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EARLINET and Satellites: Partners for Aerosol Observations. Matthias Wiegner Universität München Meteorologisches Institut. (Satellites: spaceborne passive radiometry). RTE. Radiative transfer equation. Radiative transfer equation. radiance (upward). Radiative transfer equation.
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EARLINET and Satellites: Partners for Aerosol Observations Matthias Wiegner Universität München Meteorologisches Institut (Satellites: spaceborne passive radiometry)
RTE Radiative transfer equation
Radiative transfer equation radiance (upward)
Radiative transfer equation source function
Radiative transfer equation optical depth (=0 at top at atmosphere) zenith and azimuth angle of radiance
Source Fkt. Radiative transfer equation sourcefunction
Radiative transfer equation sourcefunction Single scattering albedo
Radiative transfer equation sourcefunction phase function
RTE Radiative transfer equation
Solution Radiative transfer equation Solution
Radiative transfer equation Solution contribution from atmosphere
Radiative transfer equation Solution contribution from surface
Radiance Dependences Radiance at satellite depends on phase function, single scattering albedo air molecules, aerosol particles, cloud droplets size, refractive index, shape; heightdependent and surface properties as the vertical coordinate is the optical depth, radiance also depends on the extinction coefficient
Link Radiance and aerosols: link optical and microphysical parameters of aerosols other atmospheric and surface parameters radiances at satellite sensor
Radiance and aerosols: link optical and microphysical parameters of aerosols other atmospheric and surface parameters retrieval algorithms radiances at satellite sensor
partnership EARLINET- satellite partnership optical and microphysical parameters of aerosols other atmospheric and surface parameters retrieval algorithms calibrated, validated, supplemented radiances at satellite sensor
IntroEnde This was the introduction Main topic of my talk How can we establish an „EARLINET-Satellite partnership“?
Possible contrib. overview Possible EARLINET contributions Groundtruthing Calibration and validation of satellite data and retrieval algorithms Supply of complementary information Consequence: Definition of the small workpackage „WP8“
Possible EARLINET contributions Groundtruthing Calibration and validation of satellite data and retrieval algorithms Supply of complementary information Consequence: Definition of the small workpackage „WP8“
Ground truth (cal/val) Use the EARLINET data-base averaged data (e.g., monthly means) „point by point“ intercomparisons (lidar measurements during an overpass)
Example (1) Examples of partnership Validation and calibration of MIPAS Focus on ozone (balloon) No aerosols intercomparions yet Status: waiting for overpasses Vincenzo Rizi et al., L'Aquila
Examples of partnership Validation and calibration of SAGE Focus on stratospheric aerosols Regular measurements began in summer 02 Status: ongoing, no final results Thomas Trickl et al., Garmisch-Partenkirchen
Examples of partnership Validation and calibration of MIPAS + GOMOS Focus on water vapour and aerosols Few overpasses, but no aerosol data Status: ongoing (waiting) Gelsomina Pappalardo et al., Potenza
GTCO Examples of partnership Validation and calibration of CHRIS Focus on land surfaces Four intensive field experiments scheduled near Gilching Project for On-Board Autonomy Small Satellite Mission Compact High Resolution Imaging Spectrometer MIM in co-operation with:
Examples of partnership Goal Full characterization of surface and atmosphere of exactly the same scene Requirements co-incidence, co-location, very small satellite pixel Acquisition mode CHRIS: 18 km swath, 25 m resolution, 19 spectral bands (0.4-1.05 µm), along track (5 angles) Time and place May to August 2002 in Gilching
Examples of partnership Results/Conclusions Satellite PROBA encountered severe problems: no data were available in summer 2002. A new intensive field experiment is uncertain MIM & GTCO
Supplementary Data Possible EARLINET contributions Groundtruthing Calibration and Validation of satellite data and retrieval algorithms Supply of complementary information Consequence: Definition of the small workpackage „WP8“
Relevant Aerosol Parameters Relevant (aerosol) parameters Aerosol optical depth Aerosol type Aerosol (vertical) distribution Surface albedo Solar zenith angle Fixed wavelength (532 nm)
A-Profiles Model calculations Vertical aerosol distribution: 5 cases (1) (2)(3)(4)(5)
Sensitivity profiles Change of Radiance as a function of aerosol optical depth for different aerosol profiles fixed aerosol type Difference of isotropic radiance at TOA, rel. to „no aerosol“-case
Change of Radiance different aerosol type
Change of Radiance different aerosol type
Change of Radiance different aerosol type
Change of Radiance different aerosol type
2-layer profiles Change of Radiance as a function of aerosol optical depth for different 2-layer aerosol profiles fixed aerosol type
Change of Radiance different aerosol type
Change of Radiance different aerosol type
Change of Radiance different aerosol type
Change of Radiance different aerosol type
Change of Radiance different layer width
Conclusions Simul. Conclusions from simulations Satellite radiances are significantly influenced by aerosols: -- optical depth -- aerosol type -- aerosol profile
Examples of partnership Aerosol vertical distribution is hardly retrievable from satellites EARLINET can provide this missing information Vertical aerosol distribution is relevant for local energy budget, hydrological cycle, validation of CTM, ecology,.... ...and satellite validation as well
Benefit: Results Benefit of partnership Results/Conclusions Aerosol profiles from more than 20 lidar stations, two times a week and for three years are available. Data and instruments have undergone QA. Validation of aerosol retrievals requires a careful selection of time and place, and averaging over reasonable periods. First co-operations are initiated. EARLINET can provide aerosol data that cannot be obtained from passive radiometry.