Open AccessValidation of daily erythemal doses from Ozone Monitoring Instrument with ground‐based UV measurement data
Author(s) -
Tanskanen Aapo,
Lindfors Anders,
Määttä Anu,
Krotkov Nickolay,
Herman Jay,
Kaurola Jussi,
Koskela Tapani,
Lakkala Kaisa,
Fioletov Vitali,
Bernhard Germar,
McKenzie Richard,
Kondo Yutaka,
O'Neill Michael,
Slaper Harry,
den Outer Peter,
Bais Alkiviadis F.,
Tamminen Johanna
Publication year - 2007
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2007jd008830
Subject(s) - ozone monitoring instrument , irradiance , environmental science , nadir , total ozone mapping spectrometer , satellite , atmospheric sciences , remote sensing , cloud cover , trace gas , meteorology , ozone , on board , ultraviolet , latitude , physics , optics , ozone layer , cloud computing , geology , astronomy , computer science , operating system
The Dutch‐Finnish Ozone Monitoring Instrument (OMI) on board the NASA EOS Aura spacecraft is a nadir viewing spectrometer that measures solar reflected and backscattered light in a selected range of the ultraviolet and visible spectrum. The instrument has a 2600 km wide viewing swath and it is capable of daily, global contiguous mapping. The Finnish Meteorological Institute and NASA Goddard Space Flight Center have developed a surface ultraviolet irradiance algorithm for OMI that produces noontime surface spectral UV irradiance estimates at four wavelengths, noontime erythemal dose rate (UV index), and the erythemal daily dose. The overpass erythemal daily doses derived from OMI data were compared with the daily doses calculated from the ground‐based spectral UV measurements from 18 reference instruments. Two alternative methods for the OMI UV algorithm cloud correction were compared: the plane‐parallel cloud model method and the method based on Lambertian equivalent reflectivity. The validation results for the two methods showed some differences, but the results do not imply that one method is categorically superior to the other. For flat, snow‐free regions with modest loadings of absorbing aerosols or trace gases, the OMI‐derived daily erythemal doses have a median overestimation of 0–10%, and some 60 to 80% of the doses are within ±20% from the ground reference. For sites significantly affected by absorbing aerosols or trace gases one expects, and observes, bigger positive bias up to 50%. For high‐latitude sites the satellite‐derived doses are occasionally up to 50% too small because of unrealistically small climatological surface albedo.