What's the biggest bottleneck for better forecasting: better observations, better models, or better supercomputers?
Supercomputer quietly puts U.S. weather resources back on top
41–50 of 79 posts
Re: Supercomputer quietly puts U.S. weather resources back on top
#42I'm bothered by how the article says "three years ago European models delivered a blow to the U.S. weather apparatus". Better models by Europeans do not make the models by Americans any worse. Improved models help everyone.
And even with the new computer the European model is still better at mid range forecasts.
Re: Supercomputer quietly puts U.S. weather resources back on top
#43Earlier quoted context omitted.
Modern supercomputers essentially are large commodity clusters. Nobody builds a single fast machine ala Cray-1 anymore. It's just not scaleable past a certain point and we're long since past that. However, they still like to give them fancy names as marketing, because they cost tens of millions of dollars. The main differentiation vs a standard datacenter is low-latency high-throughput interconnects, often with a spe…
What kind of latency do they expect from these things? Less than 50 microseconds for a small RPC or small RDMA access? I'm wondering how far these things really are from commercial cloud clusters.
Less than one microsecond.
Re: Supercomputer quietly puts U.S. weather resources back on top
#44Well, this is happening just in time for all the weather patterns -- as we know them -- to change due to global warming. I guess it'll be not unlike understanding the universe according to Douglas Adams...
Re: Supercomputer quietly puts U.S. weather resources back on top
#45Earlier quoted context omitted.
Could they have built it underground?
"Underground" isn't very feasible in Florida. Most of the state is effectively a sandbar with a very high water table. Underground construction is uncommon.
"Underground" isn't very feasible in Florida.
Here in central Texas, we have the same thing, but for the opposite reasons. Our water table is pretty deep - typical wells in my town are 900ft deep. But rather than sand, we've got limestone. Typical land has inches of topsoil sitting on top of solid limestone, so excavating a basement is prohibitively expensive.
Re: Supercomputer quietly puts U.S. weather resources back on top
#46for anyone interested, this paper has a nice background on numerical weather prediction http://www.elsevierscitech.com/emails/physics/climate/the_or...
I got about 3 pages into this and felt like I was following the discussion until the discussion of an incorrect prediction result that:
> In fact, the spurious tendencies are due to an imbalance between the pressure and wind fields resulting in large amplitude high frequency gravity wave oscillations.
Since this paper was published within the last 20 years, I can't imagine what they were referring to by 'gravity waves'
Do you know what is meant by this statement?
Re: Supercomputer quietly puts U.S. weather resources back on top
#47It's a very exciting time in weather forecasting. We're getting all kinds of new observations available, from cheap LEO satellites to smartphone sensors to smart umbrellas and everything else. And faster computers! And more parallel computers! Think about every single iPhone and every single Galaxy S in the world as a useful sensor array _and_ a parallel processor... Weather forecasting accuracy is still constrained…
No one in the foreseeable future is going to use cellphones as parallel processors. First of all, the communication latencies are way too large to coordinate anything usefully. Second of all, users are already upset about the lack of battery life available for their phones.
It's not exactly parallel processing, but the Dark Sky app already does its forecasting calculations on the iPhone: http://jackadam.github.io/2011/how-dark-sky-works/
> The reason we encode velocity data as an image is so we can pass it off to the GPU on the iPhone and iPad. Both the storm prediction and the smooth animations are calculated on the device itself, rather than the server, and all the magic happens directly on the GPU.
Re: Supercomputer quietly puts U.S. weather resources back on top
#48It's a very exciting time in weather forecasting. We're getting all kinds of new observations available, from cheap LEO satellites to smartphone sensors to smart umbrellas and everything else. And faster computers! And more parallel computers! Think about every single iPhone and every single Galaxy S in the world as a useful sensor array _and_ a parallel processor... Weather forecasting accuracy is still constrained…
just curious, do you have references to smartphone sensors being utilized in numerical weather prediction? i'd been browsing through some WMO reports and other associated NWP lit recently and i'd seen stuff on GPS-RO, but nothing on anyone assimilating "smart" devices.
If you'd like to submit your own weather observations from anywhere on the globe, the National Severe Storms Laboratory has created an app[0] to report them.
Re: Supercomputer quietly puts U.S. weather resources back on top
#49I'm bothered by how the article says "three years ago European models delivered a blow to the U.S. weather apparatus". Better models by Europeans do not make the models by Americans any worse. Improved models help everyone.
I talked to a (very) senior scientist at the World Meteorological Organization not too long ago. He was of the opinion that the U.S. weather models were about 5 to 10 years behind on the European models, and that this was caused by structural underfunding over longer periods of time (i.e. past decades). As I understood it these weather models are basically humongous software programs that are developed in house, but based on publicly available science and fed by data from weather stations.
Does your software become better if you run it on a faster computer? It will certainly help, but he instilled on me the impression that the US had a bit more catching up to do than just buying a new supercomputer.
Re: Supercomputer quietly puts U.S. weather resources back on top
#50Earlier quoted context omitted.
You do not get an idea of how big it is by visiting; the stacks are off limits and much of the material must be ordered in from suburban warehouses.
They probably also have most of the bookshelves on rails? The local uni library keeps their old books on a system like this, it's really quite cool. The room can fit, say, 54 bookshelves tight-packed with no room to enter anywhere. So they put 52 shelves in on rails, and between each pair there is a wire going across. Disconnect a wire between two shelves, and all the shelves slide apart so you can enter where you op…
I'd estimate most university libraries have a system like this, though the "disconnect a wire" part is strange. Usually they're just a button on the shelf.