SOLSTICE I and II: Calibrations and Comparisons
Marty Snow, Bill McClintock, Tom Woods, and Gary Rottman
Laboratory for Atmospheric and Space Physics
Sampling of FUV time series showing SUSIM, SOLSTICE
I and SOLSTICE II. Agreement is sometimes good,
sometimes bad, and sometimes just plain ugly. Further
analysis is required to make a single consistent dataset.
0.8
200
250
300
UARS SOLSTICE G Channel Degradation (153.486 nm)
0.90
0.85
0.80
1000
2000
UARS Day (Exposure Time)
3000
3
2
1
100
0.75 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
0
4
4000
Data from UARS SOLSTICE currently availble:
FUV– full mission with occasional gaps
MUV– up to end of 1999.
150
200
250
Wavelength (nm)
300
350
2003/067 Ratio of SOLSTICEs in FUV
1.2
Known Calibration Difference
UARS SOLSTICE
SUSIM
130
140
150
Wavelength
160
UARS FUV
SORCE FUV
3.5•10-5
Oct
1995
Jul
1998
Solar Irradiance at 182.500
2.50•10-3
Mar
2001
Dec
2003
2.45•10-3
2.40•10-3
|----- ESR Calibration ---->
1.1
1.0
0.8
180
Jan
1993
Oct
1995
Jul
1998
Mar
2001
Dec
2003
1.2
1.1
1.0
0.9
Jan
1993
Oct
1995
Jul
1998
Mar
2001
Dec
2003
Solar Irradiance at 151.500
± 5%
UARS v19
SORCE
SUSIM
Oct
1995
Jul
1998
Mar
2001
Dec
2003
Irradiance Ratio at 151.500 nm
1.2
1.1
1.0
0.9
Jan
1993
Oct
1995
2.2•10
Jul
1998
Mar
2001
Dec
2003
Solar Irradiance at 155.500
± 5%
SORCE
SOLSTICE
tracks
SUSIM,
UARS
SOLSTICE
does not.
-4
2.0•10-4
UARS v19
SORCE
SUSIM
1.8•10-4
1.6•10-4
1.4•10-4
Jan
1993
Oct
1995
Jul
1998
Mar
2001
Dec
2003
Irradiance Ratio at 155.500 nm
1.2
1.1
1.0
0.9
Jan
1993
Oct
1995
1.20•10
2.30•10-3
UARS MUV
SORCE MUV
Dec
2003
Jul
1998
Mar
2001
Dec
2003
Solar Irradiance at 176.500
± 5%
1.25•10-3
200
220
240
260
280
UARS v19
SORCE
SUSIM
-3
1.15•10-3
1.10•10-3
SIM
UARS SOLSTICE (1992)
SUSIM
NOAA 16 SBUV
2.15•10-3
Mar
2001
1.30•10-3
0.9
2.20•10-3
Jul
1998
Irradiance Ratio at 145.500 nm
1.40•10-3
1.35•10-3
2.35•10-3
2.25•10-3
Oct
1995
SUSIM/SOLSTICE (normalized)
Ratio to SORCE SOLSTICE on 2003/067
1.2
Jan
1993
Jan
1993
2.6•10-4
2.4•10-4
Comparison to UARS SOLSTICE and SUSIM. Curve with
asterisks represents differences between the instruments from
1992 (see figure at top left).
4.0•10-5
5.0•10-5
170
5.0•10-5
4.5•10
UARS v19
SORCE
SUSIM
5.5•10-5
Jan
1993
0.9
0.8
120
-5
6.0•10-5
1.0
Solar Irradiance at 135.500
5.5•10-5
6.5•10
-5
1.20•10-4
1.15•10-4
1.10•10-4
1.05•10-4
1.00•10-4
9.50•10-5
9.00•10-5
8.50•10-5
1.1
X/SORCE SOLSTICE
Normalized Flux
0.95
5
UARS SOLSTICE
degradation tracking
includes one-day hits, loss
of tape recorder, and finally
loss of star trackers.
alf_cma (1.00)
alf_cru (3.30)
alf_lyr (0.36)
alf_pav (0.62)
bet_cen (2.97)
eta_uma (0.58)
tau_sco (0.72)
Extrapolated ()
1.00
Preflight uncertainty in solar
irradiance for SORCE
SOLSTICE. See McClintock,
Snow, and Woods (2005).
6
UARS/SORCE
150
7
Both SOLSTICES
consistent relative
to SUSIM.
± 5%
7.0•10-5
Jan
1993
300
Comparison to other current MUV irradiance datasets. Agreement
between SIM and UARS SOLSTICE is artificial below 250 nm.
Disagreement between SORCE and UARS SOLSTICEs is larger
than uncertainty shown in top plot of this panel.
SUSIM/SOLSTICE (normalized)
1.0
Solar Irradiance at 145.500
7.5•10-5
Combined Uncertainty in Solar Irradiance
SUSIM/SOLSTICE (normalized)
X/Avg
1.2
Initial validation of UARS
SOLSTICE and SUSIM.
Ratio of each instrument to
mean of all measurements
on that day. Updated to use
current data versions.
Woods et al. (1996)
SUSIM/SOLSTICE (normalized)
SOLSTICE V19
SUSIM V22
SOLSTICE V18
Percent Uncertainty
Ratio to Average on March 29, 1992 (ATLAS1)
1.4
Oct
1995
Jul
1998
Mar
2001
Dec
2003
Irradiance Ratio at 176.500 nm
1.2
1.1
1.0
0.9
Jan
1993
Oct
1995
Jul
1998
Mar
2001
Dec
2003
SORCE SOLSTICE tracks SUSIM, UARS SOLSTICE
matches SORCE SOLSTICE, but irradiance doesn’t
match previous solar cycle minimum.