6. Surface, climate and water
Partial Solar System §6.1, §9.5, §19; Hydrology Module – Specification; Landmarks and Water Features – Specification §2.
| Asked for | Demiurge gives |
|---|---|
| Atmosphere | CO₂, N₂, O₂, CH₄ through the planet’s life; ozone; temperature from the air. In the naturalistic route, wood burial raises oxygen until lignin decay (Build Notes) |
| Climate zones, seasons | temperature by latitude, rainfall by circulation cells, mountains and rain shadows; seasonal range by cell |
| Habitats and bands | 23 habitats; eleven climate bands |
| Rivers and lakes | Turc runoff, priority-flood drainage, rivers, basins, lakes, marsh |
| Seasonal flow | built: a regime for each river (snowmelt, glacial, monsoon, rain-fed, ephemeral), flood and low seasons by hemisphere, months frozen and dry |
| Springs | built: river heads, oases, karst springs, hot springs |
| Ocean currents | built: equatorial, subtropical and subpolar gyres, circumpolar; each coast warmed and wetted, or cooled and dried (with fogs and coastal deserts) |
| Weather | built: tropical cyclones, monsoons, thunderstorms, winter storms, blizzards, dust storms, tornadoes, floods, droughts, fog, with frequency, season and severity |
| Fire regime | built (biology): O₂ ≥ 0.16 bar and fuel |
Kelvin throughout, and a display setting
Decided 19 October, built 20 October (Decisions Log §3, §10). Every calculation works in kelvin, from the star to the culture module: the surface, the geography’s cells and zones, the hydrology, the biology’s regions, the culture’s sites, the species' limits and the data that carry temperatures (coldLimitK and heatLimitK of the races, the niches' tempK, the phonetic environment); the fields once named for Celsius are renamed (tempK, meanK, winterK, coldLimitK …), and a test fails if one comes back. Output shows °C, °F, kelvin or plain descriptions by the user’s setting, converted at the edge only (src/temperature.ts: showTemperature; --units C|F|K|words in the command lines, ExportOptions.temperature for the wiki, DisplayOptions.temperature for the RPG sheets; language-cli --temp is given in that unit). Descriptions are relative to the reader’s body (decided): a dwarf bears more cold and more heat than a human, and a serpentine race may find a temperate climate cold and a tropical one normal. Each race has a comfortable band in kelvin (the human’s moved by as much as its cold and heat limits differ: comfort.kelvin), and describeTemperature says where a temperature falls against it (freezing, cold, cool, mild, warm, hot, very hot, scorching: the bands are proposals in data/temperature.json). A report for no particular race uses the human’s band and says so ("mild for a human"). Eventide’s °C + 100 is a display of kelvin (the profile’s shiftK is −173.15), not a stored value.
Still to build Groundwater and tides at the coast
No groundwater table, aquifers or underground rivers beyond the springs. No tides at the coast beyond the sky’s tide figure.