Counter defines time period of observations upon which chart is based (i.e. 1901, Jan).  Use buttons [>>] and [<<] to browse forward and backward in time. Use [Step]-menu to choose between monthly, yearly or decadal step during browsing. Use button [2x1] to switch to dual window mode to compare pairs of charts. Use [Scroll] checkbox to (dis)enable autoscrolling. Use [time] checkbox to switch scrolling forward and backward in time. Use buttond [+] and [-] to accelarate or slow down autoscrolling.

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Given array is based on processing "Arctic and Southern Ocean Sea Ice Data"(also known as the Walsh data set, J.Walsh) monthly sea ice total concentration patterns for 1901-1997 interval.