TY  - JOUR
AU  - Bohn, B.
AU  - Corlett, G.K.
AU  - Gillmann, M.
AU  - Sanghavi, S.
AU  - Stange, G.
AU  - Tensing, E.
AU  - Vrekoussis, M.
AU  - Bloss, W. J.
AU  - Clapp, L.J.
AU  - Kortner, M.
AU  - Dorn, H.-P.
AU  - Monks, P. S.
AU  - Platt, U.
AU  - Plass-Dülmer, C.
AU  - Mihalopoulos, N.
AU  - Heard, D. E.
AU  - Clemitshaw, K. C.
AU  - Meixner, F. X.
AU  - Prevot, A. S. H.
AU  - Schmitt, R.
TI  - Photolysis frequency measurement techniques: results of a comparison within the ACCENT project
JO  - Atmospheric chemistry and physics
VL  - 8
SN  - 1680-7316
CY  - Katlenburg-Lindau
PB  - EGU
M1  - PreJuSER-1445
SP  - 5373 - 5391
PY  - 2008
N1  - Record converted from VDB: 12.11.2012
AB  - An intercomparison of different radiometric techniques measuring atmospheric photolysis frequencies j(NO2), j(HCHO) and j((OD)-D-1) was carried out in a two-week field campaign in June 2005 at Julich. Germany. Three double-monochromator based spectroradiometers (DM-SR), three single-monochromator based spectroradiometers with diode-array detectors (SM-SR) and seventeen filter radiometers (FR) (ten j(NO2))-FR, seven j((OD)-D-1)-FR) took part in this comparison. For j(NO2), all spectroradiometer results agreed within +/- 3%. For j(HCHO), agreement was slightly poorer between -8% and +4% of the DM-SR reference result. For the SM-SR deviations were explained by poorer spectral resolutions and lower accuracies caused by decreased sensitivities of the photodiode arrays in a wave-length range below 350 nm. For j((OD)-D-1), the results were more complex within +8% and -4% with increasing deviations towards larger solar zenith angles for the SM-SR. The direction and the magnitude of the deviations were dependent on the technique of background determination. All j(NO2))-FR showed good linearity with sing-le calibration factors being sufficient to convert from output voltages to j(NO2)). Measurements were feasible until sunset and comparison with previous calibrations showed good long-term stability. For the j((OD)-D-1)-FR, conversion from output voltages to j((OD)-D-1) needed calibration factors and correction functions considering the influences of total ozone column and elevation of the sun. All instruments showed good linearity at photolysis frequencies exceeding about 10% of maximum values. At larger solar zenith angles, the agreement was non-uniform with deviations explainable by insufficient correction functions. Comparison with previous calibrations for sonic J((OD)-D-1)-FR indicated drifts of calibration factors.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000259221400020
DO  - DOI:10.5194/acp-8-5373-2008
UR  - https://juser.fz-juelich.de/record/1445
ER  -