POLO: a unique dataset to derive the phase angle dependence of the Moon irradiance

Lachérade, Sophie; Aznay, Ouahid; Fougnie, Bertrand; Lebègue, Laurent

doi:10.1117/12.2067283

Cited by 12 publications

(19 citation statements)

References 4 publications

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“…This phase angle dependence of the ROLO model has been also reported by Lacherade et al (2013Lacherade et al ( , 2014 and Viticchié et al (2013) as well as its asymmetry within the Moon cycle (Lacherade et al, 2013(Lacherade et al, , 2014. Lacherade et al (2014) found a variation up to 5 % with the phase angle between ±90 • , which is the validity range of the ROLO model.…”

Section: Identifying Bias In the Lunar Irradiance Modelsupporting

confidence: 84%

“…Lacherade et al (2014) found a variation up to 5 % with the phase angle between ±90 • , which is the validity range of the ROLO model. These results are in agreement with the relative differences higher than 4 % found in this study.…”

Section: Identifying Bias In the Lunar Irradiance Modelmentioning

confidence: 61%

“…Although this model provides precise information about the change of the Moon's irradiance with the phase angle (g) and lunar librations, small systematic effects have been found in this model. Lacherade et al (2013Lacherade et al ( , 2014 and Viticchié et al (2013) found a small phase angle dependence of the ROLO calibration using the Pleiades Orbital Lunar Observations (POLO) and Meteosat Second Generation (MSG) Spinning Enhanced Visible and Infrared Imager (SEVIRI) solar bands. Cramer et al (2013) developed a novel apparatus to accurately measure the lunar spectral irradiance with the aim of estimating these systematic effects in the ROLO model.…”

Section: Introductionmentioning

confidence: 99%

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Assessment of nocturnal aerosol optical depth from lunar photometry at the Izaña high mountain observatory

et al. 2017

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Abstract. This work is a first approach to correct the systematic errors observed in the aerosol optical depth (AOD) retrieved at nighttime using lunar photometry and calibration techniques dependent on the lunar irradiance model. To this end, nocturnal AOD measurements were performed in 2014 using the CE318-T master Sun-sky-lunar photometer (lunar Langley calibrated) at the Izaña high mountain observatory. This information has been restricted to 59 nights characterized as clean and stable according to lidar vertical profiles. A phase angle dependence as well as an asymmetry within the Moon's cycle of the Robotic Lunar Observatory (ROLO) model could be deduced from the comparison in this 59-night period of the CE318-T calibration performed by means of the lunar Langley calibration and the calibration performed every single night by means of the common Langley technique. Nocturnal AOD has also been compared in the same period with a reference AOD based on daylight AOD extracted from the AErosol RObotic NETwork (AERONET) at the same station. Considering stable conditions, the difference AOD fit , between AOD from lunar observations and the linearly interpolated AOD (the reference) from daylight data, has been calculated. The results show that AOD fit values are strongly affected by the Moon phase and zenith angles. This dependency has been parameterized using an empirical model with two independent variables (Moon phase and zenith angles) in order to correct the AOD for these residual dependencies. The correction of this parameterized dependency has been checked at four stations with quite different environmental conditions (Izaña, Lille, Carpentras and Dakar) showing a significant reduction of the AOD dependence on phase and zenith angles and an improved agreement with daylight reference data. After the correction, absolute AOD differences for day-night-day clean and stable transitions remain below 0.01 for all wavelengths.

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Section: Identifying Bias In the Lunar Irradiance Modelsupporting

confidence: 84%

Section: Identifying Bias In the Lunar Irradiance Modelmentioning

confidence: 61%

Section: Introductionmentioning

confidence: 99%

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Assessment of nocturnal aerosol optical depth from lunar photometry at the Izaña high mountain observatory

et al. 2017

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“…The residual phase effects determined here for the SeaWiFS lunar observation / ROLO model ratios are consistent with the initial SeaWiFS analysis 8 and are consistent with the PLEIADES observations from the POLO data set. 10 The residual libration effects determined for the SeaWiFS lunar observation / ROLO model ratios are smaller than the libration effects observed for SNPP VIIRS reflective solar bands with wavelengths longer than 412 nm. 11,12 The coherent noise in the SeaWiFS data is high enough that the SeaWiFS data alone are not diagnostic of any residual libration effect in the SeaWiFS / ROLO comparisons.…”

Section: Seawifs Geometry Reanalysis Summarymentioning

confidence: 92%

“…PLEIADES is a French dual instrument Earth observation system, PLEIADES-1A and PLEIADES-1B, each of which is a four-band filter radiometer with a spatial resolution of 2.8 km and swath of 20 km. 10 The OBPG has developed an on-orbit calibration of SNPP VIIRS for ocean color applications. 11 SNPP VIIRS observes the Moon approximately once per month by rolling the spacecraft to achieve a nominal lunar phase angle of −51 • .…”

Section: Introductionmentioning

confidence: 99%

Geometric effects in SeaWiFS lunar observations

2015

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The radiometric stability requirements for ocean color climate data records place tight constraints on the onorbit calibration of ocean color instruments. A major component of the on-orbit calibration methodology for NASA ocean color sensors is the normalization of lunar observations for variations in observing geometry by the USGS ROLO photometric model of the Moon. SeaWiFS made 204 lunar observations over its 13-year mission. 145 radiometric trending observations were made at low phase angles (−8 • to −6 • and +5 • to +10 • ). 59 additional observations were made at high phase angles (−49 • to −27 • and +27 • to +66 • degrees). The NASA Ocean Biology Processing Group has undertaken a reanalysis of residual geometric effects in the SeaWiFS lunar observations. Ratios of SeaWiFS observations to ROLO model predictions were fit with quadratic functions of phase angle and linear functions of sub-spacecraft point and sub-solar point libration longitude and latitude angles. The resulting phase and libration fit coefficients have been used as additional geometric corrections for the SeaWiFS lunar observations. For the low phase angle observations, the phase corrections are 0.16% and the libration corrections are 0.18%. For the low and high phase angle observations, the phase corrections are 1.8% and the libration corrections are 0.22%. These geometric corrections have reduced the overall scatter in the lunar observations, bringing the high phase angle data into family with the low phase angle measurements without impacting the radiometric response in the low phase angle observations.

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AMICal Sat and ATISE: two space missions for auroral monitoring

Barthélemy¹,

Калегаев²,

Vialatte³

et al. 2018

J. Space Weather Space Clim.

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A lack of observable quantities renders it generally difficult to confront models of Space Weather with experimental data and drastically reduces the forecast accuracy. This is especially true for the region of Earth’s atmosphere between altitudes of 90 km and 300 km, which is practically inaccessible, except by means of remote sensing techniques. For this reason auroral emissions are an interesting proxy for the physical processes taking place in this region. This paper describes two future space missions, AMICal Sat and ATISE, that will rely on CubeSats to observe the aurora. These satellites will perform measurements of auroral emissions in order to reconstruct the deposition of particle precipitations in auroral regions. ATISE is a 12U CubeSat with a spectrometer and imager payloads. The spectrometer is built using the micro-Spectrometer-On-a-Chip (μSPOC) technology. It will work in the 370–900 nm wavelength range and allow for short exposure times of around 1 s. The spectrometer will have six lines of sight. The joint imager is a miniaturized wide-field imager based on the Teledyne-E2V ONYX detector in combination with a large aperture objective. Observation will be done at the limb and will enable reconstruction of the vertical profile of the auroral emissions. ATISE is planned to be launched in mid 2021. AMICal Sat is a 2U CubeSat that will embed the imager of ATISE and will observe the aurora both in limb and nadir configurations. This imager will enable measuring vertical profiles of the emission when observing in a limb configuration similar to that of ATISE. It will map a large part of the night side auroral oval with a resolution of the order of a few km. Both the spectrometer and imager will be calibrated with a photometric precision better than 10% using the moon as a wide-field, stable and extended source. Ground-based demonstrators of both instruments have been tested in 2017 in Norway and Svalbard. Even though some issues still need to be solved, the first results are very encouraging for the planned future space missions. Data interpretation will be done using the forward Transsolo code, a 1D kinetic code solving the Boltzmann equation along a local vertical and enabling simulation of the thermospheric and ionospheric emissions using precipitation data as input.

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POLO: a unique dataset to derive the phase angle dependence of the Moon irradiance

Cited by 12 publications

References 4 publications

Assessment of nocturnal aerosol optical depth from lunar photometry at the Izaña high mountain observatory

Assessment of nocturnal aerosol optical depth from lunar photometry at the Izaña high mountain observatory

Geometric effects in SeaWiFS lunar observations

AMICal Sat and ATISE: two space missions for auroral monitoring

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