Optical Design of a Novel Wide-Field-of-View Space-Based Spectrometer for Climate Monitoring

Schifano, Luca; Berghmans, Francis; Dewitte, Steven; Smeesters, Lien

doi:10.3390/s22155841

Cited by 10 publications

(9 citation statements)

References 33 publications

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“…As a possible application, the pushbroom telescope might be complemented with a spectrometer unit, for example, for climate change and/or pollution monitoring [ 14 ]. Recently, the need for compact spectrometers for enhanced climate and pollution monitoring has been put forward, as highlighted by, for example, the CHAPS instrument that targets the monitoring of local pollution in urban areas [ 21 ].…”

Section: Discussion and Future Perspectivesmentioning

confidence: 99%

“…Recently, the need for compact spectrometers for enhanced climate and pollution monitoring has been put forward, as highlighted by, for example, the CHAPS instrument that targets the monitoring of local pollution in urban areas [ 21 ]. Possible integration with an 1100–1700 nm spectrometer might enable greenhouse gas monitoring [ 14 , 15 , 16 , 17 ]. Also, as our telescope achieves an RMS spot diameter of the order of 30 µm or less at the detector plane, this telescope would be compatible with other spectrometers operating within wavelength ranges exceeding 1700 nm, while keeping a diffraction-limited design for the telescope.…”

Section: Discussion and Future Perspectivesmentioning

confidence: 99%

“…We propose an innovative two-mirror pushbroom telescope imaging the Earth with 120° FOV, featuring a spatial resolution of 2.6 km while fitting in 1 CubeSat Unit and showing a diffraction-limited performance. The telescope can be used as a stand-alone component, but also serve as input for a spectroscopy unit [ 14 ]. Pushbroom non-scanning wide FOV instruments, such as the Ozone Monitoring Instrument (OMI), TROPOMI, and the future UVN and UVNS instruments, have inspired the design of our instrument.…”

Section: Introductionmentioning

confidence: 99%

“…This wavelength range is complementary to TROPOMI [ 11 ] and would enable greenhouse gas monitoring when supplementing the telescope with a spectrometer. More specifically, carbon dioxide column densities have been observed at 1600 nm [ 15 , 16 ], while water vapor shows characteristic absorbances around 1130 nm and 1400 nm [ 14 ], and methane features a spectral line at 1670 nm [ 17 ]. Cameras and telescopes operating within the visible wavelength range (400–900 nm) are already widely available.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Freeform Wide Field-of-View Spaceborne Imaging Telescope: From Design to Demonstrator

Schifano

Vervaeke

Rosseel

et al. 2022

Sensors

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Wide field-of-view imaging optics offer a huge potential for space-based Earth observation enabling the capture of global data. Reflective imaging telescopes are often favored, as they do not show chromatic aberrations and are less susceptible to radiation darkening than their refractive counterparts. However, the main drawback of reflective telescopes is that they are limited with respect to field-of-view while featuring large dimensions. We propose the use of freeform optics to maximize the field of view while maintaining diffraction-limited image quality and minimizing system dimensions. In this paper, we present a novel freeform wide field-of-view reflective telescope, starting from the optical design, and continuing to tolerancing analysis and manufacture, towards a proof-of-concept demonstrator. The novel telescope features a full field-of-view of 120° while showing an exceptional spatial resolution of 2.6 km and fitting within 1 CubeSat unit. To the best of our knowledge, this is the widest field-of-view that has ever been realized for a space-based telescope, nearly reaching Earth observation from limb to limb from an altitude of about 700 km. We hope this design paves the way for future space missions enabling improved Earth observation and leading to enhanced monitoring of climate and climate change.

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Section: Discussion and Future Perspectivesmentioning

confidence: 99%

Section: Discussion and Future Perspectivesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Freeform Wide Field-of-View Spaceborne Imaging Telescope: From Design to Demonstrator

Schifano

Vervaeke

Rosseel

et al. 2022

Sensors

Self Cite

View full text Add to dashboard Cite

show abstract

“…We envision the use of our instrument in the near-infrared wavelength range (1100-1700 nm), complementary to TROPOMI. Its intended use is three-fold, since the telescope can be considered as a standalone instrument 6 , but can also be supplemented with a spectrometer to enable greenhouse gas monitoring (carbon dioxide, water vapor and methane) 7 , or be combined with visible imaging designs providing a more complete view on the Earth's total reflected radiation 8 .…”

Section: Introductionmentioning

confidence: 99%

Freeform wide-field-of-view imaging telescope improving spaceborne climate monitoring

Smeesters,

Schifano,

Rosseel

et al. 2023

International Optical Design Conference 2023

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Wide field-of-view imaging optics offers a huge potential for space-based Earth observation and climate change monitoring by capturing global data. We present the design and proof-of-concept demonstration of a freeform 2-mirror space-based telescope featuring a full field-of-view of 120°, nearly reaching Earth observation from limb to limb from a nominal altitude of 700 km, while showing a spatial resolution of 2.6 km, and fitting within 1 CubeSat unit. Our design benefits from freeform optics to maximize the field-of-view, while maintaining a diffraction-limited image quality and minimizing the system dimensions. Particularly, both mirror surfaces were accurately modelled and optimized using an XY polynomial description. Subsequently, the mirrors are manufactured using high-precision 5-axis milling and ultraprecision diamond tooling, after which a laboratory demonstrator setup of the telescope was realized. We believe this design paves the way towards future space missions enabling an improved Earth observation, leading to an enhanced monitoring of climate and climate change.

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Trends and Variability in Earth’s Energy Imbalance and Ocean Heat Uptake Since 2005

Hakuba,

Fourest,

Boyer

et al. 2024

Surv Geophys

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Earth’s energy imbalance (EEI) is a fundamental metric of global Earth system change, quantifying the cumulative impact of natural and anthropogenic radiative forcings and feedback. To date, the most precise measurements of EEI change are obtained through radiometric observations at the top of the atmosphere (TOA), while the quantification of EEI absolute magnitude is facilitated through heat inventory analysis, where ~ 90% of heat uptake manifests as an increase in ocean heat content (OHC). Various international groups provide OHC datasets derived from in situ and satellite observations, as well as from reanalyses ingesting many available observations. The WCRP formed the GEWEX-EEI Assessment Working Group to better understand discrepancies, uncertainties and reconcile current knowledge of EEI magnitude, variability and trends. Here, 21 OHC datasets and ocean heat uptake (OHU) rates are intercompared, providing OHU estimates ranging between 0.40 ± 0.12 and 0.96 ± 0.08 W m−2 (2005–2019), a spread that is slightly reduced when unequal ocean sampling is accounted for, and that is largely attributable to differing source data, mapping methods and quality control procedures. The rate of increase in OHU varies substantially between − 0.03 ± 0.13 (reanalysis product) and 1.1 ± 0.6 W m−2 dec−1 (satellite product). Products that either more regularly observe (satellites) or fill in situ data-sparse regions based on additional physical knowledge (some reanalysis and hybrid products) tend to track radiometric EEI variability better than purely in situ-based OHC products. This paper also examines zonal trends in TOA radiative fluxes and the impact of data gaps on trend estimates. The GEWEX-EEI community aims to refine their assessment studies, to forge a path toward best practices, e.g., in uncertainty quantification, and to formulate recommendations for future activities.

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Optical Design of a Novel Wide-Field-of-View Space-Based Spectrometer for Climate Monitoring

Cited by 10 publications

References 33 publications

Freeform Wide Field-of-View Spaceborne Imaging Telescope: From Design to Demonstrator

Freeform Wide Field-of-View Spaceborne Imaging Telescope: From Design to Demonstrator

Freeform wide-field-of-view imaging telescope improving spaceborne climate monitoring

Trends and Variability in Earth’s Energy Imbalance and Ocean Heat Uptake Since 2005

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