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Assessment of EOS Aqua AMSR-E Sea Ice Concentration Using MODIS. Emily Glick Research & Discover, GSFC Summer Intern 2008 Advisor: Donald J. Cavalieri, 614.1. What is sea ice?. Frozen seawater that floats on the ocean Found in polar regions: dark and cloudy
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Assessment of EOS Aqua AMSR-E Sea IceConcentration Using MODIS Emily Glick Research & Discover, GSFC Summer Intern 2008 Advisor: Donald J. Cavalieri, 614.1
What is sea ice? • Frozen seawater that floats on the ocean • Found in polar regions: dark and cloudy • Fluctuates according to polar seasons • Southern Hemisphere: Summer average of 1.1 million square miles, Winter average of 6.9 million square miles
Why is it important to study sea ice? Regulates exchanges of heat, moisture, and salinity in polar oceans Habitat for many species of animals High albedo; very sensitive to global change
Aqua MODIS • Great visual quality because of it's resolution • Can only be captured during the day • Picks up cloud cover Moderate Resolution Imaging Spectroradiometer Based on reflectance, or albedo
Aqua AMSR-E • Advanced Microwave Sensing Radiometer - Earth Observing System • Passive microwave technology • Much coarser resolution • Not dependent on time of day like MODIS • Doesn't pick up cloud cover • Our goal: validation & error analysis
Methods MODIS images - cloud mapping Threshold and ROI Put with AMSR-E and NT2 algorithm Polarization Ratio and Gradient Ratio Brightness Temperature: emissivity + surface temperature Output: spreadsheet of data for analysis
Antarctica Statistics (0550)1 October 2006 AMSR-E Pixels Covered By MODIS MODIS Ice Conc. Range Mean AMSR-E Ice Conc. Mean MODIS Ice Conc. AMSR Bias Relative to MODIS AMSR-MODIS RMS Diff. 528 0-100% 43.3% 68.4% -25.1% 30.0% Surface Type Surface Type Purity (%) (# of Pixels) AMSR-E Ice Conc. Mean+1SD MODIS Ice Conc. Mean+1SD AMSR Bias Relative to MODIS AMSR-MODIS RMS Diff. 100% Water 100% (67) 0.2 + 1.6% 2.2 + 3.4% -2.0% 4.1% New Ice > 80% (27) 56.3 + 12.6% 98.1 + 5.8% -41.8% 42.8% Young Ice > 80% (30) 77.8 + 12.6% 100.0 + 0.0% -22.2% 25.5% Young Ice 100% (3) 85.0 + 13.5% 100.0 + 0.0% -15.0% 18.6% FY Ice > 80% (41) 95.4 + 7.1% 99.9 + 0.2% -4.5% 8.3% FY Ice 100% (31) 96.6 + 5.4% 100.0 + 0.1% -3.4% 6.2% 100% Ice All Types 100% (210) 75.0 + 14.8% 99.8 + 0.8% -24.8% 28.8%
Antarctica Statistics (1050)1 October 2006 AMSR-E Pixels Covered By MODIS MODIS Ice Conc. Range Mean AMSR-E Ice Conc. Mean MODIS Ice Conc. AMSR Bias Relative to MODIS AMSR-MODIS RMS Diff. 864 96.0-100% 92.6% 99.9% -7.3% 9.2% Surface Type Surface Type Purity (%) (# of Pixels) AMSR-E Ice Conc. Mean+1SD MODIS Ice Conc. Mean+1SD AMSR Bias Relative to MODIS AMSR-MODIS RMS Diff. 100% Water 100% (0) - - - - New Ice > 80% (1) 53% 99.9% -46.9% - Young Ice > 80% (0) - - - - Young Ice 100% (0) - - - - FY Ice > 80% (623) 94.7 + 3.9% 100.0 + 0.2% -5.2% 6.5% FY Ice 100% (86) 98.1 + 2.4% 100.0 + 0.0% -1.9% 3.0% 100% Ice All Types 100% (808) 93.2 + 5.1% 100.0 + 0.1% -6.8% 8.4%
Antarctica Statistics (1725)1 October 2006 AMSR-E Pixels Covered By MODIS MODIS Ice Conc. Range Mean AMSR-E Ice Conc. Mean MODIS Ice Conc. AMSR Bias Relative to MODIS AMSR-MODIS RMS Diff. 3575 0-100% 98.5% 99.7% -1.2% 4.2% Surface Type Surface Type Purity (%) (# of Pixels) AMSR-E Ice Conc. Mean+1SD MODIS Ice Conc. Mean+1SD AMSR Bias Relative to MODIS AMSR-MODIS RMS Diff. 100% Water 100% (7) 0.0 + 0.0% 0.2 + 0.3% -0.2% 0.4% New Ice > 80% (1) 38.0 94.6 -56% - Young Ice > 80% (0) - - - - Young Ice 100% (0) - - - - FY Ice > 80% (3350) 99.3 + 1.8% 100.0 + 0.0% -0.7% 2.0% FY Ice 100% (1707) 99.5 + 1.3% 100.0 + 0.0% -0.5% 1.4% 100% Ice All Types 100% (3521) 99.0 + 3.2% 100.0 + 0.1% -1.0% 3.3%
Antarctica Statistics (1630)2 October 2006 AMSR-E Pixels Covered By MODIS MODIS Ice Conc. Range Mean AMSR-E Ice Conc. Mean MODIS Ice Conc. AMSR Bias Relative to MODIS AMSR-MODIS RMS Diff. 2038 87.4-100% 95.5% 99.9% -4.4% 9.0% Surface Type Surface Type Purity (%) (# of Pixels) AMSR-E Ice Conc. Mean+1SD MODIS Ice Conc. Mean+1SD AMSR Bias Relative to MODIS AMSR-MODIS RMS Diff. 100% Water 100% (0) - - - - New Ice > 80% (0) - - - - Young Ice > 80% (1) 62% 99.7% -37.7% - Young Ice 100% (0) - - - - FY Ice > 80% (1514) 98.1 + 4.2% 100.0 + 0.1% -1.9% 4.6% FY Ice 100% (405) 99.2 + 2.1% 100.0 + 0.0% -0.8% 2.2% 100% Ice All Types 100% (1930) 96.4 + 6.5% 100.0 + 0.2% -3.6% 7.4%
Antarctica Statistics (1805)2 October 2006 AMSR-E Pixels Covered By MODIS MODIS Ice Conc. Range Mean AMSR-E Ice Conc. Mean MODIS Ice Conc. AMSR Bias Relative to MODIS AMSR-MODIS RMS Diff. 5423 99.2-100% 99.6% 100.0% -0.4% 3.2% Surface Type Surface Type Purity (%) (# of Pixels) AMSR-E Ice Conc. Mean+1SD MODIS Ice Conc. Mean+1SD AMSR Bias Relative to MODIS AMSR-MODIS RMS Diff. 100% Water 100% (0) - - - - New Ice > 80% (0) - - - - Young Ice > 80% (0) - - - - Young Ice 100% (0) - - - - FY Ice > 80% (5153) 99.8 + 2.6% 100.0 + 0.0% -0.3% 2.6% FY Ice 100% (2519) 99.8 + 3.1% 100.0 + 0.0% -0.2% 3.2% 100% Ice All Types 100% (5403) 99.6 + 3.2% 100.0 + 0.0% -0.4% 3.2%
Antarctica Statistics (0550)1 October 2006 AMSR-E Pixels Covered By MODIS MODIS Ice Conc. Range Mean AMSR-E Ice Conc. Mean MODIS Ice Conc. AMSR Bias Relative to MODIS AMSR-MODIS RMS Diff. 528 0-100% 43.3% 68.4% -25.1% 30.0% Surface Type Surface Type Purity (%) (# of Pixels) AMSR-E Ice Conc. Mean+1SD MODIS Ice Conc. Mean+1SD AMSR Bias Relative to MODIS AMSR-MODIS RMS Diff. 100% Water 100% (67) 0.2 + 1.6% 2.2 + 3.4% -2.0% 4.1% New Ice > 80% (27) 56.3 + 12.6% 98.1 + 5.8% -41.8% 42.8% Young Ice > 80% (30) 77.8 + 12.6% 100.0 + 0.0% -22.2% 25.5% Young Ice 100% (3) 85.0 + 13.5% 100.0 + 0.0% -15.0% 18.6% FY Ice > 80% (41) 95.4 + 7.1% 99.9 + 0.2% -4.5% 8.3% FY Ice 100% (31) 96.6 + 5.4% 100.0 + 0.1% -3.4% 6.2% 100% Ice All Types 100% (210) 75.0 + 14.8% 99.8 + 0.8% -24.8% 28.8%
Conclusions • Large error could be unresolved weather, cloud cover, flooded ice, ... • Poor statistics for other images for comparison • More investigation needed for 0550 • Many more images will be looked at for the entire study to verify and validate AMSR-E
Questions? Thank you... Donald Cavalieri Alvaro Ivanoff George Hurtt Fellow R&D students