MERLIN: design of an IPDA LIDAR instrument

Nikolov, Susanne; Wührer, Christian; Kuhl, Christopher A.; Bode, M.; Hupfer, Werner; Lucarelli, Stefano

doi:10.1007/s12567-019-00267-7

Cited by 7 publications

(5 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To handle fluctuations in the energy emitted by the laser, the instrument has a calibration unit that records the energy emitted through the same detector and electronic chain as the signal backscattered from the Earth targets [15]. The equation for P M D , the energy monitoring flux, is simply…”

Section: Energy Monitoring Fluxesmentioning

confidence: 99%

“…A value of M cal tav = 1850 is prescribed in LIDSIM following a dedicated study by Airbus. In addition, a specific mechanism is installed to decouple the speckle patterns between each shot [15]. However, decorrelation can only be achieved at the time scale of a shot and not at the time scale of a sample [56].…”

Section: P S C T C A/s C T/t C M Tavmentioning

confidence: 99%

“…The accuracy and precision of satellite data on atmospheric methane concentration must be increased to improve the identification of anthropogenic methane sources. The use of an The MERLIN instrument is therefore an Integrated Path Differential Absorption (IPDA) lidar [14,15]. Two beams are pulsed at separate wavelengths (called On and Off) with significantly different molar methane absorptions (σ On ), but close enough in frequency and time to minimise differences other than methane absorption in their various interactions with the atmosphere, the ground or the instrument's optics and detector.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Development and Validation of an End-to-End Simulator and Gas Concentration Retrieval Processor Applied to the MERLIN Lidar Mission

et al. 2021

View full text Add to dashboard Cite

In the context of MERLIN (MEthane Remote LIdar missioN), a French–German spatial lidar mission dedicated to monitoring the atmospheric methane content, two software programs have been developed: LIDSIM (LIDar SIMulator) and PROLID (PROcessor LIDar). The objectives are to assess whether the instrument design meets the performance requirements and to study the sensitivity of this performance to geophysical parameters. LIDSIM is an end-to-end mission simulator and PROLID is a retrieval processor that provides mole fractions of methane in dry air, averaged over an atmospheric column. These two tools are described in this paper. Results of the validation tests and the first full orbit simulations are reported. Merlin target performance does not seem to be reachable but breakthrough performance is reached.

show abstract

Section: Energy Monitoring Fluxesmentioning

confidence: 99%

Section: P S C T C A/s C T/t C M Tavmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Development and Validation of an End-to-End Simulator and Gas Concentration Retrieval Processor Applied to the MERLIN Lidar Mission

et al. 2021

View full text Add to dashboard Cite

show abstract

“…In particular, the flights took place over one of the most powerful sources of methane in the European Union-the Upper Silesian coal basin (southern Poland), where methane emissions from coal ventilation shafts were assessed [20][21][22]. In general, this project is aimed at the validation of greenhouse gas satellite measurements (such as Sentinel 5-P, GOSAT-2, and MERLIN [23][24][25]) and the development of new combined active and passive remote sensing techniques for measuring greenhouse gases from space. Additionally, using the HALO aircraft, IPDA-DIAL methane measurements has been implemented for the first time [26].…”

Section: Introductionmentioning

confidence: 99%

Mobile Airborne Lidar for Remote Methane Monitoring: Design, Simulation of Atmospheric Measurements and First Flight Tests

2022

View full text Add to dashboard Cite

The results of modernization of a mobile lidar for the airborne monitoring of the methane content in the atmosphere are presented. The modernization was carried out on the basis of in situ tests, several engineering solutions, and preliminary numerical simulations. The in situ tests showed a possibility of sounding background tropospheric methane concentrations along a 500 m surface path. During the modernization, the airborne lidar for methane monitoring was supplemented with an off-axis mirror collimator, which made it possible to reduce the divergence of laser radiation by a factor of 4. The overlapping function was simulated for a biaxial scheme of the mobile lidar with radii of the light-sensitive zone of the receiving optics of 0.1, 0.3, 0.5, 0.8 and 1 mm. The dimensions of the light-sensitive zone were found to provide complete coverage of the field of view of the telescope and a laser beam; the length of the “dead” zone was estimated when a laser beam propagated parallel to the optical axis of the telescope. Airborne methane monitoring in the atmosphere in the informative wavelength range (2916.55–2917 cm‒1 on-line and 2915.00 cm‒1 off-line) was numerically simulated for midlatitude and Arctic summer. Thus, on the basis of the work carried out, the design of the mobile airborne lidar is substantiated, which is to operate as a part of the Tu-134 “Optik” aircraft laboratory of IAO SB RAS and to perform methane monitoring vertically downwards. The airborne lidar was tested during test flights and the Arctic expedition in 2022. The first experimental results of lidar measurements of the averaged methane concentration vertically downwards from sounding altitudes of 2000–3000, 380, and 270 m were obtained for mid-latitude summer and Arctic summer.

show abstract

“…Its monitoring on a global scale is a challenge to which Germany and France are contributing through the development by their respective space agencies, DLR (D eutsches Zentrum für Luft-und Raumfahrt) and CNES (Centre National d'Etudes Spatiales), with the MERLIN (MEthane Remote sensing LIdar missioN) mission planned for the end of this decade [3]. The MERLIN mission uses the CNES Myriade Evolution platform developed by Airbus France; meanwhile, Airbus Germany is developing the MERLIN instrument: an IPDA (Integrated Path Differential Absorption) lidar [4]. The data processing is described in the MERLIN ATBD (Algorithm Theoretical Basis Document, an internal project document) [5].…”

Section: Introductionmentioning

confidence: 99%

Impact of Meteorological Uncertainties in the Methane Retrieval Ground Segment of the MERLIN Lidar Mission

et al. 2022

View full text Add to dashboard Cite

MERLIN (MEthane Remote sensing LIdar missioN) is a Franco-German space mission designed to provide weighted columns of atmospheric methane through an inversion of the lidar signal using a priori information on the atmospheric state. Uncertainties about the meteorological parameters of the observed scene used in the ground segment contribute to the error budget on the retrieved methane column. With the LIDSIM (LIDar SIMulator) data simulator and the PROLID (PROcessor LIDar) inversion processor developed for MERLIN, we perform an impact experiment using ECMWF (European Centre for Medium Weather Range Forecast) ensemble forecast data. In addition, we estimate the standard deviation of the error in the methane column due to the meteorological uncertainties to be about 0.6 ppb. In addition, we innovate by discussing the impact of interpolations both in time and space, focusing on vertical extrapolations under the topography by using state-of-the-art methods to determine from the scatter between these methods the range in which the actual profile should be. We conclude that, in areas where the topography variations exceed 10 m over 10 km, an additional random error of 0.1 ppb is due to our lack of knowledge of the adjustment of atmospheric profiles to terrain. Finally, we point out that further work needs to be performed on temporal interpolation. Indeed, the 3 h time interpolation of atmospheric tides can create regional biases of up to 2 ppm (which is a major problem for models trying to identify methane sinks and sources).

show abstract

MERLIN: design of an IPDA LIDAR instrument

Cited by 7 publications

References 6 publications

Development and Validation of an End-to-End Simulator and Gas Concentration Retrieval Processor Applied to the MERLIN Lidar Mission

Development and Validation of an End-to-End Simulator and Gas Concentration Retrieval Processor Applied to the MERLIN Lidar Mission

Mobile Airborne Lidar for Remote Methane Monitoring: Design, Simulation of Atmospheric Measurements and First Flight Tests

Impact of Meteorological Uncertainties in the Methane Retrieval Ground Segment of the MERLIN Lidar Mission

Contact Info

Product

Resources

About