Philip Brohan, climate scientist at the Met Office Hadley Centre, combines information from old documents, tree-rings and large computers, into a clear picture of what the weather used to be like. At the August 2014 ACRE (Atmospheric Circulation Reconstructions over the Earth) workshop, attended by IEDRO, Philip presented this particular visualization (seen below) of mean sea level pressure as simulated by the 20th Century Reanalysis (20CR) application, which clearly shows both the progress of and need for continued data rescue efforts.
While yellow highlights mark the “glow of discovery,” locations where new observations are adding to the accuracy of the climate reconstructions, you may want to take special note of the “fog of ignorance” – grey areas which indicate where climate data is needed in a usable, digitized format which can then fed into an application such as 20CR so that scientists can paint a better picture of Earth’s past climate, and thus, paint Earth’s future as well.
This video shows four things:
1) The weather – the mean-sea-level pressure as simulated by the 20th Century Reanalysis (black contours: solid=low pressure, dashed=high).
2) The observations – grey circles mark observations that we’ve had for a while, yellow ones observations recently recovered by the ACRE and oldWeather projects.
3) The fog of ignorance – grey fog masks regions where the reconstructions are still very uncertain (as there are too few observations to constrain the reanalysis).
4) The glow of discovery – yellow highlights mark regions where the new observations have produced a large improvement in the confidence of the reconstructions.
So where is the data that’s missing? They can often be found in rooms that are not climate-controlled, recorded on disintegrating mediums, waiting to be rescued and digitized before they’re lost forever.
From precipitation strip charts to ship captain’s logs, weather observation records can be found in many formats, on every continent, dating back 100 to 250+ years, making the rescue and digitization effort a global one. Philip explains, “If we’re worried about extreme weather – unusual events, very large heatwaves – then that perspective, that extra length of our records [from the rescuing and digitizing of past weather observations] – give us more information about how likely events like that are to occur in the future.”