Airborne wind lidar observations over the North Atlantic in 2016 for the pre-launch validation of the satellite mission Aeolus

Lux, Oliver; Lemmerz, Christian; Weiler, Fabian; Marksteiner, Uwe; Witschas, Benjamin; Rahm, Stephan; Schäfler, Andreas; Reitebuch, Oliver

doi:10.5194/amt-11-3297-2018

Cited by 53 publications

(85 citation statements)

References 46 publications

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“…Based on stable atmospheric conditions (Dou et al, 2014;Liu et al, 2002) it is reasonable to assume that only small temperature and pressure variations occur with a negligible effect on the retrieved wind within a specific analysis period. However, for spaceborne or airborne lidar systems like ALADIN or the A2D, the variability in temperature and pressure can be one of the main sources of systematic errors for the Rayleigh channel wind retrieval as it modifies the instrument response calibration (Dabas et al, 2008;Marksteiner, 2013).…”

Section: Approach Using Measured Response Calibrationsmentioning

confidence: 99%

“…In addition, the A2D is expected to contribute to the optimization of the wind measurement strategies for the satellite instrument as well as to the improvement of wind retrieval and quality control algorithms during satellite operation (Durand et al, 2006;. As the first ever airborne direct-detection wind lidar, A2D has been deployed in several ground and airborne campaigns over the last 12 years (Li et al, 2010;Marksteiner, 2013;Weiler, 2017;Lux et al, 2018;Marksteiner et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

“…Different instrument response calibration approaches have been studied using both measured and simulated response calibration to characterize and calibrate the ALADIN Rayleigh channel (Tan et al, 2008;Dabas et al, 2008;Rennie et al, 2017). Currently, only measured Rayleigh response calibrations (MRRC) are used for the A2D (Marksteiner, 2013;Lux et al, 2018;Marksteiner et al, 2018). However, the atmospheric temperature affects the Rayleigh-Brillouin line shape and has a direct effect on the instrument response calibration (Dabas et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

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Rayleigh wind retrieval for the ALADIN airborne demonstrator of the Aeolus mission using simulated response calibration

et al. 2020

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Abstract. Aeolus, launched on 22 August in 2018, is the first ever satellite to directly observe wind information from the surface up to 30 km on a global scale. An airborne prototype instrument called ALADIN airborne demonstrator (A2D) was developed at the German Aerospace Center (DLR) for validating the Aeolus measurement principle based on realistic atmospheric signals. To obtain accurate wind retrievals, the A2D uses a measured Rayleigh response calibration (MRRC) to calibrate its Rayleigh channel signals. However, differences exist between the respective atmospheric temperature profiles that are present during the conduction of the MRRC and the actual wind measurements. These differences are an important source of wind bias since the atmospheric temperature has a direct effect on the instrument response calibration. Furthermore, some experimental limitations and requirements need to be considered carefully to achieve a reliable MRRC. The atmospheric and instrumental variability thus currently limit the reliability and repeatability of a MRRC. In this paper, a procedure for a simulated Rayleigh response calibration (SRRC) is developed and presented in order to resolve these limitations of the A2D MRRC. At first the transmission functions of the A2D Rayleigh channel double-edge Fabry–Pérot interferometers (FPIs) in the internal reference path and the atmospheric path are characterized and optimized based on measurements performed during different airborne and ground-based campaigns. The optimized FPI transmission functions are then combined with the laser reference spectrum and the temperature-dependent molecular Rayleigh backscatter spectrum to derive an accurate A2D SRRC which can finally be implemented into the wind retrieval. Using dropsonde data as a reference, a statistical analysis based on a dataset from a flight campaign in 2016 reveals a bias and a standard deviation of line-of-sight (LOS) wind speeds derived from a SRRC of only 0.05 and 2.52 m s−1, respectively. Compared to the result derived from a MRRC with a bias of 0.23 m s−1 and a standard deviation of 2.20 m s−1, the accuracy improved and the precision is considered to be at the same level. Furthermore, it is shown that the SRRC allows for the simulation of receiver responses over the whole altitude range from the aircraft down to sea level, thus overcoming limitations due to high ground elevation during the acquisition of an airborne instrument response calibration.

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Section: Approach Using Measured Response Calibrationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Rayleigh wind retrieval for the ALADIN airborne demonstrator of the Aeolus mission using simulated response calibration

et al. 2020

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“…Zhang et al, 2018). Further, airborne Doppler lidar can serve as a testbed and validation tool for upcoming and existing space-based Doppler lidar systems (Paffrath et al, 2009;Lux et al, 2018; ESA, 2018;Baidar et al, 2018;Tucker et al, 2018).Due to their benefits various airborne Doppler lidar systems have been developed in the past. Most of the systems are based on long-range aircraft flying in the upper troposphere at high speeds (O(250m s −1 )), thereby they are destined for sensing the free troposphere due to the coarser spatial resolution (O(5 km) for wind profiling).…”

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confidence: 99%

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An LES-based airborne Doppler lidar simulator for investigation of wind profiling in inhomogeneous flow conditions

Gasch

Wieser

Lundquist

et al. 2019

Preprint

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Abstract. Wind profiling by Doppler lidar is common practice and highly useful in a wide range of applications. Airborne observations can provide additional insights to ground-based systems by allowing for spatially resolved and targeted measurements. This study prepares the ground for an upcoming airborne Doppler lidar system by investigating the measurement process theoretically. To evaluate the future system characteristics and measurement accuracy, a first LES-based airborne Doppler lidar simulator (ADLS) has been developed. The accuracy of retrieved wind profiles under inhomogeneous flow conditions in the boundary layer is investigated. In general, when using reasonable system setups, wind profiling is possible with acceptable error margins. Results allow for determination of preferential system setups and wind profiling strategies. Under the conditions considered, flow inhomogeneities exert the dominant influence on wind profiling error. In comparison, both the errors caused by random radial velocity fluctuations due to laser system noise and beam pointing inaccuracy due to system vibrations are of smaller magnitude. Airborne Doppler lidar wind profiling at low wind speeds (

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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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Airborne wind lidar observations over the North Atlantic in 2016 for the pre-launch validation of the satellite mission Aeolus

Cited by 53 publications

References 46 publications

Rayleigh wind retrieval for the ALADIN airborne demonstrator of the Aeolus mission using simulated response calibration

Rayleigh wind retrieval for the ALADIN airborne demonstrator of the Aeolus mission using simulated response calibration

An LES-based airborne Doppler lidar simulator for investigation of wind profiling in inhomogeneous flow conditions

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

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