An improved satellite-based long record ofAustralian vegetation dynamics: AVHRR NDVIIan Grant and Paul Loto’aniu (Bureau o...
What is NDVI?• Normalised Difference Vegetation Index• Satellite index of vegetation greenness   • Change in red/near-infr...
What is NDVI?• NDVI is influenced by both   • Plant vigour and health   • Vegetation cover fraction• NDVI indicates   • Bi...
What is NDVI?• Time series monitors seasonal vegetation dynamics• Enables spatial and interannual comparisons             ...
What is NDVI?• NDVI anomaly assesses departure of vegetation  condition from long-term mean for the month        Standard ...
NDVI on AusCoverBureau of Meteorology THREDDS server  • Monthly AVHRR NDVI  • 0.01° and 0.05°  • netCDF format
NDVI Applications•   Agricultural assessment•   Grazing land management•   Drought monitoring•   Hydrological modelling•  ...
NDVI ApplicationsHydrological modelling   • AVHRR NDVI converted to     leaf area index   • Time series tracks response   ...
Why improve AVHRR data?Long time series   • MODIS starts 2000 (to ~2015)   • AVHRR starts 1982 (to ~2020)Improve   • Spati...
Processing chain•   Reception•   Collation and reformatting•   Stitching•   Georeferencing•   Calibration•   Cloud masking...
Reception      DAR                  TWN            ALSPER                  CPT                   HOB
Processing chain•   Reception•   Collation and reformatting•   Stitching•   Georeferencing•   Calibration•   Cloud masking...
StitchingOrbit stitching• Reduce data volume• Improve quality
Processing chain•   Reception•   Collation and reformatting•   Stitching•   Georeferencing•   Calibration•   Cloud masking...
Compositing                                Merge data from several days toStitched orbits                                 ...
Processing chain•   Reception•   Collation and reformatting•   Stitching•   Georeferencing•   Calibration•   Cloud masking...
Processing chain•   Reception•   Collation and reformatting•   Stitching•   Georeferencing•   Calibration•   Cloud masking...
Processing chain - The past•   Reception•   Collation and reformatting•   Stitching•   Georeferencing•   Calibration•   Cl...
Processing chain – AusCover                  Phase 1•   Reception•   Collation and reformatting•   Stitching•   Georeferen...
Processing chain – AusCover                Phase 2•   Reception•   Collation and reformatting•   Stitching•   Georeferenci...
CalibrationUse NOAA cross-calibration results   • AVHRR vs MODIS   • AVHRR vs AVHRR   • Heidinger et al. 2010
Atmospheric correctionCSIRO scheme for atmospheric radiative transfer   •Mitchell and O’Brien (1993)Total column water vap...
Atmospheric correctionBefore            After
Immediate applicationsImmediate  • National Land Use map (ABARES)  • Hydrological modelling (BoM)  • National grassland cu...
Upcoming SlideShare
Loading in...5
×

Ian Grant_An improved satellite-based long record of Australian vegetation dynamics: AVHRR NDVI

146

Published on

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
146
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
0
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide
  • 2006-03-18 05:04 UT
  • Ian Grant_An improved satellite-based long record of Australian vegetation dynamics: AVHRR NDVI

    1. 1. An improved satellite-based long record ofAustralian vegetation dynamics: AVHRR NDVIIan Grant and Paul Loto’aniu (Bureau of Meteorology, AusCover)Rob Smart (ABARES)Presentation by Ian Grant, Bureau of Meteorology
    2. 2. What is NDVI?• Normalised Difference Vegetation Index• Satellite index of vegetation greenness • Change in red/near-infrared contrast Blue Red Infrared
    3. 3. What is NDVI?• NDVI is influenced by both • Plant vigour and health • Vegetation cover fraction• NDVI indicates • Biomass production
    4. 4. What is NDVI?• Time series monitors seasonal vegetation dynamics• Enables spatial and interannual comparisons Arid Agricultural
    5. 5. What is NDVI?• NDVI anomaly assesses departure of vegetation condition from long-term mean for the month Standard deviations from 17-year mean
    6. 6. NDVI on AusCoverBureau of Meteorology THREDDS server • Monthly AVHRR NDVI • 0.01° and 0.05° • netCDF format
    7. 7. NDVI Applications• Agricultural assessment• Grazing land management• Drought monitoring• Hydrological modelling• National Carbon Accounting System• National Agricultural Monitoring System (NAMS) • Assess Exceptional Circumstances drought assistance• Water balance modelling
    8. 8. NDVI ApplicationsHydrological modelling • AVHRR NDVI converted to leaf area index • Time series tracks response of forested catchment to disturbance (bushfire, clearing, …)
    9. 9. Why improve AVHRR data?Long time series • MODIS starts 2000 (to ~2015) • AVHRR starts 1982 (to ~2020)Improve • Spatial and temporal consistency • Consistency with MODISNot just NDVI • Surface reflectance in two bands: Red & NIR • NDVI = (NIR – Red) / (NIR + Red) • Albedo ≈ (NIR + Red) / 2  Climate and water models • Biophysical variables: fAPAR, LAI
    10. 10. Processing chain• Reception• Collation and reformatting• Stitching• Georeferencing• Calibration• Cloud masking• Atmospheric correction (needs atmospheric parameters)• Compositing OR Angular normalisation
    11. 11. Reception DAR TWN ALSPER CPT HOB
    12. 12. Processing chain• Reception• Collation and reformatting• Stitching• Georeferencing• Calibration• Cloud masking• Atmospheric correction (needs atmospheric parameters)• Compositing OR Angular normalisation
    13. 13. StitchingOrbit stitching• Reduce data volume• Improve quality
    14. 14. Processing chain• Reception• Collation and reformatting• Stitching• Georeferencing• Calibration• Cloud masking• Atmospheric correction (needs atmospheric parameters)• Compositing OR Angular normalisation
    15. 15. Compositing Merge data from several days toStitched orbits • Complete spatial coverage • Fill gaps due to cloud • Reject residual cloud Compositing National coverage
    16. 16. Processing chain• Reception• Collation and reformatting• Stitching• Georeferencing• Calibration• Cloud masking• Atmospheric correction (needs atmospheric parameters)• Compositing OR Angular normalisation
    17. 17. Processing chain• Reception• Collation and reformatting• Stitching• Georeferencing• Calibration• Cloud masking• Atmospheric correction (needs atmospheric parameters)• Compositing OR Angular normalisation
    18. 18. Processing chain - The past• Reception• Collation and reformatting• Stitching• Georeferencing• Calibration• Cloud masking• Atmospheric correction• Compositing OR Angular normalisation
    19. 19. Processing chain – AusCover Phase 1• Reception• Collation and reformatting• Stitching• Georeferencing• Calibration (improved)• Cloud masking• Atmospheric correction• Compositing OR Angular normalisationFirst application of atmospheric correction to Australia’s AVHRR stitched archive
    20. 20. Processing chain – AusCover Phase 2• Reception• Collation and reformatting• Stitching• Georeferencing• Calibration (improved)• Cloud masking (improved)• Atmospheric correction• Compositing OR Angular normalisation
    21. 21. CalibrationUse NOAA cross-calibration results • AVHRR vs MODIS • AVHRR vs AVHRR • Heidinger et al. 2010
    22. 22. Atmospheric correctionCSIRO scheme for atmospheric radiative transfer •Mitchell and O’Brien (1993)Total column water vapour Aerosol Optical Depth • Numerical weather model • Chemical transport model • European Reanalysis (ERA) • ECMWF/MACC Interim • Validated against • Validated against radiosondes sunphotometers
    23. 23. Atmospheric correctionBefore After
    24. 24. Immediate applicationsImmediate • National Land Use map (ABARES) • Hydrological modelling (BoM) • National grassland curing and fire danger index historyThen? • National evapotranspiration history • National carbon flux history • Also, reflectance and albedo

    ×