Physical Basics of Remote-Sensing with Satellites

- Physical Basics of Remote-Sensing with Satellites Dr. K. Dieter Klaes EUMETSAT Meteorological Division Am Kavalleriesand 31 D-64295 Darmstadt dieter.klaes@eumetsat.int Slide: 1 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Physical Basics of Remote Sensing with Satellites 1 Introduction 2 Physical Basics 2.1 Remote Sensing 2.2 Radiation Laws 2.3 Properties of Matter 2.4 Radiative Transfer 3 Examples 4 Outlook Acknowledgment: Many thanks to Paul Menzel from CIMSS, and the ARA LMD team. Slide: 2 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Introduction Slide: 3 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing All measurement processes which perform observations/measurements of parameters, that carry information about properties at the location of interest, far from the location of interest Opposite: In-situ measurements, i.e. at the location of interest Slide: 5 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing All measurement processes which perform observations/measurements of parameters, that carry information about properties at the location of interest, far from the location of interest Opposite: In-situ measurements, i.e. at the location of interest Hence: Listening and Seeing are already techniques of Remote Sensing (Ear and Eye are Remote Sensing Sensors!!) Slide: 6 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing Example: Astrophysics: Has to rely nearly completely on Remote Sensing Slide: 7 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing Example: Astrophysics: Has to rely nearly completely on Remote Sensing Geophysics: Seismic waves Astrophysics, Meteorology, Oceanography and Geography use mostly electromagnetic waves Slide: 8 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing Remote Sensing is the science of information gathering on the Earth/Atmosphere System without physical contact to them, using electromagnetic waves. Slide: 9 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing Remote Sensing is the science of information gathering on the Earth/Atmosphere System without physical contact to them, using electromagnetic waves. Advantage: No perturbation of the probe, can measure point-, column- or profile data. Slide: 10 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing Remote Sensing is the science of information gathering on the Earth/Atmosphere System without physical contact to them, using electromagnetic waves. Advantage: No perturbation of the probe, can measure point-, column- or profile data. Disadvantage: Limited spatial (and temporal) Resolution, interpretation of data sometimes difficult. Slide: 11 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

History Sputnik 1, 4 October 1957 Explorer-1, 31 January 1958 TIROS-1, 1 April 1960, first pure Weather satellite ATS (Applications Technology Satellite), 1966, first geostationary (Weather)satellite Afterwards many TIROS, NIMBUS, ESSA, NOAA, GOES, Meteosat etc. Slide: 12 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

History: example ESSA-6 15/08/1968 Source: Berliner Wetterkarte Slide: 13 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Physical Basics Slide: 14 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

E Electromagnetic Waves B c Electromagnetic waves carry information: Electrical and magnetic fields perpendicular to each other, transversal waves perpendicular to the direction of propagation Slide: 15 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

E Electromagnetic Waves B c Electromagnetic waves carry information: Electrical and magnetic fields perpendicular to each other, transversal waves perpendicular to the direction of propagation Slide: 16 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

E Electromagnetic Waves B c Electromagnetic waves carry information: Electrical and magnetic fields perpendicular to each other, transversal waves perpendicular to the direction of propagation Characteristics: Wavelength λ Frequency ν Propagation velocity c Slide: 17 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Electromagnetic Waves = c c Speed of light /m/s Slide: 18 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Electromagnetic Waves = c λ c Speed of light /m/s λ Wavelength /m Slide: 19 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Electromagnetic Waves ν = c λ c Speed of light /m/s ν Frequency /Hz = s -1 λ Wavelength /m Slide: 20 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Electromagnetic Waves ν c = = cκ λ c Speed of light /m/s ν Frequency /Hz = s -1 λ Wavelength /m κ Wavenumber /cm -1 Slide: 21 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Slide: 22 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Slide: 23 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing with electromagnetic waves Slide: 24 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing with electromagnetic waves Sensor Slide: 25 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing with electromagnetic waves Sensor Emission Slide: 26 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing with electromagnetic waves Sensor Emission Slide: 27 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing with electromagnetic waves Sensor Sun Sensor Emission Slide: 28 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing with electromagnetic waves Sensor Sun Sensor Emission Slide: 29 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing with electromagnetic waves Sensor Sun Sensor Emission diffuse scattering of incoherent light Slide: 30 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing with electromagnetic waves Sensor Sun Sensor Transmitter Emission diffuse scattering of incoherent light Slide: 31 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing with electromagnetic waves Sensor Sun Sensor Transmitter Emission diffuse scattering of incoherent light Reflection of artificial coherent waves Slide: 32 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Remote Sensing with electromagnetic waves Sensor Sun Sensor Transmitter Receiver Emission diffuse scattering of incoherent light Reflection of artificial coherent waves Slide: 33 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Processes in Remote Sensing Sensor SUN = Source of Energy Ground Target Slide: 34 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Processes in Remote Sensing Sensor SUN = Source of Energy Absorption Ground Target Slide: 35 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Processes in Remote Sensing Sensor SUN = Source of Energy Absorption Scattered Radiation Absorption Ground Target Slide: 36 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Processes in Remote Sensing Sensor SUN = Source of Energy Absorption Scattered Radiation Absorption Ground Target Slide: 37 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Processes in Remote Sensing Sensor SUN = Source of Energy Absorption Scattered Radiation Absorption Ground Target Slide: 38 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Processes in Remote Sensing Sensor SUN = Source of Energy Absorption Scattered Radiation Absorptionlosses Absorption Ground Target Slide: 39 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Processes in Remote Sensing SUN = Source of Energy Sensor Absorption Scattered Radiation Absorptionlosses Losses from scattering Ground Target Absorption Slide: 40 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Processes in Remote Sensing SUN = Source of Energy Sensor Absorption Emission Scattered Radiation Absorptionlosses Losses from scattering Ground Target Absorption Slide: 41 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Processes in Remote Sensing SUN = Source of Energy Sensor Absorption Emission Scattered Radiation Absorptionlosses Losses from scattering Ground Target Absorption Slide: 42 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Processes in Remote Sensing SUN = Source of Energy Sensor Absorption Emission Scattered Radiation Absorptionlosses Losses from scattering Ground Target Absorption Slide: 43 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Processes in Remote Sensing SUN = Source of Energy Sensor Absorption Angular dependent scattering Emission Scattered Radiation Absorptionlosses Losses from scattering Ground Target Absorption Slide: 44 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Visible (Reflective Bands) Infrared (Emissive Bands) P. Menzel, 2007 Slide: 45 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Radiation Laws Slide: 46 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Sensor Geometry Electronics Sensor dω=sinθ dθ dϕ Optics Slide: 47 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009 P. Menzel, 2007

Reflectance To properly compare different reflective channels we need to convert observed radiance into a target physical property In the visible and near infrared this is done through the ratio of the observed radiance divided by the incoming energy at the top of the atmosphere The physical quantity is the Reflectance i.e. the fraction of solar energy reflected by the observed target P. Menzel, 2007 Slide: 48 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Emissive Bands Used to observe terrestrial energy emitted by the Earth system in the IR between 4µm and 15 µm About 99% of the energy observed in this range is emitted by the Earth Only 1% is observed below 4 µm At 4 µm the solar reflected energy can significantly affect the observations of the Earth emitted energy Slide: 49 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009 P. Menzel, 2007

Terminology of radiant energy Energy from the Earth Atmosphere over time is Flux Slide: 50 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Terminology of radiant energy Energy from the Earth Atmosphere over time is Flux which strikes the detector area Irradiance P. Menzel, 2007 Slide: 51 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Terminology of radiant energy Energy from the Earth Atmosphere over time is Flux which strikes the detector area Irradiance at a given wavelength interval Monochromatic Irradiance over a solid angle on the Earth Radiance observed by satellite radiometer P. Menzel, 2007 Slide: 53 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Terminology of radiant energy Energy from the Earth Atmosphere over time is Flux which strikes the detector area Irradiance at a given wavelength interval Monochromatic Irradiance over a solid angle on the Earth Radiance observed by satellite radiometer is described by The Planck function P. Menzel, 2007 Slide: 54 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Terminology of radiant energy Energy from the Earth Atmosphere over time is Flux which strikes the detector area Irradiance at a given wavelength interval Monochromatic Irradiance over a solid angle on the Earth Radiance observed by satellite radiometer is described by The Planck function can be inverted to P. Menzel, 2007 Brightness temperature Slide: 55 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Terminology of radiant energy Energy from the Earth Atmosphere over time is Flux which strikes the detector area Irradiance at a given wavelength interval Monochromatic Irradiance over a solid angle on the Earth Radiance observed by satellite radiometer is described by The Planck function can be inverted to P. Menzel, 2007 Brightness temperature Slide: 56 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Definitions of Radiation QUANTITY SYMBOL UNITS Energy dq Joules Flux dq/dt Joules/sec = Watts Irradiance dq/dt/da Watts/meter 2 Monochromatic dq/dt/da/dω W/m 2 /micron Irradiance or dq/dt/da/dω W/m 2 /cm -1 Radiance δθ/δτ/δα/δμ/δω W/m 2 /micron/ster or dq/dt/da/dμ/dω W/m 2 /cm -1 /ster Slide: 57 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009 P. Menzel, 2007

Spectral Characteristics of Energy Sources and Sensing Systems Slide: 58 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009 P. Menzel, 2007

Spectral Characteristics of Energy Sources and Sensing Systems 4 µm Slide: 59 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009 P. Menzel, 2007

Spectral Characteristics of Energy Sources and Sensing Systems IR 4 µm 11 µm Slide: 60 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009 P. Menzel, 2007

Planck s Law B λ = λ 5 2 hc (exp( hc ( k λ T)) 1) 2 B B ν = 2 h ν c 2 (exp( h ( k T )) 1) ν 3 B k B T h B κ = 2hc κ (exp( hc ( k T )) 1) κ = Boltzmann s constant of entropy = Temperature = Planck s number 2 3 Slide: 61 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009 B

Temperature Sensitivity of B(λ,T) for typical Earth scene temperatures B (λ, T) / B (λ, 273K) 4μm 2 6.7μm 10μm 15μm 1 microwave 200 250 300 Temperature (K) Slide: 62 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009 P. Menzel, 2007

Rayleigh-Jeans Law T hc << kt B = 2k c λ B 4 Valid in the Microwave Range (λ=0.5 cm, T = 300 K) λ Slide: 63 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Integrating Planck s Law... F = σt 4 Stefan-Boltzmann Law σ = Stefan-Boltzmann-Constant λ = max 1 2898μmK T Wien s Displacement Law Slide: 64 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Spectral Distribution of Energy Radiated from Blackbodies at Various Temperatures Slide: 65 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009 P. Menzel, 2007

Brightness temperatures (radiance temperatures (RT) equivalent blackbody temperatures (EBBT)) c = 2hc 1 hc c = 2 k B 2 T = λ c 2 c ln 1 5 λ B λ + 1 Slide: 66 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Spectral Properties of Matter Slide: 67 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Menzel, 2000 Slide: 68 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Soil Vegetation Snow Ocean P. Menzel, 2007 Slide: 69 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Menzel, 2000 Slide: 70 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Earth emitted spectra overlaid on Planck function envelopes O3 CO2 H20 CO2 Slide: 71 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Radiative Transfer Slide: 72 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Processes involved Absorption Emission Reflection Scattering Slide: 73 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Absorption and Emission Planck s Law determines the maximum possible radiation, which an object can emit at a wavelength λ Emissivity at a wavelength λ is defined as ε λ = R B λ λ hence the ratio between really emitted radiation and the black body radiation Emissivity reaches from 0 to 1 Slide: 74 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Emissivity A blackbody has ε λ = 1 A grey body has ε λ = const A selective radiator has ε λ = function (λ ) Slide: 75 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Radiation on an absorbing media Incoming radiation I λ Slide: 76 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Radiation on an absorbing media Incoming radiation I λ Transmitted τ λ I λ Slide: 77 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Radiation on an absorbing media Reflected r λ I λ Incoming radiation I λ Transmitted τ λ I λ Slide: 78 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Radiation on an absorbing media Reflected r λ I λ Incoming radiation I λ Transmitted τ λ I λ Emitted ε λ B λ (T) Slide: 79 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Conservation of energy in local thermodynamic equilibrium (LTE) requires a λ I λ = I λ r λ I λ τ I λ λ or a λ + r + τ λ λ = 1 Slide: 80 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Atmospheric Absorption of Radiation Absorption coefficient di λ = k I Source: CNES Slide: 81 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA λ Course 23 April 2009 λ ρ sec φ dz

Integration from z to the top of the Atmosphere ( ) ln I λ I λ ln I λ = = I λ sec φ z exp( k u) λ k λ udz Beer s Law where z u = sec φ ρdz k u = δ λ λ often called optical depth Slide: 82 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Transmission and Absorption τ λ = I I λ λ = exp( k u) λ Transmission of a layer above z a = 1 τ = 1 exp( k u) λ λ λ Absorption (no scattering) of a layer above z Slide: 83 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Scattering Slide: 84 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Equation of radiative transfer (RTE) (No Scattering) L λ, ζ = 1 * [ ε ( ) exp( ) 0 μ 2 λ, ζ B λ T δ λ Radiation emitted from the surface, transmitted to the satellite Slide: 85 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Equation of radiative transfer (RTE) (No Scattering) + p p Sat 0 B L λ, ζ λ ( T = 1 * [ ε ( ) exp( ) 0 μ 2 λ, ζ B λ T δ λ Radiation emitted from the surface, transmitted to the satellite ) exp( ( δ * λ δ λ ( p)) Emission of the Atmosphere μ ) dδ λ ( p) μ Slide: 86 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Equation of radiative transfer (RTE) (No Scattering) + + p p Sat 0 B L λ, ζ λ ( T = 1 * [ ε ( ) exp( ) 0 μ 2 λ, ζ B λ T δ λ Radiation emitted from the surface, transmitted to the satellite ) exp( ( δ * λ δ λ ( p)) Emission of the Atmosphere p μ ) dδ λ ( p) 0 * 1 ε ) exp( μ B ( T ) exp( δ ( p) μ ) d ( p) μ λ, ζ δ λ λ λ δ λ ( ) p SAT μ Downwelling emission of the Atmosphere, reflected at the surface and transmitted to the satellite Slide: 87 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Equation of radiative transfer (RTE) (No Scattering) + + p p Sat 0 B L λ, ζ λ ( T = 1 * [ ε ( ) exp( ) 0 μ 2 λ, ζ B λ T δ λ Radiation emitted from the surface, transmitted to the satellite ) exp( ( δ * λ δ λ ( p)) Emission of the Atmosphere p μ ) dδ λ ( p) 0 * 1 ε ) exp( μ B ( T ) exp( δ ( p) μ ) d ( p) μ λ, ζ δ λ λ λ δ λ ( ) p SAT μ Downwelling emission of the Atmosphere, reflected at the surface and transmitted to the satellite * ( 1 ε ) exp( μ ) ( ) exp( * μ )] λ, ζ δ λ B λ T W δ + Emission of cold space, transmitted to the surface through the Atmosphere, reflected there and transmitted through the Atmosphere to the satellite λ Slide: 88 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Equation of radiative transfer (RTE) variables used ζ T o T W ε p p 0 p Sat δ μ = Polarization (horizontal (h) und vertical (v)) = Surface temperature = Temperature of space = Emissivity of the surface = Pressure = Surface pressure = Pressure at satellite level = Total optical depth of the atmosphere = Cosine of zenith angle Slide: 89 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Examples Slide: 90 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

1.6 µm image 0.86 µm image 11 µm image 3.9 µm image cloud mask Snow test (impacts choice of tests/thresholds) VIS test (over non-snow covered areas) 3.9-11 BT test for low clouds aa 11-12 BT test (primarily for high cloud) 13.9 µm high cloud test (sensitive in cold regions) MODIS cloud mask example Menzel, 2001 (confident clear is green, probably clear is blue, uncertain is red, cloud is white) Slide: 91 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Slide: 92 0.64 1.64 1.38 11.01 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Climate Applications Mean surface temperature in K for April,1987 Chédin et al., 1996 Slide: 93 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Climate Applications Mean surface temperature in K for April,1988 Chédin et al., 1996 Slide: 94 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Climate Applications El Nino, 1986-1987, Surface temperature anomaly for April 1987 in comparison with April 1988. Chédin et al. 1996 Slide: 95 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Climate Applications Mean surface temperature in K for June,1988 Chédin et al., 1996 Slide: 96 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Climate Applications Mean surface temperature in K for June,1989 Chédin et al., 1996 Slide: 97 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Climate Applications La Nina, 1988-1989, Surface temperature anomaly for June 1988 in comparison with June 1989. Chédin et al. 1996 Slide: 98 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Outlook Slide: 99 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Baroclinic Instability, caused by Ex-Hurrican Floyd Slide: 100 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

High Spectral Resolution Sounding Michelson Interferometer (FTS) d 1 Source Fixed Mirror Beam Splitter d2 Detector Moving Mirror Interferogram (d 2 -d 1 ) Fourier Transformation Numerical Inversion Smith Vertical Sounding Radiance Spectrum 2001 Fourier Transform Spectrometer - The Preferred Approach Slide: 101 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

Sounding will be discussed in the classroom-course at Langen Slide: 102 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009

EUMETSAT Monitoring weather and climate from space Thank you for your attention! Slide: 103 EUM/MET/VWG/09/0162 MET/DK The Physical Basics of Remote Sensing CENTRA Course 23 April 2009