-B irradiance are investigated using field measurements at two sites in western North Carolina: Mt. Mitchell (2038 m msl) State Park and Black Mountain (951 m msl). The sites are similarly equipped with broadband and spectral radiation-sensing and aerosol sampling instruments. The aerosol scattering coefficient at 530 nm, the aerosol optical depth and diffuse-direct irradiance ratio at 500 nm was found to vary with air mass type (polluted, marine, and continental). Surface measurements of total and diffuse UV irradiance at 7 narrowband wavelength channels of the Ultraviolet Multi-Filter Rotating Shadowband Radiometer (UVMFR) are used to determine the total column ozone and aerosol optical depth. The retrieved total column ozone displayed consistent agreement with the Total Ozone Mapping Spectrometer (TOMS) measurements. Aerosol optical depth at 317, 325, 332, and 368 nm was derived for a six-month period of 1999. The seasonal pattern is influenced by the persistent summertime haze that occurs in the region. The relative strengths of ozone, Rayleigh scattering and aerosol optical depths are found to vary with wavelength. Ozone absorption is the dominant component shaping the total optical depths at shorter wavelength, accounting for nearly 70% of the optical depth at 300 nm, whereas aerosol and Rayleigh attenuation are the main contributors at longer wavelengths. The aerosol optical parameters (single scatter albedo, asymmetry parameter and complex index of refraction) in the UV region retrieved by an iterative modeling procedure applied to the broadband and spectral UV-B measurements indicate that substantial attenuation by aerosol absorption can occur, larger than those typically included in UV modeling studies. The retrieved aerosol optical parameters are used as input in a radiative transfer model to investigate the effect of their realistic values on the calculation of the UV Index (UVI) forecasted by the National Weather Service. The percentage change in calculated surface erythemallyweighted UV (as compared to calculated using the standard UVI aerosol inputs) can range from a 4% increase to a nearly 50% decrease, dependent upon the aerosol optical depth and amount of absorption by aerosols. Based on our measurements, it was found that during the summertime the UV Index can deviate by up to -5 index units from the forecast if the standard aerosol inputs are used.
机译：在北卡罗来纳州西北部的两个地点，使用现场测量来研究云覆盖和对流层气溶胶对表面水平的影响：Mitchell（2038 M MSL）州立公园和黑山（951毫米MSL）。该网站类似地配备宽带和光谱辐射传感和气溶胶采样仪器。发现530nm处的气溶胶散射系数，500nm处的气溶胶光学深度和漫射直接辐照度比，与空气质量型（污染，海洋和欧式）不同。在7个窄带波长通道（UVMFR）的7个窄带波长通道中的总和散射辐照度的表面测量用于确定总列臭氧和气溶胶光学深度。检索到的总列臭氧与总臭氧映射光谱仪（TOMS）测量结果一致。在317,325,332和368nm处获得了气溶胶光学深度，六个月为1999年。季节性模式受到该地区发生的持久夏季雾度的影响。发现臭氧，瑞利散射和气溶胶光学深度的相对强度随波长而变化。臭氧吸收是在较短波长下形成总光学深度的主光学深度，占300nm的光学深度的近70％，而气溶胶和瑞利衰减是更长波长的主要贡献者。通过施加到宽带和光谱UV-B测量的迭代建模过程检出的UV区域的气溶胶光学参数（单散散玻璃，不对称参数和复杂折射率）表明可以发生气溶胶吸收的大量衰减，大于那些通常包括在UV建模研究中。气溶胶光学参数检索被用作输入的辐射传输模型来研究它们的实际值的上由国家气象局预测紫外线指数（UVI）的计算的影响。计算表面红斑紫外线（与使用标准UVI气溶胶输入计算相比）的百分比变化可以从4％的增加到近50％的减少，取决于气溶胶光学深度和气溶胶的吸收量。基于我们的测量，发现在夏季期间，如果使用标准气溶胶输入，UV索引可以从预测中偏离-5个指标单元。

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