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

Khaykin, Sergey; Hauchecorne, Alain; Wing, Robin; Keckhut, Philippe; Godin‐Beekmann, Sophie; Porteneuve, Jacques; Mariscal, Jean-François; Schmitt, J. H. M. M.

doi:10.5194/amt-13-1501-2020

Cited by 35 publications

(31 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…(above ground level), a stronger deviation was observed which was considered to be caused by horizontal heterogeneity. In our study, however, we could almost never observe any Rayleigh clear wind profile below 4 km which prohibits the discussion of this issue raised by Khaykin et al (2020).…”

Section: Resultscontrasting

confidence: 82%

See 1 more Smart Citation

Validation of Aeolus wind products above the Atlantic Ocean

Baars¹,

Herzog²,

Heese³

et al. 2020

Preprint

View full text Add to dashboard Cite

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.

show abstract

Section: Resultscontrasting

confidence: 82%

“…For further details, the reader may refer to the stated references. Khaykin et al (2020) analyzed one wind profile of Aeolus with the Doppler lidar at Observatoire de Haute-Provence and found a good agreement between the two measurements. But below 5 km a.g.l.…”

Section: Resultsmentioning

confidence: 85%

Validation of Aeolus wind products above the Atlantic Ocean

Baars¹,

Herzog²,

Heese³

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…The laser transmitter is realized by a frequency-tripled Nd:YAG master oscillator power amplifier (MOPA) system that generates UV laser pulses at 354.89 nm wavelength with a duration of 20 ns (full width at half maximum, FWHM) and an energy of 60 mJ at 50 Hz repetition rate (3.0 W average power). Injection-seeding of the master oscillator in combination with an active frequency-stabilization technique (Lemmerz et al, 2017) provides single-frequency operation with a pulse-to-pulse frequency stability of approximately 3 MHz (rms) and a spectral bandwidth of 50 MHz (FWHM). The near-diffraction-limited beam (beam quality factor: M 2 < 1.3) is transmitted to the atmosphere via a piezoelectrically controlled mirror that is attached to the frame of a telescope in Cassegrain configuration.…”

Section: The A2d Direct-detection Wind Lidar Systemmentioning

confidence: 99%

Intercomparison of wind observations from the European Space Agency's Aeolus satellite mission and the ALADIN Airborne Demonstrator

et al. 2020

View full text Add to dashboard Cite

Abstract. Shortly after the successful launch of the European Space Agency's wind mission Aeolus, co-located airborne wind lidar observations were performed in central Europe; these observations employed a prototype of the satellite instrument – the ALADIN (Atmospheric LAser Doppler INstrument) Airborne Demonstrator (A2D). Like the direct-detection Doppler wind lidar on-board Aeolus, the A2D is composed of a frequency-stabilized ultra-violet (UV) 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 framework of the first airborne validation campaign after the launch and 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 LOS viewing directions of the satellite and the 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 (LOS*). The statistical comparison of the two instruments shows a positive bias (of 2.6 m s−1) of the Aeolus Rayleigh winds (measured along its LOS*) with respect to the A2D Rayleigh winds as well as a standard deviation of 3.6 m s−1. Considering the accuracy and precision of the A2D wind data, which were determined from comparison with a highly accurate coherent wind lidar as well as with the European Centre for Medium-Range Weather Forecasts (ECMWF) model winds, the systematic and random errors of the Aeolus LOS* Rayleigh winds are 1.7 and 2.5 m s−1 respectively. The paper also discusses the influence of different threshold parameters implemented in the comparison algorithm as well as an optimization of the A2D vertical sampling to be used in forthcoming validation campaigns.

show abstract

“…The Aeolus mission primarily aims to demonstrate improvements in atmospheric wind analyses for the benefit of numerical weather prediction (NWP) and climate studies (Stoffelen et al, 2005;Rennie and Isaksen, 2019). Despite the advancement of the Global Observing System (GOS), there are still major deficiencies, the lack of accuracy being one of the significant limitations of currently used wind observation methods (Källén, 2018). Accurate vertical profiles of the wind field from radiosondes, wind profilers, and commercial aircraft ascents and descents are mainly concentrated over continents in the Northern Hemisphere, whereas only a few profiles are available over the oceans and on most parts of the Southern Hemisphere.…”

Section: Introductionmentioning

confidence: 99%

Validation of Aeolus winds using radiosonde observations and numerical weather prediction model equivalents

et al. 2021

View full text Add to dashboard Cite

Abstract. In August 2018, the first Doppler wind lidar, developed by the European Space Agency (ESA), was launched on board the Aeolus satellite into space. Providing atmospheric wind profiles on a global basis, the Earth Explorer mission is expected to demonstrate improvements in the quality of numerical weather prediction (NWP). For the use of Aeolus observations in NWP data assimilation, a detailed characterization of the quality and the minimization of systematic errors is crucial. This study performs a statistical validation of Aeolus observations, using collocated radiosonde measurements and NWP forecast equivalents from two different global models, the ICOsahedral Nonhydrostatic model (ICON) of Deutscher Wetterdienst (DWD) and the European Centre for Medium-Range Weather Forecast (ECMWF) Integrated Forecast System (IFS) model, as reference data. For the time period from the satellite's launch to the end of December 2019, comparisons for the Northern Hemisphere (23.5–65∘ N) show strong variations of the Aeolus wind bias and differences between the ascending and descending orbit phase. The mean absolute bias for the selected validation area is found to be in the range of 1.8–2.3 m s−1 (Rayleigh) and 1.3–1.9 m s−1 (Mie), showing good agreement between the three independent reference data sets. Due to the greater representativeness errors associated with the comparisons using radiosonde observations, the random differences are larger for the validation with radiosondes compared to the model equivalent statistics. To achieve an estimate for the Aeolus instrumental error, the representativeness errors for the comparisons are determined, as well as the estimation of the model and radiosonde observational error. The resulting Aeolus error estimates are in the range of 4.1–4.4 m s−1 (Rayleigh) and 1.9–3.0 m s−1 (Mie). Investigations of the Rayleigh wind bias on a global scale show that in addition to the satellite flight direction and seasonal differences, the systematic differences vary with latitude. A latitude-based bias correction approach is able to reduce the bias, but a residual bias of 0.4–0.6 m s−1 with a temporal trend remains. Taking additional longitudinal differences into account, the bias can be reduced further by almost 50 %. Longitudinal variations are suggested to be linked to land–sea distribution and tropical convection that influences the thermal emission of the earth. Since 20 April 2020 a telescope temperature-based bias correction scheme has been applied operationally in the L2B processor, developed by the Aeolus Data Innovation and Science Cluster (DISC).

show abstract

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

Cited by 35 publications

References 34 publications

Validation of Aeolus wind products above the Atlantic Ocean

Validation of Aeolus wind products above the Atlantic Ocean

Intercomparison of wind observations from the European Space Agency's Aeolus satellite mission and the ALADIN Airborne Demonstrator

Validation of Aeolus winds using radiosonde observations and numerical weather prediction model equivalents

Contact Info

Product

Resources

About