Returns a tibble of metadata for the climate variables supported by the cd package. Used internally for unit labels, anomaly type routing, and ERA5-Land API variable names. Covers the seven core climate variables plus eight snow-related variables (four monthly natives, four annual derived) added in v0.2.0.
Value
A tibble with columns:
- variable
Short name used throughout the package.
- long_name
Human-readable label for plots and tables.
- unit
Measurement unit (degree C, percent, Pa, mm, day, mm/wk).
- anomaly_type
"absolute" for direct departures (value - baseline, reported in the variable's native unit), "pct_normal" for percent-of-normal anomalies (100 * value / baseline - 100, capped), "pct_point_diff" for departures in percentage points (used for variables that are already fractions/percentages, e.g. snow cover, snowfall fraction, where pct-of-normal is meaningless and the natural delta is value - baseline interpreted as percentage points).
- era5_name
ERA5-Land variable name for CDS API requests, or NA for derived variables.
Examples
cd_variables()
#> # A tibble: 15 × 5
#> variable long_name unit anomaly_type era5_name
#> <chr> <chr> <chr> <chr> <chr>
#> 1 tmean Mean temperature °C absolute 2m_tempe…
#> 2 tmax Maximum temperature °C absolute NA
#> 3 tmin Minimum temperature °C absolute NA
#> 4 prcp Precipitation % pct_normal total_pr…
#> 5 vpd Vapour pressure deficit Pa absolute NA
#> 6 rh Relative humidity % absolute NA
#> 7 soil_moisture Soil moisture % pct_normal NA
#> 8 swe Snow water equivalent % pct_normal NA
#> 9 snowfall Snowfall % pct_normal NA
#> 10 snowmelt Snowmelt % pct_normal NA
#> 11 snow_cover Snow cover % pct_point_d… NA
#> 12 swe_max Annual peak snow water equiv… mm absolute NA
#> 13 snowfall_fraction Snowfall fraction % pct_point_d… NA
#> 14 snowmelt_doy_50 Day of 50% melt day absolute NA
#> 15 snowmelt_rate_peak Peak weekly melt rate mm/wk absolute NA
cd_variables()$variable
#> [1] "tmean" "tmax" "tmin"
#> [4] "prcp" "vpd" "rh"
#> [7] "soil_moisture" "swe" "snowfall"
#> [10] "snowmelt" "snow_cover" "swe_max"
#> [13] "snowfall_fraction" "snowmelt_doy_50" "snowmelt_rate_peak"