PERSONAL DE APOYO
DEFERRARI guillermo Alejandro
artículos
Título:
Quality Assurance of the solar UV Network in the Antarctic
Autor/es:
LAKKALA K; REDONDAS A; MEINANDER O; TORRES CARLOS; KOSKELA T; CUEVAS E; TAALAS P; DAHLBACK A; DEFERRARI GUILLERMO; OCHOA H
Revista:
JOURNAL OF GEOPHYSICAL RESEARCH
Referencias:
Año: 2005 p. 1 - 12
ISSN:
0148-0227
Resumen:
Measuring ultraviolet radiation in the Antarctic region, where weather conditions are
extremely challenging, is a demanding task. Proper quality control of the measurements
and quality assurance of the data, which are the basis of all scientific use of data, has to
be especially well planned and executed. In this paper we show the importance of
proper quality assurance and describe the methods used to successfully operate the
NILU-UV multichannel radiometers of the Antarctic network stations at Ushuaia, 54S,
and Marambio, 64S. According to our experience, even though multichannel instruments
are supposed to be rather stable as a function of time, severe drifts can occur in the
sensitivity of the channels under these harsh conditions. During 20002003 the biggest
drifts were 35%, both at Ushuaia and Marambio, with the sensitivity of the channels
dropping at different rates. Without proper corrections in the data, this would have
seriously affected the calculated UV dose rates. As part of the quality assurance of the
network a traveling reference NILU-UV, which was found to be stable, was used to
transfer the desired irradiance scale to the site NILU-UV data. Relative lamp tests were
used to monitor the stability of the instruments. Each site NILU-UV was scaled channel
by channel to the traveling reference by performing solar comparisons. The method of
scaling each channel separately was found to be successful, even though the differences
between the raw data of the site NILU-UV and the reference instruments were, before the
data correction, as much as 40%. After the correction, the mean ratios of erythemally
weighted UV dose rates measured during the solar comparisons in 20002003 between
the reference NILU-UV and the site NILU-UV were 1.007 ± 0.011 and 1.012 ± 0.012 for
Ushuaia and Marambio, respectively, when the solar zenith angle varied up to 80. These
results make possible the scientific use of NILU-UV data measured simultaneously at
quite different locations, e.g., the Antarctic and Arctic, and the method presented is also
practicable for other multichannel radiometer networks.S,
and Marambio, 64S. According to our experience, even though multichannel instruments
are supposed to be rather stable as a function of time, severe drifts can occur in the
sensitivity of the channels under these harsh conditions. During 20002003 the biggest
drifts were 35%, both at Ushuaia and Marambio, with the sensitivity of the channels
dropping at different rates. Without proper corrections in the data, this would have
seriously affected the calculated UV dose rates. As part of the quality assurance of the
network a traveling reference NILU-UV, which was found to be stable, was used to
transfer the desired irradiance scale to the site NILU-UV data. Relative lamp tests were
used to monitor the stability of the instruments. Each site NILU-UV was scaled channel
by channel to the traveling reference by performing solar comparisons. The method of
scaling each channel separately was found to be successful, even though the differences
between the raw data of the site NILU-UV and the reference instruments were, before the
data correction, as much as 40%. After the correction, the mean ratios of erythemally
weighted UV dose rates measured during the solar comparisons in 20002003 between
the reference NILU-UV and the site NILU-UV were 1.007 ± 0.011 and 1.012 ± 0.012 for
Ushuaia and Marambio, respectively, when the solar zenith angle varied up to 80. These
results make possible the scientific use of NILU-UV data measured simultaneously at
quite different locations, e.g., the Antarctic and Arctic, and the method presented is also
practicable for other multichannel radiometer networks.S. According to our experience, even though multichannel instruments
are supposed to be rather stable as a function of time, severe drifts can occur in the
sensitivity of the channels under these harsh conditions. During 20002003 the biggest
drifts were 35%, both at Ushuaia and Marambio, with the sensitivity of the channels
dropping at different rates. Without proper corrections in the data, this would have
seriously affected the calculated UV dose rates. As part of the quality assurance of the
network a traveling reference NILU-UV, which was found to be stable, was used to
transfer the desired irradiance scale to the site NILU-UV data. Relative lamp tests were
used to monitor the stability of the instruments. Each site NILU-UV was scaled channel
by channel to the traveling reference by performing solar comparisons. The method of
scaling each channel separately was found to be successful, even though the differences
between the raw data of the site NILU-UV and the reference instruments were, before the
data correction, as much as 40%. After the correction, the mean ratios of erythemally
weighted UV dose rates measured during the solar comparisons in 20002003 between
the reference NILU-UV and the site NILU-UV were 1.007 ± 0.011 and 1.012 ± 0.012 for
Ushuaia and Marambio, respectively, when the solar zenith angle varied up to 80. These
results make possible the scientific use of NILU-UV data measured simultaneously at
quite different locations, e.g., the Antarctic and Arctic, and the method presented is also
practicable for other multichannel radiometer networks.. These
results make possible the scientific use of NILU-UV data measured simultaneously at
quite different locations, e.g., the Antarctic and Arctic, and the method presented is also
practicable for other multichannel radiometer networks.