Remote Sensing of the Atmosphere

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Core Idea

Atmospheric remote sensing measures the composition, structure, and dynamics of Earth's atmosphere from satellites. While surface remote sensing treats the atmosphere as an obstacle (to be corrected away), atmospheric remote sensing treats it as the target. Key measurements include atmospheric temperature and humidity profiles (from infrared and microwave sounders), cloud properties (from visible, infrared, and radar sensors), aerosol distribution (from multi-angle and polarimetric sensors), trace gas concentrations (from ultraviolet, visible, and infrared spectrometers), and precipitation (from radar and passive microwave). These measurements drive weather forecasting, climate monitoring, and air quality assessment.

Explainer

While most remote sensing courses focus on observing Earth's surface, the atmosphere is itself a complex, dynamic target observed by a dedicated constellation of satellites. Atmospheric remote sensing provides the data that drives weather forecasts, tracks air quality, monitors the ozone layer, and measures greenhouse gas concentrations for climate science.

Temperature and humidity profiling uses infrared and microwave sounders that measure thermal emission from the atmosphere at wavelengths where specific gases (primarily CO2 and H2O) absorb and emit. By selecting channels with different absorption strengths, sounders sample different atmospheric layers -- strong absorption channels see only the upper atmosphere, while weak absorption channels see down to the surface. This vertical sounding technique produces temperature and moisture profiles essential for initializing numerical weather prediction models.

Trace gas remote sensing exploits the spectral fingerprints of molecules. Each atmospheric gas absorbs at characteristic wavelengths: ozone in the ultraviolet, NO2 in the visible, CO and CH4 in the shortwave infrared, CO2 at 4.3 um and 15 um. Spectrometers with sufficient spectral resolution can measure the absorption depth and retrieve the column concentration of each gas. Instruments like TROPOMI, OMI, and OCO-2 have mapped air pollution, methane leaks, and carbon dioxide distribution with increasing spatial detail, informing both science and policy.

Precipitation estimation combines multiple sensor types. Passive microwave radiometers detect the scattering signature of ice particles in clouds. Cloud-profiling radar (on CloudSat and GPM) directly measures precipitation structure. Geostationary infrared imagery provides temporal context -- cold cloud tops indicate deep convection and heavy rain. The Global Precipitation Measurement (GPM) mission merges these observations to produce near-real-time global precipitation maps at 0.1-degree resolution every 30 minutes.

Practice Questions 3 questions

Prerequisite Chain

Counting to 10 → Counting to 20 → Understanding Zero → The Number Zero → Counting to Five → One-to-One Correspondence → Combining Small Groups Within 5 → Addition Within 10 → Addition Within 20 → Two-Digit Addition Without Regrouping → Two-Digit Addition with Regrouping → Addition Within 100 → Repeated Addition as Multiplication → Multiplication Facts Within 100 → Division as Equal Sharing → Division as Grouping (Measurement Division) → Division: Grouping (Repeated Subtraction) Model → Division: Fair Sharing Model → Division as Equal Sharing → Division as Grouping → Basic Division Facts → Division Facts Within 100 → Two-Digit by One-Digit Division → Division with Remainders → Remainders and Quotients in Division → Division Word Problems → Introduction to Long Division → Factors and Multiples → Prime and Composite Numbers → Equivalent Fractions → Relating Fractions and Decimals → Decimal Place Value → Reading and Writing Decimals → Comparing and Ordering Decimals → Adding and Subtracting Decimals → Multiplying Decimals → Dividing Decimals → Dividing Fractions → Mixed Number Arithmetic → Order of Operations → Integer Order of Operations → Variable Expressions → Combining Like Terms → One-Step Equations → Two-Step Equations → Solving Multi-Step Equations → Equations with Variables on Both Sides → Angle Pairs: Complementary, Supplementary, and Vertical → Parallel Lines and Transversals → Corresponding Angles → Alternate Interior Angles → Triangle Angle Sum Theorem → Exterior Angle Theorem → Triangle Inequality Theorem → Similar Triangles: AA Similarity → Similar Triangles: SSS and SAS Similarity → Proportions in Similar Triangles → Right Triangle Trigonometry Introduction → Trigonometric Ratios Review → Radian Measure → Converting Between Degrees and Radians → The Unit Circle → Graphing Sine and Cosine → Graphing Tangent and Reciprocal Trigonometric Functions → Derivatives of Trigonometric Functions → Antiderivatives → Iterated Integrals and Fubini's Theorem → Double Integrals in Cartesian Coordinates → Double Integrals over Rectangular Regions → Double Integrals in Polar Coordinates → Double Integrals: Definition and Setup → Iterated Integrals and Fubini's Theorem → Double Integrals over Rectangular Regions → Double Integrals over General Regions → Applications of Double Integrals: Area, Mass, and Moments → Triple Integrals in Cartesian Coordinates → Triple Integrals in Cylindrical and Spherical Coordinates → Change of Variables and the Jacobian Determinant → Applications of Triple Integrals: Volume and Mass → Vector Fields and Their Representations → Line Integrals of Vector Fields → Green's Theorem → Surface Integrals and Flux of Vector Fields → Surface Integrals and Flux of Vector Fields → Divergence Theorem: Flux and Outflow → Divergence Theorem → Electric Flux → Gauss's Law → Conductors in Electrostatic Equilibrium → Capacitance and Capacitors → Dielectrics → Dielectric Constant and Relative Permittivity → Electric Field Inside Dielectric Materials → Dielectric Materials and Polarization → Dielectric Susceptibility and Permittivity → Energy Density in Electric Fields → Electric Current and Current Density → Electrical Resistance and Resistivity → Ohm's Law and Circuit Elements → Electromotive Force (EMF) and Batteries → Kirchhoff's Circuit Laws: Voltage and Current → DC Circuit Network Analysis Methods → Transient Response in RC Circuits → RC Circuits → LC and RLC Circuits → AC Circuits: Fundamentals → Impedance and Reactance → AC Power and Resonance → Electromagnetic Waves → The Electromagnetic Spectrum → Electromagnetic Spectrum for Remote Sensing → Passive vs Active Remote Sensors → Remote Sensing of the Atmosphere

Longest path: 113 steps · 645 total prerequisite topics

Prerequisites (2)

Electromagnetic Spectrum for Remote Sensinghard Passive vs Active Remote Sensorshard

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