Estimated Trends in Mean Sea-Level Pressure

Estimated linear least squares trends in annual mean sea-level pressure from 1900 to 2012 from three datasets: (from left to right): National Center for Atmospheric Research (NCAR), National Oceanic and Atmospheric Administration 20th Century analysis (20CR), 20th century reanalysis and Hadley Centre Sea Level Pressure (HADSLP2)Hadley Centre analysis. Trends are reported in units of millibars per century. For reference, an x is placed over the center of action of the mode of variability reported by JM.