C. Grassotti

Oct 31, 2008

Comparison of MIRS Sea Ice Concentration and Snow Water Equivalent Retrievals with

AMSR-E Daily Products

C. Grassotti, C. Kongoli, and S.-A. Boukabara

C. Grassotti

Oct 31, 2008

MIRS-AMSR Products Comparison

• Initial preliminary comparison with AMSR-E Level 3 Daily Products (SIC and SWE) on 20 October 2008

• AMSR-E SIC: p.s. projection, 12.5 km resolution- 2 algorithms: NASA Team2, and Bootstrap- 3 products: Daily, Ascending, Descending

• AMSR-E SWE: Polar EASE projection, 25 km resolution

• Data remapped to common grid for intercomparison

C. Grassotti

Oct 31, 2008

Sea Ice Concentration

C. Grassotti

Oct 31, 2008

Sea Ice Concentration: MetopA vs. AMSR

AMSR MIRS

MIRS - AMSR

• Negative differences north of Siberia and Alaska (new or fy ice?)

C. Grassotti

Oct 31, 2008

Sea Ice Concentration: N18 vs. AMSR

AMSR MIRS

MIRS - AMSR

• Negative differences north of Siberia and Alaska (new or fy ice?)

C. Grassotti

Oct 31, 2008

Sea Ice Concentration: F16 vs. AMSR

AMSR MIRS

MIRS - AMSR

• Negative differences more extensive

C. Grassotti

Oct 31, 2008

AMSR SIC: NASA Team 2 vs. Bootstrap

Daily Ascending

Descending

• NASA Team 2 much greater along ice edge

C. Grassotti

Oct 31, 2008

AMSR SIC: NASA Team 2 vs. Bootstrap

Daily Ascending

Descending

• NASA Team 2 higher at ice edge, lower over thicker icepack

C. Grassotti

Oct 31, 2008

Snow Water Equivalent

C. Grassotti

Oct 31, 2008

Snow Water Equivalent: MetopA vs. AMSR

AMSR MIRS

MIRS - AMSR

• Snow covered areas agree approximately

• Little apparent bias, but large differences locally

C. Grassotti

Oct 31, 2008

Snow Water Equivalent: N18 vs. AMSR

AMSR MIRS

MIRS - AMSR

• Snow covered areas agree aproximately

• Little apparent bias, but large differences locally

C. Grassotti

Oct 31, 2008

Snow Water Equivalent: F16 vs. AMSR

AMSR MIRS

MIRS - AMSR

• Snow covered areas less than AMSR

• Large positive differences where both detect snow cover

C. Grassotti

Oct 31, 2008

Summary

• MIRS N18 and MetopA SIC and SWE retrievals in relatively good agreement with AMSR, and with each other (TBD: dependence on AMSR validation product, e.g. NASA Team 2 vs. Bootrap, seasonal dependence, etc.)

• AMSR: NASA Team 2 higher SIC vs. Bootstrap near ice edge

• MIRS F16 retrievals significant underestimation of SIC in NH

• MIRS F16 SWE retrievals problematic: undetected AMSR snow-covered areas and overestimation in areas where both agree

• F16 issues: Emissivity catalogs different for F16 vs. Metop and NOAA (scanning and polarization differences). Suggests use of spectral gradients rather than absolute magnitudes? Resolution a high priority.

• AMSR products not absolute validation, but good first step toward independent assessment