期刊
METROLOGIA
卷 37, 期 5, 页码 419-422出版社
BUREAU INT POIDS MESURES
DOI: 10.1088/0026-1394/37/5/16
关键词
-
Atmospheric optical depths are determined by relating ground-based measurements of direct solar radiation to the extraterrestrial value, I-0, that a filter radiometer would read outside the atmosphere. Usually I-0 is determined by the Langley extrapolation technique from a high-altitude site, where clear and highly stable atmospheric conditions may be found. Alternatively, I-0 can be measured in situ from a stratospheric balloon experiment. We have employed both methods and found agreement to better than 1%. Filter radiometers tend to change over time, especially when used operationally outdoors. Absolute calibrations in the laboratory are used to monitor the radiometric stability of filter radiometers at the Physikalisch-Meteorologisches Observatorium Davos (PMOD/WRC, Switzerland). A spectral calibration facility based on a calibrated trap detector from the Physikalisch-Technische Bundesanstalt (PTB, Germany) is used to relate the filter radiometer to an accurate and long-term traceable standard. An FEL-lamp-based standard, previously used for several years, was compared with the new trap standard via a filter radiometer at four wavelengths between 368 nm and 862 nm and revealed a systematic difference of the order of 5%. The link between radiometric and I-0 calibration is the value of the extraterrestrial solar spectrum at the filter radiometer wavelengths which can be determined from these two calibrations and compared with published values.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据