Abstract Pyrheliometer calibration must be done following strict procedures in order to ensure the required robustness and accuracy. These procedures are described in the ISO 9059:1990 and ASTM E 816 – 15 international standards. However, their application requires information that may not always be available or may be subjective, inaccurate or incomplete, as for example, the determination of “percent of cloud coverage” or “the existence of clouds 15° around the Sun”. The irradiance measurements made by the reference and test instruments involved should also be collected over wide periods after, close to and before solar noon, which might not always be the case depending on the weather conditions during calibration. When those data are not available, the standard cannot be applied properly, and the experts have to decide which data can be used for the calibration. In this study, the abovementioned two main standards for pyrheliometer calibration were thoroughly reviewed, and a harmonized protocol is proposed that uses only the main data recorded. Nineteen field pyrheliometers were calibrated to verify the proposed procedure, and the results show its robustness. After calibration, we analyzed the variability in the calibration constant and the influence of some experimental conditions on the calibration results. As in previous references, the results show that variations in solar elevation and wind speed during the day still influenced the calibration constants of most of the test devices. On the contrary, neither the angle between the wind direction and the solar azimuth nor Linke turbidity seemed to influence the calibration constants calculated. The influence of the Linke turbidity is low as the viewing geometry of all involved pyrheliometers is very similar to each other and as low turbidity prevailed. The correlation between the solar elevation and the wind speed was analyzed and calibration constants were found to vary linearly with solar elevation and wind speed, respectively. Pyrheliometer calibration measurement testing was carried out in Summer 2014 at the Plataforma Solar de Almeria (PSA) in the context of the Solar Facilities for the European Research Area 2 Project (SFERA2).

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气象条件对直接日射表校准影响的评估

摘要 太阳辐射计校准必须按照严格的程序进行，以确保所需的鲁棒性和准确性。ISO 9059:1990 和 ASTM E 816 – 15 国际标准中描述了这些程序。然而，它们的应用需要的信息可能并不总是可用或可能是主观的、不准确或不完整的，例如，确定“云覆盖百分比”或“围绕太阳 15° 的云的存在”。所涉及的参考和测试仪器进行的辐照度测量也应该在太阳正午之后、接近和之前的很长一段时间内收集，这可能并非总是如此，这取决于校准期间的天气条件。当这些数据不可用时，标准就不能正确应用，专家必须决定哪些数据可用于校准。在本研究中，对上述两个主要的直接辐射表校准标准进行了彻底审查，并提出了仅使用记录的主要数据的协调协议。校准了 19 个现场直接辐射表以验证所提出的程序，结果表明其稳健性。校准后，我们​​分析了校准常数的可变性以及一些实验条件对校准结果的影响。与之前的参考文献一样，结果表明白天太阳高度和风速的变化仍然影响大多数测试设备的校准常数。相反，风向和太阳方位角之间的角度和林克浊度似乎都不会影响计算的校准常数。Linke 浊度的影响很小，因为所有涉及的直接日射表的观察几何形状彼此非常相似，并且低浊度占主导地位。分析了太阳高度和风速之间的相关性，发现校准常数分别随太阳高度和风速呈线性变化。太阳辐射计校准测量测试于 2014 年夏季在 Plataforma Solar de Almeria (PSA) 的欧洲研究区 2 项目 (SFERA2) 的太阳能设施范围内进行。Linke 浊度的影响很小，因为所有涉及的直接日射表的观察几何形状彼此非常相似，并且低浊度占主导地位。分析了太阳高度和风速之间的相关性，发现校准常数分别随太阳高度和风速呈线性变化。太阳辐射计校准测量测试于 2014 年夏季在 Plataforma Solar de Almeria (PSA) 的欧洲研究区 2 项目 (SFERA2) 的太阳能设施范围内进行。Linke 浊度的影响很小，因为所有涉及的直接日射表的观察几何形状彼此非常相似，并且低浊度占主导地位。分析了太阳高度和风速之间的相关性，发现校准常数分别随太阳高度和风速呈线性变化。太阳辐射计校准测量测试于 2014 年夏季在 Plataforma Solar de Almeria (PSA) 的欧洲研究区 2 项目 (SFERA2) 的太阳能设施范围内进行。