ALADIN laser frequency stability and its impact on the Aeolus wind error
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Published:2021-09-28
Issue:9
Volume:14
Page:6305-6333
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ISSN:1867-8548
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Container-title:Atmospheric Measurement Techniques
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language:en
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Short-container-title:Atmos. Meas. Tech.
Author:
Lux OliverORCID, Lemmerz Christian, Weiler Fabian, Kanitz Thomas, Wernham Denny, Rodrigues Gonçalo, Hyslop Andrew, Lecrenier Olivier, McGoldrick Phil, Fabre Frédéric, Bravetti Paolo, Parrinello TommasoORCID, Reitebuch OliverORCID
Abstract
Abstract. The acquisition of atmospheric wind profiles on a global
scale was realized by the launch of the Aeolus satellite, carrying the
unique Atmospheric LAser Doppler INstrument (ALADIN), the first Doppler wind lidar in space. One major component of ALADIN is its high-power, ultraviolet
(UV) laser transmitter, which is based on an injection-seeded,
frequency-tripled Nd:YAG laser and fulfills a set of demanding requirements
in terms of pulse energy, pulse length, repetition rate, and spatial
and spectral beam properties. In particular, the frequency stability of the
laser emission is an essential parameter which determines the performance of
the lidar instrument as the Doppler frequency shifts to be detected are on
the order of 108 smaller than the frequency of the emitted UV light.
This article reports the assessment of the ALADIN laser frequency stability
and its influence on the quality of the Aeolus wind data. Excellent
frequency stability with pulse-to-pulse variations of about 10 MHz (root
mean square) is evident for over more than 2 years of operations in space
despite the permanent occurrence of short periods with significantly
enhanced frequency noise (> 30 MHz). The latter were found to
coincide with specific rotation speeds of the satellite's reaction wheels,
suggesting that the root cause are micro-vibrations that deteriorate the
laser stability on timescales of a few tens of seconds. Analysis of the
Aeolus wind error with respect to European
Centre for Medium-Range Weather Forecasts (ECMWF) model winds shows that the
temporally degraded frequency stability of the ALADIN laser transmitter has
only a minor influence on the wind data quality on a global scale, which is
primarily due to the small percentage of wind measurements for which the
frequency fluctuations are considerably enhanced. Hence, although the Mie
wind bias is increased by 0.3 m s−1 at times when the
frequency stability is worse than 20 MHz, the small contribution of 4 %
from all Mie wind results renders this effect insignificant
(< 0.1 m s−1) when all winds are considered. The impact on the
Rayleigh wind bias is negligible even at high frequency noise. Similar
results are demonstrated for the apparent speed of the ground returns that
are measured with the Mie and Rayleigh channel of the ALADIN receiver. Here, the application of a frequency stability threshold that filters out wind observations with variations larger than 20 or 10 MHz improves the accuracy of the Mie and Rayleigh ground velocities by only 0.05
and 0.10 m s−1, respectively, however at the expense of
useful ground data.
Funder
European Space Agency
Publisher
Copernicus GmbH
Subject
Atmospheric Science
Reference65 articles.
1. Abich, K., Abramovici, A., Amparan, B., Baatzsch, A., Okihiro, B. B., Barr,
D. C., Bize, M. P., Bogan, C., Braxmaier, C., Burke, M. J., Clark, K. C.,
Dahl, C., Dahl, K., Danzmann, K., Davis, M. A., Vine, G. de, Dickson, J. A.,
Dubovitsky, S., Eckardt, A., Ester, T., Barranco, G. F., Flatscher, R.,
Flechtner, F., Folkner, W. M., Francis, S., Gilbert, M. S., Gilles, F.,
Gohlke, M., Grossard, N., Guenther, B., Hager, P., Hauden, J., Heine, F.,
Heinzel, G., Herding, M., Hinz, M., Howell, J., Katsumura, M., Kaufer, M.,
Klipstein, W., Koch, A., Kruger, M., Larsen, K., Lebeda, A., Lebeda, A.,
Leikert, T., Liebe, C. C., Liu, J., Lobmeyer, L., Mahrdt, C., Mangoldt, T.,
McKenzie, K., Misfeldt, M., Morton, P. R., Müller, V., Murray, A. T.,
Nguyen, D. J., Nicklaus, K., Pierce, R., Ravich, J. A., Reavis, G., Reiche,
J., Sanjuan, J., Schütze, D., Seiter, C., Shaddock, D., Sheard, B.,
Sileo, M., Spero, R., Spiers, G., Stede, G., Stephens, M., Sutton, A.,
Trinh, J., Voss, K., Wang, D., Wang, R. T., Ware, B., Wegener, H., Windisch,
S., Woodruff, C., Zender, B., and Zimmermann, M.: In-Orbit Performance of
the GRACE Follow-on Laser Ranging Interferometer, Phys. Rev. Lett.,
123, 31101, https://doi.org/10.1103/PhysRevLett.123.031101, 2019. 2. Abshire, J. B., Sun, X., Riris, H., Sirota, J. M., McGarry, J. F., Palm, S.,
Yi, D., and Liiva, P.: Geoscience Laser Altimeter System (GLAS) on the
ICESat Mission: On-orbit measurement performance, Geophys. Res. Lett., 32, L21S02, https://doi.org/10.1029/2005GL024028, 2005. 3. Allan, D. W.: Statistics of atomic frequency standards, Proc. IEEE, 54,
221–230, https://doi.org/10.1109/PROC.1966.4634, 1966. 4. Andersson, E.: Statement of Guidance for Global Numerical Weather Prediction
(NWP), World Meteorological Organisation, available at:
https://docplayer.net/194586713-Statement-of-guidance-for-global-numerical-
weather-prediction-nwp.html
(last access: 15 September 2021), 2018. 5. Baidar, S., Tucker, S. C., Beaubien, M., and Hardesty, R. M.: The Optical
Autocovariance Wind Lidar. Part II: Green OAWL (GrOAWL) Airborne Performance
and Validation, J. Atmos. Oceanic Technol., 35, 2099–2116,
https://doi.org/10.1175/JTECH-D-18-0025.1, 2018.
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