Wind–Solar Climate-Resource Adequacy in Semi-Arid Iraq: Reconstructed ERA5 Diagnostics and Conditional CMIP6 Models

Mean-resource assessments miss days when wind and PV potential are simultaneously weak. Wind–solar resource indicators were reconstructed for the Al-Shahabi region in southeastern Iraq using 227,928 hourly ERA5 time steps across 12 grid cells during 1995–2020. Conditional resource responses were subsequently assessed using five CMIP6 models under SSP2-4.5 and SSP5-8.5.WPD is calculated from hourly 100 m wind vectors and air density; a temperature-adjusted PV proxy is derived from hourly horizontal irradiation. Historical 20th-percentile (P20) thresholdsdefine comparable low resource days. The mean wind power density was 296.74 W m⁻², while the mean daily temperature-adjusted PV resource indicator was 0.7508 kWh m⁻² d⁻¹. Simultaneous deficiencies occur on 643/9497 (6.77%) days, mostly in boreal winter. For four future scenario–horizon combinations, the equal-weight five-model mean WPD changes −3.19% to −6.98% (all five models are reduced under transfer assumptions), while concurrent low-resource frequency changes range from −0.20 to +0.63 percentage points (pp) in the ensemble mean and are not signed consistently among individual models. Sensitivity analyses show strong seasonality dependence of thresholds and wind change amplitude transferred. These results separate a relatively coherent mean wind-resource response from much less robust compound-deficitbehaviour. Because monthly change signals are imposed on historical sequences, the adjusted daily episodes are conditional threshold outcomes but not predictions for weather persistence or operational electricity system reliability.