DETECTION AND CHARACTERIZATION OF IONOSPHERIC ACTIVITY AT HIGH LATITUDE FROM SAR MEASUREMENTS

• Main Authors: Mainvis, Aymeric, Fabbro, Vincent
• Other Authors: ONERA / DEMR, Université de Toulouse Toulouse, ONERA-PRES Université de Toulouse
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2020
• Subjects: Ionosphere; radio propagation; synthetic aperture radar (SAR); [SPI]Engineering Sciences [physics]; [PHYS]Physics [physics]; Fairbanks; Faraday; Gage; Greenland; Alaska
• Online Access: https://hal.archives-ouvertes.fr/hal-02989565; https://hal.archives-ouvertes.fr/hal-02989565/document; https://hal.archives-ouvertes.fr/hal-02989565/file/DEMR20054%20preprint.pdf

International audience This paper describes a methodology to detect and characterize the ionospheric activity thanks to spaceborne synthetic aperture radar (SAR) measurements. This strategy is based on the Faraday rotation (FR) estimation which leads to the Total Electron Content (TEC) quantification and the iono-spheric phase advance assessment. The metrics are derived from these two previous quantities by using the mean value of the phase advance and the Rate of TEC Index. Both quantities are estimated along the azimuth path of the platform, where the ionosphere drastically disturbs the image synthesis. To perform the process, a fully-polarimetric SAR measurement is needed. The methodology is tested on different PALSAR acquisitions. A first case allows studying the ionospheric activity near Fairbanks, Alaska and a second one shows the occurrence of ionospheric disturbance during measurements over Greenland. The parameters succeed in detecting the ionospheric activity from a single SAR measurement. Then, the results are compared with GNSS measurements from the high-rate IGS network processed by the GAGE methodology. This shows that all scales in the ionosphere are interrelated, leading to an ionospheric scintillation event at the same time as the appearance of a TEC gradient. Simultaneous observation of the ionosphere by different means appears necessary to better understand the dynamics of this atmospheric layer.