共查询到20条相似文献，搜索用时 109 毫秒
1.
Although solar ultraviolet (UV) irradiance measurements have been made regularly from satellite instruments for almost 20 years, only one complete solar cycle minimum has been observed during this period. Solar activity is currently moving through the minimum phase between cycles 22 and 23, so it is of interest to compare recent data taken from the NOAA-9 SBUV/2 instrument with data taken by the same instrument during the previous solar minimum in 1985–1986. NOAA-9 SBUV/2 is the first instrument to make continuous solar UV measurements for a complete solar cycle. Direct irradiance measurements (e.g., 205 nm) from NOAA-9 are currently useful for examining short-term variations, but have not been corrected for long-term instrument sensitivity changes. We use the Mgii proxy index to illustrate variability on solar cycle time scales, and to provide complementary information on short-term variability. Comparisons with contemporaneous data from Nimbus-7 SBUV (1985–1986) and UARS SUSIM (1994–1995) are used to validate the results obtained from the NOAA-9 data. Current short-term UV activity differs from the cycle 21–22 minimum. Continuous 13-day periodicity was observed from September 1994 to March 1995, a condition which has only been seen previously for shorter intervals during rising or maximum activity levels. The 205 nm irradiance and Mgii index are expected to track very closely on short time scales, but show differences in behavior during the minimum between cycles 22 and 23. 相似文献
2.
A NOAA-11 SBUV/2 Mgii solar activity proxy index has been created for the period February 1989 through October 1994 from the daily discrete mode solar irradiance data using an algorithm that utilizes a thorough instrument characterization. This product represents a significant improvement over the previously released NOAA-11 SBUV/2 sweep mode-based Mgii data set. As measured by the NOAA-11 Mgii index, the amplitude of solar rotational activity declined from approximately 4–7% peak-to-peak near the maximum of solar cycle 22 in 1989–1991 to roughly 1% peak-to-peak by late-1994. Corresponding to this decrease, the 27-day averaged NOAA-11 Mgii index decreased by 5.8% over this period. The NOAA-11 Mgii data set is compared with coincident data sets from the UARS SOLSTICE and SUSIM instruments. The impact of differences in instrument resolution and observation platform are examined with respect to both the absolute value and temporal variations of the Mgii index. Periodograms of the three indexes demonstrate comparable solar variation tracking. Between October 1991 and October 1994 predominate power occurs near 27 days, with secondary maxima in the power spectra near 29 and 25 days. Overall, there is low power near 13.5 days during this period. Dynamic power spectral analysis reveals the quasi-periodic and quasi-stationary nature of the middle UV variations tracked by the Mgii index, and periods of significant power near 13.5 days in mid-1991 and late-1994 through mid-1995. 相似文献
3.
L. E. Floyd P. A. Reiser P. C. Crane L. C. Herring D. K. Prinz G. E. Brueckner 《Solar physics》1998,177(1-2):79-87
The Solar Ultraviolet Spectral Irradiance Monitor (SUSIM) has measured the solar spectral irradiance for wavelengths 115–410 nm on a daily basis since October 11, 1991. The absolutely calibrated solar UV irradiances through January 8, 1996 have been produced. Their time-dependent behavior is similar to that of the Mgii index as measured both by NOAA-9 SBUV and by SUSIM itself. The maximum long-term variation observed by SUSIM is at L and is measured to be in excess of a factor of 2. This maximum variation decreases with increasing wavelength until about 300 nm where no significant long-term variation is directly measured above SUSIM's estimated 1–2% relative accuracy. The wavelength dependence of the measured UV variability is found to roughly correspond to the mean emission height given by solar atmospheric radiative transfer models. Because SUSIM observations began when solar activity was near its peak and now extend to very near its minimum, estimates of the solar cycle 22 UV variability are generated from a combination of these measurements and solar activity proxy indices. 相似文献
4.
The Global Ozone Monitoring Experiment (GOME) is the first of a series of European satellite instruments monitoring global ozone and other relevant trace constituents in the UV/visible spectral range. On 20 April 1995, the European Space Agency (ESA) launched the GOME from Kourou, French Guyana, aboard the second European Remote Sensing satellite (ERS-2). In order to obtain the geometric albedo from the backscattered terrestrial radiance measurements, a solar irradiance measurement sequence in the spectral range between 240 nm and 790 nm is carried out once every day. The GOME solar irradiance is recorded at a moderate spectral resolution (0.2–0.4 nm), thus providing an excellent opportunity to contribute to the long-term investigation of solar flux variation associated with the 11-year solar activity cycle from space, which started in 1978 with SBUV (Solar Backscatter UV Experiment) observations on Nimbus-7 and covers solar cycles 21 and 22. This paper briefly describes the GOME spectrometer and measurement mode which are relevant to the solar viewing. Preliminary results from the solar irradiance measurements between 1995 and 1997 and comparisons to SSBUV-8 (Shuttle SBUV) in January 1996 are presented. Solar activity indices used as proxies for solar flux variation are often used to find a correlation with observed variation in atmospheric quantities, for instance, total ozone. Initial results from the GOME Mgii (280 nm) and Caii K (393 nm) solar activity index calculation are presented and discussed. The coupling of solar irradiance variability to global change is a current source of scientific and public concern. This study shows that GOME/ERS-2 (1995–2001) and the next generation of European remote sensing instruments, SCIAMACHY and GOME/METOP, have the potential to provide continuity in the measurements of solar irradiance from space well into the next century. 相似文献
5.
We have processed a 10-year set of BBSO Caii K-line filtergrams covering most of solar cycle 22. The excess K-line emission is integrated to form linear and square-root activity indices that are fitted to UV data from UARS and SME. Good fits are found both for the Mgii core–wing ratio (linear) and total L irradiance (square root) and the indices are thus good proxies for UV data. The SME L irradiance is systematically lower by 20% than predicted from our corresponding K-line indices. The 10.7 cm radio data confirms that SME underestimated the flux. The network is partly responsible for the solar cycle variation of the indices and is relatively more important in L than in Mgii and Caii K. This is due to the saturation of L equivalent width. We also report on substantial improvements to the equipment and reduction software. The system is now based on a digital CCD camera which promises more accurate measurements in the upcoming solar cycle 23. 相似文献
6.
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
7.
Electromagnetic radiation from the Sun is Earths primary energy source. Space-based radiometric measurements in the past two decades have begun to establish the nature, magnitude and origins of its variability. An 11-year cycle with peak-to-peak amplitude of order 0.1 % is now well established in recent total solar irradiance observations, as are larger variations of order 0.2 % associated with the Suns 27-day rotation period. The ultraviolet, visible and infrared spectral regions all participate in these variations, with larger changes at shorter wavelengths. Linkages of solar radiative output variations with solar magnetism are clearly identified. Active regions alter the local radiance, and their wavelength-dependent contrasts relative to the quiet Sun control the relative spectrum of irradiance variability. Solar radiative output also responds to sub-surface convection and to eruptive events on the Sun. On the shortest time scales, total irradiance exhibits five minute fluctuations of amplitude
%, and can increase to as much as 0.015 % during the very largest solar flares. Unknown is whether multi-decadal changes in solar activity produce longer-term irradiance variations larger than observed thus far in the contemporary epoch. Empirical associations with solar activity proxies suggest reduced total solar irradiance during the anomalously low activity in the seventeenth century Maunder Minimum relative to the present. Uncertainties in understanding the physical relationships between direct magnetic modulation of solar radiative output and heliospheric modulation of cosmogenic proxies preclude definitive historical irradiance estimates, as yet.Received: 26 August 2004, Published online: 16 November 2004
Correspondence to: Claus Fröhlich 相似文献
8.
We present a model for the reconstruction of spectral solar irradiance between 200 and 400?nm. This model is an extension of the total solar irradiance (TSI) model of Crouch et al. (Astrophys.?J. 677, 723, 2008) which is based on a data-driven Monte Carlo simulation of sunspot emergence, fragmentation, and erosion. The resulting time-evolving daily area distribution of magnetic structures of all sizes is used as input to a four-component irradiance model including contributions from the quiet Sun, sunspots, faculae, and network. In extending the model to spectral irradiance in the near- and mid-ultraviolet, the quiet Sun and sunspot emissivities are calculated from synthetic spectra at T eff=5750?K and 5250?K, respectively. Facular emissivities are calculated using a simple synthesis procedure proposed by Solanki and Unruh (Astron. Astrophys. 329, 747, 1998). The resulting time series of ultraviolet flux is calibrated against the data from the SOLSTICE instrument on the Upper Atmospheric Research Satellite (UARS). Using a genetic algorithm, we invert quiet Sun corrections, profile of facular temperature variations with height, and network model parameters which yield the best fit to these data. The resulting best-fit time series reproduces quite well the solar-cycle timescale variations of UARS ultraviolet observations, as well as the short-timescale fluctuations about the 81 day running mean. We synthesize full spectra between 200 and 400?nm, and validate these against the spectra obtained by the ATLAS-1 and ATLAS-3 missions, finding good agreement, to better than 3?% at most wavelengths. We also compare the UV variability predicted by our reconstructions in the descending phase of sunspot cycle 23 to SORCE/SIM data as well as to other reconstructions. Finally, we use the model to reconstruct the time series of spectral irradiance starting in 1874, and investigate temporal correlations between pairs of wavelengths in the bands of interest for stratospheric chemistry and dynamics. 相似文献
9.
M. Meftah D. Bolsée L. Damé A. Hauchecorne N. Pereira A. Irbah S. Bekki G. Cessateur T. Foujols R. Thiéblemont 《Solar physics》2016,291(12):3527-3547
Accurate measurements of the solar spectral irradiance (SSI) and its temporal variations are of primary interest to better understand solar mechanisms, and the links between solar variability and Earth’s atmosphere and climate. The SOLar SPECtrum (SOLSPEC) instrument of the Solar Monitoring Observatory (SOLAR) payload onboard the International Space Station (ISS) has been built to carry out SSI measurements from 165 to 3088 nm. We focus here on the ultraviolet (UV) part of the measured solar spectrum (wavelengths less than 400 nm) because the UV part is potentially important for understanding the solar forcing of Earth’s atmosphere and climate. We present here SOLAR/SOLSPEC UV data obtained since 2008, and their variations in three spectral bands during Solar Cycle 24. They are compared with previously reported UV measurements and model reconstructions, and differences are discussed. 相似文献
10.
We have compared three years of daily CaII K-line images from the Big Bear Solar Observatory (BBSO) with HI Lyman irradiance data from the Upper Atmosphere Research Satellite (UARS). The daily full-disk CaII K-line images are reduced to a new index of integrated excess emission, which reproduces both the 27 day rotational modulation and the solar cycle decrease in Ly irradiance. Our analysis shows that while plages reproduce the 27-day variation quite well, the total K-line emission excess above the quiet background is needed to reproduce the secular solar cycle trend in the Ly irradiance. The resulting K-line index exhibits a high degree of correlation (0.9) with the time series of measured Ly flux. 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.
Over 24 years of synoptic data from the NSO Kitt Peak Vacuum Telescope is used to investigate the coherency and source of the 27-day (synodic) periodicity that is observed over multiple solar cycles in various solar-related time series. A strong 27.03-day period signal, recently reported by Neugebauer et al. (2000), is clearly detected in power spectra of time series from integrated full-disk measurements of the magnetic flux in the 868.8 nm Fei line and the line equivalent width in the 1083.0 nm Hei line. Using spectral analysis of synoptic maps of photospheric magnetic fields, in addition to constructing maps of the surface distribution of activity, we find that the origin of the 27.03-day signal is long-lived complexes of active regions in the northern hemisphere at a latitude of approximately 18 deg. In addition, using a new time series analysis technique which utilizes the phase variance of a signal, the coherency of the 27.03-day period signal is found to be significant for the past two decades. However, using the past 120 years of the sunspot number time series, the 27.03-day period signal is found to be a short-lived, no longer than two 11-year solar cycles, quasi-stationary signal. 相似文献
13.
Periodicities of solar irradiance and solar activity indices,I 总被引：1，自引：0，他引：1
Using a standard FFT time series analysis, our results show an 8–11 months periodicity in the solar total and UV irradiances, 10.7 cm radio flux, Ca-K plage index, and sunspot blocking function. The physical origin of this period is not known, but the evidence in the results exclude the possibility that the observed period is a harmonic due to the FFT transform or detrending. Periods at 150–157 and 51 days are found in those solar data which are related to strong magnetic fields. The 51-day period is the dominant period in the projected areas of developing complex sunspot groups, but it is missing from the old decaying sunspot areas. This evidence suggests that the 51-day period is related to the emergence of new magnetic fields. A strong 13.5-day period is found in the total irradiance and projected areas of developing complex groups. This confirms those results (e.g., Donnelly et al., 1983, 1984; Bai, 1987, 1989) which show that active centers are located 180 deg apart from each other.Our study also shows that the modulation of various solar data due to the 27-day solar rotation is more pronounced during the declining portion of solar cycle than during the rising portion. This arises from that the active regions and their magnetic fields are better organized and more long-lived during the maximum and declining portion of solar cycle than during its rising portion. 相似文献
14.
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
15.
A. A. Nusinov T. V. Kazachevskaya V. V. Katyushina P. M. Svidskii Yu. N. Tsigel'nitskii D. A. Gonyukh A. N. Afanas'ev S. I. Boldyrev D. V. Lisin A. I. Stepanov 《Solar System Research》2005,39(6):470-478
The paper presents a brief review of the instruments developed for measurement of ionizing extreme UV solar radiation at wavelengths of less than 130 nm onboard the CORONAS-I and CORONAS-F satellites and summarizes the observation data. The main goal of the study was to obtain information concerning variations of fluxes of solar radiation and solar flares at various wavelengths in the extreme ultraviolet. SUFR radiometers based on the thermoluminescent method were mounted onboard both CORONAS satellites (CORONAS-I and CORONAS-F). They performed measurements at λ < 130 nm. Spectral measurements in the 30.4-nm line were made by the photoelectronic spectrometer VUSS tested on CORONAS-I. Spectral measurements in the waveband including the H Lα line (121.6 nm) were conducted by the VUSS-L instrument (a Lyman alpha spectrophotometer) onboard the CORONAS-F satellite. The basic characteristics of the instruments, which were supposed to be used in a system of space weather monitoring on patrol satellites of the hydrometeorological service of Russia, are presented. The main data on the solar radiation flux at λ < 130 nm for minimum and maximum solar activity are given for quiet conditions and during solar flares. 相似文献
16.
G. Thuillier M. DeLand A. Shapiro W. Schmutz D. Bolsée S. M. L. Melo 《Solar physics》2012,277(2):245-266
We present a new method to reconstruct the solar spectrum irradiance in the Ly α – 400 nm region, and its variability, based on the Mg ii index and neutron-monitor measurements. Measurements of the solar spectral irradiance available in the literature have been
made with different instruments at different times and different spectral ranges. However, climate studies require harmonised
data sets. This new approach has the advantage of being independent of the absolute calibration and aging of the instruments.
First, the Mg ii index is derived using solar spectra from Ly α (121 nm) to 410 nm measured from 1978 to 2010 by several space missions. The variability of the spectra with respect to a
chosen reference spectrum as a function of time and wavelength is scaled to the derived Mg ii index. The set of coefficients expressing the spectral variability can be applied to the chosen reference spectrum to reconstruct
the solar spectra within a given time frame or Mg ii index values. The accuracy of this method is estimated using two approaches: direct comparison with particular cases where
solar spectra are available from independent measurements, and calculating the standard deviation between the measured spectra
and their reconstruction. From direct comparisons with measurements we obtain an accuracy of about 1 to 2%, which degrades
towards Ly α. In a further step, we extend our solar spectral-irradiance reconstruction back to the Maunder Minimum introducing the relationship
between the Mg ii index and the neutron-monitor data. Consistent measurements of the Mg ii index are not available prior to 1978. However, we remark that over the last three solar cycles, the Mg ii index shows strong correlation with the modulation potential determined from the neutron-monitor data. Assuming that this
correlation can be applied to the past, we reconstruct the Mg ii index from the modulation potential back to the Maunder Minimum, and obtain the corresponding solar spectral-irradiance reconstruction
back to that period. As there is no direct measurement of the spectral irradiance for this period we discuss this methodology
in light of the other proposed approaches available in the literature. The use of the cosmogenic-isotope data provides a major
advantage: it provides information about solar activity over several thousands years. Using technology of today, we can calibrate
the solar irradiance against activity and thus reconstruct it for the times when cosmogenic-isotope data are available. This
calibration can be re-assessed at any time, if necessary. 相似文献
17.
An empirical model of solar UV spectral irradiance has been developed that is based on observed spectral radiance measurements and full disk Ca ii K images. The Mg ii index is then calculated from the estimated spectra in a narrow wavelength range (180 Å) near the Mg ii doublet at 2800 Å. Our long term goal is to expand this wavelength range from 10 to 4000 Å in continuing studies based on spectral data covering this wavelength range (e.g. Skylab, UARS/SUSIM, TIMED/SEE, etc.). Our previous modeling effort produced spectra in this 180 Å range and the resulting Mg ii index values for the period from 1991 through 1995 and we have used observations during this time period to validate the model results. The current paper presents results from this model based on a 21-year portion of the recently digitized Ca ii K images from the Mt Wilson Observatory (MWO) film archive. Here we present details of the model, the required model modifications, and the resulting Mg ii index from 1961 through 1981. Since the NOAA Mg ii index did not begin until 1978, the present model results are compared to a Mg ii index estimated from the F10.7 radio flux over this 21-year period. The NOAA Mg ii index, which is derived from measured UV spectra, is also included for comparison from late 1978 through 1981. 相似文献
18.
B. M. Vladimirsky V. P. Bobova N. M. Bondarenko V. K. Veretennikova 《Solar physics》1983,82(1-2):451-455
The measurements of the amplitudes envelope of Pc 3–4 geomagnetic micropulsations obtained at the Borok Geophysical Observatory were analysed by the cosinor method to search for magnetospheric pulsations with a period of about 160 m. 216 days of observations in 1974–1978 were used. It was found that Pc 3–4 amplitudes are modulated by the period 160.010 m with a stable phase. The maximum of the Pc 3–4 amplitudes follows approximately 20 m after the maximum of the solar expansion velocity (for the center of the disk) in the optical observations of Severny et al. This modulation of the Pc 3–4 amplitudes could be caused by the presence of an oscillating component in solar UV radiation over the wavelength range 100–900 Å. The amplitude of the UV flux variation may be as large as 2–4%. 相似文献
19.
T. V. Kazachevskaya A. A. Nusinov V. V. Katyushina D. A. Gonjyukh 《Solar System Research》2008,42(4):359-362
The CORONAS-I and CORONAS-F data on variations in the ionizing shortwave ultraviolet (UV) solar radiation (EUV radiation) at wavelengths of less than 130 nm and near the H Lyman-alpha line are presented. The CORONAS-I data refer to the period close to solar minimum (the index F 10.7 = 80?100), and the CORONAS-F measurements were held close to solar maximum (F10.7 = 140?280). The UV data are compared to those from the UARS and SOHO satellites and to the results obtained from the ionospheric measurements of ionosphere critical frequencies. 相似文献
20.
The Solar–Stellar Irradiance Comparison Experiment II (SOLSTICE II) is one of four experiments launched aboard the Solar Radiation and Climate Experiment (SORCE) on 25 January, 2003. Its principal
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% and to determine solar variability with a relative accuracy of 0.5% per year during a 5-year
long nominal mission. SOLSTICE II meets these objectives using a pair of identical scanning grating monochromators that can measure both solar and stellar
irradiance. Instrument radiometric responsivity was calibrated to ∼3% absolute accuracy before launch using the Synchrotron
Ultraviolet Radiation Facility (SURF) at the National Institute for Standards and Technology (NIST) in Gaithersburg, MD. During
orbital operations, SOLSTICE II has been making daily measurements of both the Sun and an ensemble of bright, stable, main-sequence B and A stars. The stellar
measurements allow the tracking of changes in instrument responsivity with a relative accuracy of 0.5% per year over the life
of the mission. SOLSTICE II is an evolution of the SOLSTICE i instrument that is currently operating on the Upper Atmosphere Research Satellite (UARS). This paper reviews the basic SOLSTICE
concept and describes the design, operating modes, and early performance of the SOLSTICE II instrument. 相似文献