An overview of and issues with sky radiometer technology and SKYNET
An overview of and issues with sky radiometer technology and SKYNET
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DOI：
10.5194/amt-13-4195-2020
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发表时间：
2020-08
影响因子：
3.8
通讯作者：
T. Nakajima;M. Campanelli;H. Che;V. Estellés;H. Irie;Sang-Woo Kim;Jhoon Kim;Dong Liu;T. Nishizawa;G. Pandithurai;V. Soni;B. Thana;Nas-Urt Tugjsurn;Kazuma Aoki;S. Go;M. Hashimoto;A. Higurashi;S. Kazadzis;P. Khatri;N. Kouremeti;R. Kudo;F. Marenco;M. Momoi;Shantikumar S. Ningombam;C. Ryder;A. Uchiyama;A. Yamazaki
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文献类型：
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作者：
T. Nakajima;M. Campanelli;H. Che;V. Estellés;H. Irie;Sang-Woo Kim;Jhoon Kim;Dong Liu;T. Nishizawa;G. Pandithurai;V. Soni;B. Thana;Nas-Urt Tugjsurn;Kazuma Aoki;S. Go;M. Hashimoto;A. Higurashi;S. Kazadzis;P. Khatri;N. Kouremeti;R. Kudo;F. Marenco;M. Momoi;Shantikumar S. Ningombam;C. Ryder;A. Uchiyama;A. Yamazaki
抽象的。本文综述了天空辐射计技术的进展和天空网络（SKYNET）的发展。它被发现，该技术已经产生了有用的现场校准方法，检索算法，并从天空辐射计观测的气溶胶，云，水汽和臭氧的数据分析。提出了一个用改进的兰利（IL）方法估算天空辐射计定标常数F0精度的公式，发现它是观测到的F0月平均不确定度的一个很好的近似值，在东京和罗马站点约为0.5%~ 2.4%，在山的站点约为0.3%~ 0.5%。萨拉斯瓦蒂和达沃斯。一个新的交叉IL（XIL）的方法也被开发出来，以纠正低估的IL方法的情况下，与大的气溶胶反演误差。气溶胶光学厚度（AOT）与其他网络比较的均方根差（RMSD）在λ≥500 nm时小于0.02，在城市地区较短波长时约为0.03，在山区比较时小于0.01。单次散射（SSA）和尺寸分布反演的准确性受到测量误差传播的影响，太阳直接辐射和散射天空辐射的校准，地面散射，云屏蔽，以及称为Skyrad包的分析软件版本。SKYNET的SSA值比AERONET的SSA值大0.07，主要误差来源被确定为低估了固体视角（SVA）和云污染。这些已知误差因子的校正将SSA差异减小到小于0.03。还审查了天空辐射计对其他大气成分的反演。可降水量的反演精度约为0.2 cm，臭氧量的反演精度约为13 DU（多布森单位）。反演的云光学特性仍然显示出与验证数据有很大的偏差，这表明需要研究差异的原因。重要的是，这些最新的研究改进本文件中介绍到现有的业务系统和未来的系统的国际天网数据中心。
Abstract. This paper is an overview of the progress in sky radiometer technology and the development of the network called SKYNET. It is found that the technology has produced useful on-site calibration methods, retrieval algorithms, and data analyses from sky radiometer observations of aerosol, cloud, water vapor, and ozone. A formula was proposed for estimating the accuracy of the sky radiometer calibration constant F0 using the improved Langley (IL) method, which was found to be a good approximation to observed monthly mean uncertainty in F0, around 0.5 % to 2.4 % at the Tokyo and Rome sites and smaller values of around 0.3 % to 0.5 % at the mountain sites at Mt. Saraswati and Davos. A new cross IL (XIL) method was also developed to correct an underestimation by the IL method in cases with large aerosol retrieval errors. The root-mean-square difference (RMSD) in aerosol optical thickness (AOT) comparisons with other networks took values of less than 0.02 for λ≥500 nm and a larger value of about 0.03 for shorter wavelengths in city areas and smaller values of less than 0.01 in mountain comparisons. Accuracies of single-scattering albedo (SSA) and size distribution retrievals are affected by the propagation of errors in measurement, calibrations for direct solar and diffuse sky radiation, ground albedo, cloud screening, and the version of the analysis software called the Skyrad pack. SSA values from SKYNET were up to 0.07 larger than those from AERONET, and the major error sources were identified as an underestimation of solid viewing angle (SVA) and cloud contamination. Correction of these known error factors reduced the SSA difference to less than 0.03. Retrievals of other atmospheric constituents by the sky radiometer were also reviewed. Retrieval accuracies were found to be about 0.2 cm for precipitable water vapor amount and 13 DU (Dobson Unit) for column ozone amount. Retrieved cloud optical properties still showed large deviations from validation data, suggesting a need to study the causes of the differences. It is important that these recent studies on improvements presented in the present paper are introduced into the existing operational systems and future systems of the International SKYNET Data Center.