scholarly journals Validation of Aeolus wind products above the Atlantic Ocean

2020 ◽  
Author(s):  
Holger Baars ◽  
Alina Herzog ◽  
Birgit Heese ◽  
Kevin Ohneiser ◽  
Karsten Hanbuch ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
European Space Agency ◽  
Space Mission ◽  
High Spectral Resolution ◽  
Horizontal Wind ◽  
Vertical Resolution ◽  
Wind Speeds ◽  
Cloud Properties ◽  
Radiosonde Observation ◽  
Wind Lidar

Abstract. In August 2018, the first Doppler wind lidar in space called ALADIN was launched on-board the satellite Aeolus by the European Space Agency ESA. Aeolus measures horizontal wind profiles in the troposphere and lower stratosphere on a global basis. Furthermore, profiles of aerosol and cloud properties can be retrieved via the high-spectral-resolution lidar (HSRL) technique. The Aeolus mission is supposed to improve the quality of weather forecasts and the understanding of atmospheric processes. We used the chance of opportunity to perform a unique validation of the wind products of Aeolus by utilizing the RV Polarstern cruise PS116 from Bremerhaven to Cape Town in November/December 2018. Due to concerted course modifications, six direct intersections with the Aeolus ground track could be achieved on the Atlantic Ocean, west of the African continent. For the validation of the Aeolus wind products, we launched additional radiosondes and used the EARLINET/ACTRIS lidar PollyXT for atmospheric scene analysis. The six analyzed cases proof the concept of Aeolus to be able to measure horizontal wind speeds in the nearly West-East direction. Good agreements with the radiosonde observation could be achieved for both Aeolus wind products – the winds observed in clean atmospheric regions called Rayleigh winds and the winds obtained in cloud layers called Mie winds according to the responsible scattering regime. Systematic and statistical errors of the Rayleigh winds were less than 1.5 m/s and 3.3 m/s, respectively, when comparing to radiosonde values averaged to the Aeolus vertical resolution. For the Mie winds, a systematic and random error of about 1 m/s was obtained from the six comparisons in different climate zones. However, it is also shown that the coarse vertical resolution of 2 km in the upper troposphere which was set in this early mission phase two months after launch led to an underestimation of the maximum wind speed in the jet stream regions. Summarizing, promising first results of the first wind lidar space mission are shown and proof the concept of Aeolus for global wind observations.

scholarly journals Validation of Aeolus wind products above the Atlantic Ocean

2020 ◽  
Vol 13 (11) ◽  
pp. 6007-6024
Author(s):  
Holger Baars ◽  
Alina Herzog ◽  
Birgit Heese ◽  
Kevin Ohneiser ◽  
Karsten Hanbuch ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
European Space Agency ◽  
Space Mission ◽  
High Spectral Resolution ◽  
Horizontal Wind ◽  
Wind Component ◽  
Vertical Resolution ◽  
Wind Speeds ◽  
Cloud Properties ◽  
Wind Lidar

Abstract. In August 2018, the first Doppler wind lidar in space called Atmospheric Laser Doppler Instrument (ALADIN) was launched on board the satellite Aeolus by the European Space Agency (ESA). Aeolus measures profiles of one horizontal wind component (i.e., mainly the west–east direction) in the troposphere and lower stratosphere on a global basis. Furthermore, profiles of aerosol and cloud properties can be retrieved via the high spectral resolution lidar (HSRL) technique. The Aeolus mission is supposed to improve the quality of weather forecasts and the understanding of atmospheric processes. We used the opportunity to perform a unique validation of the wind products of Aeolus by utilizing the RV Polarstern cruise PS116 from Bremerhaven to Cape Town in November/December 2018. Due to concerted course modifications, six direct intersections with the Aeolus ground track could be achieved in the Atlantic Ocean west of the African continent. For the validation of the Aeolus wind products, we launched additional radiosondes and used the EARLINET/ACTRIS lidar PollyXT for atmospheric scene analysis. The six analyzed cases prove that Aeolus is able to measure horizontal wind speeds in the nearly west–east direction. Good agreements with the radiosonde observations could be achieved for both Aeolus wind products – the winds observed in clean atmospheric regions called Rayleigh winds and the winds obtained in cloud layers called Mie winds (according to the responsible scattering regime). Systematic and statistical errors of the Rayleigh winds were less than 1.5 and 3.3 m s−1, respectively, when compared to radiosonde values averaged to the vertical resolution of Aeolus. For the Mie winds, a systematic and random error of about 1 m s−1 was obtained from the six comparisons in different climate zones. However, it is also shown that the coarse vertical resolution of 2 km in the upper troposphere, which was set in this early mission phase 2 months after launch, led to an underestimation of the maximum wind speed in the jet stream regions. In summary, promising first results of the first wind lidar space mission are shown and prove the concept of Aeolus for global wind observations.

scholarly journals First Results from the German Cal/Val Activities for Aeolus

2020 ◽  
Vol 237 ◽  
pp. 01008 ◽  
Author(s):  
Holger Baars ◽  
Alexander Geiß ◽  
Ulla Wandinger ◽  
Alina Herzog ◽  
Ronny Engelmann ◽  
...  
Keyword(s):  
Direct Detection ◽  
Weather Prediction ◽  
European Space Agency ◽  
High Spectral Resolution ◽  
Dual Channel ◽  
Space Agency ◽  
First Results ◽  
Global Coverage ◽  
Wind Lidar ◽  
Doppler Wind Lidar

On 22nd August 2018, the European Space Agency (ESA) launched the first direct detection Doppler wind lidar into space. Operating at 355 nm and acquiring signals with a dual channel receiver, it allows wind observations in clear air and particle-laden regions of the atmosphere. Furthermore, particle optical properties can be obtained using the High Spectral Resolution Technique Lidar (HSRL) technique. Measuring with 87 km horizontal and 0.25-2 km vertical resolution between ground and up to 30 km in the stratosphere, the global coverage of Aeolus observations shall fill gaps in the global observing system and thus help improving numerical weather prediction. Within this contribution, first results from the German initiative for experimental Aeolus validation are presented and discussed. Ground-based wind and aerosol measurements from tropospheric radar wind profilers, Doppler wind lidars, radiosondes, aerosol lidars and cloud radars are utilized for that purpose.

scholarly journals Development of Synergetic-Active Sensor-System for Evaluation of Observations by Earthcare

2020 ◽  
Vol 237 ◽  
pp. 07011
Author(s):  
Hajime Okamoto ◽  
Kaori Sato ◽  
Masahiro Fujikawa ◽  
Eiji Oikawa ◽  
Tomoaki Nishizawa ◽  
...  
Keyword(s):  
Direct Detection ◽  
Cloud Microphysics ◽  
Sensor System ◽  
High Spectral Resolution ◽  
Horizontal Wind ◽  
Observation System ◽  
Active Sensor ◽  
Wind Lidar ◽  
Multiple Field ◽  
Doppler Wind Lidar

We develop the synergetic ground-based active-sensor-system for the evaluation of observations by space-borne lidars. The system consists of second version of multi-field-view multiple-scattering polarization lidar (MFMSPL-2), multiple-field-of-view high spectral resolution polarization lidar, direct-detection Doppler wind lidar, coherent Doppler wind lidar and 94GHz cloud profiling radar. The system can simulate observed signals from sensors onboard the joint Japanese/European mission Earth Clouds, Aerosols and Radiation Explorer (EarthCARE). The observation system can provide unique opportunity to study interaction of cloud microphysics, aerosol microphysics, vertical air motion and vertical distribution of horizontal wind and it will lead to evaluate cloud-convective parameterization and to reduce uncertainties in climate change predictions.

scholarly journals 0.355-micrometer direct detection wind lidar under testing during a field campaign in consideration of ESA's ADM-Aeolus mission

2013 ◽  
Vol 6 (12) ◽  
pp. 3349-3358 ◽  
Author(s):  
S. Lolli ◽  
A. Delaval ◽  
C. Loth ◽  
A. Garnier ◽  
P. H. Flamant
Keyword(s):  
Direct Detection ◽  
Weather Prediction ◽  
European Space Agency ◽  
Geostrophic Wind ◽  
Lower Atmosphere ◽  
Wind Data ◽  
High Spectral Resolution ◽  
Horizontal Wind ◽  
Field Campaign ◽  
Remote Sensors

Abstract. The atmospheric wind field information is a key issue to numerical weather prediction (NWP) and climate studies. The Atmospheric Dynamic Mission-Aeolus is currently developed by the European Space Agency (ESA) to launch a wind sensing Doppler lidar in mid-2015. The high spectral resolution lidar concept is using backscattered laser signals from molecules and particles to provide accurate horizontal wind velocity measurements in the depth of atmosphere. The Aeolus lidar, so-called ALADIN, will operate in UV at 0.355 μm. The combination of air molecules and UV laser light is intended to provide wind data evenly distributed everywhere in the lower atmosphere (below 30 km altitude). The goal of the ESA's Aeolus mission is to enhance the present meteorological observations system over sparse wind data regions, and more importantly to provide direct wind information in the tropics where no geostrophic wind can be derived from mass fields obtained from passive radiometer satellite. The 0.355 μm lidar concept was under testing during a field campaign conducted at the Haute-Provence Observatory, France, in 1999. Several active remote sensors were deployed on the site, and it was the opportunity to address the self-consistency of wind measurements made by different lidars, a 72 MHz radar, and conventional balloon radio soundings. The paper presents the comparison of different remote sensors using two criteria: Pearson cross-correlation coefficient and root mean square error. The methodology discussed here may be useful in future ESA Aeolus validation campaigns involving different kinds of instruments.

scholarly journals The formation of planetary systems with SPICA

2021 ◽  
Vol 38 ◽  
Author(s):  
I. Kamp ◽  
M. Honda ◽  
H. Nomura ◽  
M. Audard ◽  
D. Fedele ◽  
...  
Keyword(s):  
Solar System ◽  
European Space Agency ◽  
Planetary Systems ◽  
Relevant Information ◽  
Space Mission ◽  
Detection Sensitivity ◽  
High Spectral Resolution ◽  
General Process ◽  
Infrared Telescope ◽  
Ice Content

Abstract In this era of spatially resolved observations of planet-forming disks with Atacama Large Millimeter Array (ALMA) and large ground-based telescopes such as the Very Large Telescope (VLT), Keck, and Subaru, we still lack statistically relevant information on the quantity and composition of the material that is building the planets, such as the total disk gas mass, the ice content of dust, and the state of water in planetesimals. SPace Infrared telescope for Cosmology and Astrophysics (SPICA) is an infrared space mission concept developed jointly by Japan Aerospace Exploration Agency (JAXA) and European Space Agency (ESA) to address these questions. The key unique capabilities of SPICA that enable this research are (1) the wide spectral coverage $10{-}220\,\mu\mathrm{m}$ , (2) the high line detection sensitivity of $(1{-}2) \times 10^{-19}\,\mathrm{W\,m}^{-2}$ with $R \sim 2\,000{-}5\,000$ in the far-IR (SAFARI), and $10^{-20}\,\mathrm{W\,m}^{-2}$ with $R \sim 29\,000$ in the mid-IR (SPICA Mid-infrared Instrument (SMI), spectrally resolving line profiles), (3) the high far-IR continuum sensitivity of 0.45 mJy (SAFARI), and (4) the observing efficiency for point source surveys. This paper details how mid- to far-IR infrared spectra will be unique in measuring the gas masses and water/ice content of disks and how these quantities evolve during the planet-forming period. These observations will clarify the crucial transition when disks exhaust their primordial gas and further planet formation requires secondary gas produced from planetesimals. The high spectral resolution mid-IR is also unique for determining the location of the snowline dividing the rocky and icy mass reservoirs within the disk and how the divide evolves during the build-up of planetary systems. Infrared spectroscopy (mid- to far-IR) of key solid-state bands is crucial for assessing whether extensive radial mixing, which is part of our Solar System history, is a general process occurring in most planetary systems and whether extrasolar planetesimals are similar to our Solar System comets/asteroids. We demonstrate that the SPICA mission concept would allow us to achieve the above ambitious science goals through large surveys of several hundred disks within $\sim\!2.5$ months of observing time.

scholarly journals Doppler lidar at Observatoire de Haute-Provence for wind profiling up to 75 km altitude: performance evaluation and observations

2020 ◽  
Vol 13 (3) ◽  
pp. 1501-1516 ◽  
Author(s):  
Sergey M. Khaykin ◽  
Alain Hauchecorne ◽  
Robin Wing ◽  
Philippe Keckhut ◽  
Sophie Godin-Beekmann ◽  
...  
Keyword(s):  
Middle Atmosphere ◽  
Direct Detection ◽  
European Space Agency ◽  
Horizontal Wind ◽  
Doppler Lidar ◽  
Qualitative Comparison ◽  
Horizontal Wind Speed ◽  
Wind Lidar ◽  
Wind Profiles ◽  
Hourly Observation

Abstract. A direct-detection Rayleigh–Mie Doppler lidar for measuring horizontal wind speed in the middle atmosphere (10 to 50 km altitude) has been deployed at Observatoire de Haute-Provence (OHP) in southern France starting from 1993. After a recent upgrade, the instrument gained the capacity of wind profiling between 5 and 75 km altitude with vertical resolution up to 115 m and temporal resolution up to 5 min. The lidar comprises a monomode Nd:Yag laser emitting at 532 nm, three telescope assemblies and a double-edge Fabry–Pérot interferometer for detection of the Doppler shift in the backscattered light. In this article, we describe the instrument design, recap retrieval methodology and provide an updated error estimate for horizontal wind. The evaluation of the wind lidar performance is done using a series of 12 time-coordinated radiosoundings conducted at OHP. A point-by-point intercomparison shows a remarkably small average bias of 0.1 m s−1 between the lidar and the radiosonde wind profiles with a standard deviation of 2.3 m s−1. We report examples of a weekly and an hourly observation series, reflecting various dynamical events in the middle atmosphere, such as a sudden stratospheric warming event in January 2019 and an occurrence of a stationary gravity wave, generated by the flow over the Alps. A qualitative comparison between the wind profiles from the lidar and the European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecast System is also discussed. Finally, we present an example of early validation of the European Space Agency (ESA) Aeolus space-borne wind lidar using its ground-based predecessor.

scholarly journals Intercomparison of wind observations from ESA’s satellite mission Aeolus and the ALADIN Airborne Demonstrator

2020 ◽  
Author(s):  
Oliver Lux ◽  
Christian Lemmerz ◽  
Fabian Weiler ◽  
Uwe Marksteiner ◽  
Benjamin Witschas ◽  
...  
Keyword(s):  
Direct Detection ◽  
European Space Agency ◽  
Ultra Violet ◽  
Wind Data ◽  
Random Errors ◽  
Satellite Mission ◽  
High Coverage ◽  
Wind Speeds ◽  
Dual Channel ◽  
Wind Lidar

Abstract. Shortly after the successful launch of ESA’s wind mission Aeolus, carried out by the European Space Agency, collocated airborne wind lidar observations were performed in Central Europe, employing the prototype of the satellite instrument, the ALADIN Airborne Demonstrator (A2D). Like the direct-detection Doppler wind lidar on-board Aeolus, the A2D is composed of a frequency-stabilised ultra-violet laser, a Cassegrain telescope and a dual-channel receiver to measure line-of-sight (LOS) wind speeds by analysing both Mie and Rayleigh backscatter signals. In the frame of the first airborne validation campaign after the launch still during the commissioning phase of the mission, four coordinated flights along the satellite swath were conducted in late autumn of 2018, yielding wind data in the troposphere with high coverage of the Rayleigh channel. Owing to the different measurement grids and viewing directions of the satellite and airborne instrument, intercomparison with the Aeolus wind product requires adequate averaging as well as conversion of the measured A2D LOS wind speeds to the satellite LOS. The statistical comparison of the two instruments with model wind data from the ECMWF shows biases of the A2D and Aeolus LOS wind speeds of −0.9 m s−1 and +1.6 m s−1, respectively, while the random errors are around 2.5 m s−1. The paper also discusses the influence of different threshold parameters implemented in the comparison algorithm as well as optimization of the A2D vertical sampling to be used in forthcoming validation campaigns.

scholarly journals Data quality of Aeolus wind measurements

2021 ◽  
Author(s):  
Isabell Krisch ◽  
Oliver Reitebuch ◽  
Jonas von Bismarck ◽  
Alain Dabas ◽  
Peggy Fischer ◽  
...  
Keyword(s):  
Data Quality ◽  
Weather Forecasting ◽  
European Space Agency ◽  
High Spectral Resolution ◽  
Retrieval Algorithm ◽  
High Data ◽  
Wind Measurements ◽  
Wind Lidar ◽  
Wind Profiles

<p>The European Space Agency (ESA)’s Earth Explorer Aeolus was launched in August 2018 carrying the world’s first spaceborne wind lidar, the Atmospheric Laser Doppler Instrument (ALADIN). ALADIN uses a high spectral resolution Doppler wind lidar operating at 355nm to determine profiles of line-of-sight wind components in near-real-time (NRT). ALADIN samples the atmosphere from 30km altitude down to the Earth’s surface or to the level where the lidar signal is attenuated by optically thick clouds.</p><p>The global wind profiles provided by ALADIN help to improve weather forecasting and the understanding of atmospheric dynamics as they fill observational gaps in vertically resolved wind profiles mainly in the tropics,  southern hemisphere, and over the northern hemisphere oceans. Since 2020, multiple national and international weather centres (e.g. ECMWF, DWD, Météo France, MetOffice) assimilate Aeolus observations in their operational forecasting. Additionally, the scientific exploitation of the Aeolus dataset has started.</p><p>A main prerequisite for beneficial impact and scientific exploitation is data of sufficient quality. Such high data quality has been achieved through close collaboration of all involved parties within the Aeolus Data Innovation and Science Cluster (DISC), which was established after launch to study and improve the data quality of Aeolus products. The tasks of the Aeolus DISC include the instrument and platform monitoring, calibration, characterization, retrieval algorithm refinement, processor evolution, quality monitoring, product validation, and impact assessment for NWP.</p><p>The achievements of the Aeolus DISC for the NRT data quality and the one currently available reprocessed dataset will be presented. The data quality of the Aeolus wind measurements will be described and an outlook on planned improvements of the dataset and processors will be provided.</p>

scholarly journals 0.355 μm direct detection wind lidar under testing during a field campaign in consideration of ESA's ADM-Aeolus Mission

2013 ◽  
Vol 6 (3) ◽  
pp. 4551-4575
Author(s):  
S. Lolli ◽  
A. Delaval ◽  
C. Loth ◽  
A. Garnier ◽  
P. H. Flamant
Keyword(s):  
Direct Detection ◽  
Weather Prediction ◽  
European Space Agency ◽  
Geostrophic Wind ◽  
Wind Data ◽  
High Spectral Resolution ◽  
Horizontal Wind ◽  
Observation System ◽  
Doppler Lidar ◽  
Field Campaign

Abstract. The atmospheric wind field information is a key issue to Numerical Weather Prediction (NWP) and climate studies. A space based Wind Doppler lidar mission so-called ADM-Aeolus is currently developed by the European Space Agency for a launch in 2015. Such a Doppler lidar will provide accurate direct measurements of horizontal wind velocity in the depth of atmosphere. The wind data will be evenly distributed at a global scale. The goal is to enhance the present meteorological observation system over sparse wind data regions, and more important to provide direct wind information in the tropics where no geostrophic wind can be derived from passive radiometer satellite. ADM-Aeolus is basically a 0.355 μm high spectral resolution backscatter lidar. This concept was under test during a field campaign conducted at the Haute Provence Observatory in France 1999. It was the opportunity to address the self-consistency of wind measurements made by different active remote sensors i.e. lidars and a 72-MHz radar, and balloon radio soundings.

scholarly journals WIRA-C: A compact 142-GHz-radiometer for continuous middle-atmospheric wind measurements

2018 ◽  
Author(s):  
Jonas Hagen ◽  
Axel Murk ◽  
Rolf Rüfenacht ◽  
Sergey Khaykin ◽  
Alain Hauchecorne ◽  
...  
Keyword(s):  
Time Series ◽  
Meridional Wind ◽  
Low Noise ◽  
High Spectral Resolution ◽  
Horizontal Wind ◽  
Transition Line ◽  
Compact Structure ◽  
Wind Speeds ◽  
Wind Measurements ◽  
Wind Profiles

Abstract. Ground-based microwave wind radiometry provides a method to measure horizontal wind speeds at altitudes between 35 and 75 km as it has been shown by various previous studies. No other method is capable of continuously delivering wind measurements in this altitude region. In this paper, we present the WIRA-C (WInd Radiometer for Campaigns) instrument that observes the 142.17504 GHz rotational transition line of ozone with a high spectral resolution using a low noise single side band heterodyne receiver. Because the emitting molecules are drifting with the wind, the line is Doppler shifted. Together with the pressure broadening effect, this allows the retrieval of altitude resolved wind profiles. The novel WIRA-C instrument represents the newest development in microwave wind radiometry. The main improvements include the compact structure, lower noise and an advanced retrieval setup. This paper describes the instrument and the data processing with a focus on the retrieval that takes into account a three-dimensional atmosphere and has never been used in ground-based radiometry before. The retrieval yields profiles of horizontal wind speeds with a 12 hour time resolution and a vertical resolution of 10 km for zonal and 10 to 15 km for meridional wind speeds. We give an error estimate that accounts for the thermal noise on the measured spectra and additionally estimate systematic errors using Monte Carlo methods. WIRA-C has been continuously measuring horizontal wind speeds since one year at the Maïdo observatory on La Réunion Island (21.4° S, 55.9° E). We present the time series of this campaign and compare our measurements to model data from the European Centre for Medium-range Weather Forecasts (ECMWF) and coincident measurements of the co-located Rayleigh-Mie Doppler wind lidar. We find a good agreement between our measurements and the ECMWF operational analysis for the time series, where many features are present in both datasets. The wind profiles of the coincident WIRA-C and lidar observations are consistent and agree within their respective uncertainties for the lidar measurements with long integration times.

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