HR: 1330h
AN: SH12A-1151 [PDF]
TI: Observations of Solar Spectral Irradiance Change
During Cycle 22 from NOAA-9 SBUV/2
AU: * Cebula, R P
EM: richard_cebula@ssaihq.com
AF: Science Systems and Applications, Inc. (SSAI), 10210 Greenbelt Rd., Suite 400, Lanham, MD 20706 United States
AU: DeLand, M T
EM: matthew_deland@ssaihq.com
AF: Science Systems and Applications, Inc. (SSAI), 10210 Greenbelt Rd., Suite 400, Lanham, MD 20706 United States
AB:
The NOAA-9 Solar Backscatter Ultraviolet, model 2 (SBUV/2) instrument is one of a series of
instruments providing daily solar spectral irradiance measurements in the middle and near
ultraviolet since 1978. This instrument did not have onboard monitoring of all time-dependent
response changes that affect the solar data. Thus a combination of internal and external
techniques was used to derive the instrument's long-term instrument characterization. The
corrected NOAA-9 solar spectral irradiance data between 170 and 400 nm extend from March
1985 to May 1997, spanning two solar cycle minima with a single instrument. The NOAA-9
data show an amplitude of 9.3($\pm$2.3)% (81-day averaged) at 200-205 nm for solar cycle 22. This
is consistent with the result of $\Delta$F$_{200-205}$ = 8.3($\pm$2.6)% for cycle 21
from Nimbus-7 SBUV and $\Delta$F$_{200-205}$ = 10($\pm$2)%
(daily values) for cycle 23 from UARS SUSIM. NOAA-9 data at 245-250
nm show a solar cycle amplitude of $\Delta$F$_{245-250}$ = 5.7($\pm$1.8)%.
These data were used to investigate
whether there was a trend in absolute solar spectral irradiance between the solar cycle 21 and 22
minima. We find an irradiance difference of $\pm$1% or less between the two minima. The
observed differences are less than the uncertainty in the long-term instrument calibration and
should not be considered statistically significant. NOAA-9 SBUV/2 data can be combined with
other instruments to create a 25-year record of solar UV irradiance.
DE: 7536 Solar activity cycle (2162)
DE: 7538 Solar irradiance
DE: 7549 Ultraviolet emissions
DE: 7594 Instruments and techniques
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting