{
  "version": "1.0",
  "assessment_version": "6.1",
  "regions": [
    "Europe",
    "DEU",
    "AUT",
    "CZE",
    "POL"
  ],
  "principle": "Climate zones are climatological states, not annual weather labels.",
  "canonical_external_benchmark": {
    "dataset": "Beck et al. 2023 high-resolution Köppen-Geiger maps",
    "doi": "10.1038/s41597-023-02549-6",
    "resolution": "1 km",
    "historical_periods": [
      "1901-1930",
      "1931-1960",
      "1961-1990",
      "1991-2020"
    ],
    "future_periods": [
      "2041-2070",
      "2071-2099"
    ],
    "future_scenarios": [
      "SSP1-1.9",
      "SSP1-2.6",
      "SSP2-4.5",
      "SSP3-7.0",
      "SSP4-3.4",
      "SSP4-6.0",
      "SSP5-8.5"
    ]
  },
  "operational_observational_layer": {
    "dataset": "ERA5-Land monthly means",
    "doi": "10.24381/cds.68d2bb30",
    "grid": "0.1° CDS grid (~9-11 km effective spacing)",
    "temporal_coverage": "1950-present",
    "windows": {
      "type": "rolling_30_year_climatology",
      "first_recommended": "1951-1980",
      "latest_final_as_of_2026_08": "1996-2025",
      "step_years": 1,
      "standard_normals_for_display": [
        "1961-1990",
        "1991-2020"
      ],
      "2026_rule": "Do not create a final 1997-2026 climatology before full-year 2026 data are available."
    },
    "variables": {
      "koppen_geiger": [
        "2m_temperature",
        "total_precipitation"
      ],
      "aridity": [
        "total_precipitation",
        "potential_evaporation"
      ],
      "validation_optional": [
        "volumetric_soil_water_layer_1",
        "volumetric_soil_water_layer_2",
        "runoff",
        "snow_cover_or_snow_depth",
        "leaf_area_index_high_vegetation",
        "leaf_area_index_low_vegetation"
      ]
    },
    "potential_evaporation_sign": "ECMWF downward-positive convention; evaporation is usually negative. Convert PET to positive upward water demand before P/PET."
  },
  "methods": {
    "koppen_geiger": {
      "classification": "Beck et al. 2023 rules / compatible implementation",
      "use": "bioclimatic regime classes",
      "primary_outputs": [
        "class_area_share_pct",
        "transition_area_share_pct",
        "poleward_centroid_shift_km",
        "altitudinal_shift_m"
      ]
    },
    "aridity_index": {
      "formula": "AI = annual precipitation / annual potential evapotranspiration",
      "classes": {
        "hyper_arid": "<0.03",
        "arid": "0.03-0.20",
        "semi_arid": "0.20-0.50",
        "dry_subhumid": "0.50-0.65",
        "humid": ">0.65"
      },
      "use": "water-balance-sensitive dryness layer",
      "primary_outputs": [
        "ai_mean",
        "ai_delta",
        "dryland_area_share_pct",
        "humid_to_dry_transition_pct"
      ]
    }
  },
  "validation": {
    "rule": "Proxy indicators validate consistency but never determine the direct climate-zone class.",
    "minimum_families_recommended": 4,
    "families": [
      "temperature",
      "atmospheric_demand",
      "soil_water",
      "drought",
      "snow",
      "wildfire",
      "precip_extreme",
      "runoff",
      "vegetation",
      "land_cover"
    ]
  },
  "uncertainty": {
    "classification_boundary": "Flag cells within confidence or threshold margins.",
    "source_crosscheck": "Compare operational ERA5-Land classes with Beck2023 1991-2020 reference map.",
    "spatial_weighting": "Use true grid-cell area / polygon intersection, not unweighted cell counts.",
    "mountain_regions": "Report altitudinal shifts and lower confidence near sharp orographic gradients.",
    "land_use": "Treat land-cover change as modifier/proxy, not climate class input."
  }
}