Variance

Lively Data : October 6, 2003

The LAS can not only plot data, but also compute statistics over those data. Special interest is given in variance, one of the main statistical indexes for an area variability -- i.e . the extend of the changes that occur in that area -- with the standard déviation (square root of the variance), or the Root Mean Square. The more variation there is in the area, the higher the variance (see Applications: Variability of ocean circulation).

Merged Sea Level Anomaly variance in the Gulf Stream area. To plot such a map, you have to select the variable (here Maps of Sea Level Anomalies Merged), then the area (20-55°N, 100-30°W), and afterwards click in the left menu on "Define variable". You can the whoose between "average", "minimum", "maximum", "sum" and "variance", determine the title of your plot, and the axis (x, y, t) along which the statistics will be computed. Here we choose time, and took the all available period (August 2001 - September 2003). Then click on next without doing anything on the interactive map, to go back to the previous screen, and one more time on "next", to plot the map (we did not draw the contours of the map, because they were too dense).

Use the  Live Access Server