The Performance of Dual-Frequency Polarimetric Scatterometer in Sea Surface Wind Retrieval

Abstract

The wind retrieval performance of HY-2A scanning scatterometer operating at Ku-band in HH and VV polarizations has been well evaluated in the wind speed range of 0–25 m s ⁻¹. In order to obtain more accurate ocean wind field, a potential extension of dual-frequency (C-band and Ku-band) polarimetric measurements is investigated for both low and very high wind speeds, from 5 to 45 m s ⁻¹. Based on the geophysical model functions of C-band and Ku-band, the simulation results show that the polarimetric measurements of Ku-band can improve the wind vector retrieval over the entire scatterometer swath, especially in nadir area, with the wind direction root-mean-square error (RMSE) less than 12° in the wind speed range of 5–25 m s ⁻¹. Furthermore, the results also show that C-band cross-polarization plays a very important role in improving the wind speed retrieval, with the wind speed retrieval accuracy better than 2 m s ⁻¹ for all wind conditions (0–45 m s ⁻¹). For extreme winds, the C-band HH backscatter coefficients modeled by CMOD5.N(H) and the ocean co-polarization ratio model at large incidence are used to retrieve sea surface wind vector. This result reveals that there is a big decrease of wind direction retrieval RMSE for extreme wind fields, and the retrieved result of C-band HH polarization is nearly the same as that of C-band VV polarization for low-to-high wind speed (5–25 m s ⁻¹). Thus, to improve the wind retrieval for all wind conditions, the dual-frequency polarimetric scatterometer with C-band and Ku-band horizontal polarization in inner beam, and C-band horizontal and Ku-band vertical polarization in outer beam, can be used to measure ocean winds. This study will contribute to the wind retrieval with merged satellites data and the future spaceborne scatterometer.

Journal

Journal ID (publisher-id): JOUC

Title: Journal of Ocean University of China

Publisher: Science Press and Springer (China )

ISSN (Electronic): 1672-5182

Publication date (Electronic): 24 August 2019

Publication date (Print): 01 October 2019

Volume: 18

Issue: 5

Pages: 1051-1060

Affiliations

¹Xi’an Institute of Space Radio Technology, China Academy of Space Technology, Xi’an 710100, China

²National Key Laboratory of Science and Technology on Space Microwave, Xi’an 710100, China

³Institute of Oceanology and Center for Ocean Mega-Science, Chinese Academy of Sciences, and Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China

Author notes

*Corresponding authors: LIU Shubo and WEI Enbo

Article

Publisher ID: s11802-019-4018-z

DOI: 10.1007/s11802-019-4018-z

Copyright statement: Copyright © Ocean University of China, Science Press and Springer-Verlag GmbH Germany 2019.

License:

The copyright to this article, including any graphic elements therein (e.g. illustrations, charts, moving images), is hereby assigned for good and valuable consideration to the editorial office of Journal of Ocean University of China, Science Press and Springer effective if and when the article is accepted for publication and to the extent assignable if assignability is restricted for by applicable law or regulations (e.g. for U.S. government or crown employees).

Product

Self URI (journal-page): https://www.springer.com/journal/11802