1 / 29

FIRE IMPACT ON SURFACE ALBEDO SEASONAL CYCLE

FIRE IMPACT ON SURFACE ALBEDO SEASONAL CYCLE. Yves Govaerts. METEOSAT INSTRUMENT CHARACTERISTICS. Channels Visible (VIS) : 0.4 - 1.0 m Water Vapour : 5.7 - 7.1 m Infrared : 10.5 - 12.5 m. 2 VIS detectors. Image repeat cycle : 30 min. Satellite observation.

thora
Download Presentation

FIRE IMPACT ON SURFACE ALBEDO SEASONAL CYCLE

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. FIRE IMPACT ON SURFACE ALBEDO SEASONAL CYCLE Yves Govaerts

  2. METEOSAT INSTRUMENT CHARACTERISTICS Channels Visible (VIS) : 0.4 - 1.0 m Water Vapour : 5.7 - 7.1 m Infrared : 10.5 - 12.5 m 2 VIS detectors Image repeat cycle : 30 min

  3. Satellite observation Space borne sensors sample BRFs ! METEOSAT SURFACE ALBEDO Surface albedo definition Directional Hemispherical Reflectance (DHR) BRF: Bidirectional Reflectance Factor

  4. Sensor Slot n+3 Slot n+2 Slot n+1 Slot n+ Slot n Absorbing atmosphere Scattering atmosphere The METEOSAT measurements Anisotropic surface

  5. METEOSAT as a Virtual Multi-angle sensor • Assumptions • Atmosphere is composed of one absorbing gas layer and one scattering layer • US62 atmospheric profile • Continental aerosol type • Atmospheric and surface scattering properties are constant along the day • Surface scattering properties can be represented by the RPV BRF model Reciprocity principle Sensor Sensor Sensor Sensor Slot n+3 Slot n+2 Slot n+1 Slot n+ Slot n Absorbing atmosphere Parameters • Model : • ozone (TOMS) • Total column water vapour (ECMWF) • Retrieved : • Equivalent aerosol optical thickness (1) • surface anisotropy (3) Scattering atmosphere One final product is generated every 10 days in order to minimise the cloud effects. Anisotropic surface

  6. METEOSAT SURFACE ALBEDO PROCESSED AREA(S)

  7. APPLICATIONS 1996 Early Januray 0.0 Early March 0.3 0.6 Early April Pinty, B., et al. (2000) Surface albedo retrieval from Meteosat: Part 2: Applications, Journal of Geophysical Research, 105, 18113-18134.

  8. Surface albedo change in the Meteosat VIS band as a function of the vegetation amount over different soil types. Monsoon-induced cycle of surface albedo APPLICATIONS SURFACE ALBEDO SEASONAL DYNAMICS Pinty, B.et al. (2000) Do Human-induced Fires Affect the Earth Surface reflectance at Continental Scales?, EOS Transactions of the AGU, 81, 381-389.

  9. SURFACE ALBEDO CHANGE MECHANISM Dry season Dry season DAYS OF 1996

  10. Human perturbed cycle Active fire for December 1996 SURFACE ALBEDO CHANGE MECHANISM Decrease Increase Change from November to January Change from January to April Pinty, B., Verstraete, M.M., Gobron, N., Govaerts, Y., and Roveda, F. (2000) Do Human-induced Fires Affect the Earth Surface reflectance at Continental Scales?, EOS transactions of the AGU, 81, 381-389.

  11. Fire-induced perturbation Vegetation re-growth FIRE IMPACT ON SURFACE ALBEDO North Hemisphere Dry season Dry season DAYS OF 1996

  12. Fire-induced perturbation Vegetation re-growth FIRE IMPACT ON SURFACE ALBEDO North Hemisphere Dry season Dry season DAYS OF 1996

  13. Low albedo values resulting from a decrease 3 High albedo values 1 Low albedo values 2 Probability of dark (burnt) surface FIRE IMPACT IDENTIFICATION The probability of a fire-induced surface albedo perturbation is estimated with a combination of 3 tests DAYS OF 1996

  14. FIRE IMPACT IDENTIFICATION Probability of fire-induced surface albedo perturbation South Hemisphere North Hemisphere

  15. FIRE IMPACT IDENTIFICATION Probability of fire-induced surface albedo perturbation South Hemisphere North Hemisphere

  16. FIRE IMPACT EVALUATION : EXPRESSO Number of active fires detected over the EXPRESSO area in November 1996 in each corresponding Meteosat pixel.

  17. Active fires detected with AVHRR FIRE IMPACT EVALUATION : DHR(30) Meteosat Surface Albedo over the EXPRESSO area mid November 1996

  18. FIRE IMPACT EVALUATION Probability of fire-induced surface albedo perturbation over the EXPRESSO area November 1996

  19. Active fires detected with AVHRR FIRE IMPACT EVALUATION Burned area map based on AVHRR data over the EXPRESSO region in November 1996 WHEN?

  20. FIRE IMPACT EVALUATION Comparison with the AVHRR-based burned area map

  21. FIRE IMPACT EVALUATION Correlation with the number of active fires detected with AVHRR Probability of fire-induced perturbation Percentage of burned pixel (AVHRR)

  22. Probability of fire-induced surface albedo perturbation over the EXPRESSO area

  23. 1996 Prototype Unprocessed pixels due to clouds

  24. 2000

  25. 2001

More Related