PhysSandbox
Classical MechanicsWaves & SoundElectricity & MagnetismOptics & LightGravity & OrbitsLabs
🌙Astronomy & The Sky🌡️Thermodynamics🌍Biophysics, Fluids & Geoscience📐Math Visualization🔧Engineering🧪Chemistry

More from Biophysics, Fluids & Geoscience

Other simulators in this category — or see all 44.

View category →
NewUniversity / research

Groundwater Contaminant Plume

Launch Simulator

Advection-dispersion pulse in groundwater with longitudinal/transverse spreading, retardation factor R, and a monitoring-well breakthrough curve.

NewUniversity / research

Infinite Slope Stability

Launch Simulator

Limit-equilibrium factor of safety for a shallow planar slide: slope angle, cohesion, friction, depth, and rainfall-driven pore pressure set the landslide threshold.

NewUniversity / research

Earthquake Aftershocks: Omori + Gutenberg-Richter

Launch Simulator

Modified Omori aftershock decay n(t)=K/(t+c)^p combined with Gutenberg-Richter magnitude-frequency curves, b-value, and a synthetic catalog.

NewUniversity / research

Mantle Convection Cell (Toy)

Launch Simulator

High-Prandtl-number mantle convection cartoon: Rayleigh-number vigor, thermal boundary layers, hot upwelling, and a cold subducting slab in one viscous cell.

NewSchool

Carbon Cycle (4-Box Model)

Launch Simulator

Atmosphere, ocean mixed layer, deep ocean, and land biosphere exchange linearly; add fossil emissions or GtC pulses and watch inventory split vs a toy airborne fraction.

NewSchool

Mid-Ocean Ridge: Magnetic Stripes

Launch Simulator

Symmetric stripes accrete at a spreading center as polarity flips — a 2D cartoon of Vine–Matthews–Morley marine magnetic anomalies.

PhysSandbox

Interactive physics, chemistry, and engineering simulators for students, teachers, and curious minds.

Physics

  • Classical Mechanics
  • Waves & Sound
  • Electricity & Magnetism

Science

  • Optics & Light
  • Gravity & Orbits
  • Astronomy & The Sky

More

  • Thermodynamics
  • Biophysics, Fluids & Geoscience
  • Math Visualization
  • Engineering
  • Chemistry

© 2026 PhysSandbox. Free interactive science simulators.

PrivacyTermsContact
Home/Biophysics, Fluids & Geoscience/Atmospheric Stability / Parcel Diagram

Atmospheric Stability / Parcel Diagram

Toy sounding with environmental lapse rate, dry/moist parcel ascent, LCL, LFC, equilibrium level, CAPE, CIN, and Lifted Index.

Parcel sounding

30 °C
5 °C
7 K/km
2.5 K
2 km

A lifted parcel cools dry adiabatically to LCL, then follows an approximate moist adiabat. CAPE/CIN are integrals of parcel buoyancy g(T_p−T_e)/T_e.

Measured values

LCL0.63km
LFC2.10km
Equilibrium levelnone
CAPE6919J/kg
CIN61J/kg
Lifted Index-12.0°C

Live graphs

About this model

This parcel diagram is a compact teaching analogue of a Skew-T sounding. The environmental temperature profile is controlled by a surface temperature, an environmental lapse rate, and an optional warm cap. A lifted surface parcel cools dry adiabatically at about 9.8 K/km until it reaches the lifted condensation level (LCL), estimated from the surface temperature and dew point. Above the LCL, the parcel follows an approximate saturated moist adiabat computed from a temperature- and pressure-dependent moist lapse rate. Buoyancy is evaluated as B = g(T_p − T_e)/T_e, using temperature as a simplified virtual-temperature proxy. Positive buoyancy integrated over height gives CAPE, while negative buoyancy below the level of free convection gives CIN. The LFC, equilibrium level, and 500 hPa Lifted Index are diagnostic markers. The page is deliberately qualitative: it omits entrainment, ice microphysics, pressure-coordinate exactness, wind shear, convective inhibition erosion, and full virtual-temperature/moisture corrections.

Who it's for: Meteorology, atmospheric science, hazards, and environmental physics students learning parcel theory, CAPE/CIN, and sounding interpretation.

Key terms

  • Skew-T
  • Parcel theory
  • Dry adiabat
  • Moist adiabat
  • LCL
  • LFC
  • CAPE
  • CIN
  • Lifted Index
  • Capping inversion

How it works

Atmospheric stability parcel diagram: dry and moist adiabatic parcel path, LCL, LFC, equilibrium level, CAPE, CIN, and Lifted Index.

Key equations

below LCL: Γ_d ≈ 9.8 K/km; above LCL: Γ_m(T,p)
CAPE = ∫ max(B,0) dz, CIN = −∫ min(B,0) dz, B=g(T_p−T_e)/T_e

Frequently asked questions

What does LCL mean?
The lifted condensation level is the height where a rising unsaturated parcel cools to its dew point. Above it, condensation releases latent heat, so the parcel cools more slowly along a moist adiabat.
Why can a sounding have CAPE but still not storm?
A warm layer can create CIN: the parcel is negatively buoyant before it reaches free convection. Without lift, surface heating, or erosion of the cap, the atmosphere may remain conditionally unstable but not convect.
Why is CAPE in J/kg?
CAPE is the vertical integral of buoyant acceleration. Since m²/s² equals J/kg, it approximates the kinetic-energy-per-mass reservoir available to an ideal rising parcel.
Is this a real Skew-T calculator?
No. It keeps the key geometry and diagnostics but simplifies moisture, virtual temperature, pressure coordinates, entrainment, and microphysics for interactive teaching.