Higher-order calibration on WindRAD (Wind Radar) scatterometer winds
-
Published:2023-10-20
Issue:20
Volume:16
Page:4769-4783
-
ISSN:1867-8548
-
Container-title:Atmospheric Measurement Techniques
-
language:en
-
Short-container-title:Atmos. Meas. Tech.
Author:
Li Zhen, Stoffelen AdORCID, Verhoef Anton, Wang Zhixiong, Shang Jian, Yin Honggang
Abstract
Abstract. WindRAD (Wind Radar) is a dual-frequency rotating fan-beam scatterometer instrument on the FY-3E (FengYun-3E) satellite. Scatterometers are generally calibrated using the linear NOC (NWP Ocean Calibration) method to control the main gain factor of the radar. While WindRAD is stable, the complex geometry, the design of the instrument, and the rotating antenna make the backscatter (σ∘) distributions persistently non-linear; hence NOC is insufficient. Therefore, a higher-order calibration (HOC) method is proposed. The CDF (cumulative distribution function) matching technique is employed to match the CDF of measured σ∘ instances to simulated σ∘ instances. HOC removes the non-linearities for each incidence angle. However, it is not constructed to remove the anomalous harmonic azimuth dependencies caused by the antenna rotation. These azimuth dependencies are reduced by NOCant (NOC as a function of incidence angle and relative antenna azimuth angle). Therefore, the combination of HOC and NOCant is implemented to correct both anomalous σ∘ amplitude and azimuth variations. The wind retrieval performance is evaluated with NOCant, HOC, and HOC and NOCant combined. The wind statistics and the cone distance metric both show that HOC&NOCant achieves the optimal winds for C-band and Ku-band. The calibrations have been tested on two operational input data versions; HOC works well on both data versions and HOC&NOCant can achieve the optimal wind performance for both data versions. This confirms the usefulness of HOC in the case of non-linear instrument gain anomalies.
Funder
European Organization for the Exploitation of Meteorological Satellites
Publisher
Copernicus GmbH
Subject
Atmospheric Science
Reference26 articles.
1. Chi, C. Y. and Li, F. K.: A comparative study of several wind estimation algorithms for spaceborne scatterometers, IEEE T. Geosci. Remote, 26, 115–121, https://doi.org/10.1109/36.3011, 1988. a 2. CMA: FY-3E WindRAD, CMA [data set], http://satellite.nsmc.org.cn/portalsite/default.aspx?currentculture=en-US, last access: 12 October 2023. a 3. Cornford, D., Csató, L., Evans, D. J., and Opper, M.: Bayesian Analysis of the Scatterometer Wind Retrieval Inverse Problem: Some New Approaches, J. Roy. Stat. Soc. B, 66, 609–652, https://doi.org/10.1111/j.1467-9868.2004.02054.x, 2004. a 4. Li, Z., Stoffelen, A., Verhoef, A., and Verspeek, J.: Numerical Weather Prediction Ocean Calibration for the Chinese‐French Oceanography Satellite Wind Scatterometer and Wind Retrieval Evaluation, Earth and Space Science, 8, 1–17, https://doi.org/10.1029/2020ea001606, 2021. a, b, c 5. Li, Z., Verhoef, A., Stoffelen, A., Shang, J., and Dou, F.: First Results from the WindRAD Scatterometer on Board FY-3E: Data Analysis, Calibration and Wind Retrieval Evaluation, Remote Sens.-Basel, 15, 2087, https://doi.org/10.3390/15082087, 2023. a, b, c, d, e, f, g, h, i
Cited by
2 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|