High-power and frequency-stable ultraviolet laser performance in space for the wind lidar on Aeolus

Lux, Oliver; Wernham, Denny; Bravetti, P.; McGoldrick, Phil; Lecrenier, Olivier; Riede, Wolfgang; D’Ottavi, A.; Sanctis, V. De; Schillinger, Marc; Lochard, J.; Marshall, Jon; Lemmerz, Christian; Weiler, Fabian; Mondin, L.; Ciapponi, Alessandra; Kanitz, Thomas; Elfving, Anders; Parrinello, Tommaso; Reitebuch, Oliver

doi:10.1364/ol.387728

Cited by 45 publications

(52 citation statements)

References 19 publications

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“…Note that herein only a brief description of ALADIN is provided. Further information about the satellite, instrument and its products can be found in Straume et al (2020), Kanitz et al (2020) and Reitebuch et al (2020). Detailed information about the laser employed in ALADIN can be found in Lux et al (2020).…”

Section: Aladin and Dark Current Measurementsmentioning

confidence: 99%

“…Aeolus orbits the Earth in relatively low orbit at an altitude of ~320 km and carries one single instrument, the direct-detection wind lidar ALADIN. The instrument emits short 20-ns laser pulses at a repetition rate (PRF) of 50.5 Hz and a wavelength of 354.8 nm (Lux et al, 2020) into the atmosphere where the light is scattered by molecules and particles. Part of the outgoing light is also diverted to the detectors serving as internal reference to measure the frequency of the transmitted laser pulse.…”

Section: Measurement Principlementioning

confidence: 99%

“…The European Space Agency (ESA) satellite Aeolus was successfully launched into space on 22 August 2018 (Reitebuch et al, 2020). Aeolus was selected as one of the Earth Explorer Missions of the "Living Planet Programme" in 1999, (ESA, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…Due to the measurement principle and the instrument design, the accuracy of Aeolus wind measurements is very sensitive to changes in the dark current of the ACCDs. Quite unexpectedly, already shortly after launch single pixels of the ACCDs showed suspicious behavior with increased dark current signals which lead to systematic errors in the wind results (Reitebuch et al, 2020). In order to monitor the evolution of dark current anomalies, a new dedicated dark current calibration technique has been introduced and performed throughout the mission on a regular basis providing a unique dataset for investigation.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of dark current signal measurements of the ACCDs used on-board the Aeolus satellite

Weiler¹,

Kanitz²,

Wernham³

et al. 2020

Preprint

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Abstract. Already shortly after the successful launch of the European Space Agency satellite Aeolus in August 2018, it turned out that dark current signal anomalies of single pixels (so-called hot pixels) on the Accumulation-Charge-Coupled Devices (ACCDs) of the Aeolus detectors detrimentally impact the quality of the aerosol and wind products potentially leading to wind errors of up to 4 m/s. This paper provides a detailed characterization of the hot pixels which occurred during the first one and a half years in orbit. The hot pixels are classified according to their characteristics to discuss their impact on wind measurements. Furthermore, mitigation approaches for the wind retrieval are presented and potential root causes for the hot pixel occurrence are discussed. The analysis of the dark current signal anomalies reveals a large variety of anomalies ranging from pixels with Random Telegraph Signal (RTS)-like characteristics to pixels with sporadic shifts in the median dark current signal. Moreover, the results indicate that the number of hot pixels has almost linearly increased during the observing period between 2018-09-02 until 2020-05-20 with 6 % of the ACCD pixels affected in total at the end of the period leading to 9.5 % at the end of mission lifetime. This work introduces dedicated instrument calibration modes and ground processors which allowed for a correction shortly after a hot pixel occurrence. The achieved performance with this approach avoids risky adjustments to the inflight hardware operation. It is demonstrated that the success of the correction scheme varies depending on the characteristics of each hot pixel itself. With the herein presented categorization, it is shown that multi-level RTS pixels with high fluctuation are the biggest challenge for the hot pixel correction scheme. Despite a detailed analysis in this framework, no conclusion could be drawn about the root cause of the hot pixel issue.

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Section: Aladin and Dark Current Measurementsmentioning

confidence: 99%

Section: Measurement Principlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Characterization of dark current signal measurements of the ACCDs used on-board the Aeolus satellite

Weiler¹,

Kanitz²,

Wernham³

et al. 2020

Preprint

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“…The laser damage problem of dielectric coatings is a key factor in laser systems 8,9 . The laser damage of the sputtered coatings is related to the launch and operation stability of the entire spacecraft mission 10,11 . The research on the mechanism of laser and sputtered coatings is very important.…”

mentioning

confidence: 99%

Laser-induced layers peeling of sputtering coatings at 1064 nm wavelength

Guo

Wang

Chen

et al. 2021

Sci Rep

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Large-scale layers peeling after the laser irradiation of dual ion beam sputtering coatings is discovered and a model is established to explain it. The laser damage morphologies relate to the laser fluence, showing thermomechanical coupling failure at low energy and coating layers separation at high energy. High-pressure gradients appear in the interaction between laser and coatings, resulting in large-scale layer separation. A two-step laser damage model including defect-induced damage process and ionized air wave damage process is proposed to explain the two phenomena at different energy. At relatively high energies (higher than 20 J/cm2), ionization of the air can be initiated, leading to a peeling off effect. The peeling effect is related to the thermomechanical properties of the coating materials.

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Impacts of Aeolus horizontal Line‐Of‐Sight (HLOS) wind assimilation on the Korean integrated model (KIM) forecast system

Lee

Song

Kwon

et al. 2022

Atmospheric Science Letters

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The Korean Integrated Model (KIM) forecast system, based on a hybrid fourdimensional ensemble-variational method, was extended to assimilate Horizontal Line-Of-Sight (HLOS) wind observations from the Atmospheric Laser Doppler Instrument (ALADIN) on board the Atmospheric Dynamic Mission Aeolus satellite. In a global cycling experiment, assimilation of Aeolus HLOS wind observations led to reductions in the average root-mean-square error of 0.8 and 0.5% for the zonal and meridional wind analyses when compared against European Center for Medium-Range Weather Forecasts (ECMWF) Integrated Forecast System (IFS) analyses. Even though the observed variable is wind, there was also an overall beneficial impact on analyses of the mass variables. In the Southern Hemisphere (SH), the reduced analysis errors led to forecast skill improvements out to 72 h. In contrast, in the Northern Hemisphere (NH) there was relatively little reduction of analysis errors, but wind forecasts were nevertheless improved, and these positive impacts lasted longerout to 120 h rather than 72 h. Experiments suggest that the relatively poor long-range performance in the SH high latitudes was due to problems with the mass increments derived from Aeolus wind increments via the ensemble-based part of the hybrid background error covariance (B), which eventually led to adverse effects on the wind variables as forecasts progressed in the SH. This study shows that it is necessary to estimate the ensemble B in the Antarctic region with its high elevation more accurately in order to effectively use the Aeolus observation information.

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High-power and frequency-stable ultraviolet laser performance in space for the wind lidar on Aeolus

Cited by 45 publications

References 19 publications

Characterization of dark current signal measurements of the ACCDs used on-board the Aeolus satellite

Characterization of dark current signal measurements of the ACCDs used on-board the Aeolus satellite

Laser-induced layers peeling of sputtering coatings at 1064 nm wavelength

Impacts of Aeolus horizontal Line‐Of‐Sight (HLOS) wind assimilation on the Korean integrated model (KIM) forecast system

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