CHRIS PROBA instrument

Transcription

1 CHRIS PROBA instrument Wout Verhoef ITC, The Netherlands 29 June 2009, D1L5

2 Contents Satellite and instrument Images Multi-angular analysis Toolbox

3 CHRIS-PROBA PROBA-CHRIS Project for On-Board Autonomy CHRIS (Compact High Resolution Imaging Spectrometer) is an AO hyperspectral instrument whose objective is the collection of BRDF (Bidirectional Reflectance Distribution Function) data for a better understanding of spectral reflectances. CHRIS is the prime instrument of the PROBA mission. The technology objective is to explore the capabilities of imaging spectrometers on agile small satellite platforms.

4 Satellite PROBA satellite

5 Instrument CHRIS (Compact High Resolution Imaging Spectrometer)

6 Images China's Three Gorges dam - CHRIS image, 30 July 2003

7 Images Proba image of the Gobi Desert in China

8 Georeferenced nadir acquisitions Upper Rhine Valley test-site March June July August , 713, 781 nm Source: Heike Bach, 2005

9 Spectral signatures, Upper Rhine Valley Measured nadir spectra of different land covers (Aug 03): 60 reflectance [%] maize tobacco potato miscanthus forest 50 Development of maize in 2003 (nadir spectra): wavelength [nm] Source: Heike Bach, 2005 reflectance [%] wavelength [nm]

10 Comparison with SLC simulation results Maize; Upper Rhine Valley, Aug 2003 Maize, Aug 03 (1 pixel, no smoothing) Maize, Aug 03 (simulated) Reflectance [%] Reflectance [%] Wavelength [nm] Wavelength [nm] Soil moisture: 5%; leaf chlorophyll: 40 µg/cm², LAI = 4.0, leaf water content: 0.02 g/cm², fraction brown: 35% optimised to nadir spectrum Source: Heike Bach, 2005

11 Measured and Simulated BRDF for Maize Anisotropy plots BRDF factor related to nadir BRDF, Maize, angle [ ] BRDF factor related to nadir BRDF, Maize, , simulated, LAI = 5, Cab = angle [ ] LIDF a = b = Source: Heike Bach, 2005

12 Toolbox CHRIS/Proba Toolbox Status Quo

13 Toolbox Module Implementation Module Features Specification / ATBD Implementation Reader RCI data and metadata import, mask refinement, cosmetic dropout correction Completed Completed Noise Reduction Slit correction, removal of vertical striping, dropout correction Completed Completed Cloud Screening TOA reflectance calculation, feature extraction, unsupervised cluster analysis, manual cluster labelling, probabilistic cloud mask calculation Completed Completed - GUI improvements in progress Atmospheric Correction AOD retrieval (per scene) for land and water, surface reflectance and water vapour column calculation Completed Completed Geometric Correction Geographic coregistration of different looks Going to be completed by 2nd week of Oct Pending the ATBD, going to be completed by end of Nov Aerosol Retrieval AOD retrieval (per pixel) for land Completed Cancelled

14 Toolbox Module Characteristics 1. Reader Reads all CHRIS/PROBA RCI data, quality mask data and metadata Performs on-the-fly mask refinement and cosmetic dropout correction Fully integrates CHRIS/PROBA products into the BEAM/VISAT environment 2. Noise Reduction Operates on either single scenes or acquisition set Removes noise and dropout artefacts almost completely Batch mode capable 3. Cloud Screening Operates on the noise-corrected product Interactive cloud labelling Produces either a binary mask (cluster analysis) or a probabilistic mask (spectral unmixing) 4. Atmospheric Correction Operates on the noise-corrected product, takes into account cloud mask Per scene AOD retrieval for land and water Smile correction for modes 1 and 5 Produces surface reflectance (and water vapour map for modes 1, 3, and 5) Optionally applies adjacency correction Optionally applies spectral polishing 5. Geometric Correction Requires CHRIS metadata, telemetry, ground control points Calculates latitude, longitude and viewing angles per pixel

15 Toolbox Some Screenshots

16 Toolbox More Screenshots

17 Thanks for your attention!