Measurements of Absolute, SI-traceable Lunar Irradiance with the Airborne LUnar Spectral Irradiance (air-LUSI) Instrument

Published

May 5, 2022

Author(s)

John T. Woodward IV, Kevin Turpie, Thomas Stone, S. Andrew Gadsden, Andrew Newton, Stephen Maxwell, Steven Grantham, Thomas Larason, Steven W. Brown

Abstract

The Airborne LUnar Spectral Irradiance (Air-LUSI) instrument is designed to make low uncertainty, hyperspectral measurements of the lunar spectral irradiance from an ER-2 aircraft from altitudes above 95 % to 99 % of the atmosphere. Measurements cover the Visible and Near InfraRed (VNIR) spectral region (350 nm to 980 nm) and are traceable to the International System of Units (SI). Five Demonstration Flights were conducted in November 2019 at NASA's Armstrong Flight Research Center. During that campaign, Air-LUSI measured the spectral irradiance at lunar phase angles ranging from 10o to 60o. This work provides an overview of the Air-LUSI instrument, the lunar irradiance measurements made during demonstration flights, and the resultant uncertainty budgets. Based on the flight results and laboratory measurements, we estimate the instrument is capable of measuring lunar irradiance, propagated to the Top-of-the Atmosphere (TOA), with uncertainties of 1 % or less over the spectral region from 450 nm to 970 nm. An examination of the uncertainty budget leads to a path forward toward potentially achieving uncertainties of 0.6 % in lunar irradiance over much of the spectral range for future flights.

Citation

Metrologia

Volume

59

Issue

3

Pub Type

Journals

Download Paper

https://doi.org/10.1088/1681-7575/ac64dc

Local Download

Keywords

Lunar Irradiance

Citation

Woodward IV, J. , Turpie, K. , Stone, T. , Gadsden, S. , Newton, A. , Maxwell, S. , Grantham, S. , Larason, T. and Brown, S. (2022), Measurements of Absolute, SI-traceable Lunar Irradiance with the Airborne LUnar Spectral Irradiance (air-LUSI) Instrument, Metrologia, [online], https://doi.org/10.1088/1681-7575/ac64dc, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=933044 (Accessed October 25, 2024)