The VENμS mission: Earth Observation with High Spatial and Temporal Resolution Capabilities

Transcription

1 Ben Gurion University The VENμS mission: Earth Observation with High Spatial and Temporal Resolution Capabilities G. Dedieu 1, O. Hagolle 2, A. Karnieli 3, S. Cherchali 2 P. Ferrier 2 and Y. Yaniv 4 1 CESBIO, Toulouse Cedex 9, France 2 CNES Toulouse France 3 The Remote Sensing Laboratory, Ben Gurion Univ. of the Negev, Israel 4 MBT Space Division, Israel Aircraft Industries ISRAEL Mission scientists (PI's) : Gérard Dedieu & Arnon Kanieli

2 VENµS VENµS is an Earth observation scientific mission jointly developed by CNES, the French space agency, and ISA, the Israeli Space Agency Objectives : To provide data for research on land surface functioning : land cover & land use, water and carbon exchanges, snow Data assimilation Automatic land cover mapping Validation of medium resolution satellite products Demonstration of the use of RS data for the implementation of Environmental regulations (e.g. Grenelle laws in France) To investigate and demonstrate the benefit for Earth sciences and applications of high repetitivity, high resolution remotely sensed measurements acquired by a super spectral imaging radiometer To develop and experiment a dedicated ground segment able to deliver state of the art quality products

3 Why high temporal repetitivity? June 5 th 2006 June 14 th 2006 June 23 th 2006 June 29 th 2006 Formosat-2 images (rapeseed harvest, sunflower growth)

4 Indice foliaire 2006

5 VENµS Uniqueness - Summary Temporal resolution 2 days revisit time for monitoring rapid changes : objective of a cloud free (composite) image every 7 or 10 days Spectral resolution Super spectral sensor 12 spectral bands VIS-NIR for land applications Spatial resolution Pixel size of 5.3 m for Level 1, 10m for level 2 and 3. Registration requirement: 3 m rmse Tilting capability 30 deg across and along track View angle Constant view angle can be achieved every 2 days, at constant local solar time Stereo pairs with a small angle difference at 620nm Cloud screening based on altitude, DEM generation

6 Sun-synchronic LST : 10h30 Venµs Orbits DAY 1, 3, 5, 7 Altitude: 720 km Inclination: 98.27

7 Sun-synchronic LST : 10h30 Venµs Orbits DAY 2, 4, 6, 8 Altitude: 720 km Inclination: 98.27

8 Sun-synchronic LST : 10h30 Venµs Orbits 2 days cycle: day 1 & day 2 orbits Altitude: 720 km Inclination: 98.27

9 Venµs Acquisitions: tilting capability 30 along/across track

10 Venµs Orbits and observing capabilities 30 Tilt DAY 2 DAY 1 DAY 2 DAY 1

11 Venµs Orbits and observing capabilities 30 Tilt DAY 2 DAY 1 DAY 2 DAY 1

12 Sun-synchronic LST : 10h30 Venµs Orbits and observing capabilities Altitude: 720 km Inclination: 98.27

13 Swath: km VENµS Imaging capabilities Nominal requirements 50 sites of 27x 54 km + calibration and image quality sites 140 images of 27x27 km within 2 days (>20000/year) 30 images on the most demanding orbit Data strips longer than 54 km are feasible Angular sampling could be achieved for a few sites ( and pitch) 30 roll Moon viewing for calibration

14 Camera : Band Setting Simulated vegetation reflectances for 3 different Chlorophyl content

15 Band Setting (Requirements) Bands λ0 (μm) Δλ (nm) SNR for Lmin at 5.3GSD Required Resolution (meters) SNR for Lmin at resolution Main Driver B Aerosols B Aerosols, clouds B Aerosols B Land B Land B DEM, image quality B Land B Land B Land B Land B Land B Water vapor

16 Image quality Needs Spatial and temporal image composites that can be used over a whole area to monitor seasonal and interannual evolutions Need to provide consistent and homogeneous measurements through time and space, with physical meaning (reflectances) Requirements Geometrical registration (within bands 0.25pix, multitemporal 3m) Radiometric calibration (3-5%), knowledge of the spectral responses, and spectral stability Minimisation of perturbing effects : directional and atmospheric. Maximum shift of the time of overpass throughout the mission duration: lower than ± 5 minutes Constant view zenith angle ± 2 degrees

17 Ground segment : Products Level 1: single acquisition Geometrically corrected (maps) of top of the atmosphere reflectances. One map projection per site. Level 2: single acquisition, geophysical variables Surface reflectances, atmospheric water vapor content and aerosol optical depth Level 3 : time composite, geophysical variables Surface reflectances, atmospheric water vapor content and aerosol optical depth All the acquired images will be freely available by ftp less than 1 month after acquisitions

18 Sites selection Deadline for outline proposals of Venµs sites and data use was 28th june 2006 Proposals for additional sites are still considered, as second priority, if they are located in regions with little demands Simulation of sites acquisitions is being carried out : technical feasibility, trade-off scenarios Selection of the sites is still pending on technical issues The plan is to acquire images over the selected sites during the whole 2.5 years of the mission

19 Objective of the workshop Present the current status of the mission Present levels 2 and 3 algorithms and existing/forthcoming data-sets Illustrate the benefit of the mission by some examples Answer your questions Networking of scientists interested by the Venµs mission and more generally by high resolution/high repetitivity data Listen to your needs and requests Discussion on possible additional products or innovative uses Coordination of efforts in the frame of calls for proposals (Tosca, PNTS, Interreg, FP7, ) and Sentinel-2 preparation