Table 2 Results of the numerical model validation of the physical model run D3 (test series XB1).

D₅₀, sediment size; K, hydraulic conductivity; φ, sediment transport phase angle; BSS, Brier skill score (goodness of fit; cf. Eq. 4); Δz_crest, difference between modeled and measured island crest elevation; Δx_crest, difference between modeled and measured island crest position. For all model runs, H_s = 4 m, T_p = 9.9 s, h_reef = 3 m, and T_test = 50 hours. “X” denotes that the island was destroyed during the simulation. Bold values for BSS, Δz_crest, and Δx_crest represent the best performance of the numerical model in each of the groups of model runs. Positive values for Δz_crest and Δx_crest mean that the modeled crest is higher and further landward, respectively.

Test series	D₅₀ (mm)	K (m s⁻¹)	φ (°)	BSS (−)	Δz_crest (m)	Δx_crest (m)
	Sensitivity to sediment transport phase angle φ
XB1_06_005_25	6	0.005	25	X	X	X
XB1_06_005_26	6	0.005	27	X	X	X
XB1_06_005_29	6	0.005	29	0.79	0.06	14.0
XB1_06_005_30	6	0.005	30	0.89	0.25	8.2
XB1_06_005_31	6	0.005	31	0.86	0.40	4.9
XB1_06_005_33	6	0.005	33	0.74	0.60	0.4
XB1_06_005_35	6	0.005	35	0.63	0.74	−1.9
	Sensitivity to hydraulic conductivity K
XB1_10_000_25	10	0.000	25	0.53	−0.83	21.8
XB1_10_005_25	10	0.005	25	0.68	−0.56	17.0
XB1_10_010_25	10	0.010	25	0.83	0.10	6.2
XB1_10_020_25	10	0.020	25	0.66	0.42	0.3
XB1_10_030_25	10	0.030	25	0.50	0.54	−2.7
XB1_10_040_25	10	0.040	25	0.42	0.63	−4.3
XB1_10_050_25	10	0.050	25	0.36	0.71	−5.9
	Sensitivity to sediment size D₅₀
XB1_06_005_25	6	0.005	25	X	X	X
XB1_08_005_25	8	0.005	25	X	X	X
XB1_10_005_25	10	0.005	25	0.68	−0.56	17.0
XB1_12_005_25	12	0.005	25	0.88	−0.20	9.7
XB1_14_005_25	14	0.005	25	0.77	0.08	2.1
	Sensitivity to sediment size D₅₀ and hydraulic conductivity K
XB1_06_010_25	6	0.010	25	X	X	X
XB1_07_020_25	7	0.020	25	0.83	0.31	8.3
XB1_08_030_25	8	0.030	25	0.59	0.52	−0.6
XB1_10_050_25	10	0.050	25	0.36	0.71	−5.9
XB1_12_070_25	12	0.070	25	0.21	0.86	−7.3
XB1_15_000_25	15	0.000	25	0.84	−0.17	3.5
XB1_15_050_25	15	0.050	25	0.24	0.76	−7.4