Harmonic analysis of sea surface elevation compared with satellite products and tide gauge observations.
Analysis Summary
Analyzed Constituents: K1, K2, M2, N2, O1, P1, Q1, S2
Analysis Date: 2026-10-10
Satellite Product: FES2014/TPXO9
Plots
Tide Gauge Station Map
GESLA tide gauge station locations
K₁ (lunar-solar diurnal) — model amplitude and phase
K₁ (lunar-solar diurnal) — amplitude/phase comparison with GESLA tide gauges
O₁ (principal lunar diurnal) — model amplitude and phase
O₁ (principal lunar diurnal) — amplitude/phase comparison with GESLA tide gauges
P₁ (principal solar diurnal) — model amplitude and phase
P₁ (principal solar diurnal) — amplitude/phase comparison with GESLA tide gauges
Q₁ (larger lunar elliptic diurnal) — model amplitude and phase
Q₁ (larger lunar elliptic diurnal) — amplitude/phase comparison with GESLA tide gauges
K₂ (lunar-solar semi-diurnal) — model amplitude and phase
K₂ (lunar-solar semi-diurnal) — amplitude/phase comparison with GESLA tide gauges
M₂ (principal lunar semi-diurnal) — model amplitude and phase
M₂ (principal lunar semi-diurnal) — amplitude/phase comparison with GESLA tide gauges
N₂ (larger lunar elliptic semi-diurnal) — model amplitude and phase
N₂ (larger lunar elliptic semi-diurnal) — amplitude/phase comparison with GESLA tide gauges
S₂ (principal solar semi-diurnal) — model amplitude and phase
S₂ (principal solar semi-diurnal) — amplitude/phase comparison with GESLA tide gauges
Station amplitude/phase comparison — diurnal constituents
Station amplitude/phase comparison — semi-diurnal constituents
Tide Gauge Station Comparison
Compared with 89 tide gauge stations.
Station Results (Sample)
| station | lat | lon | country | years_of_obs | constituent | model_amp | obs_amp | amp_diff | model_pha | obs_pha | pha_diff |
|---|---|---|---|---|---|---|---|---|---|---|---|
| roscoff-54-fra-refmar | 48.718 | -3.966 | FRA | 53.000 | M2 | 2.578 | 2.695 | -0.117 | -117.861 | 142.046 | 100.093 |
| roscoff-54-fra-refmar | 48.718 | -3.966 | FRA | 53.000 | S2 | 0.977 | 1.005 | -0.027 | -171.773 | -172.254 | 0.480 |
| roscoff-54-fra-refmar | 48.718 | -3.966 | FRA | 53.000 | N2 | 0.515 | 0.533 | -0.018 | -41.587 | 123.796 | -165.383 |
| roscoff-54-fra-refmar | 48.718 | -3.966 | FRA | 53.000 | K2 | 0.279 | 0.287 | -0.008 | -43.947 | -174.564 | 130.616 |
| roscoff-54-fra-refmar | 48.718 | -3.966 | FRA | 53.000 | K1 | 0.087 | 0.082 | 0.005 | 66.250 | 82.046 | -15.796 |
| roscoff-54-fra-refmar | 48.718 | -3.966 | FRA | 53.000 | O1 | 0.065 | 0.073 | -0.008 | 95.083 | -28.193 | 123.276 |
| roscoff-54-fra-refmar | 48.718 | -3.966 | FRA | 53.000 | P1 | 0.029 | 0.028 | 0.001 | 116.583 | 72.698 | 43.885 |
| roscoff-54-fra-refmar | 48.718 | -3.966 | FRA | 53.000 | Q1 | 0.020 | 0.022 | -0.002 | 139.300 | -72.558 | -148.141 |
| saint_malo-410-fra-refmar | 48.641 | -2.028 | FRA | 35.000 | M2 | 3.554 | 3.674 | -0.119 | -81.421 | 177.534 | 101.045 |
| saint_malo-410-fra-refmar | 48.641 | -2.028 | FRA | 35.000 | S2 | 1.383 | 1.434 | -0.051 | -129.993 | -132.090 | 2.098 |
| saint_malo-410-fra-refmar | 48.641 | -2.028 | FRA | 35.000 | N2 | 0.698 | 0.717 | -0.018 | -1.635 | 161.366 | -163.000 |
| saint_malo-410-fra-refmar | 48.641 | -2.028 | FRA | 35.000 | K2 | 0.400 | 0.410 | -0.010 | -1.941 | -134.593 | 132.652 |
| saint_malo-410-fra-refmar | 48.641 | -2.028 | FRA | 35.000 | K1 | 0.103 | 0.095 | 0.009 | 82.028 | 95.529 | -13.501 |
| saint_malo-410-fra-refmar | 48.641 | -2.028 | FRA | 35.000 | O1 | 0.073 | 0.082 | -0.009 | 109.270 | -15.478 | 124.748 |
| saint_malo-410-fra-refmar | 48.641 | -2.028 | FRA | 35.000 | P1 | 0.034 | 0.035 | -0.001 | 133.148 | 87.756 | 45.392 |
| saint_malo-410-fra-refmar | 48.641 | -2.028 | FRA | 35.000 | Q1 | 0.022 | 0.024 | -0.003 | 155.483 | -57.656 | -146.861 |
| st_marys-stm-gbr-da_idh | 49.918 | -6.317 | GBR | 9.000 | M2 | 1.650 | 1.758 | -0.108 | -129.974 | 131.222 | 98.805 |
| st_marys-stm-gbr-da_idh | 49.918 | -6.317 | GBR | 9.000 | S2 | 0.580 | 0.603 | -0.023 | 172.489 | 172.192 | 0.297 |
| st_marys-stm-gbr-da_idh | 49.918 | -6.317 | GBR | 9.000 | N2 | 0.316 | 0.344 | -0.028 | -56.343 | 111.930 | -168.273 |
| st_marys-stm-gbr-da_idh | 49.918 | -6.317 | GBR | 9.000 | K2 | 0.166 | 0.172 | -0.006 | -59.830 | 169.735 | 130.435 |
Methodology
Harmonic Analysis
Tidal constituents extracted using UTide harmonic analysis package. Analysis performed on high-frequency model output (10-15 min resolution) over a minimum period of 60 days.
Satellite Comparison
Model results compared with satellite-derived tidal products:
- FES2014: Finite Element Solution 2014 (1/16° resolution)
- TPXO9: OSU Tidal Prediction Software (1/30° resolution)
Satellite data regridded to model grid using conservative interpolation.