In today's lesson we will try to understand the process of how we

make the weather maps and for this,

we go back to the 60s, at that time was when they defined what is called

the primitive prognostic equations.

We are not going to put them here, as they contain very long equations

with values of the pressure, the temperature, the humidity.

We know that these meteorological variables are

related, so the resolution of the forecast equations is not simple,

because since something is not linearly called linear,

the thing is not as easy as it might seem, but we'll get there.

But, there is a problem related to the equations of weather,

that Lorentz raised, this man might be one of the people,

one of the scientists who in the year 1963

threw a jug of cold water over the predictors,

over the forecasters of the weather, because he was the one who said

that we could never exactly predict, the weather of the future.

And that was a mathematical problem, it was an insurmountable difficulty

which gave us a horizon of predictability.

Why?

Surely you have heard, of the butterfly effect.

Surely you have heard of it.

What is the idea of the butterfly effect?

Well, regarding an initial state,

if we, we have an initial state, the beginning of the atmosphere,

what we see at first, that differs very little.

Notice that, in this point here, it seems that there is only one, but in reality,

there are two little dots that are very close, but not exactly the same.

If we calculate the forecast equations we would see that they make a

evolution, and the end point of this first calculation of the prognostic equations,

we would get a little bit of difference, it is a bit different.

Note that if this is the first hour, and we want to forecast

now the second hour, starting from those two initial states, which would be

the end of first hour of forecast and we will calculate the second hour.

We would calculate again, and note that the second hour would come at this level.

If we went to the third, or fourth, or successive ones, to notice that a

and the other are one on one side and the other on the same side of this surface.

Therefore, we will not go into much detail,

but there are different regions of sensitivity,

which is a product of mathematics associated with prognostic equations.

The reality is that everyone, in the end, all cases are possible,

with a small difference from the initial state and, therefore,

seems to be unpredictable, it seems impossible to predict the weather.

This is the idea of the butterfly, do you remember the idea?

That is, if you do not keep in mind the small error of the initial state,

you can change the forecast you make for a certain period.

This will make it impossible to do the weather forecast.

Lorentz seems to be right, in fact, he was right, but forecasters are

quite clever, and we have this phrase here, and that's it.

We are talking about chaos, meteorology, air is a chaotic system,

but being chaotic does not mean it is random.

What is the meaning of that?

For chaos can be something that is impossible to predict,

to measure, but it is not a thing that can happen anything,

but in reality there are a few ways that can be followed,

and those are the paths that will really happen.

Therefore, the rest of the screen,

the rest of these areas of sensitivity do not always have to matter.

Let's try to understand a little what I'm saying.