but are considered for climatological anal-
yses only if their centre depression on the 1000 hPa geopotential height field reaches at least 20
m relative to the 24 surrounding grid points over the course of their lifetime.
7
This study is concerned with well-developed, persistent, mid- to high-latitude large-scale weather
systems, rather than their early detection and tracking. Therefore, cyclones
/media/vedurstofan/utgafa/skyrslur/2015/VI_2015_005.pdf