Class 10: Earth-Orbiting SatellitesAnd Review

Thursday 5 February

Reading: LKC 7.13 -- p. 574 - 615

Last lecture: Spectroscopy, mineral spectra

Orbit

Platform

Sensor

1957Sputnik

1999EOS

C-130

Sputnik

Sputnik 2with Laika

SEBASS Hyperspectral TIR sensor in a Twin Otter

Airborne platforms – test beds, flexible paths

Orbits

Key elements: - eccentricity - inclination - periapsis

Inclination

Low inclination High inclination

Hubble Space Telescope – low inclination

most Shuttles - low inclination

Exception: SRTM i=58º

High-inclination orbits

Special case –Sun-synchronous orbit(i ~ -81º)

Satellite is overhead at same local solar time all year

Why would you choose - late morning? - mid afternoon? - early morning?

Global coverage

Sensor characteristics

- spatial resolution and field of view- spectral resolution- spectral coverage- number of bands

Spatial resolution depends on experimenthigh – spatial detail, less emphasis on spectroscopymoderate – environmental monitoringlow – weather, oceanography

Spectral resolutionpanchromaticmultispectralhyperspectral (imaging spectroscopy)

Spectral coverage

Opticalreflected sunlightthermal infraredLiDAR

MicrowavepassiveRadar

Gamma ray, X ray, geophysical (magnetic, gravity fields)

LANDSAT – SUN-SYNCHRONOUS ORBIT

ThematicMapper

ESS 421 - 1st halftopics covered in class, reading, and labs

Images and maps - (x,y,z,,t)

Temporal data - Time-lapse movies

Spatial data - Photos and interpretation

Spectral data

Electromagnetic spectrum

Absorption and Beer’s law (=e-kz)

Transmission

Reflection

Scattering and Lambert’s law R=Io(cos i)/

Interaction of light and materials

Electronic processes (VNIR)

- electron transition (VIS), sharing (UV), crystral field (NIR)

Vibrations and overtones (SWIR-TIR)

Gas,liquid,glass, crystalline

Spectra of common materials

leaves, soil, water, clouds, snow, iron oxides, hydrated minerals

ESS 421 - 1st halfkey areas for midterm (Tuesday, 10 February 9:30-10:20)

Questions may be drawn from labs, lectures, text

Basic remote sensing parameters

irradiance, radiance, and their units

the electromagnetic spectrum

thermal emission

Atmospheric effects and scattering processes

Scattering and reflection from surfaces

Spectroscopy fundamentals

Spectra of common materials