**4. Results**

#### *4.1. The Correction Results of the Fresnel Reflection Coefficient*

Figure 6 shows the responses of four soil types at the same soil temperature and different soil moisture after the normalization method of Fresnel reflection coefficient. It can be seen that the effect of differences in the soil moisture and soil type on the Fresnel reflectance coefficient was significantly weakened compared to the previous one, indicating that the surface reflectivity of CYGNSS corrected by the proposed method can significantly attenuate the effect of factors related to the Fresnel term. However, when the incident angle was larger (greater than 65◦), the normalization effect became less effective. Excessive incident angles can significantly affect the quality of CYGNSS data [11,23], and this method used should keep the incident angle less than 65◦.

**Figure 6.** The response of normalized Fresnel reflection coefficient for the same soil temperature, different soil moisture and different soil types (sm is soil moisture, and the different lines represent different soil moisture contents).
