Troposphere study in southern California and in SFBA

Two distinct troposphere studies have been carried out this year. The first one, in collaboration with Gareth Funning and Roland Bürgmann, focused on the uplift detected above the San Gabriel valley aquifer (Figure 2, Chapter 2) in southern California.

We propose including troposphere estimates from the GPS measurements into SAR data processing (in this case ROIPAC has been used).

Every day a troposphere map is estimated from the BARD dataset in order to increase the GPS accuracy and to correct the SAR scenes acquired in the San Francisco Bay Area. Twice a day, a map of troposphere delay is released for the previous day (See Figure 3.19). The troposphere maps will be released through the new version of the BARD website (see above). The next step of this research on the troposphere is now to manage the meteorological dataset jointly with GPS observations in real-time.

Figure 3.19: Interpolated troposphere delay at the acquisition time (5 am (PDT) of the SAR scene , 2007, Sep. 20th). The zenithal troposphere delay in the SFBA can experience up to 5 cm variation. This lateral troposphere effect can impact the SAR baseline estimation and the ongoing research on the slow creep deformation of the Hayward fault.