Transfer of radiometric standards between multiple low earth orbit climate observing broadband radiometers: application to CERES

Matthews, Grant; Priestley, Kory J.; Thomas, Susan

doi:10.1117/12.734478

Cited by 4 publications

(1 citation statement)

References 2 publications

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“…MERBE has therefore completely recalibrated and regenerated all relevant instantaneous radiative flux data files from CERES devices. This was done using spectral characterization techniques and the Moon as a primary radiometric standard as documented previously (Matthews, 2008(Matthews, , 2009(Matthews, , 2018a(Matthews, , 2018b(Matthews, , 2018cMatthews et al, 2006Matthews et al, , 2007.…”

Section: 2mentioning

confidence: 99%

NASA CERES Spurious Calibration Drifts Corrected by Lunar Scans to Show the Sun Is not Increasing Global Warming and Allow Immediate CRF Detection

Matthews¹

2021

Geophysical Research Letters

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There is still much uncertainty surrounding how the Earth will respond to the rapid recent warming that has been observed, due to significant anthropogenic greenhouse gas releases in the last 120 years. The resulting changes to clouds, often referred to as cloud radiative forcing/feedback or CRF (Bony et al., 2006), remains one of the largest unknowns. More specifically, it is unclear if the rapidly arriving warmer Earth will result in more, less, or simply different types of clouds, and whether changes to say their sunlight reflection will diminish or amplify warming (i.e., as a negative or positive climate feedback).The time averaged solar flux of 1,361 2Wm arriving at Earth is currently very stable on decadal length scales, with a slight negative trend of −0.029%/decade in the 2000-2015 timeframe, so cannot by itself be responsible for current rapid surface temperature rises (see Figure 1, LASP, 2021). This work is therefore not an analysis of effects of variation in solar output on climate change (Haigh, 1996), but instead its focus is on changes to remaining planetary solar input after reflection from Earth, defined here as "albedo solar warming" (at first assuming the Solar output flux is completely constant over time). Albedo changes have the potential to be a primary driver of climate change, as they would alter the energy entering Earth from the currently stable Sun. For example, the rise in atmospheric reflectivity due to particulate aerosols emitted from the 1991 Pinatubo volcanic eruption (Soden et al., 2002), led to a temporary global cooling of around half a degree Celsius.Climate scientists and economists estimated that the size of the CRF albedo solar warming/cooling climate signal trends being looked for, are no larger than just under 0.8 2Wm /decade in magnitude (Cooke et al., 2013;Wielicki et al., 2013). This is in terms of changes to fractional Earth reflectivity, multiplied with the incoming solar flux (that averages to 1,361 2Wm with an overhead Sun). Solar flux is measured daily Abstract Orbital Earth Radiation Budget measurement comparisons to models, are critical for climate prediction confidence. Satellite systems must reduce calibration drifts for this purpose. NASA Clouds and the Earth's Radiant Energy System (CERES) measures Earth albedo reductions that if correct, would increase solar forcing and suggest greater sunlight absorption is driving much of recent temperature increases. Such results are presented, alongside those from the Moon and Earth Radiation Budget Experiment (MERBE). MERBE uses constant lunar reflectivity for tracking and compensation of instrument telescope degradation, undetectable by CERES. MERBE finds Earth albedo constant compared to that of the Moon, because Arctic solar warming effects are balanced by solar cooling elsewhere, likely due to negative feedbacks. Contrary to NASA, this shows the Sun is not increasing warming and that CERES results are not as stable as claimed and assumed. Furthermore, MERBE can actually resolve Cloud Radiative Forcing (CRF) sign...

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Section: 2mentioning

confidence: 99%

NASA CERES Spurious Calibration Drifts Corrected by Lunar Scans to Show the Sun Is not Increasing Global Warming and Allow Immediate CRF Detection

Matthews¹

2021

Geophysical Research Letters

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In-Flight Spectral Characterization and Calibration Stability Estimates for the Clouds and the Earth’s Radiant Energy System (CERES)

Matthews

2009

Journal of Atmospheric and Oceanic Technology

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It is essential to maintain global measurements of the earth radiation budget (ERB) from space, the scattered solar and emitted thermal radiative fluxes leaving the planet. These are required for the purpose of validating current climate model predictions of the planet's future response to anthropogenic greenhouse gas forcing. The measurement accuracy and calibration stability required to resolve the magnitude of modelsuggested cloud-climate feedbacks on the ERB have recently been estimated. The suggestion is for ERB data to strive for a calibration stability of 60.3% decade 21 for scattered solar, 60.5% decade 21 for emitted thermal, and an overall absolute accuracy of 1 W m 22 . The Clouds and the Earth's Radiant Energy System (CERES) is currently the only satellite program to make global ERB measurements, beginning in January 1998. However, the new climate calibration standards are beyond those originally specified by the NASA CERES program for its edition 2 data release. Furthermore, the CERES instrument optics have been discovered to undergo substantial in-flight degradation because of contaminant issues. This is not directly detectable by using established calibration methods. Hence, user-applied revisions for edition 2 shortwave (SW) data were derived to compensate for this effect, which is described as ''spectral darkening.'' Also, an entirely new in-flight calibration protocol has been developed for CERES that uses deep convective cloud albedo as a primary solar wavelength stability metric. This is then combined with a sophisticated contamination mobilization/ polymerization model. The intention is to assign spectral coloration to any optical degradation occurring to the different CERES Earth observing telescopes. This paper quantifies the stability of revised edition 2 data. It also calculates stability, which the new protocols could give CERES measurements if used. The conclusion is that the edition 2 revisions restore the originally specified stability of CERES SW data. It is also determined that the climate calibration stability goals are reachable by using the new in-flight methodologies presented in this paper. However, this will require datasets of longer than approximately 10 yr. It will also require obtaining regular raster scans of the Moon by all operational CERES instruments.

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Celestial body irradiance determination from an underfilled satellite radiometer: application to albedo and thermal emission measurements of the Moon using CERES

Matthews

2008

Appl. Opt.

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The Clouds and the Earth's Radiant Energy System (CERES) is a program that measures the Earth radiation budget (ERB) from two polar orbiting satellite platforms. CERES radiometers are designed to make stable broadband measurements of scattered solar and emitted thermal radiative flux leaving Earth with an accuracy of 1% or better. Using versatile and programmable scan modes, it is also possible for every CERES instrument to view the Moon on each orbit. However, until now, it has not been possible to derive absolute measurements of lunar irradiance using CERES because the Moon's disk fills only 10% of the telescope field of view. This work presents a method of integrating CERES raster-scan data in order to obtain a measurement of the average scattered solar and emitted thermal radiance from the entire lunar disk. The technique results in excellent agreement between CERES instruments on different satellites as to lunar albedo and emitted thermal flux. The average broadband Moon albedo is measured by CERES at a value of 0.1362 (+/-2-3%) when normalized to a static lunar phase angle of 7 degrees using the U.S. Geological Survey lunar irradiance Robotic Lunar Observatory model. The method for the first time also yields very accurate measurements of the thermal irradiance emitted from the Moon. These suggest an average long-wave flux of 977 Wm(-2) (+/-2-3% at 7 degrees phase), implying an approximate mean surface temperature of around 92 degrees C. Statistical analysis on available data suggests that a CERES instrument performing monthly lunar measurements could utilize the Moon as a stability target and reduce calibration drifts to 0.3% per decade or less within an instrument's lifetime. Given the success of the technique, a solar calibration system is proposed that will allow precise tracking of an ERB instrument's optical degradation using the Sun.

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Transfer of radiometric standards between multiple low earth orbit climate observing broadband radiometers: application to CERES

Cited by 4 publications

References 2 publications

NASA CERES Spurious Calibration Drifts Corrected by Lunar Scans to Show the Sun Is not Increasing Global Warming and Allow Immediate CRF Detection

NASA CERES Spurious Calibration Drifts Corrected by Lunar Scans to Show the Sun Is not Increasing Global Warming and Allow Immediate CRF Detection

In-Flight Spectral Characterization and Calibration Stability Estimates for the Clouds and the Earth’s Radiant Energy System (CERES)

Celestial body irradiance determination from an underfilled satellite radiometer: application to albedo and thermal emission measurements of the Moon using CERES

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