[AAS14-11] Detection and Possible Interpretation of Tropospheric Dispersive Phase Associated with Heavy Rain Events
キーワード：Heavy rain event, InSAR, Split-spectrum method
Hanssen et al., 1999 demonstrated the ability of Interferometric Synthetic Aperture Radar (InSAR) in the detection of water vapor associated with rain, using during the European Remote Sensing (ERS) satellite tandem mission. Furthermore, taking the advantage of the Advanced Land Observing Satellite (ALOS) satellite emergency observation, a localized signal related to water vapor during Seino heavy rain event was identified (Kinoshita et al., 2013). There were no surface deformation events during these former studies.
Utilizing the dispersive nature of the ionospheric layer, the range split spectrum method (SSM) separates InSAR phase into non-dispersive and dispersive phase, and thus ionospheric delay could be mitigated (Brcic et al., 2010; Rosen et al., 2010; Gomba et al., 2016). Additionally, higher-order ionospheric effects, such as geomagnetic and geometric ray-bending could be revealed using different frequency dependence of InSAR phase (Furuya et al., 2017). In contrast, tropospheric/ neutral atmospheric delay has a non-dispersive nature. Thus, if during heavy rain case, no surface deformation occurred and ionospheric contribution were negligible, water vapor can be detected in the non-dispersive phase accompanied by a virtually no dispersive phase.
In this presentation, we will show our detection results on ; (i) InSAR phase anomaly related to the water vapor during heavy rain episodes during ALOS-2 normal observation mode, (ii) unknown dispersive phase in SSM, and (iii) possible interpretation of the unknown dispersive phase during heavy rain cases.
Utilizing the dispersive nature of the ionospheric layer, the range split spectrum method (SSM) separates InSAR phase into non-dispersive and dispersive phase, and thus ionospheric delay could be mitigated (Brcic et al., 2010; Rosen et al., 2010; Gomba et al., 2016). Additionally, higher-order ionospheric effects, such as geomagnetic and geometric ray-bending could be revealed using different frequency dependence of InSAR phase (Furuya et al., 2017). In contrast, tropospheric/ neutral atmospheric delay has a non-dispersive nature. Thus, if during heavy rain case, no surface deformation occurred and ionospheric contribution were negligible, water vapor can be detected in the non-dispersive phase accompanied by a virtually no dispersive phase.
In this presentation, we will show our detection results on ; (i) InSAR phase anomaly related to the water vapor during heavy rain episodes during ALOS-2 normal observation mode, (ii) unknown dispersive phase in SSM, and (iii) possible interpretation of the unknown dispersive phase during heavy rain cases.