Atmosphere and Ocean Monitoring using GNSS reflected signals: Current Status and Prospects at GFZ

Kurzfassung

Deployment of reflected signals of Global Navigation Satellite System (GNSS) from the Earth's surface, so-called GNSS-Reflectometry (GNSS-R), has emerged as a powerful tool in obtaining a variety of geophysical parameters and surface properties. This technique can meet the growing demand for high spatiotemporal resolution geophysical data and close the data gaps due to its advantageous characteristics: it is a multistatic radar method using heretofore existing signals from numerous GNSS satellites as the transmitters. The low-costs, low-mass, and low-power recievers can be implemented in the ground-based stations or different air/space-borne platforms, such as Cyclone GNSS (CYGNSS), a constellation of eight small Low Earth Orbiting (LEO), launched in December 2016. Here, we present the derived GNSS-R surface wind speeds, validations, and comparisons to conventional remote sensing instruments. The robustness of the derived wind speeds during rain events over oceans is demonstrated being a piece of evidence for the suitability of the technique for severe weather monitoring. Using modern data scientific techniques, further accuracy of the wind speed data is sought. In different experiments on the implementation of Artificial Intelligence techniques, it is shown how such methods could lead to a higher quality of GNSS-R data products. Potentials are still being explored and new ideas are being created leading to novel GNSS-R applications. It is shown that the technique can detect precipitation over oceans. In addition to empirical evidence, physical feasibility and schemes are discussed. Besides, it is shown how the technique can also respond to ocean mesoscale eddies initiating future studies on this application.