https://www.data.gov.uk/dataset/cf063461-067b-4209-94ef-629dabddf2de/ukcp09-5km-gridded-data-long-term-average-data-mean-sea-level-pressure
UKCP09: 5km gridded data - Long-term average data -Mean sea-level pressure (hPa) - data.gov.uk
mean sea level pressure
https://www.osti.gov/dataexplorer/biblio/dataset/1130373
GSOD Based Daily Global Mean Surface Temperature and Mean Sea Level Air Pressure (1982-2011)...
The U.S. Department of Energy's Office of Scientific and Technical Information