Estimation of temporal and spatial variation of sound speed in ocean from GNSS-A measurements for observation using moored buoy

Progress in Earth and Planetary Science

Table 3 Horizontal gradient of sound speed estimated from different profiles

	Reference sound speed profile observed on:
	Each epoch			6 June 2017			5 June 2019
Epoch	ΔV	ϕ	RMS	ΔV	ϕ	RMS	ΔV	ϕ	RMS
(1)	0.27	121	0.04	–	–	–	0.27	125	0.09
(2)	0.21	136	0.05	0.18	133	0.06	0.20	129	0.07
(3)	0.14	200	0.06	0.16	197	0.06	0.23	195	0.11
(4)	0.11	184	0.05	0.11	183	0.05	0.14	180	0.09
(5)	0.18	174	0.06	0.18	171	0.08	0.18	175	0.06
(6)	0.16	164	0.05	0.14	156	0.10	–	–	–

Note. ΔV magnitude of horizontal gradient (m/s/km), ϕ azimuth angle (degrees) RMS rms error of residual between observed and calculated travel time (ms)