Were the atmospheric pressure patterns that caused extreme dry and extreme wet periods happening more frequently? (newsdeeply.com)
From year to year, winds and air pressure patterns change, causing different forces to act on the solid Earth. (nasa.gov)
This in turn is influenced by sea level pressure patterns in polar and subpolar regions — as more or less wind and currents are pushed north (Roemmich et al, 2007, Qiu, Bo et al 2006). (watertechbyrie.com)