Remote Sensing Space-based Earth exploration and planetary exploration began with the International Geophysical Year (IGY) which was also the beginning

Remote SensingRemote Sensing

Space-based Earth exploration and planetary Space-based Earth exploration and planetary exploration began with the International exploration began with the International Geophysical Year (IGY) which was also the Geophysical Year (IGY) which was also the beginning of the space race (1957)beginning of the space race (1957)

IGY was an 18-month international scientific IGY was an 18-month international scientific research project that spanned 1957-1958research project that spanned 1957-1958 Research included Earth sciences: aurora and Research included Earth sciences: aurora and

airglow, cosmic rays, geomagnetism, gravity, airglow, cosmic rays, geomagnetism, gravity, ionospheric physics, longitude and latitude ionospheric physics, longitude and latitude determinations (precision mapping), meteorology, determinations (precision mapping), meteorology, oceanography, seismology and solar activityoceanography, seismology and solar activity


Instruments for the early Instruments for the early Explorer program were Explorer program were improved and modified for improved and modified for lunar and planetary lunar and planetary exploration in the Pioneer exploration in the Pioneer (lunar) and Mariner (Venus, (lunar) and Mariner (Venus, Mars) missionsMars) missions Explorer 1 was America’s Explorer 1 was America’s

first satellitefirst satellite Continued through Continued through

Explorer 78 Explorer 78 Launched in 2000Launched in 2000


Remote sensing is traditionally used for Remote sensing is traditionally used for Earth observation, but also applies to Earth observation, but also applies to planetary explorationplanetary exploration The same or similar or instruments used for bothThe same or similar or instruments used for both

Measurements at a distance use Measurements at a distance use electromagnetic (EM) sensorselectromagnetic (EM) sensors Radio, microwaveRadio, microwave IRIR VisibleVisible UVUV


Sampling (in situ) measurementsSampling (in situ) measurements

Generally for accurate measurements of Generally for accurate measurements of composition and abundance composition and abundance

Include:Include: Mass spectrometersMass spectrometers Atmospheric particle detectorsAtmospheric particle detectors Surface analysisSurface analysis

Particle and EM radiation detectorsParticle and EM radiation detectors


Sampling (in situ) Sampling (in situ) measurements on measurements on Earth can be relatively Earth can be relatively inexpensive inexpensive

In situ measurements In situ measurements on planets/moons are on planets/moons are the most expensive the most expensive space exploration space exploration projectsprojects

Earth observation Earth observation Ground-basedGround-based AirborneAirborne Space-basedSpace-based


Atmosphere is an important element in Earth Atmosphere is an important element in Earth observationobservation

1. Direct atmospheric studies1. Direct atmospheric studies Complex circulation effects climates in many Complex circulation effects climates in many

waysways Changes in circulation importantChanges in circulation important

2. Atmospheric interaction includes:2. Atmospheric interaction includes: AbsorptionAbsorption EmissionEmission Chemical interactionsChemical interactions Water (liquid and vapor)Water (liquid and vapor)


Atmospheric absorption spectraAtmospheric absorption spectra

Mostly due to H2O, O2, CO2


Space-based observationsSpace-based observations

EM radiation sensors include:EM radiation sensors include:

Imaging dataImaging data

Spectral dataSpectral data

Spectral imaging dataSpectral imaging data Color television is an example of Color television is an example of

sequential spectral (color) imagessequential spectral (color) images


Spectral data Spectral data exampleexample

(Chandra X-ray (Chandra X-ray

Telescope data)Telescope data)

Remote SensingRemote Sensing Spectral image Spectral image data mosaicdata mosaic

Remote SensingRemote SensingSpectral image data of auroraSpectral image data of aurora

Remote Sensing – Spectral BandsRemote Sensing – Spectral Bands


Radio band

Various definitions of frequency rangeVarious definitions of frequency range 0 - 300 MHz (1 MHz = 100 - 300 MHz (1 MHz = 1066Hz)Hz) 0 - 1 GHz (1GHz = 100 - 1 GHz (1GHz = 1099Hz)Hz)

Lowest EM frequenciesLowest EM frequencies

Often used for upper-atmosphere and Often used for upper-atmosphere and ion/electron measurements ion/electron measurements


Microwave band

300 MHz - 300 GHz

Used for: Surface feature identification Atmospheric layer measurements Radio astronomy Synthetic aperture (imaging) radar


Infrared band

300 GHz - 400,000 GHz (400 THz) 1 THz = 1 Tera Hertz = 1012Hz = 1,000 GHz

Used for: Surface feature identification Atmospheric layers and thunderstorm activity Atmospheric energy exchange Energy absorption or emission in atmosphere Vegetation characteristics Planetary heat flow Stellar and galactic activity


Visible band

4x1014Hz - 8x1014Hz (400 THz - 800 THz)

Used for: Surface feature identification Clouds & precipitation Vegetation layers Ocean surfaces Mineral identification


UV band

7.5x1014Hz - 3x1016Hz

Used for: Upper atmosphere measurements Solar emissions Stellar characteristics including star birth

and star death Galaxy characteristics


X-ray band

1016 - 1019Hz

Used for: Planetary surface composition from

radioisotope emission spectra Stellar activity (primarily for stars, including our

sun, and galaxies) Excited (hot) gas in the solar system,

surrounding stars, in galaxies, and between galaxies


Gamma-ray band

1019Hz and higher (no defined maximum)

Used for: Planetary surface composition from

radioisotope emission spectra Used to identify energetic stars and galaxies Supernova detection Neutron star formation

ApplicationsApplications

Agriculture

Crop type classification Crop condition

assessment Crop yield estimation Mapping of soil

characteristics Mapping of soil

management practices Compliance monitoring

(farming practices)


Forestry

Forest mapping Clear-cut mapping Forest inventory Deforestation

evaluation Watershed evaluation Coastal forest

protection


Geology

Bedrock mapping Surface deposit mapping Surface deformation &

changes Sedimentary mapping Structural mapping Mantle & crust motion Volcanic evolution Event mapping Mineral exploration Hydrocarbon exploration Environmental geology Geo-hazard mapping Planetary mapping


Ice Pack & Hydrology

Wetlands mapping & monitoring

Soil moisture estimation

Snow pack evaluation River & lake ice Flood mapping &

monitoring Glacier dynamics River delta changes Irrigation evaluation &

monitoring


Environmental planning

Atmosphere Oceans Public health Coastal changes Industrialization Forests Rivers, lakes &

estuaries


Disaster Planning & Evaluation

Floods Tornadoes Hurricanes/cyclones Fires Earthquakes Droughts


Weather

Forecasting Adverse weather

planning Aviation & marine

weather Global atmosphere Sun-Earth

interactions


Planetary Observations

Surface characteristics

Geology Composition Activity

Atmosphere Environment Solar interactions

Documents

Remote Sensing Space-based Earth exploration and planetary exploration began with the International Geophysical Year (IGY) which was also the beginning