scholarly journals Development of the Chinese Space-Based Radiometric Benchmark Mission LIBRA

2020 ◽  
Vol 12 (14) ◽  
pp. 2179 ◽  
Author(s):  
Peng Zhang ◽  
Naimeng Lu ◽  
Chuanrong Li ◽  
Lei Ding ◽  
Xiaobing Zheng ◽  
...  
Keyword(s):  
Total Solar Irradiance ◽  
Spectral Irradiance ◽  
High Spectral Resolution ◽  
Radiometric Calibration ◽  
Reference Systems ◽  
Fixed Temperature ◽  
Imaging Spectrometer ◽  
The Earth ◽  
Reference Type ◽  
Infrared Spectrometer

Climate observations and their applications require measurements with high stability and low uncertainty in order to detect and assess climate variability and trends. The difficulty with space-based observations is that it is generally not possible to trace them to standard calibration references when in orbit. In order to overcome this problem, it has been proposed to deploy space-based radiometric reference systems which intercalibrate measurements from multiple satellite platforms. Such reference systems have been strongly recommended by international expert teams. This paper describes the Chinese Space-based Radiometric Benchmark (CSRB) project which has been under development since 2014. The goal of CSRB is to launch a reference-type satellite named LIBRA in around 2025. We present the roadmap for CSRB as well as requirements and specifications for LIBRA. Key technologies of the system include miniature phase-change cells providing fixed-temperature points, a cryogenic absolute radiometer, and a spontaneous parametric down-conversion detector. LIBRA will offer measurements with SI traceability for the outgoing radiation from the Earth and the incoming radiation from the Sun with high spectral resolution. The system will be realized with four payloads, i.e., the Infrared Spectrometer (IRS), the Earth-Moon Imaging Spectrometer (EMIS), the Total Solar Irradiance (TSI), and the Solar spectral Irradiance Traceable to Quantum benchmark (SITQ). An on-orbit mode for radiometric calibration traceability and a balloon-based demonstration system for LIBRA are introduced as well in the last part of this paper. As a complementary project to the Climate Absolute Radiance and Refractivity Observatory (CLARREO) and the Traceable Radiometry Underpinning Terrestrial- and Helio- Studies (TRUTHS), LIBRA is expected to join the Earth observation satellite constellation and intends to contribute to space-based climate studies via publicly available data.

scholarly journals Spectral and Radiometric Calibration of the Next Generation Airborne Visible Infrared Spectrometer (AVIRIS-NG)

2019 ◽  
Vol 11 (18) ◽  
pp. 2129 ◽  
Author(s):  
John W. Chapman ◽  
David R. Thompson ◽  
Mark C. Helmlinger ◽  
Brian D. Bue ◽  
Robert O. Green ◽  
...  
Keyword(s):  
Infrared Imaging ◽  
Image Data ◽  
Radiometric Calibration ◽  
Next Generation ◽  
Imaging Spectrometer ◽  
In Situ Data ◽  
Novel Approach ◽  
Infrared Spectrometer ◽  
Calibration Techniques ◽  
Spectrometer Data

We describe advanced spectral and radiometric calibration techniques developed for NASA’s Next Generation Airborne Visible Infrared Imaging Spectrometer (AVIRIS-NG). By employing both statistically rigorous analysis and utilizing in situ data to inform calibration procedures and parameter estimation, we can dramatically reduce undesirable artifacts and minimize uncertainties of calibration parameters notoriously difficult to characterize in the laboratory. We describe a novel approach for destriping imaging spectrometer data through minimizing a Markov Random Field model. We then detail statistical methodology for bad pixel correction of the instrument, followed by the laboratory and field protocols involved in the corrections and evaluate their effectiveness on historical data. Finally, we review the geometric processing procedure used in production of the radiometrically calibrated image data.

Extending the TSIS-1 Hybrid Solar Reference Spectrum (HSRS) to Span 0.202 to 200 um

2021 ◽  
Author(s):  
Odele Coddington ◽  
Erik Richard ◽  
Dave Harber ◽  
Peter Pilewskie ◽  
Tom Woods ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Solar Irradiance ◽  
Solar Spectrum ◽  
Total Solar Irradiance ◽  
Spectral Irradiance ◽  
High Spectral Resolution ◽  
Reference Spectrum ◽  
Solar Cycles ◽  
Theoretical Understanding ◽  
High Resolution Data

<p>Recently, we incorporated our new understanding of the absolute scale of the solar spectrum as measured by the Spectral Irradiance Monitor (SIM) on the Total and Spectral Solar Irradiance Sensor (TSIS-1) mission and the Compact SIM (CSIM) flight demonstration into a solar irradiance reference spectrum representing solar minimum conditions between solar cycles 24 and 25. This new reference spectrum, called the TSIS-1 Hybrid Solar Reference Spectrum (HSRS), is developed by re-normalizing independent, very high spectral resolution datasets to the TSIS-1 SIM absolute irradiance scale. The high-resolution data are from the Airforce Geophysical Laboratory (AFGL), the Quality Assurance of Ultraviolet Measurements In Europe (QASUME) campaign, the Kitt Peak National Observatory (KPNO) and the Jet Propulsion Laboratory’s (JPL) Solar Pseudo-Transmittance Spectrum (SPTS). The TSIS-1 HSRS spans 0.202 µm to 2.73 µm and has a spectral resolution of 0.01 nm or better. Uncertainties are 0.3% between 0.4 and 2.365 mm and 1.3% at wavelengths outside that range</p><p>Recently, we have extended the long wavelength limit of the TSIS-1 HSRS from 2.73 µm to 200 µm with JPL SPTS solar line data through ~ 16 µm and theoretical understanding as represented in a computed solar irradiance spectrum by R. Kurucz. The extension expands the utility of this new solar irradiance reference spectrum to include Earth energy budget studies because it encompasses an integrated energy in excess of 99.99% of the total solar irradiance.</p><p>In this work, we discuss the TSIS-1 HSRS, the extension and uncertainties, and demonstrate consistency with TSIS-1 SIM and CSIM solar spectral irradiance observations and TSIS-1 Total Irradiance Monitor (TIM) total solar irradiance observations. Additionally, we compare the TSIS-1 HSRS against independent measured and modeled solar reference spectra.</p>

Data Fusion of Total Solar Irradiance Composite Time Series Using 40 years of Satellite Measurements: First Results 

2021 ◽  
Author(s):  
Jean-Philippe Montillet ◽  
Wolfgang Finsterle ◽  
Werner Schmutz ◽  
Margit Haberreiter ◽  
Rok Sikonja
Keyword(s):  
Time Series ◽  
Data Fusion ◽  
Solar Irradiance ◽  
Total Solar Irradiance ◽  
Maunder Minimum ◽  
The Sun ◽  
Climate Reconstructions ◽  
The Earth ◽  
First Results ◽  
The Difference

<p><span>Since the late 70’s, successive satellite missions have been monitoring the sun’s activity, recording total solar irradiance observations. These measurements are important to estimate the Earth’s energy imbalance, </span><span>i.e. the difference of energy absorbed and emitted by our planet. Climate modelers need the solar forcing time series in their models in order to study the influence of the Sun on the Earth’s climate. With this amount of TSI data, solar irradiance reconstruction models  can be better validated which can also improve studies looking at past climate reconstructions (e.g., Maunder minimum). V</span><span>arious algorithms have been proposed in the last decade to merge the various TSI measurements over the 40 years of recording period. We have developed a new statistical algorithm based on data fusion.  The stochastic noise processes of the measurements are modeled via a dual kernel including white and coloured noise.  We show our first results and compare it with previous releases (PMOD,ACRIM, ... ). </span></p>

Solar spectral irradiance and total solar irradiance at a solar minimum

2014 ◽  
Vol 54 (7) ◽  
pp. 926-932 ◽  
Author(s):  
E. E. Benevolenskaya ◽  
S. N. Shapovalov ◽  
I. G. Kostuchenko
Keyword(s):  
Solar Irradiance ◽  
Solar Minimum ◽  
Total Solar Irradiance ◽  
Spectral Irradiance ◽  
Solar Spectral Irradiance

GOES High cadence Operational Total Irradiance: planned data products

2021 ◽  
Author(s):  
Martin Snow ◽  
Stephane Beland ◽  
Odele Coddington ◽  
Steven Penton ◽  
Don Woodraska
Keyword(s):  
Extreme Ultraviolet ◽  
Solar Spectrum ◽  
Total Solar Irradiance ◽  
The Other ◽  
Spectral Irradiance ◽  
First Year ◽  
X Ray ◽  
Solar Spectral Irradiance ◽  
Total Irradiance ◽  
High Cadence

<p>The GOES-R series of satellites includes a redesigned instrument for solar spectral irradiance: the Extreme ultraviolet and X-ray Irradiance Sensor (EXIS).  Our team will be using a high-cadence broadband visible light diode to construct a proxy for Total Solar Irradiance (TSI).  This will have two advantages over the existing TSI measurements:  measurements are taken at 4 Hz, so the cadence of our TSI proxy is likely faster than any existing applications, and the observations are taken from geostationary orbit, so the time series of measurements is virtually uninterrupted.  Calibration of the diode measurements will still rely on the standard TSI composites.  </p><p>The other measurement from EXIS that will be used is the Magnesium II core-to-wing ratio.  The MgII index is a proxy for chromospheric activity, and is measured by EXIS every 3 seconds.  The combination of the two proxies can be used to generate a model of the full solar spectrum similar to the NRLSSI2 empirical model.</p><p>We are in the first year of a three-year grant to develop the TSI proxy and the SSI model, so only very preliminary findings will be discussed in this presentation.</p>

scholarly journals A non-rotating origin on the instantaneous equator

1988 ◽  
Vol 128 ◽  
pp. 33-38 ◽  
Author(s):  
N. Capitaine ◽  
B. Guinot
Keyword(s):  
Specific Rotation ◽  
Universal Time ◽  
Reference Systems ◽  
The Earth ◽  
Adopted Model ◽  
Fixed Reference ◽  
Rotation Of The Earth ◽  
Definition Of ◽  
Clear Description ◽  
Angle Of Rotation

In order to give an exact and clear description of the angle of rotation of the Earth, we propose to use, as the reference point in space, a “non-rotating origin” (Guinot 1979) such that its hour angle, reckoned from the origin of the longitudes (or “non-rotating origin” in the Earth), represents strictly the specific rotation of the Earth. The position of this origin on the instantaneous equator depends only on the trajectory of the pole of rotation. We show that the estimation of the deduced angle of rotation is not critically affected by the precision with which this trajectory is known. We give therefore the formulae to obtain the non-rotating origin, at any date t, from a chosen fixed reference, and we propose a definition of the Universal Time which will remain valid, even if the adopted model for the precession and the nutation is revised. We show that the use of the non-rotating origin also simplifies the transformation of coordinates between the terrestrial and celestial reference systems.

Sign in / Sign up

Export Citation Format

Share Document