GLOBAL BIASES IN THE DWELL-LINE MEAN STOKES PARAMETERS FROM SMOS FOR NOVEMBER 2010

Joe Tenerelli25 February 2011

SUMMARYTo produce the following slides we collected all reconstructed Stokes parameters for the original the November 2010 DPGS (not reprocessed data) files onto the fixed ISEA4H9 grid and computed, at each gridpoint on earth, the median of the dwell-line averaged bias between the ocean scene model and the SMOS brightness temperatures (SMOS - model).

We have done this for both the full L1OP results and the simplified JRECON solutions (as before using the same J+/baseline weights). For both DPGS and JRECON and for each polarization a fixed-in-time OTT is applied in director cosine coordinates before projecting the biases (SMOS - model) onto the fixed earth grid.

We have only used data in the AF-FOV.

Results suggest the following:

1. Differences between DPGS and JRECON are very small for the third and fourth Stokes parameters (less than 1 K in magnitude);

2. The fourth Stokes parameter exhibits biases up to around 1 K for ascending passes and beyond 3 K in for descending passes, suggesting some mixing of the third Stokes into the fourth Stokes parameter;

3. Significant land contamination exists in both DPGS and JRECON for the third and fourth Stokes parameters, suggesting that there is still a problem inherent in the reconstruction process (including effects of antenna pattern errors);

Third Stokes Parameter, Nov 2010 Ascending Passes

DPGS

Third Stokes Parameter, Nov 2010 Ascending Passes

JRECON

Third Stokes Parameter, Nov 2010 Ascending Passes

DPGS-JRECONDifferences in the third Stokes parameter are small and noisy and are probably related to differences in the way snapshots are combined.

Third Stokes Parameter, Nov 2010 Descending Passes

DPGS

Third Stokes Parameter, Nov 2010 Descending Passes

JRECON

Third Stokes Parameter, Nov 2010 Descending Passes

DPGS-JRECONDifferences in the third Stokes parameter are small and noisy and are probably related to differences in the way snapshots are combined.

Fourth Stokes Parameter, Nov 2010 Ascending Passes

DPGS

Fourth Stokes Parameter, Nov 2010 Ascending Passes

JRECON

Fourth Stokes Parameter, Nov 2010 Ascending Passes

DPGS-JRECONDifferences in the fourth Stokes parameter are small and noisy and are probably related to differences in the way snapshots are combined.

Fourth Stokes Parameter, Nov 2010 Descending Passes

DPGS

Fourth Stokes Parameter, Nov 2010 Descending Passes

JRECON

Fourth Stokes Parameter, Nov 2010 Descending Passes

DPGS-JRECONDifferences in the fourth Stokes parameter are small and noisy and are probably related to differences in the way snapshots are combined.

First Stokes Parameter, Nov 2010 Ascending Passes

DPGS

First Stokes Parameter, Nov 2010 Ascending Passes

JRECONThere is still land contamination in the simplified reconstructions of the first Stokes parameter, though it is smaller in magnitude, closer to the coastlines, and typically of opposite sign to that obtained from DPGS L1B.

First Stokes Parameter, Nov 2010 Descending Passes

DPGS

First Stokes Parameter, Nov 2010 Descending Passes

JRECONThere is still land contamination in the simplified reconstructions of the first Stokes parameter, though it is smaller in magnitude, closer to the coastlines, and typically of opposite sign to that obtained from DPGS L1B.