February 02, 2013

Smartphone Pressure Observations Take Off

In a previous blog I mentioned a young firm, Cumulonimbus Inc, that created a new Android app, PressureNet2, that collects the pressure observations from certain smartphones.    I also mentioned the potential for such observations to greatly enhance weather predictions.
The popular Galaxy S3 has a pressure senros

Well, this project is really taking off and I encourage any of you with the right smartphones (see list below) to sign up for the app and join the network.  Right now, we at the University of Washington are acquiring the data every hour and plotting the location of the smarphone pressure observations hourly.  Below is one from today.  You can see the urban areas as dense collection areas, but back east there are plenty in rural areas.  Right now we are getting 3000-4000 observations per hour over the domain shown below.  Wow! 

But to make this the revolutionary effort it could be, we need many more observations--like 100x more.
The following smartphones and pads have pressure sensors:
 Samsung Galaxy Nexus (tablet), Samsung Galaxy S3 and Motorola Xoom (tablet)

The Galaxy S3 is a hot item now, with millions sold in North America alone.  The clear potential is for millions of observations per hour over North America alone.
Samsung Nexus

Recently, Cumulonimbus, Inc. released  PressureNet3, with substantially increase capabilities, including fun graphics for seeing your own and other's pressure observations.

So if you have one of the units, please considering downloading the app, and if you are in the market for a smartphone or tablet, seriously consider one of the above choices.  Personal information is NOT put in the database.

Why am I so excited about these observations?  Because surface pressure is a uniquely valuable surface observation since it reflects the atmosphere above (surface pressure reflects the weight of the air above the sensor).   Recent research has revealed that with sufficient surface pressure senors and a sophisticated model-based data assimilation system, one can accurately reconstruct the three-dimensional structure of the atmosphere.

Pressure observations can be taken in buildings or cars and don't suffer exposure problems like temperature and wind.

A graduate student of mine and Professor Greg Hakim, Luke Madaus, is working on assimilating both pressure AND pressure change in high-resolution numerical forecast models using traditional and non-traditional pressure observing networks.   The early work is very promising. We plan to use the dense observations from smartphones, but first have to figure how to do quality control and to determine which smartphones are moving and remaining stationary (remember we have position-GPS- and pressure from each of them).  And we will test our new capabilities on a range of examples, including Midwest convection (thunderstorms) and Pacific Northwest features (like the pesky convergence zone). 


  1. A more complete list of devices with pressure sensor:

    Pda's with pressure sensor: Samsung Galaxy Note and Note2, Samsung Galaxy S3 (SGS3) , Galaxy Nexus, Motorola Xoom and Sony Ericsson Active, Xiaomi Phone 2 -

  2. Cliff, I have a Netatmo weather station that broadcasts similar data and is assimilated in with the iOS infrastructure. Are you also gathering these data points?

  3. I've downloaded it to my Galaxy Nexus. Hopefully the service doesn't eat too much battery, but I'll make it work.

    Just another excellent example of the potential of having all these distributed, cloud-connected devices collecting data. We live in a very exciting time!

  4. Hi Cliff - totally unrelated to this post (which is cool btw), do you have any insight into or thoughts on the MAP testing that the Seattle Public Schools does? I'm curious to understand whether the teachers who are protesting have any basis for their belief that they are not worthwhile. I would logically think that having standardized tests to track progress is useful but don't know much about this topic.

    Also, I have read your posts on the Everyday Math curriculum and would love to know if you have any tips or suggestions on how a Seattle Public School parent might compensate for what the schools aren't doing well. I have a kindergartner in the system and am very concerned about his math education....

    Any insight you could share on either of the above in the blog would be greatly appreciated.

  5. I've got a Samsung Galaxy 3S and I've been using the app since the first time you mentioned it. I'm always glad to do my part! :-) I love hearing how the data is actually useful, and it really does not consume much battery, as far as I can tell.

  6. I'm getting a galaxy note2 which is also compatible. I'll be sure to get this app. how cool.

  7. Cliff, do you have any guidance for people that use this app that are not necessarily on or near the service. Specifically, advice for pilots. I went flying today and spent some time at around 3,000'-4,000'. I intended to turn the app off before I went, but I forgot. When I got home I looked at the log and there were several data points way out of line with the rest of them. I want to help, but I don't want to make things worse by providing bogus data.


  8. Unknown pilot...don't worry...our quality control software will take care of such issues! Your pressure changes would not appear to be meteorological..cliff

  9. I noticed similar anomalies in the data from my phone... and then I realized that they were pressure changes in the tunnels when I was riding the DC Metro! (There is sometimes enough of a pressure change to make your ears pop, and it was awesome to see that in my data feed). I guessed (and it seems Cliff is confirming) that all readings from coordinates reasonably close to each other by GPS location and time are compared and extreme outliers are thrown out.

  10. Have you considered the privacy issue of cell phone location?

  11. So there's no point in my using it in Europe, the data aren't used for anything?

  12. So there's no point in my having the app running here in Europe, the data isn't being used for anything?


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