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1.
Gary Rottman 《Solar physics》2005,230(1-2):7-25
The Solar Radiation and Climate Experiment (SORCE) satellite carries four scientific instruments that measure the solar radiation
at the top of the Earth's atmosphere. The mission is an important flight component of NASA's Earth Observing System (EOS),
which in turn is the major observational and scientific element of the U.S. Global Change Research Program. The scientific
objectives of SORCE are to make daily measurements of the total solar irradiance and of spectral solar irradiance from 120
to 2000 nm with additional measurements of the energetic X-rays. Solar radiation provides the dominant energy source for the
Earth system and detailed understanding of its variation is essential for atmospheric and climate studies. SORCE was launched
on January 25, 2003 and has an expected lifetime through the next solar minimum in about 2007. The spacecraft and all instruments
have operated flawlessly during the first 2 years, and this paper provides an overview of the mission and discusses the contributions
that SORCE is making to improve understanding of the Sun's influence on the Earth environment. 相似文献
2.
Thomas P. Sparn Gary Rottman Thomas N. Woods Brian D. Boyle Richard Kohnert Sean Ryan Randall Davis Robert Fulton William Ochs 《Solar physics》2005,230(1-2):71-89
The Solar Radiation and Climate Experiment, SORCE, is a satellite carrying four scientific instruments that measure the total
solar irradiance and the spectral irradiance from the ultraviolet to the infrared. The instruments were all developed by the
Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado, Boulder. The spacecraft carrying and accommodating
the instruments was developed by Orbital Sciences Corporation in Dulles, Virginia. It is three-axis stabilized with a control
system to point the instruments at the Sun, as well as the stars for calibration. SORCE was successfully launched from the
Kennedy Space Center in Florida on 25 January 2003 aboard a Pegasus XL rocket. The anticipated lifetime is 5 years, with a
goal of 6 years. SORCE is operated from the Mission Operations Center at LASP where all data are collected, processed, and
distributed. This paper describes the SORCE spacecraft, integration and test, mission operations, and ground data system. 相似文献
3.
We model total solar irradiance (TSI) using photometric irradiance indices from the San Fernando Observatory (SFO), and compare our model with measurements compiled from different space-based radiometers. Space-based measurements of TSI have been obtained recently from ACRIM-3 on board the ACRIMSAT. These data have been combined with other data sets to create an ACRIM-based composite. From VIRGO on board the Solar and Heliospheric Observatory (SOHO) spacecraft two different TSI composites have been developed. The VIRGO irradiance data have been combined by the Davos group to create a composite often referred to as PMOD (Physikalisch-Meteorologisches Observatorium Davos). Also using data from VIRGO, the Royal Meteorological Institute of Belgium (RMIB) has created a separate composite TSI referred to here as the RMIB composite. We also report on comparisons with TSI data from the Total Irradiance Monitor (TIM) experiment on board the Solar Radiation and Climate Experiment (SORCE) spacecraft. The SFO model correlates well with all four experiments during the seven-year SORCE interval. For this interval, the squared correlation coefficient R 2 was 0.949 for SORCE, 0.887 for ACRIM, 0.922 for PMOD, and 0.924 for RMIB. Long-term differences between the PMOD, ACRIM, and RMIB composites become apparent when we examine a 21.5-year interval. We demonstrate that ground-based photometry, by accurately removing TSI variations caused by solar activity, is useful for understanding the differences that exist between TSI measurements from different spacecraft experiments. 相似文献
4.
The Solar Radiation and Climate Experiment (SORCE) Mission for the NASA Earth Observing System (EOS) 总被引：1，自引：0，他引：1
The NASA Earth Observing System (EOS) is an advanced study of Earth's long-term global changes of solid Earth, its atmosphere,
and oceans and includes a coordinated collection of satellites, data systems, and modeling. The EOS program was conceived
in the 1980s as part of NASA's Earth System Enterprise (ESE). The Solar Radiation and Climate Experiment (SORCE) is one of
about 20 missions planned for the EOS program, and the SORCE measurement objectives include the total solar irradiance (TSI)
and solar spectral irradiance (SSI) that are two of the 24 key measurement parameters defined for the EOS program. The SORCE
satellite was launched in January 2003, and its observations are improving the understanding and generating new inquiry regarding
how and why solar variability occurs and how it affects Earth's energy balance, atmosphere, and long-term climate changes. 相似文献
5.
The Solar–Stellar Irradiance Comparison Experiment {II (SOLSTICE {II), aboard the Solar Radiation and Climate Experiment (SORCE)
spacecraft, consists of a pair of identical scanning grating monochromators, which have the capability to observe both solar
spectral irradiance and stellar spectral irradiance using a single optical system. The SOLSTICE science objectives are to
measure solar spectral irradiance from 115 to 320 nm with a spectral resolution of 1 nm, a cadence of 6 h, and an accuracy
of 5%, to determine its variability with a long-term relative accuracy of 0.5% per year during a 5-year nominal mission, and
to determine the ratio of solar irradiance to that of an ensemble of bright B and A stars to an accuracy of 2%. Those objectives
are met by calibrating instrument radiometric sensitivity before launch using the Synchrotron Ultraviolet Radiation Facility
at the National Institute for Standards and Technology in Gaithersburg, Maryland. During orbital operations irradiance measurements
from an ensemble of bright, stable, main-sequence B and A stars are used to track instrument sensitivity. SORCE was launched
on 25 January 2003. After spacecraft and instrument check out, SOLSTICE {II first observed a series of three stars to establish
an on-orbit performance baseline. Since 6 March 2003, both instruments have been making daily measurements of both the Sun
and stars. This paper describes the pre-flight and in-flight calibration and characterization measurements that are required
to achieve the SOLSTICE science objectives and compares early SOLSTICE{II measurements of both solar and stellar irradiance
with those obtained by SOLSTICE {I on the Upper Atmosphere Research Satellite. 相似文献
6.
The cadence and resolution of solar images have been increasing dramatically with the launch of new spacecraft such as STEREO and SDO. This increase in data volume provides new opportunities for solar researchers, but the efficient processing and analysis of these data create new challenges. We introduce a fuzzy-based solar feature-detection system in this article. The proposed system processes SDO/AIA images using fuzzy rules to detect coronal holes and active regions. This system is fast and it can handle different size images. It is tested on six months of solar data (1 October 2010 to 31 March 2011) to generate filling factors (ratio of area of solar feature to area of rest of the solar disc) for active regions and coronal holes. These filling factors are then compared to SDO/EVE/ESP irradiance measurements. The correlation between active-region filling factors and irradiance measurements is found to be very high, which has encouraged us to design a time-series prediction system using Radial Basis Function Networks to predict ESP irradiance measurements from our generated filling factors. 相似文献
7.
Total solar irradiance (TSI) measurements have been available from the TIM instrument on the SORCE spacecraft since 2003. We compare TSI data, both 24-h and 6-h averages, with photometric indices from red and K-line images obtained on a daily basis at the San Fernando Observatory (SFO). For 1253 days of data from 2 March 2003 to 5 May 2010 we compare the data in linear multiple regression analyses. The best results come from using two photometric indices, the red and K-line photometric sums, and SORCE TSI 6-h averages interpolated to the SFO time of observation. For this case, we obtain a coefficient of multiple determination, R 2, of 0.9495 and a quiet-Sun irradiance S 0?=?1360.810?±?0.004?W?m?2. These results provide further support for the hypothesis that the quiet Sun is constant over time. 相似文献
8.
Thomas N. Woods Phillip C. Chamberlin W. K. Peterson R. R. Meier Phil G. Richards Douglas J. Strickland Gang Lu Liying Qian Stanley C. Solomon B. A. Iijima A. J. Mannucci B. T. Tsurutani 《Solar physics》2008,250(2):235-267
Solar soft X-ray (XUV) radiation is highly variable on all time scales and strongly affects Earth’s ionosphere and upper atmosphere;
consequently, the solar XUV irradiance is important for atmospheric studies and for space weather applications. Although there
have been several recent measurements of the solar XUV irradiance, detailed understanding of the solar XUV irradiance, especially
its variability during flares, has been hampered by the broad bands measured in the XUV range. In particular, the simple conversion
of the XUV photometer signal into irradiance, in which a static solar spectrum is assumed, overestimates the flare variations
by more than a factor of two as compared to the atmospheric response to the flares. To address this deficiency in the simple
conversion, an improved algorithm using CHIANTI spectral models has been developed to process the XUV Photometer System (XPS)
measurements with its broadband photometers. Model spectra representative of quiet Sun, active region, and flares are combined
to match the signals from the XPS and produce spectra from 0.1 to 40 nm in 0.1-nm intervals for the XPS Level 4 data product.
The two XPS instruments are aboard NASA’s Solar Radiation and Climate Experiment (SORCE) and Thermosphere, Ionosphere, Mesosphere, Energetics, and Dynamics (TIMED) satellites. In addition, the XPS responsivities have been updated for the latest XPS data processing version. The
new XPS results are consistent with daily variations from the previous simple conversion technique used for XPS and are also
consistent with spectral measurements made at wavelengths longer than 27 nm. Most importantly, the XPS flare variations are
reduced by factors of 2 – 4 at wavelengths shorter than 14 nm and are more consistent, for the first time, with atmospheric
response to solar flares. Along with the details of the new XPS algorithm, several comparisons to dayglow and photoelectron
measurements and model results are also presented to help verify the accuracy of the new XUV irradiance spectra. 相似文献
9.
10.
Clette Frédéric Lefèvre Laure Bechet Sabrina Ramelli Renzo Cagnotti Marco 《Solar physics》2021,296(9):1-16
Solar Physics - The final version (V.19) of the total solar irradiance data from the SOlar Radiation and Climate Experiment (SORCE) Total Irradiance Monitor has been released. This version includes... 相似文献
11.
Knowledge of solar spectral irradiance (SSI) is important in determining the impact of solar variability on climate. Observations of UV SSI have been made by the Solar Ultraviolet Spectral Irradiance Monitor (SUSIM) on the Upper Atmosphere Research Satellite (UARS), the Solar-Stellar Irradiance Comparison Experiment (SOLSTICE), and the Solar Irradiance Monitor (SIM), both on the Solar Radiation and Climate Experiment (SORCE) satellite. Measurements by SUSIM and SORCE overlapped from 2003 to 2005. SUSIM and SORCE observations represent ～?20 years of absolute UV SSI. Unfortunately, significant differences exist between these two data sets. In particular, changes in SORCE UV SSI measurements, gathered at moderate and minimum solar activity, are a factor of two greater than the changes in SUSIM observations over the entire solar cycle. In addition, SORCE UV SSI have a substantially different relationship with the Mg ii index than did earlier UV SSI observations. Acceptance of these new SORCE results impose significant changes on our understanding of UV SSI variation. Alternatively, these differences in UV SSI observations indicate that some or all of these instruments have changes in instrument responsivity that are not fully accounted for by the current calibration. In this study, we compare UV SSI changes from SUSIM with those from SIM and SOLSTICE. The primary results are that (1) long-term observations by SUSIM and SORCE generally do not agree during the overlap period (2003?–?2005), (2) SUSIM observations during this overlap period are consistent with an SSI model based on Mg ii and early SUSIM SSI, and (3) when comparing the spectral irradiance for times of similar solar activity on either side of solar minimum, SUSIM observations show slight differences while the SORCE observations show variations that increase with time between spectra. Based on this work, we conclude that the instrument responsivity for SOLSTICE and SIM need to be reevaluated before these results can be used for climate-modeling studies. 相似文献
12.
Aparicio A. J. P. Lefèvre L. Gallego M. C. Vaquero J. M. Clette F. Bravo-Paredes N. Galaviz P. Bautista M. L. 《Solar physics》2018,293(12):1-23
The Spectral Irradiance Monitor (SIM) instrument on board the Solar Radiation and Climate Experiment (SORCE) performs daily measurements of the solar spectral irradiance (SSI) from 200 to 2400 nm. Both temporal and spectral corrections for instrument degradation have been built on physical models based on comparison of two independent channels with different solar exposure. The present study derives a novel correction for SIM degradation using the total solar irradiance (TSI) measurements from the Total Irradiance Monitor (TIM) on SORCE. The correction is applied to SIM SSI data from September 2004 to October 2012 over the wavelength range from 205 nm to 2300 nm. The change in corrected, integrated SSI agrees within \(0.1~\mbox{W}\,\mbox{m}^{-2}\) (\(1\sigma\)) with SORCE TIM TSI and independently shows agreement with the SATIRE-S and NRLSSI2 solar models within measurement uncertainties.
相似文献13.
The solar soft X-ray (XUV) radiation is important for upper atmosphere studies as it is one of the primary energy inputs and
is highly variable. The XUV Photometer System (XPS) aboard the Solar Radiation and Climate Experiment (SORCE) has been measuring
the solar XUV irradiance since March 2003 with a time cadence of 10 s and with about 70% duty cycle. The XPS measurements
are between 0.1 and 34 nm and additionally the bright hydrogen emission at 121.6 nm. The XUV radiation varies by a factor
of ∼2 with a period of ∼27 days that is due to the modulation of the active regions on the rotating Sun. The SORCE mission
has observed over 20 solar rotations during the declining phase of solar cycle 23. The solar XUV irradiance also varies by
more than a factor of 10 during the large X-class flares observed during the May–June 2003, October–November 2003, and July
2004 solar storm periods. There were 7 large X-class flares during the May–June 2003 storm period, 11 X-class flares during
the October–November 2003 storm period, and 6 X-class flares during the July 2004 storm period. The X28 flare on 4 November
2003 is the largest flare since GOES began its solar X-ray measurements in 1976. The XUV variations during the X-class flares
are as large as the expected solar cycle variations. 相似文献
14.
The solar soft X-ray (XUV) radiation is highly variable on both short-term time scales of minutes to hours due to flares and
long-term time scales of months to years due to solar cycle variations. Because of the smaller X-ray cross sections, the solar
XUV radiation penetrates deeper than the extreme ultraviolet (EUV) wavelengths and thus influences the photochemistry and
ionization in the mesosphere and lower thermosphere. The XUV Photometer System (XPS) aboard the Solar Radiation and Climate
Experiment (SORCE) is a set of photometers to measure the solar XUV irradiance shortward of 34 nm and the bright hydrogen
emission at 121.6 nm. Each photometer has a spectral bandpass of about 7 nm, and the XPS measurements have an accuracy of
about 20%. The XPS pre-flight calibrations include electronics gain and linearity calibrations in the laboratory over its
operating temperature range, field of view relative maps, and responsivity calibrations using the Synchrotron Ultraviolet
Radiation Facility (SURF) at the National Institute of Standards and Technology (NIST). The XPS in-flight calibrations include
redundant channels used weekly and underflight rocket measurements from the NASA Thermosphere-Ionosphere-Mesosphere-Energetics-Dynamics
(TIMED) program. The SORCE XPS measurements have been validated with the TIMED XPS measurements. The comparisons to solar
EUV models indicate differences by as much as a factor of 4 for some of the models, thus SORCE XPS measurements could be used
to improve these models. 相似文献
15.
S. Vijayan 《Journal of Astrophysics and Astronomy》2008,29(1-2):359-361
Precise measurement of irradiance over the earth under various circumstances like solar flares, coronal mass ejections, over an 11-year solar cycle, etc. leads to better understanding of Sun-earth relationship. To continuously monitor the irradiance over earth-space regions several satellites at several positions are required. For that continuous and multiple satellite monitoring we can use GPS (Global Positioning System) satellites (like GLONASS, GALILEO, future satellites) installed with irradiance measuring and monitoring instruments. GPS satellite system consists of 24 constellations of satellites. Therefore usage of all the satellites leads to 24 measurements of irradiance at the top of the atmosphere (or 12 measurements of those satellites which are pointing towards the Sun) at an instant. Therefore in one day, numerous irradiance observations can be obtained for the whole globe, which will be very helpful for several applications like Albedo calculation, Earth Radiation Budget calculation, monitoring of near earth-space atmosphere, etc. Moreover, measuring irradiance both in ground (using ground instruments) and in space at the same instant of time over a same place, leads to numerous advantages. That is, for a single position we obtain irradiance at the top of the atmosphere, irradiance at ground and the difference in irradiance from over top of the atmosphere to the ground. Measurement of irradiance over the atmosphere and in ground at a precise location gives more fine details about the solar irradiance influence over the earth, path loss and interaction of irradiance with the atmosphere. 相似文献
16.
Regular solar spectral irradiance (SSI) observations from space that simultaneously cover the UV, visible (vis), and the near-IR
(NIR) spectral region began with SCIAMACHY aboard ENVISAT in August 2002. Up to now, these direct observations cover less
than a decade. In order for these SSI measurements to be useful in assessing the role of the Sun in climate change, records
covering more than an eleven-year solar cycle are required. By using our recently developed empirical SCIA proxy model, we
reconstruct daily SSI values over several decades by using solar proxies scaled to short-term SCIAMACHY solar irradiance observations
to describe decadal irradiance changes. These calculations are compared to existing solar data: the UV data from SUSIM/UARS,
from the DeLand & Cebula satellite composite, and the SIP model (S2K+VUV2002); and UV-vis-IR data from the NRLSSI and SATIRE
models, and SIM/SORCE measurements. The mean SSI of the latter models show good agreement (less than 5%) in the vis regions
over three decades while larger disagreements (10 – 20%) are found in the UV and IR regions. Between minima and maxima of
Solar Cycles 21, 22, and 23, the inferred SSI variability from the SCIA proxy is intermediate between SATIRE and NRLSSI in
the UV. While the DeLand & Cebula composite provide the highest variability between solar minimum and maximum, the SIP/Solar2000
and NRLSSI models show minimum variability, which may be due to the use of a single proxy in the modeling of the irradiances.
In the vis-IR spectral region, the SCIA proxy model reports lower values in the changes from solar maximum to minimum, which
may be attributed to overestimations of the sunspot proxy used in modeling the SCIAMACHY irradiances. The fairly short timeseries
of SIM/SORCE shows a steeper decreasing (increasing) trend in the UV (vis) than the other data during the descending phase
of Solar Cycle 23. Though considered to be only provisional, the opposite trend seen in the visible SIM data challenges the
validity of proxy-based linear extrapolation commonly used in reconstructing past irradiances. 相似文献
17.
The solar spectral irradiance (SSI) dataset is a key record for studying and understanding the energetics and radiation balance in Earth’s environment. Understanding the long-term variations of the SSI over timescales of the 11-year solar activity cycle and longer is critical for many Sun–Earth research topics. Satellite measurements of the SSI have been made since the 1970s, most of them in the ultraviolet, but recently also in the visible and near-infrared. A limiting factor for the accuracy of previous solar variability results is the uncertainties for the instrument degradation corrections, which need fairly large corrections relative to the amount of solar cycle variability at some wavelengths. The primary objective of this investigation has been to separate out solar cycle variability and any residual uncorrected instrumental trends in the SSI measurements from the Solar Radiation and Climate Experiment (SORCE) mission and the Thermosphere, Mesosphere, Ionosphere, Energetic, and Dynamics (TIMED) mission. A new technique called the Multiple Same-Irradiance-Level (MuSIL) analysis has been developed, which examines an SSI time series at different levels of solar activity to provide long-term trends in an SSI record, and the most common result is a downward trend that most likely stems from uncorrected instrument degradation. This technique has been applied to each wavelength in the SSI records from SORCE (2003?–?present) and TIMED (2002?–?present) to provide new solar cycle variability results between 27 nm and 1600 nm with a resolution of about 1 nm at most wavelengths. This technique, which was validated with the highly accurate total solar irradiance (TSI) record, has an estimated relative uncertainty of about 5% of the measured solar cycle variability. The MuSIL results are further validated with the comparison of the new solar cycle variability results from different solar cycles. 相似文献
18.
Solar radiation is the primary energy source for many processes in Earth's environment and is responsible for driving the
atmospheric and oceanic circulation. The integrated strength and spectral distribution of solar radiation is modified from
the space-based {Solar {Radiation and {Climate (SORCE) measurements through scattering and absorption processes in the atmosphere
and at the surface. Understanding how these processes perturb the distribution of radiative flux density is essential in determining
the climate response to changes in concentration of various gases and aerosol particles from natural and anthropogenic sources,
as is discerning their associated feedback mechanisms. The past decade has been witness to a tremendous effort to quantify
the absorption of solar radiation by clouds and aerosol particles via airborne and space-based observations. Vastly improved
measurement and modeling capabilities have enhanced our ability to quantify the radiative energy budget, yet gaps persist
in our knowledge of some fundamental variables. This paper reviews some of the many advances in atmospheric solar radiative
transfer as well as those areas where large uncertainties remain. The SORCE mission's primary contribution to the energy budget
studies is the specification of the solar total and spectral irradiance at the top of the atmosphere. 相似文献
19.
S. Turck-Chièze P. Lamy C. Carr P. H. Carton A. Chevalier I. Dandouras J. M. Defise S. Dewitte T. Dudok de Wit J. P. Halain S. Hasan J. F. Hochedez T. Horbury P. Levacher M. Meissonier N. Murphy P. Rochus A. Ruzmaikin W. Schmutz G. Thuillier S. Vivès 《Experimental Astronomy》2009,23(3):1017-1055
The DynaMICCS mission is designed to probe and understand the dynamics of crucial regions of the Sun that determine solar
variability, including the previously unexplored inner core, the radiative/convective zone interface layers, the photosphere/chromosphere
layers and the low corona. The mission delivers data and knowledge that no other known mission provides for understanding
space weather and space climate and for advancing stellar physics (internal dynamics) and fundamental physics (neutrino properties,
atomic physics, gravitational moments...). The science objectives are achieved using Doppler and magnetic measurements of
the solar surface, helioseismic and coronographic measurements, solar irradiance at different wavelengths and in-situ measurements
of plasma/energetic particles/magnetic fields. The DynaMICCS payload uses an original concept studied by Thalès Alenia Space
in the framework of the CNES call for formation flying missions: an external occultation of the solar light is obtained by
putting an occulter spacecraft 150 m (or more) in front of a second spacecraft. The occulter spacecraft, a LEO platform of
the mini sat class, e.g. PROTEUS, type carries the helioseismic and irradiance instruments and the formation flying technologies.
The latter spacecraft of the same type carries a visible and infrared coronagraph for a unique observation of the solar corona
and instrumentation for the study of the solar wind and imagers. This mission must guarantee long (one 11-year solar cycle)
and continuous observations (duty cycle > 94%) of signals that can be very weak (the gravity mode detection supposes the measurement
of velocity smaller than 1 mm/s). This assumes no interruption in observation and very stable thermal conditions. The preferred
orbit therefore is the L1 orbit, which fits these requirements very well and is also an attractive environment for the spacecraft
due to its low radiation and low perturbation (solar pressure) environment. This mission is secured by instrumental R and
D activities during the present and coming years. Some prototypes of different instruments are already built (GOLFNG, SDM)
and the performances will be checked before launch on the ground or in space through planned missions of CNES and PROBA ESA
missions (PICARD, LYRA, maybe ASPIICS). 相似文献
20.
Curtis D.W. Berg P. Gordon D. Harvey P.R. Smith D.M. Zehnder A. 《Solar physics》2002,210(1-2):115-124
The Ramaty High-Energy Spectroscopic Imager (RHESSI) spacecraft is a NASA Small Explorer (SMEX) class mission. RHESSI is designed
to image solar X-rays and gamma rays with high-energy resolution. The Instrument Data Processing Unit (IDPU) serves as the
central RHESSI instrument on-board data-processing element. It controls and monitors the instrument operations, and provides
a flexible telemetry collection and formatting system. The system responds autonomously to optimize science data collection
over a wide dynamic range of conditions, handling up to 40 Mbps of telemetry during solar flares. This paper presents an overview
of the IDPU hardware and software design. 相似文献