Ifrågasätterskan

Lena Synnerholms webbplats. / Lena Synnerholm's website.

Climate zones

What does the expressions you use for climate zones mean?

I use a somewhat modified version of classification according to Martin Martin Wahl (1869 – 1946).  He made a distinction between four main climate zones:

• Polar zone = “Hash, long winter, cold summer.  Warmest month’s mean temperature below +10°C [+50°F]”.
• Temperate zone = “Winter with lasting frost and remaining snow.  Warmest month’s mean temperature at least +10°C [+50°F].”
• Subtropical zone = “Long, hot summer, warmest month’s mean temperature is more than +20°C [+68°F].  Short, mild winter with occurring transient frost.  Coldest month’s mean temperature at least +3°C [+38°F]”
• Tropical zone = “Frost-free.  All month’s mean temperature above +15°C [+60°F]”

The quotes are taken from Nordisk Skolatlas (Nordic School Atlas) from 1992.  It is not made clear what constitute the border between “coniferous” and “deciduous” forest climates.  However, it seems to be slightly warmer than the high temperature limit of subarctic climate according to Wladimir Köppen’s definition.
The modifications I have done are:

• A special mountain climate zone for peaks with permafrost.
• No temperate rainforest climate.  It is classified as either coniferous or deciduous forest climate depending on temperature.
• No difference between scrubland and desert climate.  Actually, I did not think about the scrubland when I made the maps.  So it came to be treated as if it was desert.
• Subtropical grassland climate is divided between wet summer and winter.
• Tropical savanna climate is divided between monsoon and grassland climate.

The correspondences are:
• Polar climate (ice covered land and polar desert). = Ice sheet.

• Alpine due to high latitude. = Tundra.
• Alpine due to high altitude. / Mountains which tops has permafrost. = About the same as tundra, but due to high altitude instead of high latitude.
• Cold temperate, drier climate. = As cold as coniferous forest climate, yet to dry for trees.
• Cold temperate climate. / Cold temperate, moister climate. = Coniferous forest climate.
• Warm temperate, moister climate. = Deciduous forest climate.
• Warm temperate, moister climate. / Warm temperate, semi-arid climate. = Temperate grassland climate.
• Moist, subtropical climate with wet summer. = Subtropical monsoon climate.
• Moist, subtropical climate with wet winter. = Mediterranean climate.
• Semi-arid, subtropical climate with wet summer. = Subtropical grassland climate, but only if the wet and warm season has to correspond.
• Semi-arid, subtropical climate with wet winter. = Subtropical grassland climate, yet only if the wet and cold season has to correspond.
• Arid, subtropical climate. = Subtropical scrubland and desert climate.
• Arid, tropical climate. = Tropical scrubland and desert climate.
• Semi-arid, tropical climate with seasonal rain. = Tropical savanna climate, but it rains too little for the growth of forest.
• Moist, tropical climate with seasonal rain. = Tropical savanna climate, yet it rains enough for the growth of forest.
• Moist, tropical climate with rain all year round. = Tropical rainforest climate.

The colours represent approximately the same climates as on the world maps showing vegetation instead.  But it felt wrong to use them on a terraformed or heavily engineered planet.

© Lena Synnerholm.
Last changed the 14th of October 2019.