Johnson B Carol, Litorja Maritoni, Fowler Joel B, Shirley Eric L, Barnes Robert A, Butler James J
Appl Opt. 2013 Nov 20;52(33):7963-80. doi: 10.1364/AO.52.007963.
Exo-atmospheric solar irradiance measurements made by the solar irradiance community since 1978 have incorporated limiting apertures with diameters measured by a number of metrology laboratories using a variety of techniques. Knowledge of the aperture area is a critical component in the conversion of radiant flux measurements to solar irradiance. A National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) sponsored international comparison of aperture area measurements of limiting apertures provided by solar irradiance researchers was performed, the effort being executed by the National Institute of Standards and Technology (NIST) in coordination with the EOS Project Science Office. Apertures that had institutional heritage with historical solar irradiance measurements were measured using the absolute aperture measurement facility at NIST. The measurement technique employed noncontact video microscopy using high-accuracy translation stages. We have quantified the differences between the participating institutions' aperture area measurements and find no evidence to support the hypothesis that preflight aperture area measurements were the root cause of discrepancies in long-term total solar irradiance satellite measurements. Another result is the assessment of uncertainties assigned to methods used by participants. We find that uncertainties assigned to a participant's values may be underestimated.
自1978年以来，太阳辐照度领域进行的大气层外太阳辐照度测量采用了有限孔径，这些孔径的直径由多个计量实验室使用各种技术进行测量。孔径面积的知识是将辐射通量测量转换为太阳辐照度的关键组成部分。美国国家航空航天局（NASA）的地球观测系统（EOS）发起了一项国际比对，对太阳辐照度研究人员提供的有限孔径的孔径面积测量进行比对，这项工作由美国国家标准与技术研究院（NIST）与EOS项目科学办公室协调执行。对具有历史太阳辐照度测量机构传承的孔径，使用NIST的绝对孔径测量设施进行测量。测量技术采用了使用高精度平移台的非接触式视频显微镜。我们已经量化了参与机构的孔径面积测量之间的差异，并且没有发现证据支持这样的假设，即飞行前孔径面积测量是长期太阳总辐照度卫星测量差异的根本原因。另一个结果是对参与者使用的方法所分配的不确定度进行了评估。我们发现，分配给参与者测量值的不确定度可能被低估了。
