Roger De Abreu, Matt Arkett, Dean Flett Canadian Ice Service Pablo Clemente-Colón, Sean Helfrich, Brian Melchior U.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 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, 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

R-1Beaufort Sea :00:21SWBHH

PALSAR Beaufort Sea :41:12WB1HH

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-PALSAR RADARSAT-1

R-1Beaufort Sea :00:21SWBHHR-1Baffin Bay :14:27SWAHH

PALSAR Baffin Bay :13:57WB1HH

North American Ice Service De Abreu et al. IICWG VIII – Frascati, Italy July 15/ Summer FYI - MYI ALOS-PALSAR 2:13:57 UTC RADARSAT-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

R-1Beaufort Sea :00:21SWBHH

North American Ice Service De Abreu et al. IICWG VIII – Frascati, Italy PALSAR Beaufort Sea :41:12WB1HH

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, :14:27 SWA HH R-1 Feb. 25, :56 SWB

North American Ice Service De Abreu et al. IICWG VIII – Frascati, Italy R-1 July 15, :14:27 SWA HH PALSAR July 16, :13:57 WB1 HH

North American Ice Service De Abreu et al. IICWG VIII – Frascati, Italy R-1 July 15, :14:27 SWA HH PALSAR July 16, :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 Extra Slides

North American Ice Service De Abreu et al. IICWG VIII – Frascati, Italy Analysis Objectives Separately 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 Methodology 1.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

North American Ice Service De Abreu et al. IICWG VIII – Frascati, Italy C-band modelled and observed backscatter Nghiem, JPL, 2007