www.argans.co.uk

SMOS L2 Ocean Salinity

Level 2 Ocean Salinity

13-14 September 2010

ARGANS & L2OS ESL

www.argans.co.uk

SMOS L2 Ocean Salinity

• Wind speed retrieval in Model 1 without retrieving wind direction;• Dual from Full versus Full from Full ;• EAFFOV versus AFFOV versus small xi-eta;• Increasing threshold for valid number of measurements;• Appendix;

www.argans.co.uk

SMOS L2 Ocean Salinity

Model_1 retrieving WSn instead of UN10 and VN10

www.argans.co.uk

SMOS L2 Ocean Salinity

Model_1 retrieving WSn instead of UN10 and VN10

• Contents

www.argans.co.uk

SMOS L2 Ocean Salinity

Model_1 retrieving WSn instead of UN10 and VN10

www.argans.co.uk

SMOS L2 Ocean Salinity

Model_1 retrieving WSn instead of UN10 and VN10

• Contents

www.argans.co.uk

SMOS L2 Ocean Salinity

Model_1 retrieving WSn instead of UN10 and VN10

• Contents

www.argans.co.uk

SMOS L2 Ocean Salinity

Model_1 retrieving WSn instead of UN10 and VN10

• Better rate of successful retrievals for the modification of Roughness Model 1 not retrieving wind direction;

• Much better convergence for the model with fixed wind direction;• Model 1 with fixed wind direction slightly better correlates with Model 2;• Retrieved Wind Speed for Model 1 with variable wind direction closer to

ECMWF initial data;• Recommend using Model 1 with fixed wind direction

www.argans.co.uk

SMOS L2 Ocean Salinity

Dual from Full versus Full from Full

www.argans.co.uk

SMOS L2 Ocean Salinity

Dual from Full versus Full from Full

www.argans.co.uk

SMOS L2 Ocean Salinity

Dual from Full versus Full from Full

• Contents

www.argans.co.uk

SMOS L2 Ocean Salinity

Dual from Full versus Full from Full

• More successful retrievals for Full-from-Full (FF): 74% instead of 69 %;• Better convergence for FF; there are more points failed to reach

convergence for DF;• Better chi2 results for FF;• TEC retrieval for FF has lower cross-track bias;

• Recommend using Full Pol from Full Pol rather than Dual Pol from Full Pol;

www.argans.co.uk

SMOS L2 Ocean Salinity

EAFFOV vs AFFOV vs small xi-eta

www.argans.co.uk

SMOS L2 Ocean Salinity

EAFFOV vs AFFOV vs small xi-eta

• Contents

www.argans.co.uk

SMOS L2 Ocean Salinity

EAFFOV vs AFFOV vs small xi-eta

#GP: 64790, 40733, 34467

www.argans.co.uk

SMOS L2 Ocean Salinity

EAFFOV vs AFFOV vs small xi-eta

www.argans.co.uk

SMOS L2 Ocean Salinity

EAFFOV vs AFFOV vs small xi-eta

• Contents

www.argans.co.uk

SMOS L2 Ocean Salinity

EAFFOV vs AFFOV vs small xi-eta

• Reducing field of view decreases edge effects but does not eliminate them completely;

• Changing field of view does not affect significantly grid point distribution against chi2;

• Reducing field of view improves chi2 values, in particularly near the edges, but the edge effect is still well seen;

• Recommend not using AFFOV or xieta reduced instead of EAFFOV;

www.argans.co.uk

SMOS L2 Ocean Salinity

Increasing threshold for valid number of measurements

Extended AFFOVThreshold: 16(“min”); 30 (“low”); 50; 75

www.argans.co.uk

SMOS L2 Ocean Salinity

Increasing threshold for valid number of measurements

Extended AFFOVThreshold: 16(“min”); 30 (“low”); 50; 75

www.argans.co.uk

SMOS L2 Ocean Salinity

Increasing threshold for valid number of measurements

AFFOVThreshold: 16(“min”); 30 (“low”); 50; 75

www.argans.co.uk

SMOS L2 Ocean Salinity

Increasing threshold for valid number of measurements

• Increasing threshold Tg_num_meas_valid sharply improves quality of results: edge effects and East-West bias are practically eliminated with a proper threshold;

• Increasing Tg_num_meas_valid reduces amount of available gridpoints, especially after the threshold exceeds 80-100; compromise value of the threshold should be selected, about 50-60;

• Effect of increasing Tg_num_meas_valid is much stronger than redaction of the field of view, from the point of reducing biases and edge effects; if we have to use FOV reduction, it could be more efficiently used in combination with increased Tg_num_meas_valid;

• Recommend increasing Tg_num_meas_valid initially to 50;

www.argans.co.uk

SMOS L2 Ocean Salinity

Appendix

All pictures in this presentation are apparently affected/contaminated by sun that is illustrated on this slide; some results look more affected than the others – in most cases this is defined only by the colour scale used;