The twentieth century reanalysis varies in quality in both time and space, because it depends on the limited and variable supply of historical surface pressure observations. This video shows monthly weather (pressure, wind and temperature anomalies) from the reanalysis for 137 years (1872-2008) masked by fog where there are too few observations to allow a precise reconstruction.

All data are taken from the 20CR monthly composites (esrl.noaa.gov/psd/data/gridded/data.20thC_ReanV2.html) The necessary climatologies are just the means of 20CR monthlies over 1981-2010.

The fog is based on the relative entropy (en.wikipedia.org/wiki/Kullback%E2%80%93Leibler_divergence) of the analysis MSLP field with respect to climatology.

Loading more stuff…

Hmm…it looks like things are taking a while to load. Try again?

Loading videos…