A Spaceborne GNSS-R Sea Ice Detection Method Based on Scene Semantic Objects

Sea ice is regarded as an indicator of temperature change. In recent years, the spaceborne Global Navigation Satellite System Reflectometry (GNSS-R) technology has made remarkable progress in sea ice detection. Delay-Doppler maps (DDMs) as one of the significant observations can reflect different characteristics for sea ice and open water, and a single DDM is usually viewed as the unit of feature extraction; however, it is easily influenced by wave height, wind, and other factors. Therefore, this letter proposes building scene semantic objects to enhance the reliability of observation and reflect the object characteristics. The synergism between DDMs and the spatial correlation of specular points was considered. Afterward, histogram features were extracted to express the distribution of scattered energy. The random forest (RF) model was developed to distinguish sea ice from open water. The performance of the method by using TechDemoSat-1 (TDS-1) dataset was evaluated with the sea ice concentration products provided by Ocean and Sea Ice Satellite Application Facility (OSISAF). The results show that the overall accuracy is 98.17%, which outperforms traditional observation methods.

I. Introduction

Sea ice is the product of seawater freezing in the high latitudes of the Earth and plays a pivotal role in the study of global climate change. Analyzing the temporal and spatial distribution of sea ice has important practical significance for climate monitoring, marine resource development, and polar transportation [1].