机载多普勒散射计海风海流联合反演研究

赵文成; 林文明; 何宜军; 鲍青柳

doi:10.12284/hyxb2023169

机载多普勒散射计海风海流联合反演研究

doi: 10.12284/hyxb2023169

赵文成^1,,
林文明^{2, 3, ,},
何宜军^{2, 3},
鲍青柳⁴

1.
南京信息工程大学电子与信息工程学院，江苏南京 210044
2.
南京信息工程大学海洋科学学院，江苏南京 210044
3.
自然资源部空间海洋遥感与应用重点实验室，北京 100081
4.
航天宏图信息技术股份有限公司，北京 100195

基金项目: 国家自然科学基金重大科研仪器研制项目（42027805）。

详细信息

作者简介:
赵文成（1999—），男，河南省周口市人，研究方向为雷达信号处理和海洋微波遥感。E-mal：1094058435@qq.com

通讯作者:
林文明（1984—），男，福建省仙游县人，教授，研究方向为海洋微波遥感、先进数据处理方法、雷达定标技术以及海面风场遥感及应用。E-mail：wenminglin@nuist.edu.cn

中图分类号: P715.7
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出版历程
- 收稿日期: 2023-09-21
- 修回日期: 2023-10-29
- 网络出版日期: 2023-12-29
- 刊出日期: 2023-12-01

Joint retrieval of wind and current using airborne Doppler scatterometer

Zhao Wencheng^1
,,
Lin Wenming^{2, 3
, ,},
He Yijun^{2, 3},
Bao Qingliu⁴

1.
School of Electronic and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
2.
School of Marine Sciences, Nanjing University of Information Science and Technology, Nanjing 210044, China
3.
Key Laboratory of Space Ocean Remote Sensing and Application, Ministry of Natural Resources, Beijing 100081, China
4.
Piesat Information Technology Co., Ltd., Bejing 100195, China

摘要

摘要: 多普勒散射计能够获取海面后向散射系数和多普勒频移，从而实现海面风场和海表流场的同步观测。本文基于机载多普勒散射计的观测数据，对多普勒散射计海面风场和海表流场联合反演模型进行研究，并与风场流场独立反演结果进行对比。结果表明，联合反演的流场精度显著优于独立反演结果；然而以欧洲中期天气预报中心的海面风场为参考时，联合反演风场的精度略低于独立反演结果。这说明多普勒频移信息对海面风场反演的贡献不太显著，但雷达后向散射系数信息（即风场）对流场反演有积极的作用，通过联合反演算法能够更有效地消除海面风场对流场反演的影响。研究结果有助于进一步理解海面风场和海表流场反演时的相互影响，并为星载多普勒散射计的数据处理提供了参考。
- 多普勒散射计 /
- 海面风场 /
- 海表流场 /
- 联合反演算法
Abstract: Doppler scatterometer is able to measure radar backscattering coefficient and Doppler frequency over sea surface, such that it can be used to retrieve sea surface wind and sea surface current simultaneously. This paper performs a study on the joint wind and current retrieval based on the observation data from an airborne Doppler scatterometer, which results are compared with those of independent retrieval. The results indicate that the accuracy of sea surface current is significantly improved by introducing the radar backscattering coefficients into the joint inversion method, however, the accuracy of the retrieved wind field from the joint inversion method is slightly lower than that of the independent wind inversion, compared to the European Centre for Medium-Range Weather Forecasts winds. This implies that the Doppler information has little influence on the wind retrieval, while the radar backscattering coefficients (the wind) have a remarkable impact on the sea surface current retrieval. The joint inversion algorithm can mitigates the effects of sea surface wind for the current retrieval. The results of this study provide a new insight to the interplay between wind inversion and current retrieval, and also provide a reference for the data processing of spaceborne Doppler scatterometer.
- Doppler scatterometer /
- sea surface wind /
- sea surface current /
- joint inversion

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图 1 观测几何

Fig. 1 Observation geometry

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图 2 机载多普勒散射计脉冲时序

Fig. 2 Airborne Doppler scatterometer pulse timing

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图 3 Ka波段机载多普勒散射计干涉相位差示意图

Fig. 3 Illustration of the interference phase difference of Ka-band Doppler scatterometer

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图 4 Ka波段海面多普勒频移谱模型

Fig. 4 Ka-band sea surface Doppler shift spectrum model

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图 5 独立反演结果

Fig. 5 Independent inversion results

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图 6 联合反演结果

Fig. 6 Joint inversion results

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图 7 海面风场反演精度评估

Fig. 7 Evaluation of the retrieved sea surface wind

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表 1 各架次飞行情况

Tab. 1 Flight situation of each sortie

架次	飞行日期	飞行时间	海流计数据	数据大小/GB
1	8月6日	14:30–17:30	无	166
2	8月11日	14:30–17:10	有	387
3	8月15日	14:00–18:00	无	283

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表 2 机载多普勒散射计技术指标

Tab. 2 Technical specifications of airborne Dopplerscatterometer

项目	技术指标
中心频率	35.9 GHz
脉冲带宽	5 MHz
脉冲时宽	4 μs
脉冲间隔	4 μs
采样频率	56 MHz
极化方式	VV
入射角	50°
飞行高度	3～3.5 km
飞行速度	180～200 km/h
发射峰值功率	20 W
脉冲重复周期	100 μs

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表 3 不同反演算法下反演结果与海流计数据对比

Tab. 3 Comparison of the inversion results of different retrieval algorithms with respect to the ocean current meter data

纬度	经度	海流计流速/（m·s⁻¹）	海流计流向/（°）	独立反演流速/（m·s⁻¹）	独立反演流向/（°）	联合反演流速/（m·s⁻¹）	联合反演流向/（°）
21.770 3°N	112.093 7°E	0.057 4	219.85	0.086 8	178.86	0.098 4	209.83
21.706 7°N	112.094 2°E	0.246 1	176.95	0.352 5	169.55	0.313 3	194.62
21.647 1°N	112.098 7°E	0.189 4	83.06	0.356 3	98.13	0.306 3	85.64
21.515 1°N	112.106 2°E	0.057 9	162.67	0.125 2	178.68	0.092 3	175.32

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表 4 不同反演算法下海表流场反演精度

Tab. 4 Retrieval accuracy of sea surface current field under different retrieval algorithms

反演精度评估	Bias	SD	RMSE
独立反演流速/（m·s^–1）	0.09	0.05	0.11
独立反演流向/（°）	–4.23	22.95	23.33
联合反演流速/（m·s^–1）	0.06	0.03	0.07
联合反演流向/（°）	5.81	10.58	12.07

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