Science Highlights and Final Updates from 17 Years of Total Solar Irradiance Measurements from the SOlar Radiation and Climate Experiment/Total Irradiance Monitor (SORCE/TIM)

AbstractThe 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 all calibrations updated to the end of the mission and provides irradiance data from 25 February 2003 through 25 February 2020. These final calibrations are presented along with the resulting final data products. An overview of the on-orbit operations timeline is provided as well as the associated changes in the time-dependent uncertainties. Scientific highlights from the instrument are also presented. These include the establishment of a new, lower TSI value; accuracy improvements to other TSI instruments via a new calibration facility; the lowest on-orbit noise (for high sensitivity to solar variability) of any TSI instrument; the best inherent stability of any on-orbit TSI instrument; a lengthy (17-year) measurement record benefitting from these stable, low-noise measurements; the first reported detection of a solar flare in TSI; and observations of two Venus transits and four Mercury transits.

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The periodic variation of 6.7 days for total solar radiation

Proceedings of the International Astronomical Union ◽

10.1017/s1743921309992432 ◽

2009 ◽

Vol 5 (S264) ◽

pp. 84-86

Author(s):

W. Q. Gan ◽

Y. P. Li

Keyword(s):

Magnetic Field ◽

Solar Radiation ◽

Power Spectrum ◽

Solar Irradiance ◽

Solar Magnetic Field ◽

Solar Rotation ◽

Periodic Variation ◽

Total Solar Irradiance ◽

Total Solar Radiation ◽

Total Irradiance

AbstractAnalyzing the power spectrum of Total Solar Irradiance (TSI) for the period from 2003 February 25 to 2009 July 6, observed with the Total Irradiance Monitor (TIM) onboard SOlar Radiation and Climate Experiment (SORCE), we found that there are quite a number of periodic variations. The outstanding shortest one is the period of 6.7 days, about one fourth of the period of solar rotation. Checking the solar magnetic field for the same period of time observed with MDI onboard SOHO, we found that there is about 90 degree difference in longitude for the distribution of solar magnetic field. We therefore conclude that both the 90 degree difference in longitude for the distribution of solar magnetic field and the solar rotation are the reason resulting in the periodic variation of 6.7 days for the total solar radiation.

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Simplified Thermal Model for Absolute Radiometer Simulation

Journal of Solar Energy Engineering ◽

10.1115/1.4049939 ◽

2021 ◽

Vol 143 (5) ◽

Author(s):

Andre Godoi Lopes ◽

Ricardo Toshiyuki Irita ◽

Luiz Angelo Berni ◽

Waldeir Amaral Vilela ◽

Graziela da Silva Savonov ◽

...

Keyword(s):

Heat Transfer ◽

Solar Radiation ◽

Thermal Behavior ◽

Solar Irradiance ◽

Thermal Model ◽

Thermal Contact ◽

Total Solar Irradiance ◽

Space Environment ◽

Simplified Model ◽

Material Volume

Abstract The study of solar radiation in space has become something necessary, motivating the launch of radiometers on board satellites dedicated to perform total solar irradiance (TSI) measurements and to build a record of their behavior over the years, thus making these data essential for meteorology and climatology. In this study, we propose a simplified model to understand the thermal behavior of absolute radiometers, which are used in this type of measurement. The model considers the heat transfer among parts through conduction and loss only by radiation since the instrument operates in a space environment. The goal is to understand how each component interferes with sensitivity and response time of the instrument depending on its design, material, volume, and thermal contact. The model was applied to data generated by a prototype for validation.

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A Very Simple Low Noise Voltage Preamplifier For High Sensitivity Noise Measurements

10.1063/1.3140546 ◽

2009 ◽

Cited By ~ 4

Author(s):

G. Cannatà ◽

G. Scandurra ◽

C. Ciofi ◽

Massimo Macucci ◽

Giovanni Basso

Keyword(s):

High Sensitivity ◽

Low Noise ◽

Noise Voltage ◽

Noise Measurements

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Changing of the Guard for the Total Solar Irradiance Record

10.5194/egusphere-egu2020-11489 ◽

2020 ◽

Author(s):

Greg Kopp ◽

David Harber ◽

Karl Heuerman ◽

Brandon Stone

Keyword(s):

Solar Irradiance ◽

Radiant Energy ◽

Total Solar Irradiance ◽

Data Availability ◽

Solar Research ◽

New Processing ◽

The Many ◽

Measurement Record ◽

Future Plans

<p>The uninterrupted, 41-year-long, spaceborne total solar irradiance (TSI) record has recently undergone several changes in the instruments contributing to these measurements of the net incoming radiant energy providing nearly all the power driving the Earth&#8217;s climate system. Two long-term instruments, NASA&#8217;s SORCE/TIM and TCTE/TIM, have recently been powered off. This ends the 17-year record from the SORCE/TIM, which established the currently-accepted TSI value of 1361 W&#160;m<sup>&#8209;2</sup> after its launch in 2003. ESA&#8217;s SoHO/VIRGO continues to acquire measurements that extend its 24-year record, but data availability has been on hold as a new processing methodology is implemented. NASA&#8217;s recently-launched TSIS&#8209;1/TIM is presently continuing the measurements of these stalwart legacy instruments. This new TSI instrument is demonstrating higher on-orbit accuracy than any prior such instrument has achieved, with daily measurement updates that are available to the community for climate- and solar-research purposes. I will discuss the many recent changes to the spaceborne TSI measurement record, the current measurement-accuracy improvements and stabilities achieved and their implications for Earth energy-balance studies, and the future plans to maintain measurement continuity.</p>

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Variations in Solar Brightness

The Role of the Sun in Climate Change ◽

10.1093/oso/9780195094138.003.0006 ◽

1997 ◽

Author(s):

Douglas V. Hoyt ◽

Kenneth H. Shatten

Keyword(s):

Solar Irradiance ◽

Monochromatic Light ◽

Light Output ◽

Total Solar Irradiance ◽

Astronomical Unit ◽

Geomagnetic Disturbances ◽

Solar Constant ◽

Total Irradiance ◽

Total Light ◽

Solar Brightness

In the last chapter we saw that sunspots, aurorae, and geomagnetic disturbances vary in an 11-year cycle. So do many other solar features, including faculae and plages, which are bright regions seen in visible and monochromatic light, respectively. If both bright faculae and dark sunspots follow 11-year cycles, does this mean the sun’s total light output varies? Or are these two contrasting features balanced so that the sun’s output of light remains constant? The light output of the sun is often discussed in two different ways: either as the solar luminosity, which is the sun’s omnidirectional radiant output, or as the solar constant, the output seen in the direction of the Earth. In this chapter, we explore the variable solar light output that has been the subject of vigorous discussions. The total solar irradiance or solar constant is defined as the total radiant power passing through a unit area at Earth’s mean orbital distance of 1 astronomical unit. Today the most common units of solar irradiance are watts per square meter (W/m2). Power is defined as energy per unit time, so the solar irradiance can also be expressed in calories per square centimeter per minute. Modern experiments indicate that the sun’s radiant output is about 1367 W/m2, with an uncertainty of about 4 W/m2. About 150 years of effort by many people have been required to establish the value to this accuracy. The sun’s radiant output is not an easy quantity to measure, and we will discuss some of the struggles required to measure it. In the late 1800s, many scientists considered the solar total irradiance or solar irradiance to be constant. Oceanographers Dove and Maury vigorously supported this viewpoint, so the solar irradiance was called the solar constant. For the next century, virtually every paper concerning the sun’s radiant output used the term solar constant. No physical justification for this nomenclature existed, only a philosophical bias. Yet by the 1950s this bias proved so strong and so prevalent that support for individuals who wished to measure variations in the solar constant became almost nonexistent.

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Overview of the Solar Radiation and Climate Experiment (SORCE) Seventeen-Year Mission

Solar Physics ◽

10.1007/s11207-021-01869-3 ◽

2021 ◽

Vol 296 (8) ◽

Cited By ~ 1

Author(s):

Thomas N. Woods ◽

Jerald W. Harder ◽

Greg Kopp ◽

Debra McCabe ◽

Gary Rottman ◽

...

Keyword(s):

Solar Radiation ◽

Solar Irradiance ◽

Near Infrared ◽

Total Solar Irradiance ◽

Spectral Irradiance ◽

Climate Data ◽

Science Data ◽

Near Ultraviolet ◽

Battery Capacity ◽

Data Gap

AbstractThe Solar Radiation and Climate Experiment (SORCE) was a NASA mission that operated from 2003 to 2020 to provide key climate-monitoring measurements of total solar irradiance (TSI) and solar spectral irradiance (SSI). Three important accomplishments of the SORCE mission are i) the continuation of the 42-year-long TSI climate data record, ii) the continuation of the ultraviolet SSI record, and iii) the initiation of the near-ultraviolet, visible, and near-infrared SSI records. All of the SORCE instruments functioned well over the 17-year mission, which far exceeded its five-year prime mission goal. The SORCE spacecraft, having mostly redundant subsystems, was also robust over the mission. The end of the SORCE mission was a planned passivation of the spacecraft following a successful two-year overlap with the NASA Total and Spectral Solar Irradiance Sensor (TSIS) mission, which continues the TSI and SSI climate records. There were a couple of instrument anomalies and a few spacecraft anomalies during SORCE’s long mission, but operational changes and updates to flight software enabled SORCE to remain productive to the end of its mission. The most challenging of the anomalies was the degradation of the battery capacity that began to impact operations in 2009 and was the cause for the largest SORCE data gap (August 2013 – February 2014). An overview of the SORCE mission is provided with a couple of science highlights and a discussion of flight anomalies that impacted the solar observations. Companion articles about the SORCE instruments and their final science data-processing algorithms provide additional details about the instrument measurements over the duration of the mission.

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Solar Panel Orientation and Modeling Based on Hourly Clearness Index

ASME 2012 6th International Conference on Energy Sustainability, Parts A and B ◽

10.1115/es2012-91359 ◽

2012 ◽

Author(s):

Mohammad H. Naraghi ◽

Gregory Etienne

Keyword(s):

New York ◽

New York City ◽

Solar Irradiance ◽

Total Solar Irradiance ◽

Solar Panel ◽

Solar Panels ◽

Clearness Index ◽

Index Method ◽

Irradiance Data ◽

Solar Noon

Published hourly solar irradiance data are used to calculate the hourly clearness indices for three municipalities (Los Angles, Orlando and New York City). The clearness index method is then used to model the hourly total solar irradiance (summation of beam, diffuse and ground reflected) on an arbitrarily oriented surface. The orientations of solar panel for maximum annual solar irradiance for these locations are determined. It is shown that in some cases the southward solar panels do not yield maximum annual solar irradiance. Further, it is shown that using the hourly clearness index results in solar irradiance distribution that is not symmetric with respect to the solar noon.

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Solar Monitoring has a Past and Present: Does it have a Future?

International Astronomical Union Colloquium ◽

10.1017/s0252921100024477 ◽

1994 ◽

Vol 143 ◽

pp. 4-10 ◽

Cited By ~ 1

Author(s):

Richard C. Willson

Keyword(s):

United States ◽

Solar Irradiance ◽

The United States ◽

Total Solar Irradiance ◽

Collaborative Effort ◽

Solar Cycles ◽

Earth Observing System ◽

Total Irradiance ◽

Sustained Effort

Intrinsic variations of total solar irradiance have, after nearly a century of sustained effort, been demonstrated by flight experiments during solar cycles 21 and 22. This accomplishment has been the result of a collaborative effort on behalf of several groups of researchers in both the United States and Europe. The overriding concern at this point of time is whether the integrity of the precision long-term solar total irradiance database, which began at the maximum of solar cycle 21 and continues in the present, will be lost in the late 1990’s, prior to the inception of experiments planned for the NASA Earth Observing System beginning in 2002. Experiments are not currently in place to prevent an unbridgeable discontinuity in the precision total solar irradiance database.

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Quasi-10-Day and 4-Day Periodicities in Solar Irradiance

Symposium - International Astronomical Union ◽

10.1017/s0074180900238412 ◽

1998 ◽

Vol 185 ◽

pp. 119-120

Author(s):

M.V. Nikonova ◽

N.V. Klochek ◽

L.E. Palamarchuk

Keyword(s):

Solar Irradiance ◽

Noise Signal ◽

Total Solar Irradiance ◽

Artificial Noise ◽

Instrumental Effects ◽

Data Set ◽

Equipment Operation ◽

Data Gaps ◽

Final Data ◽

Further Development

There are many investigations of the total solar irradiance (TSI) variability over the time scales from days to years. Particular emphasis has been placed on the sources of this variability and on the problems concerning stable equipment operation. The investigations made aboard SMM/ACRIM showed a relation between solar variability and various solar activity manifestations. Even then the TSI power spectrum revealed some peculiar periodicity in the range from 9 to 11 days that was not explained and also a well-defined quasi-4-day periodicity (Froelich and Pap, 1989). Their distinctive feature is that they manifest themselves in many processes both on Sun and on Earth. An understanding of their nature is of importance to solar-terrestrial physics. The earlier investigations of Nimbus-7 data pointed out the possible effect of solar sources of unknown nature and also some residual instrumental effects on the behaviour of TSI variations. As a further development of these studies the spectral analysis was made of the TSI variations using the final data set derived over the range from November 1978 to April 1992 aboard Nimbus-7. In our study the data gaps were filled with an artificial noise signal. The autocorrelation function (ACF) was used for detrending and filtering of the data.

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