We propose to derive local sea level variations by using the Signal-to-Noise Ratio (SNR) of the GNSS reflected signals at four GNSS single antenna sites (ILDG, TAR0, FFT2, LYTT) located at different latitudes. For these sites representing various ocean conditions (waves, tides, storm surges, etc…), tides estimates by SNR are highly consistent to tide gauges records as highlighted by tidal harmonic analysis, with a Root-Sum-Square (RSS) ranging from few centimeter in micro-tidal environment to near a decimeter in macro-tidal environment.

SNR non-tidal residuals (NTR) are compared to two modelled sea level responses to meteorological forcing, namely the analytical Local Inverse Barometer (LIB) model and the numerical Dynamic Atmospheric Correction (DAC). Both DAC and LIB models are coherent with this non-tidal SNR residual in a 2-days to 2-months time window with correlations reaching 0.7 and high coherences. Several noteworthy atmospheric events are observed in the time series of about one year. During intense events, SNR and models are highly correlated. According to the results obtained in this study, we conclude that the GNSS reflectometry technique is relevant to derive sea level variations at tidal periods but also for studying the behaviour of the sea surface in response to atmospheric forcing at short-term scales.

我们建议通过使用位于不同纬度的四个 GNSS 单天线站点（ILDG、TAR0、FFT2、LYTT）的 GNSS 反射信号的信噪比（SNR）来推导当地海平面变化。对于代表各种海洋条件（波浪、潮汐、风暴潮等）的这些站点，SNR 的潮汐估计与潮汐谐波分析强调的潮汐测量记录高度一致，其根和平方 (RSS) 范围从几个微潮环境中的厘米到大潮环境中的接近分米。

SNR 非潮汐残差 (NTR) 与两个模拟的海平面对气象强迫的响应进行比较，即分析本地逆气压计 (LIB) 模型和数值动态大气校正 (DAC)。DAC 和 LIB 模型在 2 天到 2 个月的时间窗口内都与这种非潮汐 SNR 残差一致，相关性达到 0.7 和高相关性。在大约一年的时间序列中观察到几个值得注意的大气事件。在剧烈事件期间，SNR 和模型高度相关。根据本研究中获得的结果，我们得出结论，GNSS 反射测量技术与推导潮汐期间的海平面变化有关，也与研究海面在短期尺度上响应大气强迫的行为有关。