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Geophysics & Environmental Physics

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Geophysics & Environmental Physics

Hydrothermal Vents

Fissures on the ocean floor near volcanically active mid-ocean ridges that vent geothermally heated, mineral-rich seawater into the ocean.

Geothermally Heated Seawater T ~ 350–400 °C °C (Vent Fluid Temperature)
Geophysics & Environmental Physics

Ice Core Analysis

The retrieval and paleoclimatological analysis of cylindrical ice samples extracted from deep polar ice sheets and alpine glaciers.

Paleotemperature Proxy δ¹⁸O = ((¹⁸O/¹⁶O)_sample / (¹⁸O/¹⁶O)_standard - 1) × 1000‰ Parts per thousand (‰ δ¹⁸O) / ppm (CO₂)
Geophysics & Environmental Physics

Insolation

The solar electromagnetic radiation power reaching a specified surface area per unit time.

S = S₀ (R₀ / R)² cos Z W/m² or kWh/m²/day
Geophysics & Environmental Physics

Ionosphere

An ionized layer of Earth's upper atmosphere (~60 km to 1,000 km) where extreme solar UV and X-ray radiation ionize atmospheric gas atoms…

Plasma Frequency f_p = (1 / 2π) √(n_e e² / (ε₀ m_e)) Electrons/m³ (Electron Density n_e)
Geophysics & Environmental Physics

Ionospheric Scintillation

Rapid fluctuations in amplitude and phase of satellite radio signals caused by small-scale electron density irregularities in the…

Scintillation Index S₄ = √(⟨I²⟩ - ⟨I⟩²) / ⟨I⟩ Dimensionless S₄ Index
Geophysics & Environmental Physics

Isostasy

The state of gravitational equilibrium between Earth's lithospheric crust blocks floating at depths determined by their thickness and…

Airy Model: h_root = h_mountain (ρ_crust / (ρ_mantle - ρ_crust)) Meters (Crustal Root Depth)
Geophysics & Environmental Physics

La Niña

The cool climate phase of the El Niño-Southern Oscillation (ENSO) characterized by abnormally cold sea surface temperatures in the central…

ENSO Index: Southern Oscillation Index (SOI) > 0, Sea Surface Temp Anomaly < -0.5 °C Sea Surface Temperature Anomaly (°C)
Geophysics & Environmental Physics

Lehmann Discontinuity

The seismic boundary at a depth of ~5,150 km marking the transition between Earth's liquid outer core and solid inner core.

Depth z ≈ 5150 km (Outer Core - Inner Core Boundary) km (Boundary Depth)
Geophysics & Environmental Physics

Lithosphere

The rigid, brittle outermost mechanical shell of Earth comprising the entire crust and uppermost solid mantle.

Elastic Thickness h_e ~ 10–200 km km (Lithospheric Thickness)
Geophysics & Environmental Physics

Magnetosphere

The region of space surrounding Earth dominated by Earth's geomagnetic field, shielding the planet from harmful solar wind plasma.

Magnetopause Distance R_mp ≈ (B₀² / (2 μ₀ ρ v²))^(1/6) Earth Radii (R_E ~ 10 R_E sunward)
Geophysics & Environmental Physics

Mantle Convection

The slow, highly viscous thermal convection currents within Earth's solid silicate mantle transporting internal core heat toward the…

Ra = (ρ g α ΔT d³) / (κ η) (Rayleigh Number > Ra_critical) cm/year (Convection Motion Speed)
Geophysics & Environmental Physics

Milankovitch Cycles

Cyclical variations in Earth's orbital eccentricity, axial tilt (obliquity), and precession that alter the seasonal and latitudinal…

Eccentricity (100ky), Obliquity (41ky), Precession (23ky) Geologic Climate Cycles (Years)
Geophysics & Environmental Physics

Nutation

Small periodic nodding oscillations superimposed upon Earth's long-term rotational axis precession.

Principal Nutation Period T = 18.6 years, Amplitude = 9.2″ Arcseconds (17.2″ in longitude, 9.2″ in obliquity)
Geophysics & Environmental Physics

Ocean Acidification

The ongoing long-term reduction in the pH of Earth's oceans caused by the absorption of anthropogenic carbon dioxide from the atmosphere.

CO₂ + H₂O ⇌ H₂CO₃ ⇌ H⁺ + HCO₃⁻, H⁺ + CO₃²⁻ ⇌ HCO₃⁻ pH Units (Logarithmic Scale)
Geophysics & Environmental Physics

Ocean Currents

Continuous, directed large-scale movements of seawater generated by wind stress, Coriolis force, temperature, salinity differences, and…

Geostrophic Ocean Flow: 2 Ω sin φ v_ocean = (1 / ρ) (dP / dx) Sv (Sverdrups = 10⁶ m³/s) or m/s
Geophysics & Environmental Physics

Paleoclimatology

The scientific study of Earth's past climate conditions across geologic history using indirect environmental proxy records.

Climate Proxies: Ice Cores, Tree Rings, Coral δ¹⁸O, Speleothems Geologic Climate History
Geophysics & Environmental Physics

Paleomagnetism

The study of the historical record and orientation of Earth's magnetic field preserved in iron-bearing minerals in rocks, sediments, or…

Remanent Magnetization Vector (Declination & Inclination) Degrees (° Declination / Inclination)
Geophysics & Environmental Physics

Plate Tectonics

The unifying geophysical theory stating that Earth's rigid outer lithosphere is divided into major tectonic plates drifting over the…

Plate Motion Velocity v_plate ~ 1–10 cm/year cm/year (Plate Drift Speed)
Geophysics & Environmental Physics

Precession of the Equinoxes

The slow continuous conical rotation of Earth's rotational axis in space, taking ~25,800 years to complete one full cycle.

Precession Period T ≈ 25,772 years (Axial Wobble Rate ~ 50.3″/year) Years per Cycle (~25,800 years)
Geophysics & Environmental Physics

Radiative Forcing

The net change in Earth's energy balance per unit area at the tropopause due to an environmental driver of climate change.

ΔF = F_incoming - F_outgoing W/m² (Watts per square meter)
Geophysics & Environmental Physics

Radiometric Dating in Geology

A geochronological technique used to determine the absolute age of rocks and minerals by measuring radioisotope parent-to-daughter ratios.

t = (1 / λ) ln(1 + D / P) (Parent P → Daughter D) Ma or Ga (Millions / Billions of Years)
Geophysics & Environmental Physics

Radon Gas Migration

The environmental migration of radioactive Radon-222 gas from decaying uranium in rocks and soil into indoor building spaces.

Decay Chain: ²³⁸U → ²²⁶Ra → ²²²Rn (Half-life = 3.82 days) Bq/m³ or pCi/L (Activity Concentration)
Geophysics & Environmental Physics

Relative Humidity

The ratio of the actual vapor pressure of water in an air parcel to the saturation vapor pressure at the same temperature, expressed as a…

RH = (e / e_s(T)) × 100% Percentage (%)
Geophysics & Environmental Physics

Remote Sensing in Geophysics

The acquisition of geophysical information about Earth's surface and atmosphere from a distance using satellite or airborne sensors.

NDVI = (NIR - Red) / (NIR + Red) Multi-Spectral Satellite Imagery