Brightening the world

We launched oldWeather three years ago today (October 12th, 2010). It was an exciting but scary moment – would she float? We’d done everything we could, but you’re never quite sure until the splash has settled.

One thing we did know at launch was where we were going: The map of past climate variability and change contains some very large blank areas – great expanses of space and time where we knew almost nothing of what the weather had done. Ours was a voyage of exploration: We would sail, via the archives, into these regions and rescue their weather observations, adding systematically and permanently to the scientific records on which our understanding of the climate is based.

And it’s worked very well. As with any research project we’ve encountered plenty of surprises along the way, but they’ve been good surprises – we knew about the weather in the logs, but we didn’t realise just how much else was in there. So we’ve added detailed ship histories, maps, geographical databases, illustrations of the course of WW1, tales of life on board, …

But our primary aim is still the weather, and we’ve recovered an enormous account of historical weather information, more than 1.6 million new observations from our original set of Royal Navy logs alone. These new basic observations are a permanent foundation on which scientists all over the world can build new reconstructions and products, and today we can see such a building appear.

Gil Compo and colleagues, from NOAA/CIRES/University of Colorado, are using our new observations in an atmospheric reanalysis (20CR). Essentially they combine surface weather observations (such as ours) with information on sea temperature and sea-ice, and a physical model of the atmosphere, to make a detailed and comprehensive picture of the global weather. It takes some of the world’s largest supercomputers to do this analysis: 20CR was produced at the US National Energy Research Scientific Computing Center and the US Oak Ridge Leadership Computing Facility. But it’s worth the effort – not only do they make a global weather reconstruction, but they also calculate the accuracy of their reconstruction, and we can compare their new reconstruction with one they made earlier, to see how much difference our observations have made.

So the video above has four components:

  1. The weather. The reanalysis calculates everything about the weather: winds, temperatures, clouds, rainfall, the jet stream, … but I can’t show all that in one video so we’re only seeing mean-sea-level-pressure. The solid black contours show where this is low (bad weather), and the dashed contours where it is high (good weather).
  2. The observations. Grey dots mark observations we’ve had since before oldWeather started. Yellow dots mark new observations. Most (but not quite all) new observations are from oldWeather. (We are only part of a wider recovery program).
  3. The fog of ignorance. Grey fog marks the areas where we still don’t have enough observations to say exactly what the weather was doing.
  4. The glow of discovery. Yellow highlighting marks the areas where the reconstruction is much better than it was before (mostly because of our new observations).

That’s a lot to get in one image, but it’s the yellow that matters. Our work has cleared the fog, and illuminated the weather, over a huge area of land and ocean. The improvement stretches over about 20% of the Earth’s surface – more than 100 million square kilometres – and is there for every hour of the 9+ years covered by the Royal Navy logs we read.

That’s not a bad return for our three years hard work.

7 responses to “Brightening the world”

  1. Yvan Dutil says :

    I am impressed that the 20CR has started to produce some results. It is amazing to observe the teleconnections between weather, Central Africa seems to be the past with the largest improvement even if the new data are mostly coming from the sea, By the way, do you know if the ERA-20C has released it data. They were about to fining now.

    • Philip says :

      ERA-20C has not yet released it’s data. They are about to do so, but reanalysis produces so much data that it needs special servers to distribute it. It will be some time yet (probably months) before we can use it.

    • Yvan Dutil says :

      To be honest, I am under the impression that a significant part of the improvement in many regions comes from an improvement in the algorithm used because they are already well sampled.

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