Global product vs regional product

Lively Data, January 16, 2009

The LAS provides a regional product for the Mediterranean Sea with some parameters  optimized for the Mediterranean signal  characteristics.

This Ssalto/Duacs regional multi-mission processing includes a higher spatial resolution than global products, an adapted filtering in order to reduce noise, an adjustment of parameters for the data selection area, etc., improving the data quality and the mapping procedure. Furthermore, the presence of islands and complex coastlines was taken into account to eliminate coastal data with invalid measurements, or to improve the corrections near the coasts.

Maps of Sea Level Anomalies (SLA) in cm the October 31, 2007 with the difference between the Regional Product (Mediterranean Sea) and the Global product for the Delayed time data (left) and the Near-Real Time data (right). For the DT map (left), select "Compare two" option, then  DT - Mediterranean - (Maps of) Sea Level Anomalies, followed by the DT - Global - (Maps of) Sea Level Anomalies. The "difference plot" is already selected by default, so you then only have to select time for the two variables (31-Oct-2007). The same thing is produced for the NRT map on the right.

The difference  between the Regional Product (Mediterranean Sea) and the Global product can reach several centimetres. The highest differences are near the coasts (North of Adriatic Sea, Alboran Sea) and affect largest area for the NRT product. These extrema values are probably due to coastal artefacts or to the difference quality between DT and NRT products.

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