Telescope pointed at the moon collecting spectral data for climate calibration.

Unlocking Climate Insights: How Lunar Measurements Could Revolutionize Earth Data

Jordan Keane in Climate & Environment December 2025 • 5 min read.

"Dive into the groundbreaking research using lunar spectral irradiance for more accurate climate monitoring and bridging satellite data gaps."

For years, scientists have diligently tracked changes on our planet using satellites, gathering crucial data about everything from vegetation cover to ice albedo. But what happens when satellite missions end or experience gaps in coverage? Maintaining consistent climate data records is essential for understanding long-term changes, and that's where the Moon comes in. Recent advancements propose using the Moon as a reliable calibration standard, ensuring data consistency across different satellite missions.

Traditionally, climate scientists have relied on solar diffusers and well-characterized Earth surface sites for calibration. However, these methods have limitations, including the degradation of solar diffusers and the need for constant maintenance of surface sites. These challenges can introduce uncertainties and potential gaps in data, making it difficult to accurately assess climate trends. Lunar calibration offers a promising alternative, sidestepping atmospheric corrections and providing a consistent reference point for all Earth-orbiting satellites.

The National Institute of Standards and Technology (NIST) has been at the forefront of this exciting research, developing innovative techniques to measure lunar spectral irradiance with unprecedented accuracy. This new level of precision opens up the possibility of using the Moon not only to track changes in sensor response but also as a means of absolute calibration. By improving the accuracy of climate data, we can gain a clearer understanding of our changing world and make more informed decisions about its future.

The Moon as a Climate Calibration Standard: Addressing Key Challenges

Telescope pointed at the moon collecting spectral data for climate calibration.

The recent study published in the Journal of Research of the National Institute of Standards and Technology highlights a significant step forward in using the Moon for climate data calibration. The research team successfully measured lunar spectral irradiance with an uncertainty of less than 1% between 420 nm and 1000 nm. This level of precision meets the stability requirements for many climate data records derived from satellite images, including those related to vegetation, aerosols, and snow and ice albedo.

Achieving this level of accuracy involves overcoming several challenges, including accounting for atmospheric effects and ensuring traceability to international standards. The NIST team employed a novel apparatus consisting of a telescope coupled to a non-imaging spectrograph, located at the Fred Lawrence Whipple Observatory in Arizona. This setup allowed for continuous spectral coverage, eliminating the need to interpolate between filter passbands, a common source of error in previous measurements.

Here are some of the key challenges addressed in the study:

Atmospheric Correction: Correcting for the effects of ozone and stratospheric aerosols is crucial for accurate measurements. The team used data from NASA's Ozone Monitoring Instrument (OMI) and the second-generation Stratospheric Aerosol and Gas Experiment (SAGE II) to account for these atmospheric components.
SI-Traceability: Establishing traceability to the Système Internationale (SI) radiometric units is essential for ensuring the reliability and comparability of measurements. This was achieved by measuring the spectral irradiance of an artificial moon using a NIST-calibrated spectrograph.
Temporal Variability: Accounting for the time-dependence of lunar irradiance due to the continually-evolving relative positions of the Sun, Moon, and observer is necessary for precise calibration. The team used a model developed by the USGS to address this factor.

The implications of this research extend beyond just improving data accuracy. The measurement technique developed by NIST also yields detailed information about the atmosphere at the measurement site. This suggests that lunar observations could be a valuable tool for aerosol monitoring, particularly during the polar winter when sun photometers are not available. Furthermore, lunar measurements can provide nighttime data to complement daytime aerosol observations, offering a more complete picture of atmospheric conditions.

The Future of Lunar Calibration: Towards More Accurate Climate Data

While this study represents a major advancement, the research team emphasizes that it's just the first step in a long-term program. Future measurements for different lunar phases and libration angles will further refine the USGS model and potentially uncover systematic effects. Improvements in laboratory calibration, the use of higher-altitude observatories, and laser-based techniques could also contribute to even greater accuracy. By continuing to explore the potential of lunar calibration, we can unlock a new level of precision in climate data, leading to a more informed and sustainable future.

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Everything You Need To Know

Why is the Moon being considered as a calibration standard for climate data?

The Moon is being considered because it offers a consistent reference point for calibrating Earth-orbiting satellites, addressing limitations of traditional methods like solar diffusers and well-characterized Earth surface sites. These traditional methods face challenges such as degradation and maintenance issues, leading to potential uncertainties in climate data. Lunar calibration sidesteps atmospheric corrections, providing a reliable way to maintain data consistency across different satellite missions, which is crucial for understanding long-term climate changes. The lunar spectral irradiance serves as a stable benchmark, ensuring that data from various satellites can be compared accurately over time, even when missions have gaps or end completely.

How does the National Institute of Standards and Technology (NIST) measure lunar spectral irradiance, and what makes their approach unique?

The National Institute of Standards and Technology (NIST) measures lunar spectral irradiance using a novel apparatus consisting of a telescope coupled to a non-imaging spectrograph, located at the Fred Lawrence Whipple Observatory in Arizona. This setup allows for continuous spectral coverage, eliminating the need to interpolate between filter passbands, a common source of error in previous measurements. NIST also ensures traceability to the Système Internationale (SI) radiometric units by measuring the spectral irradiance of an artificial moon using a NIST-calibrated spectrograph. This meticulous approach results in unprecedented accuracy, enabling the use of the Moon for tracking sensor response changes and absolute calibration.

What are the main challenges in using the Moon for climate data calibration, and how are these challenges being addressed?

The main challenges in using the Moon for climate data calibration include atmospheric correction, SI-traceability, and temporal variability. Atmospheric correction involves accounting for the effects of ozone and stratospheric aerosols, which is done using data from NASA's Ozone Monitoring Instrument (OMI) and the second-generation Stratospheric Aerosol and Gas Experiment (SAGE II). SI-traceability is established by measuring the spectral irradiance of an artificial moon using a NIST-calibrated spectrograph. Temporal variability, caused by the changing positions of the Sun, Moon, and observer, is addressed using a model developed by the USGS. Overcoming these challenges is crucial for achieving the level of precision required for reliable climate data records.

What are the broader implications of using lunar measurements for climate science, beyond just improving data accuracy?

Beyond improving data accuracy, the measurement technique developed by NIST yields detailed information about the atmosphere at the measurement site, suggesting that lunar observations could be a valuable tool for aerosol monitoring, especially during the polar winter when sun photometers are not available. Lunar measurements can also provide nighttime data to complement daytime aerosol observations, offering a more complete picture of atmospheric conditions. This additional atmospheric information enhances our understanding of climate processes and contributes to more comprehensive environmental monitoring.

What future advancements are anticipated in lunar calibration techniques, and how might they further enhance climate data accuracy?

Future advancements in lunar calibration techniques include measurements for different lunar phases and libration angles to refine the USGS model, potentially uncovering systematic effects. Improvements in laboratory calibration, the use of higher-altitude observatories, and laser-based techniques could also contribute to even greater accuracy. These advancements aim to unlock a new level of precision in climate data. By continuing to explore the potential of lunar spectral irradiance calibration, we can achieve a more informed and sustainable future, allowing for better monitoring and understanding of our planet's climate.