Clouds and atmosphere
☁️ Earth Systems

Atmosphere & Ocean

The fluid envelopes that make Earth habitable. Atmospheric layers, clouds, pressure systems, currents, and circulation patterns.

Live Data • March 28, 2026

📡 Live Atmosphere-Ocean Status

Real-time • March 28, 2026
Global Mean Sea Level
+108.2
mm above 1993 baseline
↑ +4.2mm this year
CO₂ Concentration
427.8
ppm (Mauna Loa)
↑ +2.6 ppm/year
ENSO Index (ONI)
-0.4
Weak La Niña conditions
→ Neutral expected Q3
Ocean Heat Content
+15.2
ZJ above 1971-2000 avg
↑ Record high
Arctic Sea Ice Extent
13.8
million km²
↓ 5% below avg
Ocean pH (Global Avg)
8.07
Acidification ongoing
↓ -0.12 since 1750
🧪 Atmospheric Composition

Major Components (Dry Air)

Nitrogen (N₂) 78.08%
Oxygen (O₂) 20.95%
Argon (Ar) 0.93%
Carbon Dioxide (CO₂) 0.0428%
Other gases 0.003%

Trace Greenhouse Gases

Methane (CH₄) 1,923 ppb
Nitrous Oxide (N₂O) 336 ppb
Ozone (O₃) - surface 20-100 ppb
Water Vapor 0-4% (variable)
CFCs (total) ~1 ppb (declining)

⚠️ Note: Despite being only 0.04% of the atmosphere, CO₂ is critical for Earth's temperature. Pre-industrial level was 280 ppm.

🌍 Atmospheric Layers

🛸
Exosphere
500 - 10,000 km

Transition to space. Satellites orbit here. Molecules can escape to space.

~1,500°C
Temperature (varies)
~0
Pressure (near vacuum)
H, He
Main gases
Key Features
  • No clear upper boundary - gradually merges with space
  • Geocorona (hydrogen cloud) extends to 100,000 km
  • GPS satellites orbit at ~20,200 km
  • Geostationary satellites at 35,786 km
  • Particles can travel 100s of km without collisions
🌌
Thermosphere
80 - 500 km

Extremely hot (1,500°C) but feels cold due to few molecules. Aurora occurs here.

500-2,000°C
Temperature
10⁻⁶ mb
Pressure
400 km
ISS Orbit
100 km
Kármán Line
Key Features
  • Aurora: Charged particles from solar wind collide with gases
  • Ionosphere: Ionized layer reflects radio waves (60-1000 km)
  • International Space Station: Orbits at ~400 km
  • Kármán Line: Official edge of space at 100 km
  • Temperature increases with altitude (absorbs UV and X-rays)
  • Satellites in LEO experience drag, slowly losing altitude
☄️
Mesosphere
50 - 80 km

Coldest layer (-90°C at mesopause). Meteors burn up here creating "shooting stars."

-90°C
Min Temp (top)
0.01 mb
Pressure
99.9%
Meteors burn here
Key Features
  • Mesopause: Coldest point in atmosphere (-90°C)
  • Noctilucent clouds: Highest clouds, visible at twilight
  • Sprites & elves: Lightning phenomena above thunderstorms
  • Too high for aircraft, too low for spacecraft = "ignorosphere"
  • Temperature decreases with altitude
  • Only explored by sounding rockets
🛩️
Stratosphere
12 - 50 km

Contains ozone layer (UV protection). Temperature increases with height. Jets cruise here.

-60 to 0°C
Temperature
1 mb
Pressure (top)
15-35 km
Ozone Layer
12 km
Jet Cruise Alt
Key Features
  • Ozone layer: Absorbs 97-99% of UV radiation
  • Temperature inversion: Warms with altitude (ozone absorbs UV)
  • Stable air: No convection, no weather
  • Commercial jets: Cruise in lower stratosphere (10-12 km)
  • Weather balloons: Reach 30-40 km
  • Volcanic eruptions can inject aerosols, cooling climate

✓ Good news: Ozone hole recovering! Expected full recovery by 2066 (Antarctic) thanks to Montreal Protocol banning CFCs.

⛅
Troposphere
0 - 12 km (18 km at equator)

Where we live. Contains 80% of atmosphere mass. ALL weather happens here.

+15 to -60°C
Temperature
1013 mb
Sea Level Pressure
-6.5°C/km
Lapse Rate
80%
Of Atmosphere Mass
Key Features
  • All weather: Clouds, rain, snow, storms, hurricanes
  • Convection: Hot air rises, cold air sinks = mixing
  • Lapse rate: ~6.5°C cooler per 1 km altitude
  • Tropopause: Boundary with stratosphere (jets avoid turbulence)
  • Variable height: 8 km at poles, 18 km at equator
  • Water vapor: 99% of atmospheric water is here
  • Greenhouse effect: Traps heat, maintains habitable temperature

🔄 Pressure Systems

H ➜

High Pressure

Anticyclone

  • Air sinks & spreads out
  • Clockwise rotation (NH)
  • Clear skies, fair weather
  • Light winds at center
⟷
L ➜

Low Pressure

Cyclone

  • Air rises & converges
  • Counter-clockwise (NH)
  • Clouds, rain, storms
  • Strong winds

Global Pressure Belts

Equatorial Low (ITCZ)

0° - Rising hot air, convergence zone, heavy rainfall, tropical rainforests

Subtropical High

~30° N/S - Descending air, deserts form (Sahara, Sonoran, Kalahari)

Subpolar Low

~60° N/S - Rising air, polar front, stormy, mid-latitude cyclones

💨 Jet Streams
Polar Jet Stream
~60°N, 9-12 km altitude
Subtropical Jet Stream
~30°N, 10-16 km altitude

What Are Jet Streams?

  • Narrow bands of fast-moving air (160-320 km/h)
  • Flow from west to east in both hemispheres
  • Meander in wave patterns (Rossby waves)
  • Located near tropopause (8-12 km)
  • Form at boundaries between air masses
  • Crucial for weather prediction

Weather Impacts

  • Storm steering: Guides mid-latitude cyclones
  • Cold outbreaks: Southward dips bring Arctic air
  • Heat waves: Northward ridges trap hot air
  • Blocking patterns: Persistent weather extremes
  • Flight times: Faster eastbound, slower westbound
⚠️ Climate Change Effect

Arctic warming faster than lower latitudes is weakening the temperature gradient that drives the polar jet. This causes more meandering patterns ("wavy jet stream"), leading to more persistent extreme weather events - prolonged heat waves, cold snaps, floods, and droughts.

☁️ Cloud Classification

Click any cloud type for detailed information, weather prediction tips, and formation process.

High Clouds (6-12 km)

Made of ice crystals | Prefix: Cirro-

🪶
Cirrus
"Curl of hair"
Wispy, hair-like streaks. Fair weather, but may indicate front approaching in 24-48 hours.
Weather signal Fair → Change
Altitude 6-13 km
Composition Ice crystals

Formation: Ice crystals form from water vapor at high altitude. Wind stretches them into characteristic wisps. "Mare's tails" indicate strong upper winds.

🌤️
Cirrostratus
"Curl + layer"
Thin, milky sheet covering sky. Creates halo around sun/moon. Rain likely in 12-24 hours.
Weather signal Rain coming
Key feature 22° halo

Forecasting tip: "Ring around the moon, rain coming soon." Ice crystals refract light creating 22° halo. Often precedes warm fronts.

🐑
Cirrocumulus
"Curl + heap"
"Mackerel sky" - small white ripples. Usually fair weather, rare cloud type.
Weather signal Fair weather
Pattern Fish scale ripples

Saying: "Mackerel sky, mackerel sky, never long wet, never long dry." Small-scale turbulence at high altitude creates the ripple pattern.

Middle Clouds (2-6 km)

Water droplets & ice | Prefix: Alto-

☁️
Altostratus
"High + layer"
Gray/blue sheet covering sky. Sun appears "watery." Steady rain likely within hours.
Weather signal Rain in 6-12 hrs
Visibility Sun dimly visible

Formation: Wide-scale lifting ahead of warm front. Thickens into nimbostratus as front approaches. Ground shadows faint or absent.

🌥️
Altocumulus
"High + heap"
Gray/white patches or rolls. Morning altocumulus may indicate afternoon thunderstorms.
Weather signal Variable
Element size 1-5° wide

Test: Hold arm out, element width = 1-3 fingers (cirrocumulus = smaller, 1 finger). Summer morning altocumulus + humid air = thunderstorms by afternoon.

🛸
Lenticular
"Altocumulus lenticularis"
Lens/UFO shaped. Forms over mountains. Indicates strong mountain winds, turbulence.
Location Downwind of mountains
For pilots Severe turbulence

Air flows over mountain, oscillates in standing waves. Cloud forms at wave crests. Appears stationary but air constantly flows through it.

Low Clouds (0-2 km)

Water droplets | No prefix

🌫️
Stratus
"Layer"
Gray blanket, uniform layer. Drizzle possible. Fog is stratus touching ground.
Weather Drizzle, gray
Base height 0-600 m

Forms from lifted fog or cooling of moist air layer. May persist for days. Common in coastal areas, valleys. "Marine layer" in California.

🌥️
Stratocumulus
"Layer + heap"
Lumpy, gray/white rolls. Most common cloud type globally. Usually no precipitation.
Coverage ~23% of Earth
Weather Mostly dry

Forms from spreading cumulus or breaking stratus. Important for climate - reflects sunlight, provides cooling. Uncertain how climate change affects coverage.

🌧️
Nimbostratus
"Rain + layer"
Dark gray, thick layer. Continuous moderate rain or snow for hours. Sun completely hidden.
Weather Steady rain/snow
Duration Hours to days

Associated with warm fronts, occluded fronts. Extends through multiple layers. No thunder/lightning - that's cumulonimbus. "Nimbus" = rain-bearing.

☁️

Cumulus

Puffy "cotton ball" clouds with flat bases and cauliflower tops. Fair weather cumulus = nice day. Can grow into storms.

Fair weather type Cumulus humilis
Growing type Cumulus congestus
Formation Convection (thermals)
⛈️

Cumulonimbus

THE thunderstorm cloud. Can reach 12+ km. Produces lightning, heavy rain, hail, tornadoes. Anvil top from hitting tropopause.

Height Up to 20 km
Updrafts Up to 50 m/s
Hazards All severe weather
✨ Special & Rare Cloud Types
🌊
Asperitas
Wave-like, chaotic undersides. Newest official cloud type (2017). Dramatic but usually not severe.
🍃
Morning Glory
Rare roll cloud in Australia. Can be 1000 km long. Glider pilots ride them.
🎭
Mammatus
Pouch-like bulges underneath clouds. Often seen after severe storms. Dramatic sunset lighting.
💫
Noctilucent
Highest clouds (80 km). Visible at twilight, electric blue. Made of ice on meteor dust.
🍄
Pyrocumulus
Forms from fire heat. Can create own thunderstorms (pyrocumulonimbus) and fire tornadoes.
🌈
Nacreous
Polar stratospheric clouds. Iridescent colors. Beautiful but indicate ozone destruction.

🌊 Ocean Zones

Depth Zones

☀️ Epipelagic (Sunlight Zone)
0 - 200 m
Photosynthesis occurs. 90% of marine life. All coral reefs.
🌅 Mesopelagic (Twilight Zone)
200 - 1,000 m
Some light penetrates. Many bioluminescent creatures.
🌑 Bathypelagic (Midnight Zone)
1,000 - 4,000 m
No light. Cold (4°C). Giant squid, anglerfish.
⬛ Abyssopelagic (Abyss)
4,000 - 6,000 m
Near-freezing. Extreme pressure. Sparse life.
⚫ Hadopelagic (Trenches)
6,000 - 11,000 m
Ocean trenches. Mariana Trench: 10,994 m. Extreme life forms.

Ocean Statistics

Ocean Coverage 71% of Earth
Total Volume 1.335 billion km³
Average Depth 3,688 m
Deepest Point 10,994 m (Challenger Deep)
Average Salinity 35 g/kg (3.5%)
Heat Capacity 1000x atmosphere
CO₂ Absorbed ~30% of human emissions
Explored Only ~5-10%

💡 Key insight: Oceans have absorbed 90% of the excess heat from global warming, preventing even more atmospheric warming - but at the cost of marine ecosystem health.

🌊 Ocean Circulation

Surface Currents (Wind-Driven)

Top 400m, driven by prevailing winds. Form circular gyres in each ocean basin. Transport heat from equator toward poles.

Major Warm Currents

Gulf Stream: Warms Western Europe (+10°C warmer than same latitudes elsewhere)
Kuroshio: Warms Japan, Pacific Northwest
Brazil Current: Warms SE South America
Agulhas: Warms SE Africa, leaks into Atlantic

Major Cold Currents

California: Cools US West Coast, creates fog
Humboldt (Peru): World's most productive fishery, creates Atacama Desert
Benguela: Creates Namib Desert
Labrador: Brings icebergs south (Titanic)

Thermohaline Circulation

"The Great Ocean Conveyor Belt" - deep circulation driven by temperature (thermo) and salinity (haline) differences. Takes ~1000 years for full cycle.

🔵 NORTH ATLANTIC
Warm surface water cools, releases heat to atmosphere
Evaporation increases salinity → dense water sinks
↓ 2-4 km deep ↓
North Atlantic Deep Water (NADW) flows south
↓
Circulates around Antarctica
↓
Spreads into Pacific & Indian Oceans
↓
🔴 Gradually upwells, warms, returns at surface

⚠️ Climate Risk (2026 Update)

AMOC (Atlantic Meridional Overturning Circulation) now 15-20% weaker than 1950. Freshwater from Greenland ice melt reduces salinity, preventing sinking.

Risk: Further weakening could severely cool NW Europe, shift tropical rain belts, and accelerate sea level rise on US East Coast. Tipping point possible.

⬆️ Upwelling & Downwelling

Coastal Upwelling

Wind blows parallel to coast → surface water moves offshore (Ekman transport) → deep, cold, nutrient-rich water rises to replace it.

Peru/Humboldt 20% of world's fish catch
California Creates fog, cool summers
Benguela (Namibia) Creates coastal desert
Canary (NW Africa) Rich fishing grounds

Importance

  • Nutrients: Brings nitrogen, phosphorus to surface
  • Phytoplankton: Explosive growth at base of food web
  • Fisheries: Most productive fishing zones globally
  • Climate: Cools coastal regions, creates fog
  • CO₂: Some outgassing, but also carbon sequestration

El Niño risk: Stops Peru upwelling → fishery collapse, anchoveta die-off, economic impacts, seabird/seal mortality.

🔄 ENSO: El Niño & La Niña

Current ENSO Status (March 2026)
Weak La Niña
ONI: -0.4°C
Expected to transition to neutral conditions by Q3 2026.
Following the strong El Niño of 2023-2024.

🔴 El Niño

Warm water moves east across Pacific. Trade winds weaken or reverse. Typically raises global temperature by 0.1-0.2°C.

Global Effects

  • South America: Heavy rains, floods in Peru/Ecuador
  • Australia: Drought, increased wildfire risk
  • Indonesia: Drought, forest fires
  • Africa: Drought in south/east
  • US: Wet South, warm North, less snowpack
  • Atlantic: Fewer hurricanes (wind shear)
  • India: Weaker monsoon, potential drought

Recent Strong Events

2023-2024 +2.0°C (Super)
2015-2016 +2.6°C (Super)
1997-1998 +2.4°C (Super)

🔵 La Niña

Cold water dominates eastern Pacific. Trade winds strengthen. Often follows El Niño. Can last 2-3 years ("double/triple dip").

Global Effects

  • South America: Drought in Peru/Ecuador
  • Australia: Heavy rains, floods
  • Indonesia: Heavy rains
  • Africa: Floods in east
  • US: Dry South, cold North, more snow
  • Atlantic: More hurricanes (less shear)
  • India: Stronger monsoon, potential floods

Recent Events

2020-2023 "Triple dip"
2010-2012 Strong
2007-2008 Strong

⚪ Neutral

Normal Pacific conditions. Neither warming nor cooling anomaly. ONI between -0.5°C and +0.5°C.

ENSO Thresholds

El Niño ONI ≥ +0.5°C
Neutral -0.5 to +0.5°C
La Niña ONI ≤ -0.5°C

ENSO Cycle

  • Irregular cycle: 2-7 years
  • Most powerful climate fluctuation
  • Affects weather worldwide
  • Predictable 6-9 months ahead
🔄 Other Climate Oscillations

Beyond ENSO, several other oscillations affect regional climate patterns. Here's their current status as of March 2026:

NAO
North Atlantic Oscillation
Positive

Pressure difference between Iceland Low and Azores High. Affects Europe, eastern North America.

Positive phase Mild, wet Europe
Negative phase Cold Europe, snowy
PDO
Pacific Decadal Oscillation
Cool Phase

20-30 year cycle in North Pacific. Affects fisheries, precipitation, temperature patterns.

Warm phase Enhances El Niño
Cool phase Enhances La Niña
IOD
Indian Ocean Dipole
Neutral

Temperature difference across Indian Ocean. Affects Australia, Indonesia, East Africa.

Positive Australia drought
Negative Australia floods
AO
Arctic Oscillation
Negative

Pressure pattern over Arctic. When negative, polar vortex weakens, cold air spills south.

Positive Cold stays Arctic
Negative Cold outbreaks
MJO
Madden-Julian Oscillation
Phase 5

30-60 day cycle of tropical rainfall moving eastward. Affects monsoons, tropical cyclones.

Cycle 30-60 days
8 phases Around globe
AMO
Atlantic Multidecadal Oscillation
Warm Phase

60-80 year cycle in Atlantic. Affects hurricanes, Sahel rainfall, European climate.

Warm phase More hurricanes
Cool phase Fewer hurricanes
🧪 Ocean Acidification

The Other CO₂ Problem

Ocean absorbs ~30% of atmospheric CO₂. This forms carbonic acid, lowering pH. Ocean is now 30% more acidic than pre-industrial times.

Pre-industrial pH 8.19
Current pH (2026) 8.07
Change -0.12 units (30% more acidic)
2100 projection 7.8-7.95

Impacts

  • Coral reefs: Harder to build skeletons, bleaching
  • Shellfish: Thinner shells, larvae mortality
  • Pteropods: "Sea butterflies" shells dissolving
  • Fish: Behavior changes, smell/hearing affected
  • Plankton: Some species affected, base of food web
  • Kelp forests: Some may benefit (more CO₂)

⚠️ Irreversible: Ocean acidification takes thousands of years to reverse naturally. Current rate is fastest in 300 million years.

Explore Related Topics

🌡️ Climate Controls 🌀 Storm Systems 🌧️ Precipitation 📊 Climate Change 🐠 Aquatic Biomes