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1*ROBERT B. LEE III and 2*ROBERT S. WILSON1Retired NASA Langley Research Center, Hampton, VA
1Science Application International Corp. (SAIC) Hampton, VA
ACCURACY AND PRECISION OF EARTH RADIATION BUDGET EXPERIMENT [ERBE]
SOLAR MONITOR ON THE EARTH RADIATION BUDGET SATELLITE [ERBS]
2
ESTIMATED ERBE SOLAR MONITOR TOTAL SOLAR IRRADIANCE [TSI] MEASUREMENT
ACCURACIES & PRECISIONS
MEASUREMENT ACCURACY
~ 0.25% [3 SIGMAS]
MEASUREMENT PRECISION
~ 0.02% [3 SIGMAS]
4
ERBS/ERBE SOLAR MONITOR TOTAL SOLAR IRRADIANCE [TSI] MEASUREMENTS: OCT. 25, 1984 THROUGH MARCH 24, 2004
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1984 1989 1994 1999 2004YEAR
TSI,
Wm
-2
-1
0
1
2
3
4
5
6
7
8
9
STD
EV T
SI, W
m-2
MEASUREMENTS STDEV MEASUREMENTS
+ 3.4 Wm-2
5
1984-2005, Earth Radiation Budget Satellite (ERBS)/Earth Radiation Budget Experiment
(ERBE) Total Solar Irradiance (TSI) measurements
- THE ERBS/ERBE SOLAR MONITOR IS OPERATING NOMINALLY,
AND PRODUCING EXCELLENT TSI MEASUREMENTS.
- The ERBS SPACECRAFT & ERBE SOLAR MONITOR IS EXPECTED
TO BE OPERATIONAL THROUGH 2009, SUNSPOT MAXIMUM.
- HOWEVER, THE ERBS/ERBE SOLAR MONITOR TSI PROCESSING HAS
BEEN STOPPED DUE TO THE LOST OF FUNDING.
8
EARTH RADIATION BUDGET SATELLITE (ERBS), LAUNCHED OCTOBER 5, 1984 AND STILL OPERATING
ERBE NONSCANNINGACR SENSORS
9
EARTH RADIATION BUDGET EXPERIMENT (ERBE) NONSCANNING ACTIVE-CAVITY RADIOMETERS (ACR)
WERE LAUNCHED ABOARD THE ERBS SPACECRAFT OCT. 1984
SOLAR MONITOR
15
ERBS/ERBE SOLAR MONITOR TOTAL SOLAR IRRADIANCE (TSI) MEASUREMENTS: MARCH 30, 2005/ 0.8-SECOND AVERAGES
4000
4500
5000
5500
6000
6500
7000
7500
0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.79 HOURS UNIVERSAL TIME, FRACTION OF HOUR
OU
TPU
T SI
GN
AL,
DIG
ITA
L C
OU
NTS
16
ERBS/ERBE SOLAR MONITOR TOTAL SOLAR IRRADIANCE (TSI) MEASUREMENTS: MARCH 30, 2005/ 0.8-SECOND AVERAGES
4000
4500
5000
5500
6000
6500
7000
7500
0.44 0.46 0.48 0.5 0.52 0.549 HOURS UNIVERSAL TIME, FRACTION OF HOUR
OU
TPU
T SI
GN
AL,
DIG
ITA
L C
OU
NTS
SHUTTER CLOSED
SHUTTER OPENEDSUN OBSERVATIONS
SOLAR OBSERVATIONS
17
ERBE SOLAR MONITOR DATA REDUCTION EQUATIONTSIins = [Dsa x (rE-S)2 x )/{cosθ x (Ra)(αa)(APA)}] x
[(VC2 - VO
2) + σ x (VFPA-SA)(εc x TC4 - εSH x TO
4) + Σpi] WHERE:
Dsa = DIFFRACTION CORRECTION AT SECONDARY APERTURE (SA)rE-S = EARTH-SUN DISTANCE, AU RH = ACTIVE CAVITY (C) HEATER (H) RESISTANCE, OHMSαC = ACTIVE CAVITY (C) ABSORPTANCE
APA = PRIMARY APERTURE (PA) AREAVC = ACTIVE CAVITY HEATER (H) VOLTAGE, CLOSED (C) SHUTTER (SH)VO = ACTIVE CAVITY HEATER (H) VOLTAGE, OPENED (O) SHUTTER (SH)
σ = STEFAN-BOLTZMAN CONSTANT, 5.6697 x 10-8 Wm-2K-1
εc = CAVITY (C) EMITTANCE, 0.98 εSH = SHUTTER (SH) EMITTANCE, 0.05 VFPAO-SA = VIEW FACTOR FROM PA OPENING TO SECONDARY APERTURE
TC = PRIMARY CAVITY TEMPERATURE, CLOSED (C) SHUTTER TO = PRIMARY CAVITY TEMPERATURE, OPENED (O) SHUTTER Pi = POWER EXCHANGES OF CAVITY WITH SURROUNDINGS
18
ERBS/ERBE SOLAR MONITOR CHARACTERISTICSSYMBOL UNIT VALUE UNCERTAINTY SYMBOL DESCRIPTION
@ 1365 Wm-2
Dsa --- 1.0000 ??? SA DIFFRACTION rE-S AU 1.034 0.01% SUN-EARTH DISTANCEVC
2 SQ. VOLTS 78.950 0.014% SHUTTER CLOSEDHEATER VOLTAGE
VO2 SQ. VOLTS 28.204 0.025% SHUTTER OPENED
HEATER VOLTAGEcosθ --- 0.04% SUN CONE ANGLERH OHMS 729.66 0.007% HEATER RESISTANCEαC ---- 0.99988 0.002% CAVITY ABSORPTANCEAPA cm2 0.50643 0.25% PRIMARY APERTURE AREAσ Watts-K-4-cm-2 5.6697E-8 0.01% STEFAN-BOLTZMAN CONSTANTεc --- 0.98 0.04% CAVITY EMITTANCE εSH --- 0.05 0.04% CAVITY EMITTANCE VFPA-SA) --- 0.0141 0.04% VIEW FACTOR PA TO SATC
4 KELVIN [293 K]4 0.001% CLOSED CAVITY TEMP.TO
4 KELVIN [293 K]4 0.001% CLOSED CAVITY TEMP.ΣPi} Watts-cm-2 0.3 0.01% CAVITY POWER EXCHANGE
WITH SURROUNDINGS.
19
DATA REDUCTION
- LOW FREQUENCY OF ERBS/ERBE SOLAR MONITOR TOTAL SOLAR IRRADIANCE [TSI] MEASUREMENTS ARE IDEAL FOR LONG-TERM CLIMATE STUDIES BECAUSE OF THE ABSENCE OF LONG-TERM SENSOR DEGRADATION.
- EACH TOTAL SOLAR IRRADIANCE VALUE IS A 3 MINUTE AVERAGE OF 2-8 MEASUREMENTS.
- TSI MEASUREMENTS ARE OBTAINED AT LEAST EVERY 14 DAYS ON A WEDNESDAY.
20
PRIMARY TSI CORRECTIONS
- NOMALIZATION TO MEAN EARTH-SUN DISTANCE [1AU], +3.34%.
- LW FLUX LOSSES OUT OF SECONDARY APERTURE WHEN SHUTTER IS OPENED, +0.44%.
- ΣPi ; ; +0.02%.
21
ERBS/ERBE SOLAR MONITOR TOTAL SOLAR IRRADIANCE (TSI) MEASUREMENTS: MARCH 30, 2005/ 0.8-SECOND AVERAGES
4000
4500
5000
5500
6000
6500
7000
7500
0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.79 HOURS UNIVERSAL TIME, FRACTION OF HOUR
OU
TPU
T SI
GN
AL,
DIG
ITA
L C
OU
NTS
22
ERBS/ERBE SOLAR MONITOR TOTAL SOLAR IRRADIANCE (TSI) MEASUREMENTS: MARCH 30, 2005/ 0.8-SECOND AVERAGES
7260
7265
7270
7275
7280
7285
7290
7295
7300
0.37 0.38 0.39 0.4 0.41 0.42 0.43 0.449 HOURS UNIVERSAL TIME, FRACTION OF HOUR
OU
TPU
T SI
GN
AL,
DIG
ITA
L C
OU
NTS
SHUTTER CLOSED
SHUTTER OPENEDSUN OBSERVATIONSPRE-SOLAR
OBSERVATIONS
23
ERBS/ERBE SOLAR MONITOR TOTAL SOLAR IRRADIANCE (TSI) MEASUREMENTS: MARCH 30, 2005/ 0.8-SECOND AVERAGES
7260
7265
7270
7275
7280
7285
7290
7295
7300
0.54 0.55 0.56 0.57 0.58 0.59 0.6 0.619 HOURS UNIVERSAL TIME, FRACTION OF HOUR
OU
TPU
T SI
GN
AL,
DIG
ITA
L C
OU
NTS
SHUTTER CLOSED
SHUTTER OPENEDSPACE OBSERVATION
POST SOLAR OBSERVATIONS
24
ACCURACY OF SOLAR MONITOR TEMPERATURE DRIFTS
~ 0.01 CELSIUS TEMPERATURE DRIFT BETWEEN CONSECUTIVE SHUTTER OR SOLAR MEASUREMENT [>0.01% TSI MEASUREMENT PRECISION].
25
ERBE/ERBS SOLAR MONITOR TOTAL SOLAR IRRADIANCE (TSI) PRELIMINARY MEASUREMENTS: MARCH 30, 2005
4000
4500
5000
5500
6000
6500
7000
7500
9.38 9.43 9.48 9.53 9.58UT TIME, HOURS
DIG
ITA
L C
OU
NTS
19.519.5519.619.6519.719.7519.819.8519.919.9520
TEM
PER
ATU
RE,
CEL
SIU
S
SOLAR MONITOR INSTANTEOUS COUNTS BAFFLE TEMP APERTURE TEMP HEAT SINK TEMP
26
ERBE SOLAR MONITOR TOTAL SOLAR IRRADIANCE [TSI]MEASUREMENTS VS HEAT SINK TEMPERATURE
1358
1360
1362
1364
1366
1368
1370
1372
1374
0 5 10 15 20 25 30 35 40HEAT SINK TEMPERATURE, CELSIUS
TOTA
L SO
LAR
IRR
AD
IAN
CE,
Wm
-2
27
ACCURACY OF SOLAR MONITOR ANGULAR CORRECTIONS
~ 0.04% UNCERTAINTY DUE TO NON-COSINE SENSOR RESPONSE [0.5 Wm-2 @ 1365 Wm-2
TSI LEVEL]
28
ERBE/ERBS SOLAR MONITOR TOTAL SOLAR IRRADIANCE (TSI) PRELIMINARY MEASUREMENTS: MARCH 30, 2005
4000
4500
5000
5500
6000
6500
7000
7500
9.38 9.43 9.48 9.53 9.58UT TIME, HOURS
DIG
ITA
L C
OU
NTS
-2
0
2
4
6
8
10
12
SUN
AN
GLE
, DEG
REE
S
SOLAR MONITOR SIGNAL EVERY 0.8 SECOND SUN ANGLE
30
ERBE SOLAR MONITOR TSI MEASUREMENTS VS SUN ANGULAR DISTANCE FROM SM OPTICAL AXIS
1358
1360
1362
1364
1366
1368
1370
1372
1374
0 1 2 3 4 5 6ANGULAR DISTANCE TO OPTICAL AXIS, DEGREES
TSI,
Wm
-2
31
ERBS/ERBE SOLAR MONITOR RAW TSI DATAJ U L I A N C A L E N D A R T I M E T S I T S I T S I T S I T S I T S I
D A Y Y E A R / H O U R S / M E A S U R E S U N M E A S U R E M E A S U R E M E A S U R E M E A S U R EM O N T H / M I N U T E S / S U N S H U T T E R B E F O R E B E F O R E A F T E R A F T E R
D A Y S E C O N D S O P E N E D R E F E R E N C E R E F E R E N C E R E F E R E N C E R E F E R E N C ES H U T T E R S H U T T E R S H U T T E R S H U T T E R S H U T T E RO P E N E D C L O S E D C L O S E D C L O S E D C L O S E D
Y Y : M M : D D H H : M M : S S S T D S T D S T DD A T E J M Y / M / D H : M I : S C O U N T S C O U N T S C O U N T S C O U N T S C O U N T S C O U N T SD A T E J M Y / M / D H : M I : S C X S D C X R C 1 S D R C 1 R C 2 S D R C 22 4 4 6 0 0 6 8 4 1 1 0 1 8 4 3 1 2 4 3 1 9 . 6 3 7 2 6 8 . 6 2 . 8 7 2 6 3 . 4 2 . 92 4 4 6 0 1 0 8 4 1 1 0 5 6 1 9 4 4 4 3 0 4 . 2 3 7 2 6 5 . 2 2 . 4 7 2 6 6 1 . 22 4 4 6 0 6 3 8 4 1 2 2 8 8 3 5 1 2 4 2 3 6 . 4 3 7 2 6 5 1 . 6 7 2 6 3 . 2 2 . 92 4 4 6 0 8 9 8 5 0 1 2 3 1 6 6 5 6 4 2 4 7 . 2 1 . 5 7 2 6 6 . 6 0 . 9 7 2 6 6 . 8 1 . 32 4 4 6 1 0 3 8 5 0 2 0 6 1 3 2 1 4 4 2 6 1 . 2 2 . 8 7 2 6 7 . 4 1 . 5 7 2 6 6 . 4 2 . 62 4 4 6 1 1 7 8 5 0 2 2 0 1 3 3 2 8 4 1 0 8 . 4 4 . 3 7 1 6 1 . 8 3 . 2 7 1 6 2 3 . 62 4 4 6 1 1 7 8 5 0 2 2 0 1 3 5 3 6 4 1 0 2 . 4 4 7 1 6 1 . 8 3 . 1 7 1 6 1 . 2 2 . 42 4 4 6 1 1 7 8 5 0 2 2 0 1 3 7 4 4 4 1 1 0 . 4 2 . 9 7 1 6 0 . 6 3 . 8 7 1 6 1 . 2 3 . 32 4 4 6 1 3 1 8 5 0 3 0 6 1 1 1 0 2 4 4 3 0 1 . 8 1 . 6 7 2 6 1 . 2 1 . 8 7 2 5 9 . 8 0 . 82 4 4 6 1 4 5 8 5 0 3 2 0 1 2 5 7 4 4 3 3 9 . 2 1 . 9 7 2 6 5 . 2 2 . 6 7 2 6 6 . 2 1 . 32 4 4 6 1 5 9 8 5 0 4 0 3 1 7 3 0 0 8 4 3 1 8 . 6 2 . 3 7 2 3 1 . 8 1 . 9 7 2 3 2 1 . 42 4 4 6 1 5 9 8 5 0 4 0 3 1 7 3 2 1 6 4 3 1 7 . 8 1 . 8 7 2 3 2 1 . 4 7 2 3 1 . 6 1 . 52 4 4 6 1 7 3 8 5 0 4 1 7 1 3 5 6 4 8 4 4 1 6 . 2 3 . 7 7 2 7 4 . 4 3 . 6 7 2 7 4 . 8 1 . 82 4 4 6 1 8 7 8 5 0 0 5 1 1 2 4 9 4 4 4 2 1 1 . 9 7 2 6 0 1 . 2 7 2 5 8 . 8 1 . 12 4 4 6 1 9 4 8 5 0 0 5 8 1 2 4 0 0 4 4 2 8 1 . 9 7 2 5 7 . 8 1 . 6 7 2 5 5 . 6 1 . 52 4 4 6 2 1 5 8 5 0 5 2 9 1 2 3 9 2 8 4 4 7 9 . 6 2 . 7 7 2 6 7 1 . 7 7 2 6 7 . 2 1 . 52 4 4 6 2 3 5 8 5 0 6 1 8 1 2 0 9 3 6 4 4 2 7 3 . 2 7 2 2 2 . 2 2 7 2 2 2 . 2 22 4 4 6 2 3 5 8 5 0 6 1 8 1 2 1 1 4 4 4 4 2 1 . 2 1 . 5 7 2 2 3 1 . 2 7 2 2 1 . 8 1 . 52 4 4 6 2 4 3 8 5 0 6 2 6 1 2 1 0 4 0 4 4 9 5 . 4 4 7 2 6 5 . 6 2 . 8 7 2 6 6 1 . 22 4 4 6 2 5 7 8 5 0 7 1 0 1 2 3 5 4 3 4 4 9 8 . 2 1 . 5 7 2 6 5 1 . 4 7 2 6 3 . 8 1 . 32 4 4 6 2 7 1 8 5 0 7 2 4 1 2 1 4 5 5 4 4 8 3 . 2 1 . 9 7 2 6 1 . 4 1 . 5 7 2 6 1 1 . 22 4 4 6 2 8 5 8 5 0 8 0 7 1 4 0 4 4 7 4 4 9 1 . 6 2 . 9 7 2 7 1 . 2 3 . 3 7 2 7 1 . 2 2 . 92 4 4 6 2 9 9 8 5 0 8 2 1 1 1 5 8 2 3 4 3 4 1 . 6 2 . 7 7 1 8 9 1 . 9 7 1 8 7 . 8 1 . 92 4 4 6 2 9 9 8 5 0 8 2 1 1 2 0 0 3 1 4 3 3 1 . 8 2 . 6 7 1 8 8 . 6 1 . 5 7 1 8 8 1 . 22 4 4 6 2 9 9 8 5 0 8 2 1 1 2 0 2 3 9 4 3 3 1 . 2 2 . 3 7 1 8 7 . 4 2 . 7 7 1 8 7 . 2 1 . 52 4 4 6 3 1 3 8 5 0 9 0 4 1 3 3 0 0 7 4 4 3 1 . 2 3 . 5 7 2 6 1 . 8 2 . 8 7 2 6 2 . 8 1 . 52 4 4 6 3 2 7 8 5 0 9 1 8 1 2 1 7 3 5 4 4 0 9 . 8 1 . 9 7 2 6 4 . 6 2 . 5 7 2 6 3 . 6 1 . 52 4 4 6 3 4 1 8 5 1 0 0 2 1 3 3 9 4 3 4 3 1 6 1 . 9 7 2 2 3 . 8 1 . 1 7 2 2 4 . 2 1 . 32 4 4 6 3 4 1 8 5 1 0 0 2 1 3 4 1 5 1 4 3 0 6 2 . 1 7 2 2 4 2 7 2 2 3 1 . 92 4 4 6 3 5 5 8 5 1 0 1 6 1 3 1 5 4 3 4 3 5 3 . 6 2 . 3 7 2 6 7 . 4 2 . 1 7 2 6 7 . 6 1 . 52 4 4 6 3 5 9 8 5 1 0 2 0 1 7 5 7 5 1 4 3 6 1 . 6 3 . 9 7 2 7 8 . 2 3 7 2 7 7 . 2 2 . 42 4 4 6 3 7 0 8 5 1 0 3 1 1 2 0 4 4 7 4 3 0 5 . 8 3 . 2 7 2 6 0 3 . 1 7 2 6 1 . 2 1 . 52 4 4 6 3 8 3 8 5 1 1 1 3 1 3 0 9 5 1 4 2 9 1 3 . 4 7 2 6 3 . 6 3 7 2 6 3 . 6 2 . 92 4 4 6 3 9 7 8 5 1 1 2 7 1 3 3 5 2 7 4 2 6 4 . 2 1 . 5 7 2 6 2 . 4 1 . 5 7 2 6 3 1 . 92 4 4 6 4 1 7 8 5 1 2 1 8 1 1 4 7 1 1 4 1 7 1 . 4 2 . 2 7 2 1 8 . 8 1 . 5 7 2 1 7 . 6 1 . 72 4 4 6 4 1 7 8 5 1 2 1 8 1 1 4 9 1 9 4 1 5 9 . 2 2 . 3 7 2 1 8 . 4 1 . 5 7 2 1 7 . 4 1 . 12 4 4 6 4 2 5 8 5 1 2 2 5 1 4 4 4 1 5 4 2 3 1 2 7 2 6 1 1 . 6 7 2 6 0 . 2 1 . 32 4 4 6 4 3 9 8 6 0 1 0 8 1 1 4 1 1 9 4 2 4 4 3 . 5 7 2 6 7 . 2 3 . 5 7 2 6 8 3 . 12 4 4 6 4 5 3 8 6 0 1 2 2 1 2 5 6 3 1 4 2 4 2 . 8 4 7 2 6 2 . 8 3 . 7 7 2 6 2 . 8 3 . 22 4 4 6 4 7 7 8 6 0 2 1 5 1 2 1 0 3 9 4 2 2 8 . 6 1 . 8 7 2 3 4 . 6 1 . 8 7 2 3 4 1 . 22 4 4 6 4 7 7 8 6 0 2 1 5 1 2 1 2 4 7 4 2 1 9 . 6 1 . 8 7 2 3 3 . 8 1 . 8 7 2 3 2 . 4 1 . 82 4 4 6 4 9 5 8 6 0 3 0 5 1 2 4 8 3 1 4 3 1 0 . 4 2 . 5 7 2 6 1 1 . 6 7 2 6 0 . 2 1 . 52 4 4 6 4 9 5 8 6 0 3 0 5 1 2 5 0 3 9 4 2 9 9 . 8 1 . 9 7 2 5 9 . 2 1 . 5 7 2 5 8 . 2 2 . 82 4 4 6 5 2 3 8 6 0 4 0 2 1 2 3 9 2 7 4 3 1 0 . 6 1 . 8 7 2 2 7 . 2 1 . 9 7 2 2 7 . 6 1 . 3
32
ERBS/ERBE SOLAR MONITOR RAW TSI DATAT S I A N G L E B A F F L E B A F F L E B A F F L E S I N G L E E A R T H E A R T H A V E R A G E D
M E A S U R E B E T W E E N T E M P T E M P T E M P T S I S U N S U N T S IA F T E R S U N & C E L S I U S C E L S I U S C E L S I U S V A L U E D I S T A N C E D I S T A N C E V A L U E
R E F E R E N C E A C R N A V A LS H U T T E R O P T I C A L T O C A L C U L A T E D T A B L E T OC L O S E D A X I S S U N L O W H I G H S U N
S T D A N G L E P R E C I S I O N P R E C I S I O N A N G L EC O U N T S D E G R E E S D E G R E E S D E G R E E S D E G R E E S D E G R E E S A U A U D E G R E E S
S D R C 2 A G 0 T B T A T H S O L D S M E S D P E S D T P T A2 . 9 3 . 3 1 9 . 7 9 1 9 . 6 1 9 . 6 5 1 3 6 5 . 9 0 . 9 9 2 3 5 5 5 0 . 9 9 2 3 1 2 1 1 3 6 61 . 2 2 . 3 3 1 9 . 9 3 2 0 . 1 1 1 9 . 9 8 1 3 6 5 . 3 0 . 9 9 1 3 4 3 6 0 . 9 9 1 3 0 2 3 1 3 6 5 . 32 . 9 1 . 9 3 1 9 . 4 4 1 9 . 6 7 1 9 . 4 8 1 3 6 1 . 5 0 . 9 8 3 3 7 3 8 0 . 9 8 3 3 4 0 8 1 3 6 3 . 81 . 3 1 . 1 4 1 9 . 4 5 1 9 . 6 2 1 9 . 4 8 1 3 6 5 . 1 0 . 9 8 4 3 6 0 3 0 . 9 8 4 3 4 7 8 1 3 6 5 . 12 . 6 1 . 0 8 1 9 . 2 5 1 9 . 4 8 1 9 . 2 8 1 3 6 5 . 7 0 . 9 8 6 2 2 9 7 0 . 9 8 6 1 6 8 9 1 3 6 5 . 43 . 6 2 . 7 5 2 9 . 2 6 2 9 . 3 8 2 9 . 2 6 1 3 6 4 . 9 0 . 9 8 8 9 2 0 4 0 . 9 8 8 9 3 1 1 1 3 6 4 . 92 . 4 0 . 8 6 2 9 . 2 8 2 9 . 4 2 9 . 2 8 1 3 6 5 . 2 0 . 9 8 8 9 2 0 4 0 . 9 8 8 9 3 1 1 1 3 6 4 . 93 . 3 3 . 7 6 2 9 . 3 1 2 9 . 4 2 2 9 . 3 1 1 3 6 5 0 . 9 8 8 9 2 0 4 0 . 9 8 8 9 3 1 1 1 3 6 4 . 90 . 8 1 . 1 1 1 9 . 7 4 1 9 . 9 4 1 9 . 7 6 1 3 6 4 . 9 0 . 9 9 2 2 3 7 6 0 . 9 9 2 1 9 9 1 1 3 6 51 . 3 0 . 8 1 9 . 4 7 1 9 . 6 4 1 9 . 4 9 1 3 6 5 . 3 0 . 9 9 6 0 3 6 4 0 . 9 9 6 0 6 9 3 1 3 6 5 . 11 . 4 2 . 2 8 2 2 . 6 8 2 2 . 7 9 2 2 . 6 8 1 3 6 4 . 7 1 . 0 0 0 0 8 6 8 1 . 0 0 0 0 6 9 6 1 3 6 4 . 71 . 5 2 . 0 6 2 2 . 6 9 2 2 . 8 2 2 . 6 9 1 3 6 4 . 7 1 . 0 0 0 0 8 6 8 1 . 0 0 0 0 6 9 6 1 3 6 4 . 71 . 8 0 . 4 6 1 8 . 6 1 1 8 . 8 1 1 8 . 6 5 1 3 6 5 . 1 1 . 0 0 4 0 2 1 6 1 . 0 0 4 0 6 4 2 1 3 6 5 . 21 . 1 1 . 2 5 1 9 . 9 4 2 0 . 1 4 1 9 . 9 5 1 3 6 4 . 2 1 . 0 0 7 7 4 2 1 . 0 0 7 7 3 7 3 1 3 6 4 . 41 . 5 0 . 8 9 2 0 . 2 1 2 0 . 4 2 0 . 2 2 1 3 6 4 . 9 1 . 0 0 9 4 4 9 6 1 . 0 0 9 4 4 6 1 1 3 6 4 . 41 . 5 1 . 7 4 1 9 . 4 1 1 9 . 5 8 1 9 . 4 2 1 3 6 4 . 1 1 . 0 1 3 6 7 0 3 1 . 0 1 3 6 7 0 8 1 3 6 4 . 3
2 3 . 2 3 2 3 . 5 4 2 3 . 6 4 2 3 . 5 3 1 3 6 4 . 4 1 . 0 1 6 0 8 5 7 1 . 0 1 6 1 2 6 8 1 3 6 4 . 71 . 5 1 . 0 2 2 3 . 5 6 2 3 . 6 4 2 3 . 5 4 1 3 6 4 . 7 1 . 0 1 6 0 8 5 7 1 . 0 1 6 1 2 6 8 1 3 6 4 . 71 . 2 1 . 8 7 1 9 . 4 8 1 9 . 6 5 1 9 . 4 9 1 3 6 5 . 2 1 . 0 1 6 5 4 9 2 1 . 0 1 6 5 5 1 3 1 3 6 4 . 91 . 3 2 . 2 1 9 . 4 5 1 9 . 6 5 1 9 . 4 7 1 3 6 3 . 8 1 . 0 1 6 6 2 9 5 1 . 0 1 6 6 3 5 5 1 3 6 41 . 2 1 . 6 2 1 9 . 7 7 1 9 . 9 7 1 9 . 7 9 1 3 6 4 . 8 1 . 0 1 5 7 8 2 1 . 0 1 5 7 8 5 1 3 6 4 . 52 . 9 3 . 7 1 9 1 9 . 1 9 1 9 . 0 2 1 3 6 5 . 3 1 . 0 1 4 0 3 7 8 1 . 0 1 4 0 2 8 8 1 3 6 5 . 41 . 9 4 . 7 2 2 6 . 8 3 2 6 . 9 4 2 6 . 8 2 1 3 6 5 . 4 1 . 0 1 1 5 2 6 1 1 . 0 1 1 5 3 6 1 1 3 6 4 . 91 . 2 1 . 5 4 2 6 . 8 6 2 6 . 9 7 2 6 . 8 5 1 3 6 4 . 7 1 . 0 1 1 5 2 6 1 1 . 0 1 1 5 3 6 1 1 3 6 4 . 91 . 5 1 . 9 1 2 6 . 8 9 2 6 . 9 9 2 6 . 8 8 1 3 6 4 . 6 1 . 0 1 1 5 2 6 1 1 . 0 1 1 5 3 6 1 1 3 6 4 . 91 . 5 2 . 0 4 1 9 . 7 1 1 9 . 8 8 1 9 . 7 3 1 3 6 4 . 8 1 . 0 0 8 3 2 6 8 1 . 0 0 8 3 1 1 2 1 3 6 4 . 41 . 5 2 . 9 7 1 9 . 6 4 1 9 . 8 3 1 9 . 6 5 1 3 6 4 . 7 1 . 0 0 4 6 6 8 8 1 . 0 0 4 6 9 3 9 1 3 6 4 . 91 . 3 3 . 8 9 2 3 . 3 4 2 3 . 4 6 2 3 . 3 2 1 3 6 4 . 7 1 . 0 0 0 7 1 . 0 0 0 6 8 6 8 1 3 6 4 . 81 . 9 0 . 8 3 2 3 . 3 7 2 3 . 5 1 2 3 . 3 6 1 3 6 4 . 9 1 . 0 0 0 7 1 . 0 0 0 6 8 6 8 1 3 6 4 . 81 . 5 2 . 8 8 1 9 . 1 9 1 9 . 4 1 9 . 2 1 1 3 6 4 . 7 0 . 9 9 6 6 9 6 2 0 . 9 9 6 7 3 7 4 1 3 6 52 . 4 3 . 2 9 1 8 . 3 5 1 8 . 5 6 1 8 . 3 9 1 3 6 5 . 2 0 . 9 9 5 5 1 8 4 0 . 9 9 5 5 3 6 9 1 3 6 51 . 5 2 . 7 8 2 0 . 0 6 2 0 . 2 1 2 0 . 0 7 1 3 6 5 . 9 0 . 9 9 2 6 1 6 2 0 . 9 9 2 6 0 7 1 1 3 6 5 . 72 . 9 3 . 6 6 1 9 . 6 7 1 9 . 8 3 1 9 . 6 8 1 3 6 5 . 1 0 . 9 8 9 4 3 8 7 0 . 9 8 9 4 8 5 1 1 3 6 5 . 11 . 9 2 . 3 3 1 9 . 7 1 1 9 . 8 9 1 9 . 7 1 1 3 6 4 . 2 0 . 9 8 6 6 2 2 6 0 . 9 8 6 6 0 4 2 1 3 6 3 . 81 . 7 4 . 0 5 2 3 . 8 7 2 3 . 9 7 2 3 . 8 5 1 3 6 4 . 3 0 . 9 8 3 9 2 8 0 . 9 8 3 9 3 6 3 1 3 6 4 . 61 . 1 0 . 5 3 2 3 . 9 1 2 4 2 3 . 8 8 1 3 6 4 . 8 0 . 9 8 3 9 2 8 0 . 9 8 3 9 3 6 3 1 3 6 4 . 61 . 3 1 . 7 2 1 9 . 9 3 2 0 . 1 1 1 9 . 9 3 1 3 6 4 . 9 0 . 9 8 3 4 8 4 5 0 . 9 8 3 4 5 4 4 1 3 6 4 . 63 . 1 2 . 8 8 1 9 . 4 4 1 9 . 6 1 1 9 . 4 6 1 3 6 5 . 3 0 . 9 8 3 3 5 7 4 0 . 9 8 3 3 7 7 1 1 3 6 53 . 2 2 . 6 7 1 9 . 8 2 1 9 . 9 8 1 9 . 8 3 1 3 6 5 . 1 0 . 9 8 4 2 2 1 8 0 . 9 8 4 1 8 4 7 1 3 6 5 . 11 . 2 3 . 7 2 2 . 5 4 2 2 . 6 7 2 2 . 5 2 1 3 6 4 . 9 0 . 9 8 7 8 1 5 6 0 . 9 8 7 8 0 4 9 1 3 6 4 . 61 . 8 0 . 9 5 2 2 . 5 7 2 2 . 7 2 2 . 5 5 1 3 6 4 . 5 0 . 9 8 7 8 1 5 6 0 . 9 8 7 8 0 4 9 1 3 6 4 . 61 . 5 4 . 3 7 1 9 . 9 6 2 0 . 1 4 1 9 . 9 6 1 3 6 4 . 9 0 . 9 9 1 9 3 3 4 0 . 9 9 1 9 2 5 9 1 3 6 4 . 72 . 8 2 . 5 4 2 0 . 0 1 2 0 . 2 2 0 . 0 1 1 3 6 4 . 7 0 . 9 9 1 9 3 3 4 0 . 9 9 1 9 2 5 9 1 3 6 4 . 71 . 3 3 . 5 5 2 3 . 2 9 2 3 . 3 7 2 3 . 2 7 1 3 6 5 . 2 0 . 9 9 9 6 6 6 0 . 9 9 9 6 5 0 5 1 3 6 5
33
SOLAR MONITOR MEASUREMENT PRECISION
- COMPARISONS AMONG TSI SPACECRAFT TIME SERIES.- COMPARISONS BETWEEN TSI MEASURMENTS AND EMPIRICAL DATA FITS BASED UPON SOLAR MAGNETIC INDICES.
- COMPARISONS AMONG ERBE ACR TSI MEASUREMENTS.
34
ACTIVE LONG-TERM SPACECRAFT MISSION TOTAL SOLAR IRRADIANCE (TSI) DATA SETS
1356
1358
1360
1362
1364
1366
1368
1370
1984 1989 1994 1999 2004Calendar Year
Tota
l Sol
ar Ir
radi
ance
, Wm
-2
1356
1358
1360
1362
1364
1366
1368
1370
VIRGO ACRIMSAT SORCE EMPIRICAL FIT ERBS
+ 2.8 Wm-2
35
SOLAR MONITOR MEASUREMENT PRECISION
- COMPARISONS AMONG TSI SPACECRAFT TIME SERIES.
- COMPARISONS BETWEEN TSI MEASURMENTS AND EMPIRICAL DATA FITS BASED UPON SOLAR MAGNETIC INDICES [WHEN LESS THAN 3 SIMULTANEOUS SPACECRAFT TSI DATA SETS ARE AVAILABLE].- COMPARISONS AMONG ERBE ACR TSI MEASUREMENTS.
36
LONG-TERM SPACECRAFT TOTAL SOLAR IRRADIANCE (TSI) MISSIONS DATA SETS
1358
1360
1362
1364
1366
1368
1370
1372
1374
1978 1983 1988 1993 1998 2003 2008Calendar Year
Tota
l sol
ar Ir
radi
ance
, Wm
-2
UARS ACRIM II VIRGO ACRIMSAT SORCE NIMBUS-7 SMM ACRIM I ERBS
+2.8 Wm-2
VALIDATION REGIONS
37
SOLAR MAGNETIC INDICES
0
100
200
300
400
500
600
700
4/28/1983 4/28/1987 4/28/1991 4/28/1995 4/28/1999 4/28/2003
TIME
SS N
UM
BER
& P
PSI
0
50
100
150
200
250
300
350
400
10.7
-CM
SO
LAR
FLU
X
SUNSPOT NUMBER PPSI 10.7-CM SOLAR FLUX
38
.
INDICES OF SOLAR MAGNETIC ACTIVITY
0
50
100
150
200
250
1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004Calendar Year
10.7
-cm
Sol
ar F
lux,
1022
Wm
-2H
z-1
0
20
40
60
80
100
120
140
160
180
Suns
pot N
umbe
r or P
PSI
Prompt Photometric Sunspot Index (PPSI) F10.7-cm Solar Flux Sunspot Number
39
REGRESSION FIT MODELTHE MODEL IS DERIVED FROM MULTI-REGRESSION ANALYSIS OF THE MARCH 1985 TO AUGUST 1989 ERBS IRRADIANCE MEASUREMENTS, THE CORRESPONDING PHOTOMETRIC SUNSPOT INDEX (PSI, SUNSPOT DARKENING), AND THE 10.7-CM SOLAR RADIO FLUX (F10,FACULAE BRIGHTENING) VALUES. THE RESULTING IRRADIANCE REGRESSION FIT I*,ARE
IERBS = 1362.9 - (7053 x PPSI) + [0.02953 x 1022 (F10)] - [0.00005 x 1044(F10)2]
AND
IN7 = 1369.9 - (592 x PPSI) + [0.02561 x 1022 (F10)] - [0.00005 x 1044(F10)2]
WHERE F10 IS EXPRESSED IN SOLAR FLUX UNITS (1 sfu=10-22 Wm-2 Hz-1) AND PPSI IS EXPRESSED IN UNITS OF 10-5 Wm-2.
40
ERBS ERBE SOLAR MONITOR TOTAL SOLAR IRRADIANCE (TSI) MEASURMENTS: OCT. 25, 1984 - MARCH 24, 2004
1362
1363
1364
1365
1366
1367
1368
1984 1989 1994 1999 2004TIME
TOTA
L SO
LAR
IRR
AD
IAN
CE
(TSI
), W
m-2
-1
0
1
2
3
4
5
6
7
8
9
STD
EV T
SI, W
m-2
MEASUREMENTS EMPIRICAL FIT STDEV MEASUREMENTS
+ 2.8 Wm-2
MARCH-APRIL 1992 OCTOBER 29, 2003 SOLAR STORM
42
ERBE SOLAR MONITOR MEASUREMENT OF TSI DECREASES DUE SUNSPOT DARKENING: MARCH 23 THRU APRIL 3, 1992
1363.5
1364
1364.5
1365
1365.5
1366
1366.5
1992.224 1992.229 1992.234 1992.239 1992.244 1992.249YEAR
TOTA
L SO
LAR
IRR
AD
IAN
CE
(TSI
), W
m-2
-2
0
2
4
6
8
10
12
TSI S
IGM
AS,
Wm
-2
TSI MEASUREMENT TSI EMPIRICAL FIT MEASUREMENT SIGMAS
TSI FIT = 1362.9 - (7053 x PPSI) + [0.02953 x 1022 (F10)] - [0.00005 x 1044(F10)2]
43
ACTIVE CAVITY RADIOMETER [ACR]: DIFFERENCES BETWEEN TOTAL SOLAR IRRADIANCE [TSI] EMPIRICAL MODEL FIT AND LONG-TERM
SPACECRAFT MEASUREMENTS
DIFERENCES BETWEEN EMPIRICAL MODEL FIT AND SPACECRAFT TOTAL SOLAR IRRADIANCE (TSI) MEASUREMENTS
-5
-4
-3
-2
-1
0
1
2
1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004CALENDAR YEAR
TOTA
L SO
LAR
IRR
AD
IAN
CE,
Wm
-2
-5
-4
-3
-2
-1
0
1
2
MODEL-UARS MODEL-ERBS MODEL-SORCE MODEL-SOHO
44
SOLAR MONITOR MEASUREMENT PRECISION
- COMPARISONS AMONG TSI SPACECRAFT TIME SERIES.
- COMPARISONS BETWEEN TSI MEASURMENTS AND EMPIRICAL DATA FITS BASED UPON SOLAR MAGNETIC INDICES.
- COMPARISONS AMONG ERBE ACR TSI MEASUREMENTS.
46
ERBE NONSCANNING TOTAL ACTIVE-CAVITY RADIOMETERS (ACR’s)
TOTAL WIDE FOV [TWFOV] ACR
TOTAL MEDIUM FOV [TMFOV] ACR
SOLAR MONITORACR
47
ELEVATION GEOMETRY FOR INTERNAL CALIBRATIONS [OFFSETS], SOLAR CALIBRATIONS [GAINS], AND
NOMINAL EARTH-VIEWING [OFFSETS] MEASUREMENTS
48
ERBE TOTAL WIDE FOV [TWFOV] & TOTAL MEDIUM FOV [TMFOV] ACR SENSORS
TOTAL WIDE FOV ACR SENSOR
TOTAL MEDIUM FOV ACR SENSOR
SOLAR MONITOR ACR SENSOR
49
365-DAY RUNNING MEANS OF ERBS/ERBE TWFOV & TMFOV ACR TOTAL SOLAR IRRADIANCE (TSI) MEASUREMENTS COMPARED WITH REFERENCE
SOLAR MONITOR TSI VALUES
1364
1364
1365
1365
1366
1366
1367
1367
1984 1989 1994 1999 2004Calendar Year
Tota
l sol
ar ir
radi
ance
(TSI
), W
m-2
TMFOV TWFOV Solar Monitor (SM)
0.2%
10-YEAR TSI VARIABILITY CYCLE
0.07% TWFOV RESPONSE DECREASE
50
52-WEEK RUNNING MEANS OF ERBS/ERBE TWFOV & TMFOV ACR TOTAL SOLAR IRRADIANCE (TSI) MEASUREMENTS COMPARED
WITH REFERENCE SOLAR MONITOR TSI VALUES
1364
1364
1365
1365
1366
1366
1367
1367
1984 1989 1994 1999 2004Calendar Year
Tota
l sol
ar ir
radi
ance
(TSI
), W
m-2
TMFOV TWFOV Solar Monitor (SM) TWFOV CORRECTED
0.2%
10-YEAR TSI VARIABILITY CYCLE
TWFOVCORRECTED
TWFOVUNCORRECTED
51
.
- The EARTH RADIATION BUDGET SATELLITE (ERBS) SPACECRAFT AND THE EARTH RADIATION BUDGET EXPERIMENT (ERBE) SOLAR MONITOR IS EXPECTED TO BE OPERATIONAL THROUGH 2009, SUNSPOT MAXIMUM.
52
Publication References
1. ERBS : R. B. Lee III et al., 1995, Long-term total solar irradiance variability during sunspot cycle 22, JGR, vol. 100, no. A2, 1667-1675. R. B. Lee III et al., 1998, Validation of 1985-1997 active cavity radiometer spacescraft measurements of total solar irradiance variability, Proc. Conference on Earth Observing Systems, SPIE , 3439, 377-388, July 19-21, 1998, San Diego, CA.
2. NIMBUS7 : Kyle, H. L. et al., 1993, Nimbus 7 Earth Radiation Budget Calibration History, I, The Solar Channels, Rep. RP-1316, NASA Goddard Space Flight Center, Greenbelt, Md.
3. UARS, SMM, ACRIMSAT: Willson, R. C., 1997, Total solar irradiance trend During solar cycles 21 and 22, Science, 277,1963-1965, September 26, 1997. Wilson R.C., 2001, The ACRIMSAT/ACRIM III experiment – extending the precision, long-term total solar irradiance climate database, The Earth Observer 13 (3): 14-17.
4. SOLCON/SOVA 1/VIRGO,: Crommelynck, D., Fichot, A., Domingo, V., Lee, R. B.,1996, Preliminary Results of”SOLCON Solar Constant Observations from the ATLAS missions, Geophysical Research Letters, 23, No. 17 , 2293-2295. Dewitte, S., Joukoff, A., Crommelynck, D., Lee, R.B., Helizon, R., Wilson, R.S., 2001, Contribution of the Solar Constant (SOLCON) program to the long-term total solar irradiance observations, J Geophys Res 106 (A8): 15759-15765.
5. PMOD/VIRGO: M. Anklin, C. Frohlich, W. Finsterle,D. Crommelynck, S. Dewitte, 1998, Assessment of the degradation of VIRGO radiometers onboard SOHO, Metrologia, 37, 387-391.
53
Data Source References1.ERBS: The 1984-1999 measurements can be obtained from the Langley Distributed Active Archive Center [DAAC] by telnet eosdis.larc.nasa.gov,login name: ims, password: larcims or by NCSA Mosaic using the URL addresshttp://eosdis.larc.nasa.gov
2. UARS, SMM: The 1991-1998 measurements can be obtained from the ACRMSAT web page acrim.com or the Langley Distributed Active Archive Center [DAAC] by telnet eosdis.larc.nasa.gov,login name: ims, password: larcims or by NCSA Mosaic using the URL address http://eosdis.larc.nasa.gov
3. NIMBUS 7 The 1980-1993 measurements can be obtained from the Goddard Distributed Active Archive Center [DAAC] using the URL address http://daac.gsfc.nasa.gov
5. SOLCON/ SOVA 1/VIRGO: Dominique Crommelynck ,Royal Meteorological Institute of Belgium Avenue Circulaire, 3,1180 Bruxelles, Phone Number: (32 2) 3730600, Fax Number : (32 2) 3746788 E-Mail: [email protected]
54
ERBS/ERBE SOLAR MONITOR RAW TSI DATAJULIAN CALENDAR TIME TSI TSI TSI TSI TSI TSIDAY YEAR/ HOURS/ MEASURE SUN MEASURE MEASURE MEASURE MEASURE
MONTH/ MINUTES/ SUN SHUTTER BEFORE BEFORE AFTER AFTERDAY SECONDS OPENED REFERENCEREFERENCEREFERENCEREFERENCE
SHUTTER SHUTTER SHUTTER SHUTTER SHUTTEROPENED CLOSED CLOSED CLOSED CLOSED
YY:MM:DDHH:MM:SS STD STD STDDATEJM Y/M/D H:MI:S COUNTS COUNTS COUNTS COUNTS COUNTS COUNTSDATEJM Y/M/D H:MI:S CX SDCX RC1 SDRC1 RC2 SDRC22446006 841101 84312 4319.6 3 7268.6 2.8 7263.4 2.92446010 841105 61944 4304.2 3 7265.2 2.4 7266 1.22446063 841228 83512 4236.4 3 7265 1.6 7263.2 2.92446089 850123 16656 4247.2 1.5 7266.6 0.9 7266.8 1.32446103 850206 13214 4261.2 2.8 7267.4 1.5 7266.4 2.62446117 850220 13328 4108.4 4.3 7161.8 3.2 7162 3.62446117 850220 13536 4102.4 4 7161.8 3.1 7161.2 2.42446117 850220 13744 4110.4 2.9 7160.6 3.8 7161.2 3.32446131 850306 111024 4301.8 1.6 7261.2 1.8 7259.8 0.82446145 850320 12574 4339.2 1.9 7265.2 2.6 7266.2 1.32446159 850403 173008 4318.6 2.3 7231.8 1.9 7232 1.42446159 850403 173216 4317.8 1.8 7232 1.4 7231.6 1.52446173 850417 135648 4416.2 3.7 7274.4 3.6 7274.8 1.82446187 850051 12494 4421 1.9 7260 1.2 7258.8 1.12446194 850058 12400 4428 1.9 7257.8 1.6 7255.6 1.52446215 850529 123928 4479.6 2.7 7267 1.7 7267.2 1.52446235 850618 120936 4427 3.2 7222.2 2 7222.2 22446235 850618 121144 4421.2 1.5 7223 1.2 7221.8 1.52446243 850626 121040 4495.4 4 7265.6 2.8 7266 1.22446257 850710 123543 4498.2 1.5 7265 1.4 7263.8 1.32446271 850724 121455 4483.2 1.9 7261.4 1.5 7261 1.22446285 850807 140447 4491.6 2.9 7271.2 3.3 7271.2 2.92446299 850821 115823 4341.6 2.7 7189 1.9 7187.8 1.92446299 850821 120031 4331.8 2.6 7188.6 1.5 7188 1.22446299 850821 120239 4331.2 2.3 7187.4 2.7 7187.2 1.52446313 850904 133007 4431.2 3.5 7261.8 2.8 7262.8 1.52446327 850918 121735 4409.8 1.9 7264.6 2.5 7263.6 1.52446341 851002 133943 4316 1.9 7223.8 1.1 7224.2 1.32446341 851002 134151 4306 2.1 7224 2 7223 1.92446355 851016 131543 4353.6 2.3 7267.4 2.1 7267.6 1.52446359 851020 175751 4361.6 3.9 7278.2 3 7277.2 2.42446370 851031 120447 4305.8 3.2 7260 3.1 7261.2 1.52446383 851113 130951 4291 3.4 7263.6 3 7263.6 2.92446397 851127 133527 4264.2 1.5 7262.4 1.5 7263 1.92446417 851218 114711 4171.4 2.2 7218.8 1.5 7217.6 1.72446417 851218 114919 4159.2 2.3 7218.4 1.5 7217.4 1.12446425 851225 144415 4231 2 7261 1.6 7260.2 1.32446439 860108 114119 4244 3.5 7267.2 3.5 7268 3.12446453 860122 125631 4242.8 4 7262.8 3.7 7262.8 3.22446477 860215 121039 4228.6 1.8 7234.6 1.8 7234 1.22446477 860215 121247 4219.6 1.8 7233.8 1.8 7232.4 1.82446495 860305 124831 4310.4 2.5 7261 1.6 7260.2 1.52446495 860305 125039 4299.8 1.9 7259.2 1.5 7258.2 2.82446523 860402 123927 4310.6 1.8 7227.2 1.9 7227.6 1.3