| Autor: |
Padullés, R., Cardellach, E., de la Torre Juárez, M., Tomás, S., Turk, F. J., Oliveras, S., Ao, C. O., Rius, A. |
| Zdroj: |
Atmospheric Chemistry & Physics Discussions; 2015, Vol. 15 Issue 13, p18747-18785, 39p |
| Abstrakt: |
This study describes the first experimental observations showing that hydrometeors induce polarimetric signatures in Global Navigation Satellite System (GNSS) signals. This evidence is relevant to the PAZ Low Earth Orbiter, which will test the concept and applications of polarimetric GNSS Radio Occultation (RO) (i.e. ROs obtained with a two-polarization antenna). A ground field campaign was carried out in preparation for PAZ to verify the theoretical sensitivity studies about this concept (Cardellach et al., 2015). The main aim of the campaign is to identify and understand the factors that might affect the polarimetric GNSS observables. Studied for the first time, GNSS signals measured with two polarimetric antennas (H, horizontal and V, vertical) are shown to discriminate heavy rain events, by comparing the measured phase difference between the H and V phase delays (ΔΦ) in different weather scenarios. The measured phase difference indicates higher dispersion under rain conditions. When individual events are examined, significant increases of ΔΦ occur when the radio signals cross rain cells. Moreover, the amplitude of such signal is much higher than the theoretical prediction for precipitation; thus other sources of polarimetric signatures have been explored and identified. Modelling of other hydrometeors like melting particles and ice crystals have been proposed to explain the obtained measurements, with good agreement in more than 90 % of the cases. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
