Pie in the sky

How not to forecast the weather. …

I have just been looking at the methods the Wikipedia outlines for Meteorology. After leading me off a few times to try and understand big words (I'm still not sure what non-linear means) I decided to give up and report in on my efforts.

He who would have much to do, let him fit out a ship -or a woman.

Never mind the secrecy that certain climate scientists in establishment have, even with the best kiss and tell policies and the superest duperist computers in the world and some of the best mathematicians, serious solutions to the problems of aerial mechanics can never get any better than weather-lore and seat of the pants, gut feelings.

Here is a sample of what the meteorologists have to do just to get a meagre few days expert guess-work:
A supercomputer. You don't need me to draw you a picture of one of those. At the moment the state of the art have a capacity for 1.759 PFLOPS. (1,759,000,000,000,000,000,000 calculations per second and the calculation need not be a binary number increment, too neither.)

Assuming the thing doesn't have a bias (The Met Office has one that is alleged to scope out in favour of the CRU but it can't be verified as they haven't got it working properly since they had it installed.)
Assuming the thing doesn't have a bias, you need the rest of your eggs in one basket.

This involves setting up stations all over the region with meteorological measuring equipment that reports in on time to make a bench mark every 6 hours:

Originally posted by Wikipedia:

Models are initialized using observed data from radiosondes, weather satellites, and surface weather observations. The irregularly-spaced observations are processed by data assimilation and objective analysis methods, which perform quality control and obtain values at locations usable by the model's mathematical algorithms (usually an evenly-spaced grid). The data are then used in the model as the starting point for a forecast.

What they are aiming to get is an ensemble a starting point that works out what might be happening in between the reporting stations.

Originally posted by Wikipedia again:

The forecasts are computed using mathematical equations for the physics and dynamics of the atmosphere. These equations are non-linear and are impossible to solve exactly. Therefore, numerical methods obtain approximate solutions. Different models use different solution methods.

Some global models use spectral methods for the horizontal dimensions and finite difference methods for the vertical dimension, while regional models and other global models usually use finite-difference methods in all three dimensions.

Regional models also can use finer grids to explicitly resolve smaller-scale meteorological phenomena, since they do not have to solve equations for the whole globe.

The key term in that last paragraph is non-linear equations it applies to all dynamics concerning fluids. They are literally equations that don't add-up. How can they add up, even with a super-computer?

By the time it has crunched the numbers the continuum has changed. You van count the ripples in a stream but not work out the speed of the flow for any one of them. They change constantly; otherwise they wouldn't be ripples would they?

Every cubic inch of a gas changes with the temperature from any outside heat source. And because the pressure changes with temperature, the gas has its own heat source too.

And that's not counting the behaviour of water in the gas. Which is something in itself that can never be known. Then there is the behaviour of carbon dioxide. The bug in the works for climate researchers.

How does that behave? How does it shed heat? How does it react with water? It's stuff not even considered.

Well, I hope you get the point. At present weather models can produce by using statistics, guesswork, unresolvable equations and comparisons with other mopdels; very good forecasts for the first few days.
But after 4 or 5 days it all falls apart.

I have the feeling it would still do so even if the current batch of no-hopers applied the concept of weather turning into earthquakes, things wouldn't be all that much better after 7 or so days.

Guess why.

2 thoughts on “Pie in the sky”

1. Weatherlawyer says:

Its the Met Office's Unified Model that gives us the potential gauge for earthquakes.In other words they have the answers, not the potential for answers, the actual answers to the first part of their problems with computing forecasts.There is just no way to convince anyone that the idea is a good one…Pity that.Here is a fairly good world wide surface level pressure chart:https://www.fnmoc.navy.mil/efs/dynamic/US058VMET-GIFwxg.EFS.no_atl_gale_0.gifYou have to set your browser to accept a certificate each time you go to their website. Its most straight-forward in Opera, Konqueror too but I gather some browsers are not so obvious. IE used to be crap with it IIRC.I wonder why I forgot about this site. I spent a few hours yesterday trying to find something -anything, like it. This morning the RH sidebar here was showing pictures of it.My own pictures!Damn. I need a wife or a brain or something.NURSE!!

2. Weatherlawyer says:

Will the workstation Eta run on such-and-such workstation? The workstation Eta has been ported and tested on all machines that are available to us within EMC/NCEP. This includes HP, SGI, IBM, and LINUX workstations. Some limited testing has also been done on a DEC in cooperation with the University of Maryland. Originally posted by Workstation Eta FAQ:

Does my computer have enough memory and speed to run the model? Whenever people ask the "How much machine is required" question, we have to give a pat "It depends" answer.This response drives people crazy, but changes to model dimensions and resolution have a profound impact on the memory and CPU requirements to complete a model run within a reasonable amount of time.A machine with 256 MB of RAM is probably sufficient to run a moderately sized (in terms of grid points) domain.