Regional Validation of Jason-2 Dual-Frequency Ionosphere Delays

In this study, we validated the Jason-2 (J2) dual-frequency ionosphere delay measurements in terms of vertical total electron content (VTEC) in the Geophysical Data Record (GDR) with the coarse resolution JPL Global Ionospheric Maps (GIM), the regional ionospheric maps generated by the Crustal Motion Observation Network of China (CMONOC), and the Jason-1 (J1) interleaved tandem mission (with J2) ionosphere delay measurements. The estimates of the relative biases and their uncertainties (95% confidence, in TEC units) for various comparison cases with different data spans and regions are (1) J2–GIM: −3.07 ± 0.18 TECu (or 6.75 ± 0.40 mm in the range delay), (2) J2–CMONOC: −2.87 ± 0.38 TECu (6.31 ± 0.84 mm), (3) J1–GIM: −0.19 ± 0.18 TECu (0.42 ± 0.40 mm), and (4) J2–J1 via double-differencing, that is, (J2–GIM)–(J1–GIM): −2.88 ± 0.26 TECu (6.34 ± 0.57 mm). The scatter (RMS, about the mean differences) between J2 and GIM, CMONOC, or J1 is about 3∼8 TECu (6.6∼17.6 mm). We conclude that the results from global and regional analysis are consistent and that the J2 ionosphere delay is about 6∼10 mm (95% confidence) shorter than the delay computed by GIM, J1, or the regional model.