Spectral performance analysis of the Aeolus Fabry-Pérot and Fizeau interferometers during the first years of operation

Abstract. In August 2018, the European Space Agency (ESA) launched the first Doppler wind lidar into space which has since then been providing continuous profiles of the horizontal line-of-sight wind component at a global scale. Aeolus data has been successfully assimilated into several NWP models and demonstrated a positive impact on the quality of the weather forecasts. In order to provide valuable input data for NWP models, a detailed characterization of the Aeolus instrumental performance as well as the realization and minimization of systematic error sources is crucial. In this paper, Aeolus interferometer spectral drifts and their potential as systematic error sources for the aerosol and wind product are investigated by means of instrument spectral registration (ISR) measurements that are performed on a weekly basis. During these measurements, the laser frequency is scanned over a range of 11 GHz in steps of 25 MHz and thus spectrally resolves the transmission curves of the Fizeau interferometer and the Fabry-Perot interferometers (FPIs) used in Aeolus. Mathematical model functions are derived in order to analyze the measured transmission curves by means of non-linear fit procedures. The obtained fit parameters are used to draw conclusions about the Aeolus instrumental alignment and potentially ongoing drifts. The introduced instrumental functions and analysis tools may also be applied for the upcoming missions using similar spectrometers as for instance EarthCARE (ESA) which is based on the Aeolus FPI design.

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Aeolus: ESA’s wind mission. Status and future challenges

10.5194/egusphere-egu21-1676 ◽

2021 ◽

Author(s):

Tommaso Parrinello ◽

Anne Grete Straume ◽

Jonas Von Bismark ◽

Sebastian Bley ◽

Viet Duc Tran ◽

...

Keyword(s):

World Wide ◽

Positive Impact ◽

European Space Agency ◽

Weather Forecast ◽

Horizontal Line ◽

Space Agency ◽

Future Challenges ◽

The Status ◽

Other World ◽

Atmospheric Backscatter

The European Space Agency (ESA)&#8217;s wind mission, Aeolus, was launched on 22 August 2018. It is a member of the ESA Earth Explorer family and its main objective is to demonstrate the potential of Doppler wind Lidars in space for improving weather forecast and to understand the role of atmospheric dynamics in climate variability. Aeolus carries a single instrument called ALADIN: a high sophisticated spectral resolution Doppler wind Lidar which operates at 355 which is the first of its kind to be flown in space.Aeolus provides profiles of single horizontal line-of-sight winds (primary product) in near-real-time (NRT), and profiles of atmospheric backscatter and extinction. The instrument samples the atmosphere from about 30 km down to the Earth&#8217;s surface, or down to optically thick clouds. The required precision of the wind observations is 1-2.5 m/s in the troposphere and 3-5 m/s in the stratosphere while the systematic error requirement be less than 0.7 m/s. The mission spin-off product includes information about aerosol and cloud layers. The satellite flies in a polar dusk/dawn orbit (6 am/pm local time), providing ~16 orbits per 24 hours with an orbit repeat cycle of 7 days. Global scientific payload data acquisition is guaranteed with the combined usage of Svalbard and Troll X-band receiving stations.After almost three years in orbit and despite performance issues related to its instrument ALADIN, Aeolus has achieved most of its objectives. Positive impact on the weather forecast has been demonstrated by multiple NWP centres world-wide with four European meteorological centres now are assimilating Aeolus winds operationally. Other world-wide meteo centers wull start to assimilate data in 2021. The status of the Aeolus mission will be presented, including overall performance, planned operations and exploitation. Scope of the paper is also to inform about the programmatic highlights and future challenges.

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Validation of Aeolus Level 2B wind products using wind profilers, ground-based Doppler wind lidars, and radiosondes in Japan

10.5194/amt-2021-243 ◽

2021 ◽

Author(s):

Hironori Iwai ◽

Makoto Aoki ◽

Mitsuru Oshiro ◽

Shoken Ishii

Keyword(s):

Systematic Error ◽

Random Error ◽

European Space Agency ◽

Horizontal Line ◽

Positive Trend ◽

Random Errors ◽

Space Agency ◽

Scattering Ratio ◽

Wind Bias ◽

Wind Profilers

Abstract. The first space-based Doppler wind lidar (DWL) onboard the Aeolus satellite was launched by the European Space Agency (ESA) on 22 August 2018 to obtain global profiles of horizontal line-of-sight (HLOS) wind speed. In this study, the Raleigh-clear and Mie-cloudy winds for periods of baseline 2B02 (from 1 October to 18 December 2018) and 2B10 (from 28 June to 31 December 2019 and from 20 April to 8 October 2020) were validated using 33 wind profilers (WPRs) installed all over Japan, two ground-based coherent Doppler wind lidars (CDWLs), and 18 GPS-radiosondes (GPS-RSs). In particular, vertical and seasonal analyses were performed and discussed using WPR data. During the baseline 2B02 period, a positive bias was found to be in the ranges of 0.46–1.69 m s−1 for Rayleigh-clear winds and 1.63–2.42 m s−1 for Mie-cloudy winds using the three independent reference instruments. The biases of Rayleigh-clear and Mie-cloudy winds were in the ranges of −0.82−+0.45 m s−1 and −0.71−+0.16 m s−1 during the baseline 2B10 period, respectively. The systematic error for the baseline 2B10 was improved as compared with that for the baseline 2B02. The vertical analysis using WPR data showed that the systematic error was slightly positive in all altitude ranges up to 11 km during the baseline 2B02 period. During the baseline 2B10 period, the systematic errors of Rayleigh-clear and Mie-cloudy winds were improved in all altitude ranges up to 11 km as compared with the baseline 2B02. Immediately after the launch of Aeolus, both Rayleigh-clear and Mie-cloudy biases were small. Within the baseline 2B02, the Rayleigh-clear and Mie-cloudy biases showed a positive trend. For the baseline 2B10, the Rayleigh-clear wind bias was generally negative at all months except August 2020, and Mie-cloudy wind bias gradually fluctuated. The systematic error was close to zero with time in 2020 and did not show a marked seasonal trend. The dependence of the Rayleigh-clear wind bias on the scattering ratio was investigated, showing that the scattering ratio had a minimal effect on the systematic error of the Rayleigh-clear winds during the baseline 2B02 period. On the other hand, during the baseline 2B10 period, there was no significant bias dependence on the scattering ratio. Without the estimated representativeness error associated with the comparisons using WPR observations, the Aeolus random error was determined to be 6.71 (5.12) and 6.42 (4.80) m s−1 for Rayleigh-clear (Mie-cloudy) winds during the baseline 2B02 and 2B10 periods, respectively. The main reason for the large random errors is probably related to the large representativeness error due to the large sampling volume of the WPRs. Using the CDWLs, the Aeolus random error estimates were in the range of 4.49–5.31 (2.93–3.19) and 4.81–5.21 (3.30–3.37) m s−1 for Rayleigh-clear (Mie-cloudy) winds during the baseline 2B02 and 2B10 periods, respectively. By taking the GPS-RS representativeness error into account, the Aeolus random error was determined to be 4.01 (3.24) and 3.02 (2.89) m s−1 for Rayleigh-clear (Mie-cloudy) winds during the baseline 2B02 and 2B10 periods, respectively.

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First validation of Aeolus wind observations by airborne Doppler wind lidar measurements

Atmospheric Measurement Techniques ◽

10.5194/amt-13-2381-2020 ◽

2020 ◽

Vol 13 (5) ◽

pp. 2381-2396 ◽

Cited By ~ 8

Author(s):

Benjamin Witschas ◽

Christian Lemmerz ◽

Alexander Geiß ◽

Oliver Lux ◽

Uwe Marksteiner ◽

...

Keyword(s):

Early Stage ◽

European Space Agency ◽

Global Scale ◽

Horizontal Resolution ◽

Line Of Sight ◽

Horizontal Line ◽

Random Errors ◽

Space Agency ◽

Wind Lidar ◽

German Aerospace

Abstract. Soon after the launch of Aeolus on 22 August 2018, the first ever wind lidar in space developed by the European Space Agency (ESA) has been providing profiles of the component of the wind vector along the instrument's line of sight (LOS) on a global scale. In order to validate the quality of Aeolus wind observations, the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt e.V., DLR) recently performed two airborne campaigns over central Europe deploying two different Doppler wind lidars (DWLs) on board the DLR Falcon aircraft. The first campaign – WindVal III – was conducted from 5 November 2018 until 5 December 2018 and thus still within the commissioning phase of the Aeolus mission. The second campaign – AVATARE (Aeolus Validation Through Airborne Lidars in Europe) – was performed from 6 May 2019 until 6 June 2019. Both campaigns were flown out of the DLR site in Oberpfaffenhofen, Germany, during the evening hours for probing the ascending orbits. All together, 10 satellite underflights with 19 flight legs covering more than 7500 km of Aeolus swaths were performed and used to validate the early-stage wind data product of Aeolus by means of collocated airborne wind lidar observations for the first time. For both campaign data sets, the statistical comparison of Aeolus horizontal line-of-sight (HLOS) observations and the corresponding wind observations of the reference lidar (2 µm DWL) on board the Falcon aircraft shows enhanced systematic and random errors compared with the bias and precision requirements defined for Aeolus. In particular, the systematic errors are determined to be 2.1 m s−1 (Rayleigh) and 2.3 m s−1 (Mie) for WindVal III and −4.6 m s−1 (Rayleigh) and −0.2 m s−1 (Mie) for AVATARE. The corresponding random errors are determined to be 3.9 m s−1 (Rayleigh) and 2.0 m s−1 (Mie) for WindVal III and 4.3 m s−1 (Rayleigh) and 2.0 m s−1 (Mie) for AVATARE. The Aeolus observations used here were acquired in an altitude range up to 10 km and have mainly a vertical resolution of 1 km (Rayleigh) and 0.5 to 1.0 km (Mie) and a horizontal resolution of 90 km (Rayleigh) and down to 10 km (Mie). Potential reasons for those errors are analyzed and discussed.

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ENVIRONMENTAL MODEL OF ENTREPRENEURSHIP IN THE SUSTAINABLE DEVELOPMENT FUNCTION WITH GLOBALIZATION CONDITIONS

Knowledge International Journal ◽

10.35120/kij2801189r ◽

2018 ◽

Vol 28 (1) ◽

pp. 189-193

Author(s):

Jovana Radulović ◽

Tijana Milanović ◽

Radica Jovanović

Keyword(s):

Sustainable Development ◽

Positive Impact ◽

Global Scale ◽

Social Aspect ◽

The Sustainable Development ◽

Business Plans ◽

Financial Gain ◽

Employment Education ◽

Market Factors ◽

Scientific Truth

In the conditions of the global economic crisis, technical and technological and social changes, entrepreneurship is imposed as a counterbalance to globalization, due to uncertain market factors and destabilized national economies. One of the world's socioeconomic side effects is global solidarity: a way of thinking about society and the environment that makes ecology along with small and medium-sized enterprises the main parameters of economic reforms on a global scale. Bearing in mind that entrepreneurship represents a specific, tangible approach to making profit in terms of observing and exploiting business opportunities in the market, dictated by innovative, technological and social conditions, companies around the world, and at the level of development strategies of government governments, implement the concept of sustainable development into their business plans , focusing not only on financial gain, but also on the social aspect of having a positive impact on society. The ecological dimension of sustainable development relates primarily to the broader notion of profit making: the ability of society to change for the better in the fields of employment, education, recycling and cultural activities. Companies based on ecological principles are now called sustainable / ecological enterprises, and an economy based on the study of environmental resources for environmental economies. However, the education itself and the development of ethics on the environment in the environment are largely hampered by the development of ecological entrepreneurship, since the destruction of the Earth's ecosystems is not provable with sufficient scientific truth, and on the other hand, global NGOs constantly point to the advantage of an ecological business model as an investment asset because the environmental problem global, and therefore allows for international cooperation, while ecological companies create value in the same way as ecosystems: not producing waste or wasting unsustainable resources.

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A Structure Nondestructive Evaluation Using Laser-Generated Ultrasonic Application

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.261-263.1367 ◽

2004 ◽

Vol 261-263 ◽

pp. 1367-1372

Author(s):

Jae Yeol Kim ◽

S.U. Yoon ◽

Kyeung Cheun Jang ◽

Myung Soo Ko ◽

Jae Sin An

Keyword(s):

Light Beam ◽

Laser Frequency ◽

Test Material ◽

Time Shift ◽

Ultrasonic Signals ◽

Fabry Perot ◽

Convex Mirror ◽

Type Size ◽

Pulse Type ◽

Stable Frequency

In the present study, a Nd;YAG Laser (pulse type) was used to emit ultrasonic signals to a test material. In addition, a total ultrasonic investigation system was designed by adopting a Fabry-Perot interferometer, which receives ultrasonic signals without any contact. For non-destructive test SM45C, which contains some flaws was used as a test material. Because it is easy to align light beam in receiver, and the length of the light beam does not change much even if convex mirror leans towards one side, confocal Fabry-Perot interferometer, which has stable frequency, and PI control are used to correct interfered and unstable signals from temperature, fluctuation and time shift of laser frequency. Stable signals are always obtained by the feedback of PI circuit signals in the confocal Fabry-Perot interferometer. The type, size and position of flaws inside the test material were examined by achieving the stabilization of an interferometer. This study presented a useful method, which could quantitatively investigate the fault of objects by using a Fabry-Perot interferometer.

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JWST Noise Floor. II. Systematic Error Sources in JWST NIRCam Time Series

The Astronomical Journal ◽

10.3847/1538-3881/abd8d4 ◽

2021 ◽

Vol 161 (3) ◽

pp. 115

Author(s):

Everett Schlawin ◽

Jarron Leisenring ◽

Michael W. McElwain ◽

Karl Misselt ◽

Kenneth Don ◽

...

Keyword(s):

Time Series ◽

Systematic Error ◽

Error Sources ◽

Noise Floor

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Retrieval of atmospheric backscatter and extinction profiles with the aladin airborne demonstrator (A2D)

EPJ Web of Conferences ◽

10.1051/epjconf/201817602021 ◽

2018 ◽

Vol 176 ◽

pp. 02021 ◽

Cited By ~ 1

Author(s):

Alexander Geiss ◽

Uwe Marksteiner ◽

Oliver Lux ◽

Christian Lemmerz ◽

Oliver Reitebuch ◽

...

Keyword(s):

Direct Detection ◽

European Space Agency ◽

Backscatter Coefficient ◽

Detection Scheme ◽

Space Agency ◽

Fabry Perot ◽

Lidar Ratio ◽

Wind Lidar ◽

Wind Retrievals ◽

Atmospheric Backscatter

By the end of 2017, the European Space Agency (ESA) will launch the Atmospheric laser Doppler instrument (ALADIN), a direct detection Doppler wind lidar operating at 355 nm. An important tool for the validation and optimization of ALADIN’s hardware and data processors for wind retrievals with real atmospheric signals is the ALADIN airborne demonstrator A2D. In order to be able to validate and test aerosol retrieval algorithms from ALADIN, an algorithm for the retrieval of atmospheric backscatter and extinction profiles from A2D is necessary. The A2D is utilizing a direct detection scheme by using a dual Fabry-Pérot interferometer to measure molecular Rayleigh signals and a Fizeau interferometer to measure aerosol Mie returns. Signals are captured by accumulation charge coupled devices (ACCD). These specifications make different steps in the signal preprocessing necessary. In this paper, the required steps to retrieve aerosol optical products, i. e. particle backscatter coefficient βp, particle extinction coefficient αp and lidar ratio Sp from A2D raw signals are described.

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Designing for a green chemistry future

Science ◽

10.1126/science.aay3060 ◽

2020 ◽

Vol 367 (6476) ◽

pp. 397-400 ◽

Cited By ~ 58

Author(s):

Julie B. Zimmerman ◽

Paul T. Anastas ◽

Hanno C. Erythropel ◽

Walter Leitner

Keyword(s):

Green Chemistry ◽

Molecular Level ◽

Positive Impact ◽

Systems Design ◽

Global Scale ◽

Design Stage ◽

Sustainable Society ◽

Material Basis ◽

Chemical Products ◽

Definition Of

The material basis of a sustainable society will depend on chemical products and processes that are designed following principles that make them conducive to life. Important inherent properties of molecules need to be considered from the earliest stage—the design stage—to address whether compounds and processes are depleting versus renewable, toxic versus benign, and persistent versus readily degradable. Products, feedstocks, and manufacturing processes will need to integrate the principles of green chemistry and green engineering under an expanded definition of performance that includes sustainability considerations. This transformation will require the best of the traditions of science and innovation coupled with new emerging systems thinking and systems design that begins at the molecular level and results in a positive impact on the global scale.

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Frequency Stabilization of the Diode Laser to the Extra Reference Cavity

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.198-199.1235 ◽

2012 ◽

Vol 198-199 ◽

pp. 1235-1240

Author(s):

Xiao Dong Liu ◽

Hai Dong Lei ◽

Jian Jun Zhang

Keyword(s):

Semiconductor Laser ◽

Diode Laser ◽

Laser Frequency ◽

Frequency Stabilization ◽

Resonance Peak ◽

Experimental Setup ◽

Laser Frequency Stabilization ◽

Reference Cavity ◽

Fabry Perot ◽

Important Study

The Semiconductor laser frequency stabilization is the important study topic because of its increasing popular. We introduce a simply experimental setup method of the frequency stabilization of a 780 nm diode laser by only a tiny current in the laser audio modulation, photodiode receiver, and locking the transmission peaks. Use this method, the laser can be locked to the resonance peak of the Fabry-Perot cavity. The linewidth of laser is below 400 kHz, and it runs continually above 3 hours.

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The ExoMars Trace Gas Orbiter – First Martian Year in Orbit

10.5194/egusphere-egu2020-22228 ◽

2020 ◽

Author(s):

Håkan Svedhem ◽

Oleg Korablev ◽

Igor Mitrofanov ◽

Daniel Rodionov ◽

Nicholas Thomas ◽

...

Keyword(s):

Surface Science ◽

Dust Storm ◽

European Space Agency ◽

High Sensitivity ◽

Global Scale ◽

Trace Gas ◽

Full Potential ◽

Water Ice ◽

Surface Hydrogen ◽

Space Agency

The Trace Gas Orbiter, TGO, has in March 2020 concluded its first Martian year in its 400km, 74 degrees inclination, science orbit. It has been a highly successful year, starting with the rise, plateau and decay of the major Global Dust Storm in the summer of 2018. This has enabled interesting results to be derived on the water vapour distribution, dynamic behaviour and upward transport as a consequence of the dust storm. The characterisation of the minor species and trace gasses is continuing and a large number of profiles is produced every day. A dedicated search of methane has shown that there is no methane above an altitude of a few km, with an upper limit established at about 20 ppt (2&#8729;10-11). The solar occultation technique used by the spectrometers has definitely proven its strength, both for its high sensitivity and for its capability of making high resolution altitude profiles of the atmosphere. Climatological studies have been initiated and will become more important now that a full year has passed, even if the full potential will be visible only after a few Martian years of operation. The FREND instrument has characterised the hydrogen in the shallow sub-surface on a global scale at a spatial resolution much better than previous missions have been able. It has found areas at surprisingly low latitudes with significant amounts of sub-surface hydrogen, most likely in the form of water ice. The CaSSIS camera has made a high number of images over a large variety of targets, including the landing sites of the 2020 ESA and NASA rovers, Oxia Planum and the Jezero Crater. Stereo imaging has enabled topographic information and precise 3-D landscape synthesis.This presentation will summarise the highlights of the first Martian year and discuss planned activities for the near and medium term future.The ExoMars programme is a joint activity by the European Space Agency (ESA) and ROSCOSMOS, Russia. It consists of the ExoMars 2016 mission, launched 14 March 2016, with the Trace Gas Orbiter, TGO, and the Entry Descent and Landing Demonstrator, EDM, named Schiaparelli, and the ExoMars 2020 mission, to be launched in July/August 2020, carrying a Rover and a surface science platform to the surface of Mars.

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