The TSIS‐1 Hybrid Solar Reference Spectrum Coddington, O. M.; Richard, E. C.; Harber, D. ...
Geophysical research letters,
28 June 2021, Letnik:
48, Številka:
12
Journal Article
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We present a new solar irradiance reference spectrum representative of solar minimum conditions between solar cycles 24 and 25. The Total and Spectral Solar Irradiance Sensor‐1 (TSIS‐1) Hybrid Solar ...Reference Spectrum (HSRS) is developed by applying a modified spectral ratio method to normalize very high spectral resolution solar line data to the absolute irradiance scale of the TSIS‐1 Spectral Irradiance Monitor (SIM) and the CubeSat Compact SIM (CSIM). The high spectral resolution solar line data are the Air Force Geophysical Laboratory ultraviolet solar irradiance balloon observations, the ground‐based Quality Assurance of Spectral Ultraviolet Measurements In Europe Fourier transform spectrometer solar irradiance observations, the Kitt Peak National Observatory solar transmittance atlas, and the semi‐empirical Solar Pseudo‐Transmittance Spectrum atlas. The TSIS‐1 HSRS spans 202–2730 nm at 0.01 to ∼0.001 nm spectral resolution with uncertainties of 0.3% between 460 and 2365 nm and 1.3% at wavelengths outside that range.
Plain Language Summary
The Sun's irradiance spectrum is used in many applications, such as constraining the solar forcing in climate models and converting measured satellite radiance to reflectance. A growing body of literature has provided evidence that the currently available solar reference spectra differ by more than their reported uncertainties. Such differences lead to biased results when different reference spectra are adopted in the aforementioned applications. This motivates our work to provide a new high‐resolution solar reference spectrum at higher accuracy than any previously reported. Our ability to produce such a data set is due to the state‐of‐the‐art measurements of the Sun's irradiance spectrum made since March 2018 by the next‐generation Spectral Irradiance Monitor (SIM) instrument on the Total and Spectral Solar Irradiance Sensor‐1 (TSIS‐1) satellite mission and the Compact SIM (CSIM) technology demonstration mission. The TSIS‐1 SIM and CSIM have order‐of‐magnitude reduction in uncertainty relative to predecessor instruments primarily because of a first‐of‐its‐kind spectral radiometric calibration facility capable of characterizing the instruments to higher fidelity. We develop this new, high‐resolution, solar irradiance reference spectrum by adjusting high spectral resolution solar line data to the irradiance scale of the more accurate, but lower spectral resolution, TSIS‐1 SIM and CSIM observations.
Key Points
The TSIS‐1 Spectral Irradiance Monitor and Compact SIM instruments observe the Sun's irradiance spectrum at high accuracy
The TSIS‐1 Hybrid Solar Reference Spectrum consists of high resolution solar line data normalized to the TSIS‐1 SIM irradiance spectrum
The TSIS‐1 Hybrid Solar Reference Spectrum has at least 0.01 nm spectral resolution, spans 202–2730 nm, and is accurate to 0.3%–1.3%
A SOLAR IRRADIANCE CLIMATE DATA RECORD Coddington, O.; Lean, J. L.; Pilewskie, P. ...
Bulletin of the American Meteorological Society,
07/2016, Letnik:
97, Številka:
7
Journal Article
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We present a new climate data record for total solar irradiance and solar spectral irradiance between 1610 and the present day with associated wavelength and time-dependent uncertainties and ...quarterly updates. The data record, which is part of the National Oceanic and Atmospheric Administration’s (NOAA) Climate Data Record (CDR) program, provides a robust, sustainable, and scientifically defensible record of solar irradiance that is of sufficient length, consistency, and continuity for use in studies of climate variability and climate change on multiple time scales and for user groups spanning climate modeling, remote sensing, and natural resource and renewable energy industries. The data record, jointly developed by the University of Colorado’s Laboratory for Atmospheric and Space Physics (LASP) and the Naval Research Laboratory (NRL), is constructed from solar irradiance models that determine the changes with respect to quiet sun conditions when facular brightening and sunspot darkening features are present on the solar disk where the magnitude of the changes in irradiance are determined from the linear regression of a proxy magnesium (Mg) II index and sunspot area indices against the approximately decade-long solar irradiance measurements of the Solar Radiation and Climate Experiment (SORCE). To promote long-term data usage and sharing for a broad range of users, the source code, the dataset itself, and supporting documentation are archived at NOAA’s National Centers for Environmental Information (NCEI). In the future, the dataset will also be available through the LASP Interactive Solar Irradiance Data Center (LISIRD) for user-specified time periods and spectral ranges of interest.
The lack of long and reliable time series of solar spectral irradiance (SSI) measurements makes an accurate quantification of solar contributions to recent climate change difficult. Whereas earlier ...SSI observations and models provided a qualitatively consistent picture of the SSI variability, recent measurements by the SORCE (SOlar Radiation and Climate Experiment) satellite suggest a significantly stronger variability in the ultraviolet (UV) spectral range and changes in the visible and near-infrared (NIR) bands in anti-phase with the solar cycle. A number of recent chemistry-climate model (CCM) simulations have shown that this might have significant implications on the Earth's atmosphere. Motivated by these results, we summarize here our current knowledge of SSI variability and its impact on Earth's climate. We present a detailed overview of existing SSI measurements and provide thorough comparison of models available to date. SSI changes influence the Earth's atmosphere, both directly, through changes in shortwave (SW) heating and therefore, temperature and ozone distributions in the stratosphere, and indirectly, through dynamical feedbacks. We investigate these direct and indirect effects using several state-of-the art CCM simulations forced with measured and modelled SSI changes. A unique asset of this study is the use of a common comprehensive approach for an issue that is usually addressed separately by different communities. We show that the SORCE measurements are difficult to reconcile with earlier observations and with SSI models. Of the five SSI models discussed here, specifically NRLSSI (Naval Research Laboratory Solar Spectral Irradiance), SATIRE-S (Spectral And Total Irradiance REconstructions for the Satellite era), COSI (COde for Solar Irradiance), SRPM (Solar Radiation Physical Modelling), and OAR (Osservatorio Astronomico di Roma), only one shows a behaviour of the UV and visible irradiance qualitatively resembling that of the recent SORCE measurements. However, the integral of the SSI computed with this model over the entire spectral range does not reproduce the measured cyclical changes of the total solar irradiance, which is an essential requisite for realistic evaluations of solar effects on the Earth's climate in CCMs. We show that within the range provided by the recent SSI observations and semi-empirical models discussed here, the NRLSSI model and SORCE observations represent the lower and upper limits in the magnitude of the SSI solar cycle variation. The results of the CCM simulations, forced with the SSI solar cycle variations estimated from the NRLSSI model and from SORCE measurements, show that the direct solar response in the stratosphere is larger for the SORCE than for the NRLSSI data. Correspondingly, larger UV forcing also leads to a larger surface response. Finally, we discuss the reliability of the available data and we propose additional coordinated work, first to build composite SSI data sets out of scattered observations and to refine current SSI models, and second, to run coordinated CCM experiments.
We present an overview of the background, scientific goals, and execution of the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) project of April 2008. We then summarize ...airborne measurements, made in the troposphere of the Alaskan Arctic, of aerosol particle size distributions, composition, and optical properties and discuss the sources and transport of the aerosols. The aerosol data were grouped into four categories based on gas-phase composition. First, the background troposphere contained a relatively diffuse, sulfate-rich aerosol extending from the top of the sea-ice inversion layer to 7.4 km altitude. Second, a region of depleted (relative to the background) aerosol was present within the surface inversion layer over sea-ice. Third, layers of dense, organic-rich smoke from open biomass fires in southern Russia and southeastern Siberia were frequently encountered at all altitudes from the top of the inversion layer to 7.1 km. Finally, some aerosol layers were dominated by components originating from fossil fuel combustion. Of these four categories measured during ARCPAC, the diffuse background aerosol was most similar to the average springtime aerosol properties observed at a long-term monitoring site at Barrow, Alaska. The biomass burning (BB) and fossil fuel layers were present above the sea-ice inversion layer and did not reach the sea-ice surface during the course of the ARCPAC measurements. The BB aerosol layers were highly scattering and were moderately hygroscopic. On average, the layers produced a noontime net heating of ~0.1 K day−1 between 3 and 7 km and a slight cooling at the surface. The ratios of particle mass to carbon monoxide (CO) in the BB plumes, which had been transported over distances >5000 km, were comparable to the high end of literature values derived from previous measurements in wildfire smoke. These ratios suggest minimal precipitation scavenging and removal of the BB particles between the time they were emitted and the time they were observed in dense layers above the sea-ice inversion layer.
ACHIEVING CLIMATE CHANGE ABSOLUTE ACCURACY IN ORBIT Wielicki, Bruce A.; Young, D. F.; Mlynczak, M. G. ...
Bulletin of the American Meteorological Society,
10/2013, Letnik:
94, Številka:
10
Journal Article
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The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission will provide a calibration laboratory in orbit for the purpose of accurately measuring and attributing climate change. ...CLARREO measurements establish new climate change benchmarks with high absolute radiometric accuracy and high statistical confidence across a wide range of essential climate variables. CLARREO's inherently high absolute accuracy will be verified and traceable on orbit to Système Internationale (SI) units. The benchmarks established by CLARREO will be critical for assessing changes in the Earth system and climate model predictive capabilities for decades into the future as society works to meet the challenge of optimizing strategies for mitigating and adapting to climate change. The CLARREO benchmarks are derived from measurements of the Earth's thermal infrared spectrum (5–50μm), the spectrum of solar radiation reflected by the Earth and its atmosphere (320–2300 nm), and radio occultation refractivity from which accurate temperature profiles are derived. The mission has the ability to provide new spectral fingerprints of climate change, as well as to provide the first orbiting radiometer with accuracy sufficient to serve as the reference transfer standard for other space sensors, in essence serving as a “NIST National Institute of Standards and Technology in orbit.” CLARREO will greatly improve the accuracy and relevance of a wide range of space-borne instruments for decadal climate change. Finally, CLARREO has developed new metrics and methods for determining the accuracy requirements of climate observations for a wide range of climate variables and uncertainty sources. These methods should be useful for improving our understanding of observing requirements for most climate change observations.
The response of the Northern Hemisphere winter stratosphere to the Pacific decadal oscillation (PDO) is examined using the Whole Atmosphere Community Climate Model. A 200-yr preindustrial control ...simulation that includes fully interactive chemistry, ocean and sea ice, constant solar forcing, and greenhouse gases fixed to 1850 levels is analyzed. Based on principal component analysis, the PDO spatial pattern, frequency, and amplitude agree well with the observed PDO over the period 1900–2014. Consistent with previous studies, the positive phase of the PDO is marked by a strengthened Aleutian low and a wave train of geopotential height anomalies reminiscent of the Pacific–North American pattern in the troposphere. In addition to a tropospheric signal, a zonal-mean warming of about 2K in the northern polar stratosphere and a zonal-mean zonal wind decrease of about 4 m s−1 in the PDO positive phase are found. When compositing PDO positive or negative winters during neutral El Niño years, the magnitude is reduced and depicts an early winter forcing of the stratosphere compared to a late winter response from El Niño. Contamination between PDO and ENSO signals is also discussed. Stratospheric sudden warmings occur 63% of the time in the PDO positive phase compared to 40% in the negative phase. Although this sudden warming frequency is not statistically significant, it is quantitatively consistent with NCEP–NCAR reanalysis data and recent observational evidence linking the PDO positive phase to weak stratospheric vortex events.
The Earth system responds to solar variability on a wide range of timescales. Knowledge of total solar irradiance (TSI) and solar spectral irradiance (SSI) spanning minutes to centuries is needed by ...scientists studying a broad array of research applications. For these purposes, the NOAA National Centers for Environmental Information (NCEI) Climate Data Record Program established the Solar Irradiance Climate Data Record. Version 2 of the Naval Research Laboratory's solar variability models that are derived from and demonstrate consistency with irradiance observations specifies TSI and SSI for the Solar Irradiance Climate Data Record. We establish the veracity of the Naval Research Laboratory models on the timescales and over the wavelength range for which the Sun is known to vary and, thereby, specify the utility of these models. Through comparisons with irradiance observations and independent models, we validate NRLTSI2 estimates of TSI on solar rotational (~27‐day), solar cycle (~11‐year), and multidecadal (spacecraft era) variability timescales. Similarly, we validate NRLSSI2 estimates of SSI rotational variability in the ultraviolet through the mid‐visible spectrum. Validation of NRLSSI2 estimates at longer wavelengths, particularly in the near‐infrared, and for the full spectrum at solar cycle timescales and longer is not possible with the current observational record due to instrumental noise and instrument instability. We identify where key new data sets, such as observations from the Total and Spectral Solar Irradiance Sensor‐1, are expected to provide a fuller understanding of total and spectral solar irradiance variability on multiple timescales.
Plain Language Summary
An understanding of total and spectral solar irradiance is essential for Earth atmospheric and climate studies because the Sun's energy incident at the top of Earth's atmosphere is the dominant energy source driving a myriad of interactions that establish Earth's climate. We describe how the National Oceanographic and Atmospheric Administration's Solar Irradiance Climate Data Record is meeting the goal to model variability in the Sun's irradiance, identify limitations in our current understanding of solar irradiance variability on multiple timescales and over a broad spectral range, and highlight where new observations are expected to provide a fuller understanding.
Key Points
The Naval Research Laboratory's solar variability models, NRLTSI2 and NRLSSI2, establish the Solar Irradiance Climate Data Record (CDR)
The CDR total and spectral (between 265 and 500 nm) solar rotational estimates are validated by observations on 27‐day solar rotations
On solar cycle timescales and longer, particularly in the spectrum, differences in observational data sets preclude model validation
This work describes two achievements to a key data set. First, we present version 2 of the Total and Spectral Solar Irradiance Sensor‐1 Hybrid Solar Reference Spectrum (TSIS‐1 HSRS), which has ...recently been recognized as a new solar irradiance reference standard (https://calvalportal.ceos.org/). Second, we present a new “full spectrum extension” of the TSIS‐1 HSRS. The TSIS‐1 HSRS observational composite solar irradiance reference spectrum spans 0.202–2.730 μm and encompasses more than 97% of the energy in the total solar irradiance (TSI). Version 2 is an incremental update that corrects the radiometric baseline between 0.202 and 0.210 μm and updates the solar lines at wavelengths longward of 0.743 μm to those listed in the most recent database. The full spectrum extension builds off version 2 of the TSIS‐1 HSRS and supports applications that require a solar spectrum encompassing nearly 100% of the energy in the TSI. It spans 0.115–200 μm and was developed by incorporating additional observations and theoretical knowledge where no direct observations currently exist.
Plain Language Summary
The Sun's irradiance spectrum is used in many applications such as constraining the solar forcing in climate models. Recently, the TSIS‐1 Hybrid Solar Reference Spectrum (HSRS), a spectrum developed by adjusting high spectral resolution solar line data to the irradiance scale of the more accurate, but lower spectral resolution, Total and Spectral Solar Irradiance Sensor‐1 (TSIS‐1) Spectral Irradiance Monitor (SIM) and Compact SIM observations, was formally recognized as a new standard. In this work, we provide an incremental update to that reference spectrum. Furthermore, we extend it to the “full spectrum,” beyond the wavelength range of direct observations of the Sun's irradiance spectrum. The HSRS Extension differs by less than 0.1% in its integral quantity to observations of the total solar irradiance. Above the range of the SIM observations, the solar line data are normalized to the irradiance scale of a theoretical spectrum and then adjusted in magnitude to match the SIM observations at their long wavelength cut‐off. Below the range of the SIM observations, Solar Stellar Irradiance Comparison Experiment observations from the Solar Radiation and Climate Experiment mission are incorporated.
Key Points
Version 2 of the Total and Spectral Solar Irradiance Sensor‐1 (TSIS‐1) Hybrid Solar Reference Spectrum (HSRS) is an incremental update from the original release in 2021
The HSRS Extension builds upon the TSIS‐1 HSRS with independent observations and theoretical knowledge where no observations exist
The HSRS Extension has at least 0.1 nm spectral resolution, spans 0.115–200 μm, and integrates to the total solar irradiance
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