Extreme Precipitation Hazard Assessment for İzmir (Türkiye): EURO-CORDEX Ensemble-Based IDF Analysis under RCP4.5 and RCP8.5 - CRIZ-ERS

This dataset contains the extreme precipitation hazard assessment for İzmir Metropolitan Area developed within the CLIMAAX project.

The analysis is based on EURO-CORDEX regional climate model simulations (0.11° resolution). Annual maximum precipitation was derived from daily precipitation data for the baseline period (1976–2005) and mid-century projections (2041–2070) and (2071-2100) under RCP4.5 and RCP8.5 scenarios.

A Generalised Extreme Value (GEV) distribution was fitted pixel-by-pixel to derive Intensity–Duration–Frequency (IDF) curves for 24-hour duration events. Multi-model ensemble statistics (median, 10th and 90th percentiles) were computed to represent model uncertainty.

The dataset includes IDF return levels and relative climate change signals (%).

File-Level Descriptions

IDF Datasets

• idf_ensemble_median_1976-2005_historical.nc
• Ensemble median Intensity–Duration–Frequency (IDF) dataset for the historical baseline period (1976–2005).
• idf_ensemble_median_2041_2070_rcp_4_5.nc
• Ensemble median IDF dataset for mid-century (2041–2070) under RCP4.5.
• idf_ensemble_median_2041_2070_rcp_8_5.nc
• Ensemble median IDF dataset for mid-century (2041–2070) under RCP8.5.
• idf_ensemble_median_2071_2100_rcp_8_5.nc
• Ensemble median IDF dataset for late-century (2071–2100) under RCP8.5.

idf_change_ensemble_median_*.zip

Relative change (%) in extreme precipitation between future and baseline periods for each return period (2–500 years).

idf_ensemble_members_*.zip

Per-model IDF outputs for all GCM–RCM members before ensemble aggregation.

PrMax Dataset

• prMax_ensemble_members_*.zip
• Annual maximum 24-hour precipitation for each GCM–RCM model and scenario.
  These files are the direct input to the GEV fitting and IDF derivation

Plots

• Plots_ensemble_median_*.zip
• Visualisations of projected changes in extreme precipitation for each scenario and period.

Workflow Files

• Extreme_Precipitation_Hazard_Assessment_izmir.ipynb
  Interactive notebook implementing the complete hazard workflow.

Hazard Dataset Characteristics

• Climate model source: EURO-CORDEX (EUR-11, 0.11° resolution)

• Variable: Daily precipitation

• Duration: 24-hour accumulation

• Return periods: 2–500 years

• Statistical method: Generalised Extreme Value (GEV) fitting

• Ensemble statistics: Median, 10th, 90th percentile

• Output metric: Absolute return levels (mm) and relative change (%)