Troll-Paffen

The Troll–Paffen scheme partitions Earth’s climates into 38 seasonal‑interference types based on the interaction of three “seasonal climates”: illumination (astronomic insolation seasons), temperature (thermic seasons) and moisture (hygric seasons) and outputs zones from polar ice‑deserts through tropical rain‑forest

<figure> <img src="assets/outputtrollpfaffenexample.svg" alt="Example Troll–Paffen climate regions" width="100%"> <figcaption><strong>Figure.</strong> Example Troll–Paffen classification map.</figcaption> </figure>

The following classes can be attributed:

Code	Class
1	Polar ice-deserts
2	Polar frost-debris belt
3	Tundra
4	Sub-polar tussock grassland and moors
5	Oceanic humid coniferous woods
6	Continental coniferous woods
7	Highly continental dry coniferous woods
8	Evergreen broad-leaved and mixed woods
9	Oceanic deciduous broad-leaved and mixed woods
10	Sub-oceanic deciduous broad-leaved and mixed woods
11	Sub-continental deciduous broad-leaved and mixed woods
12	Continental deciduous broad-leaved and mixed woods as well as wooded steppe
13	Highly continental deciduous broad-leaved and mixed woods as well as wooded steppe
14	Deciduous broad-leaved and mixed wood and wooded steppe
15	Thermophile dry wood and wooded steppe
16	Humid deciduous broad-leaved and mixed wood
17	High grass-steppe with perennial herbs
18	Humid steppe with mild winters
19	Short grass-, dwarf shrub-, or thorn-steppe
20	Steppe with short grass, dwarf shrubs and thorns
21	Central and East-Asian grass and dwarf shrub steppe
22	Semi-desert and desert with cold winters
23	Semi-desert and desert with mild winters
24	Sub-tropical hard-leaved and coniferous wood
25	Sub-tropical grass and shrub-steppe
26	Sub-tropical thorn- and succulents-steppe
27	Sub-tropical steppe with short grass
28	Sub-tropical semi-deserts and deserts
29	Sub-tropical high-grassland
30	Sub-tropical humid forests
31	Evergreen tropical rain forest
32	Rain-green humid forest
33	Half-deciduous transition wood
34	Rain-green dry wood and savannah
35	Tropical thorn-succulent wood and savannah
36	Tropical dry climates with humid months in winter
37	Tropical semi-deserts and deserts
38	Not Classified / NA

In the provided implementation, twelve monthly temperatures and precipitations are first reduced to statistics (min, max, mean, range, annual total), as well as derived metrics—growing‑degree days above 5 °C and the average number of humid months where daily rainfall exceeds twice daily temperature (via getgrowingdegreedays and gethumidmonths). A decision tree then applies Troll–Paffen thresholds (e.g. tempmax < 0 °C → “Polar ice‑desert”, ranges of growing‑degree days and humid‑month counts for boreal, temperate, steppe, subtropical and tropical belts, with hemisphere‑adjusted seasonal humidity criteria).

You can call this model using:

using Biome
using Rasters

# Minimal inputs (Troll–Paffen uses temp & precip in the driver)
tempfile = "/path/to/temp.nc"   # monthly mean temperature (stacked in 3rd dim)
precfile = "/path/to/prec.nc"   # monthly precipitation (same grid/stacking)

temp_raster = Raster(tempfile, name="temp")
prec_raster = Raster(precfile,  name="prec")

setup = ModelSetup(TrollPfaffenModel();
                   temp=temp_raster,
                   prec=prec_raster)

# Process full grid (or pass "lonmin/lonmax/latmin/latmax")
run!(setup; coordstring="alldata", outfile="output_TrollPfaffen.nc")

References

Troll, C. (1964). Karte der Jahreszeiten-Klimate der Erde. ERDKUNDE, 18(1), Article 1. https://doi.org/10.3112/erdkunde.1964.01.02