Aeolus First Year in Orbit Power System Performance

Simonelli, Giulio; Brandt, C.; Rezazad, Mehrdad

doi:10.1109/espc.2019.8932017

Cited by 2 publications

(1 citation statement)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…-Initially lower laser energy with a more rapid decline than expected (Simonelli et al, 2019;Lux et al, 2020b), -Switch to second laser with different beam characteristics which were also changing over time (Straume et al, 2020), -Occurrence of increased background noise for some pixels (hot pixels) on the ACCD (Accumulation Charge-Coupled Devices) of ALADIN (Weiler et al, 2021a), -Changes in the wind accuracy according to differences in temperature at the main telescope mirror of ALADIN (Weiler et al, 2021b). DISC and ESA have worked hard on these features to improve the stability of the instrument and its products.…”

Section: Introductionmentioning

confidence: 92%

Long-term validation of Aeolus L2B wind products at Punta Arenas, Chile and Leipzig, Germany

Baars

Walchester

Basharova

et al. 2022

Preprint

View full text Add to dashboard Cite

Abstract. Ground-based observations of horizontal winds have been performed in Leipzig (51.12 N, 12.43 E), Germany, and at Punta Arenas (53.35 S, 70.88 W), Chile, in the framework of the German initiative EVAA (Experimental Validation and Assimilation of Aeolus observations) with respect to the validation of the Mie and Rayleigh wind products of Aeolus (L2B data). In Leipzig, at the Leibniz Institute for Tropospheric Research (TROPOS), radiosondes have been launched on each Friday for the Aeolus overpasses (ascending orbit) since mid of May 2019. In Punta Arenas, scanning Doppler cloud radar observations have been performed in the frame of the DACAPO-PESO campaign (dacapo.tropos.de) for more than 3 years from end 2018 until end 2021. We present two case studies and long‐term statistics of the horizontal winds derived with the ground-based reference instruments compared to Aeolus Horizontal Line-of-Sight (HLOS) winds. It was found that the deviation of the Aeolus HLOS winds from the ground-reference is usually of Gaussian shape which allowed the use of the median bias and the scaled median absolute deviation (MAD) for the determination of the systematic and random error of Aeolus wind products, respectively. The case study from August 2020 with impressive atmospheric conditions in Punta Arenas shows that Aeolus is able to also capture strong wind speeds up to more than 100 m/s. The long-term validation has been performed for all product baselines since the change to the second laser (called FM-B) in June 2019 until summer 2022 and also partly for the era of the first laser (FM-A). The long-term validation showed that the systematic error of the Aeolus wind products could be significantly lowered with the changes introduced into the processing chain (different baselines) during the mission lifetime. While in the early mission phase, systematic errors of more than 2 m/s (absolute values) were observed for both wind types (Mie cloudy and Rayleigh clear), these biases could be reduced with the algorithm improvements, such as the introduction of the correction for temperature fluctuations at the main telescope of Aeolus (M1 temperature correction) with Baseline 09. Hence, since Baseline 10, a significant improvement of the Aeolus data was found leading to a low bias (close to 0 m/s) and nearly similar values for the mid-latitudinal sites on both hemispheres. The random errors for the wind products were first decreasing with increasing baseline but later increasing again due to the performance losses of the Aeolus emitter. However, the systematic error is only slightly affected by this issue, so that one can conclude that the uncertainty introduced by the reduced atmospheric return signal received by Aeolus is mostly affecting the random error. Even when considering these issues, we can confirm the general validity of Aeolus observations during its lifetime. This proves the general concept of this space explorer mission to perform active wind observations from space.

show abstract

Section: Introductionmentioning

confidence: 92%

Long-term validation of Aeolus L2B wind products at Punta Arenas, Chile and Leipzig, Germany

Baars

Walchester

Basharova

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

Long-term validation of Aeolus L2B wind products at Punta Arenas, Chile, and Leipzig, Germany

Baars,

Walchester,

Basharova

et al. 2023

Atmos. Meas. Tech.

View full text Add to dashboard Cite

Abstract. Ground-based observations of horizontal winds have been performed at Leipzig (51.35∘ N, 12.43∘ E), Germany, and at Punta Arenas (53.15∘ S, 70.91∘ W), Chile, in the framework of the German initiative EVAA (Experimental Validation and Assimilation of Aeolus observations) with respect to the validation of the Mie and Rayleigh wind products of Aeolus (L2B data). In Leipzig, at the Leibniz Institute for Tropospheric Research (TROPOS), radiosondes have been launched for the Aeolus overpasses on each Friday (ascending orbit) since the middle of May 2019. In Punta Arenas, scanning Doppler cloud radar observations have been performed in the framework of the DACAPO-PESO campaign (dacapo.tropos.de) for more than 3 years from the end of 2018 until the end of 2021 and could be used to validate Aeolus measurements on its ascending and descending orbits. We present two case studies and long‐term statistics of the horizontal winds derived with the ground-based reference instruments compared to Aeolus horizontal line-of-sight (HLOS) winds. The wind products of Aeolus considered are the Mie cloudy and Rayleigh clear products. It was found that the deviation of the Aeolus HLOS winds from the ground reference is usually of Gaussian shape, which allowed the use of the median bias and the scaled median absolute deviation (MAD) for the determination of the systematic and random errors of Aeolus wind products, respectively. The case study from August 2020 with impressive atmospheric conditions at Punta Arenas shows that Aeolus is able to capture strong wind speeds of up to more than 100 m s−1. The long-term validation was performed in Punta Arenas covering the period from December 2018 to November 2021 and in Leipzig from May 2019 until September 2022. This analysis showed that the systematic error of the Aeolus wind products could be significantly lowered during the mission lifetime with the changes introduced into the processing chain (different versions are called baselines). While in the early mission phase, systematic errors of more than 2 m s−1 (absolute values) were observed for both wind types (Mie and Rayleigh), these biases could be reduced with the algorithm improvements, such as the introduction of the correction for temperature fluctuations at the main telescope of Aeolus (M1 temperature correction) with Baseline 09. Hence, since Baseline 10, a significant improvement in the Aeolus data was found, leading to a low systematic error (close to 0 m s−1) and similar values for the midlatitudinal sites in both hemispheres. The random errors for both wind products were first decreasing with an increasing baseline but later increasing again due to performance losses of the Aeolus lidar instrument. Nevertheless, no significant increase in the systematic error in the Aeolus wind products was found. Thus, one can conclude that the uncertainty introduced by the reduced atmospheric return signal received by Aeolus mostly affects the random error. Even when considering all the challenges during the mission, we can confirm the general validity of Aeolus observations during its lifetime. Therefore, this space explorer mission could demonstrate that it is possible to perform active wind observations from space with the applied technique.

show abstract

Aeolus First Year in Orbit Power System Performance

Cited by 2 publications

References 1 publication

Long-term validation of Aeolus L2B wind products at Punta Arenas, Chile and Leipzig, Germany

Long-term validation of Aeolus L2B wind products at Punta Arenas, Chile and Leipzig, Germany

Long-term validation of Aeolus L2B wind products at Punta Arenas, Chile, and Leipzig, Germany

Contact Info

Product

Resources

About