roger de abreu, matt arkett, dean flett canadian ice service
DESCRIPTION
Evaluation of ALOS PALSAR for Operational Ice Monitoring Preliminary Observations. Roger De Abreu, Matt Arkett, Dean Flett Canadian Ice Service Pablo Clemente-Colón, Sean Helfrich, Brian Melchior U.S. National Ice Center. Outline. Overview of PALSAR L-Band Expectations - PowerPoint PPT PresentationTRANSCRIPT
Roger De Abreu, Matt Arkett, Dean FlettCanadian Ice Service
Pablo Clemente-Colón, Sean Helfrich, Brian MelchiorU.S. National Ice Center
Evaluation of ALOS PALSAR for
Operational Ice Monitoring
Preliminary Observations
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
• Overview of PALSAR• L-Band Expectations• Motivation, Obectives• Data Collection• Preliminary Observations• Final Words
Outline
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
PALSAR OverviewPALSAR Overview
• Launched October 2006• L-Band SAR PALSAR• Primary difference is wavelength• Strong basis for comparison of ScanSAR modes
ScanSAR Modes Only
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
Expectations for L-Band• Dierking and Busche (TGARS, 2006) -- Sea Ice Monitoring by L-
Band SAR: An Assessment Based on Literature and Comparisons of JERS-1 and ERS-1 Imagery
• L-Band and C-Band SAR Scattering Signature of Sea Ice for Operational Applications -- Son Nghiem, JPL, 2007.
• Very good at mapping ice deformation, e.g. ridges, rubble fields• Better penetration into sea ice could yield unique and
complementary information to C-band information• L-band signatures are significantly less sensitive to wet snow than
C-band • However, less capable of identifying thin ice and separating FYI
and MYI, especially at high incidence angles.
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
Study Objectives
• Identify what unique and complementary sea ice
information PALSAR can provide compared to C-band
SARs (focus on RADARSAT-1)• Identify the role(s) PALSAR data could play in NAIS
operational programs– Complementary role to RADARSAT?– Contingency role to C-band SARs?
• Better understand the potential for future multi-frequency SAR platforms/missions
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
Data Collection• Collect concurrent
RADARSAT-1/2 and PALSAR ScanSAR image pairs
• Collect seasonally over major operational ice regimes
• Collect under range of wind conditions
• Collect over various incidence angles and polarizations
• Where possible, collect in situ data to support analysis
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
Case Study Locations
• 4 case studies from two PALSAR and R-1 pairs
• All HH polarization
• Collected June 10 (spring) and July 15/16 (smmer)
• ASF Convert tool used to ingest and geoproject data
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
(9+ Thick FYI w/traces of old ice;
Vast floes)
• Rough interfloe areas more apparent in wet conditions in L-band• Thick FYI floes more easily identifiable in L-Band
June 10th 2007 Spring Thick FYI Regime
ALOS-PALSARRADARSAT-1
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
July 15/16 2007 Summer FYI - MYI
ALOS-PALSAR 2:13:57 UTCRADARSAT-1 22:14:27 UTC
• Floes appear much more homogeneous in R-1• PALSAR appears to provide considerable more contrast within
and between floes• Aids in identifying FYI and MYI concentrations
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, ItalyPALSAR Beaufort Sea 20070610 20:41:12 WB1 HH
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
June 10th 2007 – Mackenzie Delta
RADARSAT-1: 15:00:21 UTC
• Wet ice lost in clutter at C- band – Better at L-band• Need to understand the ocean clutter better
ALOS-PALSAR: 20:41:12 UTC
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
R-1 July 15, 2007 22:14:27 SWA HH R-1 Feb. 25, 2007 21:56 SWB
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
R-1 July 15, 2007 22:14:27 SWA HH PALSAR July 16, 2007 2:13:57 WB1 HH
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
R-1 July 15, 2007 22:14:27 SWA HH PALSAR July 16, 2007 2:13:57 WB1 HH
• L-band has better penetration in melt conditions• Improved separation of second year ice from FYI
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
Summary• Preliminary examination of summer scenes indicates
that PALSAR does appear to be “seeing” more of the ice surface under wet snow
• In melt conditions, when C-band monitoring is challenged, PALSAR appears to do a better job typing and characterizing ice.
• Better floe definition in FYI and MYI regimes• Better separation of FYI and MYI floes
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
Next Steps• Quantitatively characterize these differences • Involve ice analysts to further/validate visual assessment• Extend to PALSAR VV data• Incorporate R-2 data (HH/HV) and possibly TerraSAR X.• Collect field-validated datasets – e.g. Southern Beaufort
Sea – IPY CFL. • Focus on winter freeze-up and PALSAR’s ability to type
thin ice types• Collect and analyze Great Lakes dataset• Icebergs in ice
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
Acknowledgements
• CIS JAXA AO --- Evaluation of L-Band ScanSAR Data for Regional Ice Monitoring in Support of Navigation
• NESDIS/NIC AO
• Alaska SAR Facility – ALOS North American Node
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
Analysis ObjectivesSeparately and combined with C-band, assess PALSAR’s
ability to:• Separate sea ice from open water• Type (classify) sea ice over a broad range of thicknesses• Provide other information
– floe size, floe shape
– surface deformation
– surface melt conditions
Focus on situations where C-band does not work well• Spring and summer ice typing • Ice and water separation under windy conditions
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
Analysis Methodology1. Pre-launch assessment of L-band SAR based on
airborne data sets and backscatter modelling
Completed -- L-Band and C-Band SAR Scattering Signature of Sea Ice for Operational Applications -- Son Nghiem, JPL, 2007.
North American Ice Service
De Abreu et al.
IICWG VIII – Frascati, Italy
L-band modelled and observed backscatter
Nghiem, JPL, 2007