Weather

Vieneo is a tidally locked exomoon with a dense, high-pressure atmosphere and perpetual cloud cover, resulting in a uniquely complex and dynamic climate. The weather simulation in Rise: The Vieneo Province has evolved into a sophisticated planetary model with dynamic interactions between temperature, humidity, convection, terrain, wind, and time of day. Weather conditions are calculated per-location using global environmental maps and physical models.

Atmospheric Characteristics

• Atmospheric Pressure: ~2.6 bar at sea level
• Diurnal Cycle: 14.43-hour day
• Peak Temperature Lag: ~3.5 hours after local solar noon (≈87.3° longitude offset)
• Midday Temperature Rise: Typically less than 10°C due to dense cloud cover

Measured Global Averages

• Turbulence: Avg 0.358 (scale 0–1)
  • Comparable to light-to-moderate convective activity on Earth. Peak turbulence occurs near equatorial storm zones, with transient strong updrafts.
• Relative Humidity (RH): Avg 58.2%
  • Min: 18.3%, Max: 100%
• Precipitation:
  • Avg: 0.076 mm/hr
  • Max: 16 mm/hr (severe storm cells)
  • Scale runs from 2–16, aligning with mm/hr intensity
• Wind Speeds:
  • Avg: 4.71 m/s (~10.5 mph)
  • Max observed: 56.4 m/s (~126 mph)
  • Area with >20 m/s winds: 0.4%
• Visibility:
  • Avg: 40.1 km
  • <1 km: 2.0%
  • <5 km: 3.5%
  • <10 km: 3.6%
  • >30 km: 94.5%

Flight Rules Classification (Ceiling AGL and Visibility)

• Instrument Flight Rules (IFR): 7.4%
• Marginal VFR (MVFR): 47.6%
• Average Ceiling: 1.16 km AGL (~3,800 ft)

Core Maps Used

• Vapor Map: Relative humidity and dew point derivation
• Temperature Deviation Map: Surface temperature variation based on season and time
• Convection Map: Storm potential and turbulence
• Wind Speed Map: Baseline surface and aloft wind speeds
• Wind Direction Map: Orographic and directional wind effects
• Elevation Map: Terrain height for ceiling and visibility calculations

Diurnal and Seasonal Effects

• Temperature modulates with solar angle
• Seasonal subsolar movement causes ±10–12°C swings

Temperature and Dew Point

• Range: -55°C to +47°C
• Dew point derived from vapor map via exponential approximation
• Max dew point spread: ~21.5°C

Relative Humidity

• Computed using Magnus-Tetens formula:

RH = exp((17.625 × Td)/(243.04 + Td)) / exp((17.625 × T)/(243.04 + T))

Turbulence (Storm Potential)

• Simulates jet stream drift via Rossby wave patterns
• Daily peak near midday
• Affects gusts, cloud formation, and precipitation
• More widespread than on Earth due to dense atmosphere and solar heating dynamics

Precipitation

• Triggered when RH × Turbulence > 0.44 below ~6.5 km altitude
• Intensity scaled 2–16 (in mm/hr)
• Can cool surface by up to 6°C
• Planetary precip coverage targets ~7.5%

Wind Modeling

• Layered up to 63 km altitude
• Gusts enhanced by turbulence
• Strongest winds seen in mid-latitude and equatorial storm belts

Orographic Lifting and Visibility

• Visibility reduced when upwind terrain is higher and RH is high
• Modulated by dew point spread and wind speed

Visibility Calculations

• Fog: Triggered by small T–Td delta and elevated terrain
• Precipitation visibility effects:
  • Light (2–6): ~2 km visibility
  • Moderate (10–12): ~1–5 km
  • Heavy (>12): ~0.5–4.5 km
• Wind Mixing:
  • 5–15 m/s: improves visibility
  • >20 m/s: can cause haze and dust
• Final Clamp: Visibility range: 0.05–25 km

Ceiling Calculations

• Formula: (T - Td) × 0.12192 km/°C
• Adjusted for terrain height difference
• Minimum ceiling enforced over Deois
• If ceiling <150 m AGL below midcloud, visibility is reduced

Sanity Checks and Constraints

• Fog forces min precip to 2.0
• Syncs ceiling and visibility to avoid logical conflicts

Notes to Pilots

• Cloud Bases: Widespread stratiform decks, often 1–2 km AGL
• Low Visibility Zones: Mountainous or humid regions prone to IFR
• Storm Zones: Mostly near equator or mid-latitudes
• Winds Aloft: Jet-stream equivalents exist—expect wind shear
• Turbulence: More persistent than Earth; strong convection common

Summary of Key Ranges

Parameter	Min	Max
Temperature (Surface)	-55°C	+47°C
Dew Point Spread	0°C	~21.5°C
Precipitation	2.0 mm/hr	16.0 mm/hr
Wind Speed	~0 m/s	~83 m/s
Visibility	0.05 km	25.0 km
Ceiling (AGL)	0.0 km	~5.0+ km

Imagery

Global weather radar map showing precipitation clusters

See Also

• Atmosphere
• Player Portal

Notes

The system is designed for future upgrades including airborne radar, storm particles, and localized weather patterns. Orographic effects and fog are computed dynamically using directional wind sampling.