Projection of SORCE Total Solar Irradiance Measurements5-10 Days Forward for Near Real-Time Applications"
Climate Science Branch, NASA Langley Research Center"
Shashi K. Gupta1, David P. Kratz2, Paul W. Stackhouse, Jr.2,"Parnchai Sawaengphokhai1, and Anne C. Wilber1"
""
1Science Systems and Applications, Inc., Hampton, Virginia"2NASA Langley Research Center, Hampton, Virginia"
""""
2014 SORCE Science Conference"Cocoa Beach, Florida"28-31 January 2014"
Background and Motivation"
Climate Science Branch, NASA Langley Research Center"
• SORCE TSI Version-14 daily data (up to 30 June 2013) currently in use for CERES processing."
"• Planned to use SORCE TSI for a CERES sub-project." FLASHFlux: Fast Longwave and Shortwave Radiative fluxes.""• TOA and Surface LW and SW fluxes in one week of real-time.""• Satellite observations and coincident meteorology from GMAO
available within 2 days of real-time.""• TSI data needed to start processing. Seven-day latency of
SORCE created the need to project TSI at least 5 days forward.""• Objective was to accomplish this with minimal uncertainty even
though no expectation of projecting day-to-day fluctuations."
SORCE Interruption and Source Change"
Climate Science Branch, NASA Langley Research Center"
• With interruption of SORCE data in July 2013, plans changed."
• ACRIM3 data was considered. Latency generally too long." In late January 2014, data available to 17 September 2013.""• Composite dataset from RMIB considered. Latency less" than one month. Data available up to 07 January 2014."
• RMIB composite can be used for CERES, not for FLASHFlux."
• Hoping that TCTE data will come online soon and will be" available with a latency comparable to that of SORCE."
• Explored statistics of available data for help in projection." Long timeseries in hand allowed testing of our methods."
Statistics Explored"
Climate Science Branch, NASA Langley Research Center"
• Value for last available day (i.e., persistence) and averages over previous 10, 30, and 90 days examined."• Two sample years were chosen for study."
"Year of high sunspot activity - 1991""Year of low sunspot activity – 2009"
• 1991 data is WRC composite offset to match SORCE."
1356
1358
1360
1362
1364
1366
036
573
010
9514
6018
2521
9025
5529
2032
8536
5040
1543
8047
4551
1054
7558
4062
0565
7069
3573
0076
6580
3083
9587
6091
2594
9098
5510
220
1058
510
950
1131
511
680
Total
Sola
r Irra
dianc
e (W
m-2)
Day Starting 01 Jan 1983
SOLCON-1AU01 Jan 1983 - 30 Jun 2013
SORCE Total Solar Irradiance Version-14
Mean = 1361.0750 S.D. = 0.5177
TSI Timeseries for 1991 (upper) and 2009 (lower)"
Climate Science Branch, NASA Langley Research Center"
1358
1359
1360
1361
1362
1363
1364
0 30 60 90 120 150 180 210 240 270 300 330 360 390
Total
Solar
Irrad
iance
(Wm-2 )
Day of Year
Measured TSI
Total Solar Irradiance - Comparison with Annual Mean - 1991
Mean = 1361.5573RMS Diff. = 0.7788
1358
1359
1360
1361
1362
1363
1364
0 30 60 90 120 150 180 210 240 270 300 330 360 390
Total
Solar
Irrad
iance
(Wm-2 )
Day of Year
Measured TSI
Total Solar Irradiance - Comparison with Annual Mean - 2009
Mean = 1360.5630RMS Diff. = 0.0609
Projection by Persistence - 1991"
Climate Science Branch, NASA Langley Research Center"
1358
1359
1360
1361
1362
1363
1364
0 30 60 90 120 150 180 210 240 270 300 330 360 390
Tota
l Sol
ar Ir
radi
ance
(Wm
-2)
Day of Year
Measured TSI Projected TSI
XX
XXXXXXX
XX
XXX
X
X
X X X
XX
X
X
X
XX
X
XX
X
X
XX
X
X X
X
X
X
X
X
XX
X
XXX
XX
XXXXX
X
X
XX XX
XX
X
X
XXXX
XXXX
X
XXXX
X
XX
XX
X
XX
X
XXX
X
X
X
XXXX
XXX
XX
XXXXXXXXX
XXXXXXX
XXXX X
XXXX
XXX
X
XXX X
X XXX
XX
X
XX
XXXXXX
X
XXXXX
XXXXXX
X
X
XXX
X
X
X
XXXX
XXX
XX
XX X
X
X
XX
X
X
X
X
X
XXXXX
XXXXXXX
XXXXX
X
X
XXX
X
X
X
XX
X
XXXX
X
XXXX
XXX
XXX
X X
X
XX
X
X
XXXXX
X
XX
X
XXXX
XXXXX
X
X
XXXXXXXX
XXXX
X
XX
X
X
X
X XX
X
X
X
XXXXXXXXXX
XX
XXXX
X
X
X
X
XXX
X
X
X
XXX
XXXXXXXXXX
XXXXXXX
XXXXX
XXXXXXXX
XXXX
XXX
XXXX
X
X
XXX
XX
XXX
X
1358
1359
1360
1361
1362
1363
1364
1358 1359 1360 1361 1362 1363 1364
Proj
ecte
d TS
I (W
m-2
)
Measured TSI (Wm-2)
5-Day Projection Based on Persistence for 1991
Mean X = 1361.5573Mean Y = 1361.5841Mean Bias = 0.0269
RMS Difference = 0.9933
Projection by 10-Day Averaging - 1991"
Climate Science Branch, NASA Langley Research Center"
XXXXX
XXXXXXXXXX
XXX
XXXX
XXXX
XXXXX X X
XX
XXXXX
XX
XX
XXXXXXXXXXX XXX XXXXXXX
XX
XXXXXX XXXXXXXXXXX X XX
XXX
XXXXXX
XXXXX
XXXX
XXXXXXXXXXXXXXXX XXXXXXXX XXXX XX XXXXXXXXXXXX
XXXXXXXXXXXXXX X XXXX
XXXXXXX
XXX
XXXX XX X XXXXXXXXXXXXXXXXXXXXXXXX X X
XXX
XXXXXXX
XXX
XXXXXXXX
XXX XX
XXX
XXXXXX XX
XXXXXXX X XXXXXX
XXXXXXXX
XXXXXXXX
XX
X
X
XXXXX
XXXX
XXXXXXXXXXXXX
XX
X
X
XX
XXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXX
XXXXXXX
XXXXXX X X
1358
1359
1360
1361
1362
1363
1364
1358 1359 1360 1361 1362 1363 1364
Proj
ecte
d TS
I (W
m-2
)
Measured TSI (Wm-2)
1358
1359
1360
1361
1362
1363
1364
0 30 60 90 120 150 180 210 240 270 300 330 360 390
Tota
l Sol
ar Ir
radi
ance
(Wm
-2)
Day of Year
Measured TSI Projected TSI
10-Day Averaging
5-Day Projection by 10-Day Averaging for 1991
Mean X = 1361.5573Mean Y = 1361.5966Mean Bias = 0.0393
RMS Difference = 0.9303
Projection by 30-Day Averaging - 1991"
Climate Science Branch, NASA Langley Research Center"
XXXXXXXXXXXXXXXX X X X XXXXXXXXXXXX X X X X X XXXXXX XX XXXXXXXXXXX XXX XXXX
XXXXX
XXXXXX XXXXXXXXXXX X X X XXXXXXXXX XXXXXXXXXXXXXXXXXXXX
XXXXX XXXXXXXX XXXX XX XXXXXXXXXXXXXXXXXXXXXXXXXX X X XXXXXXXXXX XXXXXXX XX X XXXXXXXXXX
XXXXXXXXXXXXXX X X X XXXXXXXXXXXXXXXXXXXXXXX X X XXXXXXXX X XXXXXXXXX X XXXXXXXXXXX
XXXXXXXXXXX X X X XXXXXXXXX
X XXXXXXXXXXXXXX X X XXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXX X XXXXXXXXXXXXX X X
1358
1359
1360
1361
1362
1363
1364
1358 1359 1360 1361 1362 1363 1364
Proj
ecte
d TS
I (W
m-2
)
Measured TSI (Wm-2)
1358
1359
1360
1361
1362
1363
1364
0 30 60 90 120 150 180 210 240 270 300 330 360 390
Tota
l Sol
ar Ir
radi
ance
(Wm
-2)
Day of Year
Measured TSI Projected TSI
30-Day Averaging
5-Day Projection by 30-Day Averaging for 1991
Mean X = 1361.5573Mean Y = 1361.6103Mean Bias = 0.0530
RMS Difference = 0.8309
Projection by 90-Day Averaging - 1991"
Climate Science Branch, NASA Langley Research Center"
XXXXXXXXXXXXXXXX X X X XXXXXXXXXXXX X X X X X XXXXXX XX XXXXXXXXXXX XXX XXXXXXXXXXXXXXX XXXXXXXXXXX X X X XXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXX XXXXXXXX XXXX XX XXXXXXXXXXXXXXXXXXXXXXXXXX X X XXXXXXXXXX XXXXXXX XX X XXXXXXXXXXXXXXXXXXXXXXXX X X X XXXXXXXXXXXXXXXXXXXXXXX X X XXXXXXXX X XXXXXXXXX X XXXXXXXXXXXXXXXXXXXXXX X X X XXXXXXXXXX XXXXXXXXXXXXXX X X XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX X XXXXXXXXXXXXX X X
1358
1359
1360
1361
1362
1363
1364
1358 1359 1360 1361 1362 1363 1364
Proj
ecte
d TS
I (W
m-2
)
Measured TSI (Wm-2)
Mean X = 1361.5573Mean Y = 1361.6085Mean Bias = 0.0512
1358
1359
1360
1361
1362
1363
1364
0 30 60 90 120 150 180 210 240 270 300 330 360 390
Tota
l Sol
ar Ir
radi
ance
(Wm
-2)
Day of Year
Measured TSI Projected TSI
90-Day Averaging
5-Day Projection by 90-Day Averaging for 1991
RMS Difference = 0.7926
Projection by Persistence - 2009"
Climate Science Branch, NASA Langley Research Center"
1358
1359
1360
1361
1362
1363
1364
0 30 60 90 120 150 180 210 240 270 300 330 360 390
Tota
l Sol
ar Ir
radi
ance
(Wm
-2)
Day of Year
Measured TSI Projected TSI
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXX
1358
1359
1360
1361
1362
1363
1364
1358 1359 1360 1361 1362 1363 1364
Proj
ecte
d TS
I (W
m-2
)
Measured TSI (Wm-2)
Mean X = 1360.5630Mean Y = 1360.5636Mean Bias = 0.0006
5-Day Projection Based on Persistence for 2009
RMS Difference = 0.0628
Projection by 10-Day Averaging - 2009"
Climate Science Branch, NASA Langley Research Center"
1358
1359
1360
1361
1362
1363
1364
0 30 60 90 120 150 180 210 240 270 300 330 360 390
Tota
l Sol
ar Ir
radi
ance
(Wm
-2)
Day of Year
Measured TSI Projected TSI
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
1358
1359
1360
1361
1362
1363
1364
1358 1359 1360 1361 1362 1363 1364
Proj
ecte
d TS
I (W
m-2
)
Measured TSI (Wm-2)
5-Day Projection by 10-Day Averaging for 2009
Mean X = 1360.5630Mean Y = 1360.5617Mean Bias = -0.0013
RMS Difference = 0.0707
Projection by 30-Day Averaging - 2009"
Climate Science Branch, NASA Langley Research Center"
1358
1359
1360
1361
1362
1363
1364
0 30 60 90 120 150 180 210 240 270 300 330 360 390
Tota
l Sol
ar Ir
radi
ance
(Wm
-2)
Day of Year
Measured TSI Projected TSI
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
1358
1359
1360
1361
1362
1363
1364
1358 1359 1360 1361 1362 1363 1364
Proj
ecte
d TS
I (W
m-2
)
Measured TSI (Wm-2)
5-Day Projection by 30-Day Averaging for 2009
Mean X = 1360.5630Mean Y = 1360.5590Mean Bias = -0.0040
RMS Difference = 0.0577
Projection by 90-Day Averaging - 2009"
Climate Science Branch, NASA Langley Research Center"
1358
1359
1360
1361
1362
1363
1364
0 30 60 90 120 150 180 210 240 270 300 330 360 390
Tota
l Sol
ar Ir
radi
ance
(Wm
-2)
Day of Year
Measured TSI Projected TSI
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
1358
1359
1360
1361
1362
1363
1364
1358 1359 1360 1361 1362 1363 1364
Proj
ecte
d TS
I (W
m-2
)
Measured TSI (Wm-2)
5-Day Projection by 90-Day Averaging for 2009
Mean X = 1360.5630Mean Y = 1360.5517Mean Bias = -0.0112
RMS Difference = 0.0594
Summary Results - 1991"
Climate Science Branch, NASA Langley Research Center"
0.02
0.03
0.04
0.05
0.06
0.07
0 10 20 30 40 50 60 70 80 90 100
Mea
n B
ias
(Wm
-2)
Averaging Period (Days)
5-Days 7-Days 10-Days
0.7
0.8
0.9
1.0
1.1
1.2
0 10 20 30 40 50 60 70 80 90 100
RM
S D
iffer
ence
(Wm
-2)
Averaging Period (Days)
5-Days 7-Days 10-Days
Bias and RMS Difference Between Projected and Actual TSI Values for Different Averaging Periods and Projection Lengths - 1991
Table 2. Comparison of mean bias and root mean square difference (RMSD) for between measured and projected total solar irradiance (TSI) values for different averaging periods and projection lengths. The year 1991 (a high solar activity year) was used in this illustration. Values of statistical parameters are in Wm-2.
Projection Length (Days)
Statistical Parameter
Averaging Period (Days)
1 10 30 90
5 Bias 0.0269 0.0393 0.0530 0.0512 RMSD 0.9933 0.9303 0.8309 0.7926
7 Bias 0.0347 0.0406 0.0562 0.0523 RMSD 1.0944 0.9491 0.8402 0.7930
10 Bias 0.0454 0.0409 0.0597 0.0534 RMSD 1.0758 0.9639 0.8411 0.7920
Summary Results - 2009"
Climate Science Branch, NASA Langley Research Center"
Table 3. Comparison of mean bias and root mean square difference (RMSD) for between measured and projected total solar irradiance (TSI) values for different averaging periods and projection lengths. The year 2009 (a quiet sun year) was used in this illustration. Values of statistical parameters are in Wm-2.
Projection Length (Days)
Statistical Parameter
Averaging Period (Days)
1 10 30 90 5 Bias 0.0006 -0.0013 -0.0040 -0.0112 RMSD 0.0628 0.0707 0.0577 0.0594 7 Bias 0.0002 -0.0021 -0.0045 -0.0117 RMSD 0.0716 0.0707 0.0588 0.0601
10 Bias -0.0014 -0.0032 -0.0054 -0.0123 RMSD 0.0816 0.0786 0.0600 0.0608
0.04
0.05
0.06
0.07
0.08
0.09
0 10 20 30 40 50 60 70 80 90 100
RM
S D
iffer
ence
(Wm
-2)
Averaging Period (Days)
5-Days 7-Days 10-Days
Bias and RMS Difference Between Projected and Actual TSI Values for Different Averaging Periods and Projection Lengths - 2009
-0.020
-0.015
-0.010
-0.005
0.000
0.005
0 10 20 30 40 50 60 70 80 90 100
Mea
n B
ias
(Wm
-2)
Averaging Period (Days)
5-Days 7-Days 10-Days
Timeseries of Annual Averages and RMS Differences"
Climate Science Branch, NASA Langley Research Center"
1360.0
1360.5
1361.0
1361.5
1362.0
1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013
Total
Sola
r Irra
dianc
e (W
m-2) Annual Average
31-Year (1983-2013) Mean = 1361.0774
0.0
0.2
0.4
0.6
0.8
1.0
1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013
RMS
Diffe
renc
e (W
m-2)
Year
RMS Difference
Annual Averages (1983-2013) and RMS Difference From Annual Average
Summary and Concluding Remarks"
Climate Science Branch, NASA Langley Research Center"
• The original goal was to use daily SORCE TSI data with 7-day latency" and project it 5 days forward for use in FLASHFlux processing.""• With that or similar data stream available, we can project 5 days" forward using averages of previous 10, 30, or 90 days with" uncertainties < 1.0 Wm-2 during years of high sunspot activity;" < 0.1 Wm-2 during quiet years. Corresponding biases are <0.1 Wm-2 and ≅0.01 Wm-2 respectively. Based on these results, we chose to" use 90-day averaging in our projections." "• With the present interruption of SORCE data, its use for FLASHFlux" is on hold. When TCTE data become available (hopefully, with" similar latency) use for FLASHFlux will be reconsidered. In the " meantime, FLASHFlux will continue to use a value of 1361 Wm-2.""• Edition-4 of CERES processing is using SORCE Version-14 up to" 30 June 2013. Composite data provided by Royal Meteorological" Institute of Belgium (RMIB) scaled to match SORCE data will be " used from 1 July 2013 onward until TCTE data become available."
Back-up Slides"
Climate Science Branch, NASA Langley Research Center"
Need for Projection"
Climate Science Branch, NASA Langley Research Center"
• Today’s date: 29 Jan 2014.""• Satellite observations and" meteorology available for: 27 Jan 2014." For processing to start, TSI needed.""• Latest SORCE data available for: 22 Jan 2014." Hence, the need to project SORCE 5 days. "
Lag Correlations"
Climate Science Branch, NASA Langley Research Center"
JJ
J
J
J
J
J
J
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0 1 2 3 4 5 6 7 8 9 10
Auto
corre
latio
n
Lag (Days)
J Auto_Corr_1991
Auto_Corr_2009
Autocorrelation in 1991 and 2009 TSI Timeseries
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