Climate long term memory: The figure shows the scaling exponent α of the fluctuation function for near surface temperature during the 20th century. The power spectrum is S(f) ~ f ^-β, β =2α-1. Data are available in inhabited areas and along ship routes. α is determined by Detrended Fluctuation Analysis in 4-15 years.

Cyclones in a warmer climate: Change of cyclone frequency in a warm (2 x CO₂) compared to the pre-industrial climate (before 1860). Results from the AR4 A1B-scenario; numbers are frequencies for cyclone observations in (1000 km²)-areas (in %, local climate maxima 20%).

Blocking detection: The Tibaldi-Molteni blocking index is supplemented by additional filter criteria to eliminate cut-off lows and subsynoptic structures.We introduce three blocking filters and analyse their sensitivities: (i) a quantile filter requiring a minimum geopotential height anomaly to reject cut-off lows, (ii) an extent filter to extract scales above a minimum zonal width, and (iii) a persistence filter to extract events with a minimum duration. Practical filter application is analysed in two case studies and the blocking climatologies for the Northern and the Southern Hemisphere.