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Technical milestone reached: global earth system simulations with 1.2 km resoln
- martinpw 4y agoThe article talks about 1.2km horizontal resolution. Is it a 3d grid? If so what is the vertical resolution? Or is the vertical dimension integrated within 2d boxes?
- counters 4y agoYes, these are fully 3D simulations. The vertical resolution is slightly harder to describe because models like these typically use more complicated vertical coordinates than just "meters above ground". E.g. a technical article on the ICON-A formulation [1] says that it uses a "hybrid sigma" coordinate - so something that follows a combination of pressure and terrain. For a very high-resolution simulation that resolves clouds, you'd need to crank this up to O(100 m) in the bottom of the model, but it can space out as you get higher in the atmosphere. [1]: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2017MS001242 https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2017MS00...
- robertlagrant 4y agoWhy did they target 1.2km instead of 1? Or any other number?
- kzrdude 4y agoI guess best ask the authors. > Our ICON-ESM configuration is already used in production mode for scientific purpose with horizontal resolutions of 10 km, 5 km and 2.5 km. With the 1.2 km configuration we have now opened the door for a new class of numerical models which will allow us to investigate local impacts of climate change, such as extremes of precipitation, storms and droughts. Some evidence of them using 10 km cells and then subdividing into halves, gets you down to 1.25 km.
- rongopo 4y agoThe grid is not squared, is hexagonal, surely it relates to that.
- hackandthink 4y agoBeing curious about the implementation language. Viewing the code is not easy. If you guess Fortran, you might be right: (different ICON Project) "The infrastructure, ICON-Land, for this ICON-A land component has been newly designed in a Fortran2008 object-oriented, modular, and flexible way." https://mpimet.mpg.de/fileadmin/publikationen/Reports/WEB_BzE_135.pdf https://mpimet.mpg.de/fileadmin/publikationen/Reports/WEB_Bz... Fortran alive and kicking: https://developer.nvidia.com/cuda-fortran https://developer.nvidia.com/cuda-fortran
- downvotetruth 4y ago1.25 ~ 1.3: Round half to odd prefers preserving the existing scale of tie numbers avoiding out-of-range results when possible for numeral systems of even radix.
- deleted 4y ago[deleted]
- a_square_peg 4y agoThis is fantastic - would be really exciting to see this level of resolution making its way to global operational weather forecasts (currently at ~10km).
- counters 4y agoIt's far too expensive with dubious impacts on forecast quality. Adaptive mesh approaches are far more suitable for high res global weather modeling... Why simulate the area under boring, dynamically unimportant areas?
- SergeAx 4y agoAt least three industries will be grateful for high-res wind predictions: aerospace, maritime and wind-generation.
- Maursault 4y ago> Why simulate the area under boring, dynamically unimportant areas? Butterflies... terrifying large, kilometer-scale butterflies.
- counters 4y agoWhich is *exactly* why ultra-high resolution global weather simulation has dubious prospects for improving forecasts. When you're at spatial scales where you need to parameterize convection, there's an inherent "smoothness" to model solutions that suppresses noisy errors. If you go to cloud-resolving scales - which is needed for simulations like the ones here - you don't get the benefit of that smoothness anymore, because you need to actually resolve scales of motion that are incredibly fine. It's a losing proposition; you'll never get it "perfect", so you're much more likely to spin up an error cascade with significant impacts on forecast down the line, through things like the structure of organized convection. But dynamically uninteresting, quasi-balanced setups and modes? There's far less to worry about in terms of the butterfly effect, and any errors you might worry about will be dwarfed by the fact that we don't have good data to assimilate in places like the remote oceans anyways. It's also worth pointing out that the mathematics and understanding of error / perturbation growth in the atmosphere are well-understood. In fact, this fundamentally underpins how we've developed data assimilation approaches over the past two or three decades that allow us to effectively leverage new datasets such as satellite data to increase forecast quality and reliability at longer lead times. So it's somewhat trivial to actually directly quantify these "butterflies."
- Victerius 4y agoI have only one question. Does this mean that we are getting closer to a cloud-hosted ultimate map for games like Call of Duty and Ace Combat? I want to dogfight over Ohio, land at Offutt to play Warzone in Omaha, then take a MRAP and drive to NY.
- Etching 4y agoSince I can't reply to the RoP thread, you said, "Is this about the brown-skinned male Elf and the brown-skinned and beardless female Dwarf? This horse has been beaten to death and back on YouTube and Reddit, and the consensus is that it's fine and faithful to the texts." This is absolutely ASININE in how in accurate it is. The show is BARELY related to the works it is allegedly based on. And brown people aren't the problem, since Haradrim/Easterlings exist in Tolkien's Legendarium. Where is Celeborn? Why is Isildur around 1500 years before he was born? Why is Durin III Durin IV's father, when the dwarves only allow one person at a time to be named Durin due to their belief that each Durin is a reincarnation of the previous one? Why is Gil-galad able to pardon Galadriel (for killing orcs) when it was the Valar who banned her from Valinor, and she isn't pardoned until three thousand plus years later when she rejects the ring. Why is her motivation to get revenge when in the text her motive is to create her own kingdom to rule (kind of like Satan in Christian theology, which is why she's interesting, since her primary conflict is her own pride versus her own wisdom). Speaking of wisdom, why is she a petulant, hot-headed teenager when she's thousands of years old? Why is she going around hunting orcs when what she was doing on Middle-earth in the Second Age ruling various places and being immersed in Elvish politics (and of particular note, her issues with Celibrimbor and Annatar). Why is she going around swinging her sword like an anime protagonist? She might be tall and athletic, but there is scarcely anything written about her in battle, save for her bringing down the walls of Dol Guldur (which typically is done with magic, or a wrecking crew, not an anime sword). Why is she attempting to swim from Valinor to Middle-earth? Why is she in Númenor when she literally never went there? There's a LOT more I could ask about her, and that's just one character. This show is fan fiction LOOSELY based on the writings. VERY loosely. That is all. I'll enjoy my ban now.
- teraflop 4y ago1:1 scale multiplayer world maps have existed for decades, e.g. in Microsoft Flight Simulator. The difficulty of making a "large" map comes from what you want to simulate and in how much detail, not from how big it is per se.
- superkuh 4y ago"I don't know, Timmy, being God is a big responsibility" https://qntm.org/responsibility https://qntm.org/responsibility , Topic relevant short scifi on Earth simulation.
- teddyh 4y agoPreviously here on HN: https://news.ycombinator.com/item?id=7267811 https://news.ycombinator.com/item?id=7267811
- ThrowawayTestr 4y agoDevs is a great mini-series that has similar themes.
- raydiatian 4y agoSo great. “Uh-oh” for me was one of those Lovecraftian moments of unraveling.
- raydiatian 4y agoAlso IIRC, Devs is loosely based on the above linked short story.
- qbit 4y agoAlso relevant and mind-expanding essay: Simulation, Consciousness, Existence Hans Moravec, 1998. https://frc.ri.cmu.edu/~hpm/project.archive/general.articles/1998/SimConEx.98.html https://frc.ri.cmu.edu/~hpm/project.archive/general.articles...
- argiope 4y agoThank you for sharing that essay. I found it fascinating.
- plantain 4y ago>throughput of 2.5 simulated days per day Will need to be at least 10x faster to be operationally useful.
- gmuslera 4y agoThis is for short term weather prediction or long term climate modelling? The 2.5 simulated days per day points into the short term direction.
- guenthert 4y agoI wouldn't think that a temporal resolution measured in days is needed or all that helpful for climate modeling.
- contravariant 4y agoI'm not sure the added precision is helpful if it's just 2.5 days ahead. An extra week of accurate forecasts is a bit pointless if it takes 8 days.
- magicalhippo 4y agoAs mentioned in the article, the system is based on the ICON Earth System model[1], which has the following description: The Earth system model provides a numerical laboratory for research on the climate dynamics on time scales of a season to millennia. Necessarily most processes are parameterized to allow the computationally efficient integration over long periods. It's also mentioned it will contribute to DestinE[2]: Destination Earth (DestinE) aims to develop – on a global scale - a highly accurate digital model of the Earth to monitor and predict the interaction between natural phenomena and human activities. [...] The initial focus will be on the effects of climate change and extreme weather events, their socio-economic impact and possible adaptation and mitigation strategies. [1]: https://mpimet.mpg.de/en/science/models/icon-esm/ https://mpimet.mpg.de/en/science/models/icon-esm/ [2]: https://digital-strategy.ec.europa.eu/en/policies/destination-earth https://digital-strategy.ec.europa.eu/en/policies/destinatio...
- OrvalWintermute 4y agoThis sounds alot less than Nvidia's FourCastNet? https://resources.nvidia.com/en-us-fleet-command/watch-27?xs=423538 https://resources.nvidia.com/en-us-fleet-command/watch-27?xs... How do these two compare?
- counters 4y agoThey're complete different classes of models. The modeling system in the linked article is a high-fidelity numerical simulation of the coupled Earth system. It's a giant PDE solver for Navier-Stokes applied to the Earth's atmospheres and oceans, coupled together with a great deal of additional physics simulation. The intent is to reproduce, in simulation, the Earth's atmospheric and oceans with the highest fidelity. This set of simulations is the culmination of nearly 70 years of investment, going back to the very first applications of digital computers for solving complex math equations (one of the first simulations bought for ENIAC was a crude quasi-geostrophic atmospheric mode / weather forecast). NVIDIA's FourCastNet, while very cool, is quite literally a facsimile of this type of system. It's really not even in the same ballpark.
- sp332 4y agoYou realize "facsimile" means "copy", right? You didn't explain how they are different.
- fastneutron 4y agoIt’s an example of a surrogate model. It’s an ML model trained on the output of large numerical simulations like the OP, rather doing the simulation itself. Surrogate models are nice because they can emulate the output of the full fidelity calculation in a fraction of the runtime, but they typically are trained within a range of validity outside of which they cannot reliably extrapolate.
- counters 4y agoIt's a deep learning based emulator of a full-complexity NWP system, but it is far from a production-ready or operational technique.
- rongopo 4y agoHow is this going to change seasonal-scale forecasts?
- rongopo 4y agoThe real key of this story is in the "simulating — rather than parameterising".
- singularity2001 4y agois fixed resolution really the way to go? I'd imagine big patches of the ocean and deserts being modeled as single nodes being way more efficient without compromising fidelity.
- kimburgess 4y agoAlthough final output in those regions is perhaps less relevant, their state would still have an impact on other areas as the simulation progresses.
- adamius 4y agoHow does such a simulation work? Eg how do hou predict the temperature at x,y? Is it ground type, water, sand?Altitude? Neighboring values thereof? What are the inputs? Do you give it a starting point and apply it to a bunch of elements like some giant automata like game of life? Some kind of finite element analysis thing? So many questions.
- Certhas 4y agoIf only there was a way to find out...
- adamius 4y agoI know, right? But together we can still dream.
- adgjlsfhk1 4y agogiant partial differential equations
- diroussel 4y agoHere is a very brief and basic introduction to numerical simulation: Simulation of dynamic systems is a big deep area. In general you use what is called numerical simulation where you have a model describing your system, in the form of a partial differential equal equations. You start with the chosen initial conditions, choose a delta-t as your time increment, and solve the equation for those inputs. That result is the input to the next iteration. The most basic algorithm to solve such an equation is “Newton’s method” but no one actually uses that, they use many more advanced methods. But if you are learning that is where you start. This approach has advanced greatly over the last 70 years. Doing numerical simulation is why early computing work got funding, to simulated nuclear reaction inside bombs. Now numerical simulation is the occupation of all the worlds top super computers. It’s used for climate simulation, bridge strength, how sky scrapers flex in the wind, testing car crashes or even simulating the strength of ceramics. Oh and it used a lot in financial simulations to model risk and calculate the price of assets.