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Global irradiance calibration of multifilter UV radiometers
Author(s) -
Piedehierro A. A.,
Cancillo M. L.,
Serrano A.,
Antón M.,
Vilaplana J. M.
Publication year - 2016
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2015jd023935
Subject(s) - irradiance , radiometer , zenith , calibration , solar zenith angle , remote sensing , environmental science , ozone layer , solar irradiance , ultraviolet , instrumentation (computer programming) , sunlight , radiation , ozone , meteorology , optics , computer science , physics , geography , mathematics , statistics , operating system
It is well known that the amount of ultraviolet solar radiation (UV) reaching the Earth's surface is governed by stratospheric ozone, which has exhibited notable variations since the late 1970s. A thorough monitoring of UV radiation requires long‐term series of accurate measurements worldwide, and to keep track of its evolution, it is essential to use high‐quality instrumentation with an excellent long‐term performance capable of detecting low UV signal. There are several UV monitoring networks worldwide based on multifilter UV radiometers; however, there is no general agreement about the most suitable methodology for the global irradiance calibration of these instruments. This paper aims to compare several calibration methods and to analyze their behavior for different ranges of solar zenith angle (SZA). Four methods are studied: the two currently most frequently used methods referred to in the literature and two new methods that reduce systematic errors in calibrated data at large solar zenith angles. The results evidence that proposed new methods show a clear improvement compared to the classic approaches at high SZA, especially for channels 305 and 320 nm. These two channels are of great interest for calculating the total ozone column and other products such as dose rates of biological interest in the UV range (e.g., the erythemal dose).