NSF UV SPECTRORADIOMETER NETWORK 2009-2010 OPERATIONS REPORT
7.7. Summit, Greenland
The instrument at Summit was installed in August 2004. UV measurements from the years 2004-2010 are
compared in the following.
Figure 7.7.1 shows total ozone measured by satellites between 1991 and 2010. Total ozone in February and
early March of 2010 was substantially above the long-term average while ozone values measured during
other times of 2009 and 2010 were generally varying about the long-term average. However, there were
several short periods in 2009 and 2010 when total ozone was well below the average. Most notable is the
period of 19-22 August 2010 when total ozone was about 60 DU below the mean.
Figure 7.7.2 shows UV irradiance integrated over the wavelength range of 298.51 - 303.03 nm. UV levels
depend strongly on the height of the Sun above the horizon. There is a spike in UV intensities on 20
August, which is coinciding with the period of low ozone. Variability is considerably larger in spring than
fall due to the higher ozone variations earlier in the year. The low ozone values of February and March
2010 occurred during a time when the solar elevation was smaller than 15°. For these elevation angles, UV
irradiances in the 298.51 - 303.03 nm interval are very small and the effect of the low ozone values is
therefore not obvious in Figure 7.7.2.
Figure 7.7.3 and Figure 7.7.4 show the daily maximum UV Index and the DNA-weighted daily dose,
respectively. Variability is smaller compared to the short-wavelength integral depicted in Figure 7.7.2 due
to the smaller ozone-sensitivity of those quantities.
Figure 7.7.5 shows measurements in the 337.5-342.5 nm band, integrated over 24 hours. This band is not
affected by the atmospheric ozone content. Data show remarkable little day-to-day variation and change
from one year to the next. On one hand, this is a confirmation of the consistency of calibrations applied
during the four years of operation. On the other hand, the low level of variability is also a consequence of
constant, high surface albedo at Summit, which mitigates attenuation of UV radiation by clouds.
600
Summit: Total Column Ozone
550
Total Column Ozone (DU)
1991-2007
500
Average 1991-2007
2008
450
2009
2010
400
350
300
250
200
1-Jan
20-Feb
10-Apr
30-May
19-Jul
7-Sep
27-Oct
16-Dec
Date
Figure 7.7.1. Total column ozone at Summit. Data were provided by TOMS/Nimbus7 (1991-1993),
TOMS/Earth Probe (1996-2004) and OMI (2005-2010).
PAGE 7-28
BIOSPHERICAL INSTRUMENTS INC.
CHAPTER 7: EXAMPLES OF NETWORK DATA
Integrated Spectral Irradiance (μW/cm²)
3.5
Summit: 298.507 - 303.03 nm Integrated Spectral Irradiance
3
2004
2005
2006
2007
2008
2009
2010
2.5
2
1.5
1
0.5
0
1-Jan
20-Feb
10-Apr
30-May
19-Jul
7-Sep
27-Oct
16-Dec
Date
Figure 7.7.2. Noon-time integrated spectral UV irradiance (298.51 - 303.03 nm) at Summit of the years
2004-2010.
8
Daily Maximum UV
2004
2005
2006
2007
2008
2009
2010
7
Noon-time UV Index
6
5
4
3
2
1
0
1-Jan
20-Feb
10-Apr
30-May
19-Jul
7-Sep
27-Oct
16-Dec
Date
Figure 7.7.3. Daily maximum UV Index at Summit of the years 2004-2010.
BIOSPHERICAL INSTRUMENTS INC.
PAGE 7-29
NSF UV SPECTRORADIOMETER NETWORK 2009-2010 OPERATIONS REPORT
0.07
DNA-Weighted Daily Dose (kJ/m²)
Summit: DNA-Weighted Daily Dose
0.06
0.05
2004
2005
2006
2007
2008
2009
2010
0.04
0.03
0.02
0.01
0
1-Jan
20-Feb
10-Apr
30-May
19-Jul
7-Sep
27-Oct
16-Dec
Date
Figure 7.7.4. DNA-weighted daily dose at Summit of the years 2004-2010.
Daily Integrated Irradiation (kJ/m²)
160
Summit: 337.5 - 342.5 nm Integrated Irradiation
140
2004
2005
2006
2007
2008
2009
2010
120
100
80
60
40
20
0
1-Jan
20-Feb
10-Apr
30-May
19-Jul
7-Sep
27-Oct
16-Dec
Date
Figure 7.7.5. Daily irradiation of the 337.5-342.5 nm band for Summit using data of the years 2004-2010.
PAGE 7-30
BIOSPHERICAL INSTRUMENTS INC.