Fig. 1. Reef island response to SLR.

(A) Aerial photograph of Fatato, Funafuti atoll, Tuvalu; white dashed line indicates central profile line. (B) Experimental setup in the physical and numerical model. (C to E) Physical model data (black circles) and numerical model results (black line) of (C) incident significant wave height H_s,INC, (D) infragravity significant wave height H_s,IG, and (E) mean water level wl for a run with H_s = 4 m, T_p = 9.9 s, and h_reef = 1 m. Vertical black dashed lines represent the reef platform edge. (F) Measured and modeled reef island morphology after 50 hours (H_s = 4 m and T_p = 9.9 s in the numerical model; representing 7 hours, H_s = 0.08 m, and T_p = 1.3 s in the physical model) with sea level raised from h_reef = 2.5 m to h_reef = 3 m for the optimal combination of the relevant model parameters (D₅₀ = 14 mm; K = 0.005 m s⁻¹; ϕ = 25^o). (G to I) Measured (red circles) and modeled (black line) time series of (G) island crest elevation z_crest, (H) island crest position x_crest, and (I) overwash discharge Q_crest. The 1:50 scale physical experiment results are plotted at the prototype scale.