利用机载GNSS反射信号反演海面风速的研究

Retrieval of ocean surface wind speed using reflected GNSS signals measured from aircraft

全球卫星导航定位系统的反射信号(GNSS—R)遥感技术作为一种新型的、低成本的、高机动性的海面微波遥感测风技术,与其他测风手段优势互补,可以增加测风手段的多样性,弥补局部测风手段不足的状况。研究了接收机在机载高度时,GPS反射信号功率理论模型四部分函数的性质,在此基础之上,数值模拟了机载高度下理论相关功率波形,基于海面风速对波形峰值与后沿的影响,提出了一种能够兼顾所有理论波形信息的二维插值风速反演方法。利用该方法,结合实测机载数据对海面风速进行反演,反演的风速均值与附近测站风速均值相差为1.4 m/s,与浮标数据相一致。

As a new ocean surface wind speed measurement tool using active microwave remote sensing, there are several advantages of using global navigation satellite system reflection （GNSS--R）such as high temporal and spatial resolution, low cost, rich of GNSS resources, high flexibility in comparison with other remote sensing tools, which can offset the lack of regional wind speed measurement means. The characteristics of four parts in Z-V theoretical model were studied respectively and the numerical simulations of waveforms were performed at aircraft altitude. Furthermore, a bidimensional interpolation wind speed retrieval method was proposed on the basis of the fact that wind speed has effect on waveform peak and tail. Combining the aircraft data with the specific development condition of sea, the ocean surface wind was retrieved. The result shows that the mean wind speed retrieved from this method is agreed with that recorded from a nearby station with a bias of 1.4 m/s, and almost in accord with that recorded from a nearby buoy.