Video 2.3.2 The GRIB format

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來自 Universitat de Barcelona 的課程

Strategies for winning. Meteorology in a round the world regatta

42 個評分

Universitat de Barcelona

Strategies for winning. Meteorology in a round the world regatta

42 個評分

In this course you can learn about the mechanics of global weather, the foundations of ocean meteorology, predictive modeling and how sailors receive data via satellite and use high-performance navigation software. This course looks at oceanic meteorology and climatology through the lens of the sport of sailing. You will gain a basic knowledge of meteorology needed by sailors to take part in a regatta such as the Barcelona World Race, the only double-handed, round the world regatta with no stops. You will learn about the strategies employed during a round the world regatta and how these are put to use on board the latest ocean racing yachts.

從本節課中

Meteorological predictions

In this module you will learn: How meteorological predictions are made. What numerical weather models and equations look like. This will be explained by Tomàs Molina in Module 2.1 You will look at the forecasting structures that help us to interpret the information given by the models: Advection, troughs, ridges, barometric swamps and low pressure systems. These will be explained by Tomàs Molina in Module 2.2 What the basic prediction models used by sailors are. This will be explained by Marcel van Triest in Module 2.3 Remember you can access to the help forum . If you are experiencing difficulty learning or accessing course content, or if you simply want more information.

Video 2.3.1 Types of information available1:50

Video 2.3.2 The GRIB format3:37

與講師見面

Tomàs Molina

[MUSIC]

We just have to look at the information on board.

Is an example of what effects quite complicated to make any sense of this.

Depends on the distance and viceversa if they look at it here and

measure it so many knots.

There's much better information we had available.

Information that's called GRIB and GRIB is short for gridded binary.

It was invented in 1988 roughly as a data exchange format by

the World Meteorological Organization

to exchange large sets of information between the various countries.

It's something that if you ever you will hear about it,

the GRIB files, the GRIB files.

Well, it's nothing, it's like the PDF files but GRIB is a specific format for

If you open it up in an editor, it looks pretty chaotic.

No one can make any sense out of this, but you can see that it starts with the four

letters, GRIB, and that comes back again and again.

It's a standard format, it's the same in each country in the world,

every meteorological organization that makes use of it.

Universal standard, and they exchange information like this.

However, once you open it up and that will take you back to this picture.

Once you open up a grid file it becomes completely different.

It becomes like this.

All of a sudden you can see the wind speed, and if you put your mouse here,

it will say over here how many knots is blowing,

what the pressure is, what the direction is.

Over here if it's raining or not, and how much.

It's called motif time [INAUDIBLE].

Here for the past ten days, various hours.

We can step through that as we please.

So all this end road information that needed a lot of interpretation

has become usable by a computer.

Today we live in the age of computers.

So we need that kind of information to make calculations.

And assumptions and predictions for our strategy.

So what is available on this famous grid format?

Well first of all there are plenty of different models.

Alright.

A higher resolution model.

That's a high resolution model.

This is a high resolution model of the United States here.

High resolution means the calculations are done at a smaller scale,

taking into account smaller scale of things like sea breezes,

but even like mountains, headlands.

All that sort of stuff.

What kind of variables are available?

Hundreds.

Literally hundreds of variables are available.

Ultraviolet radiation.

All kinds of stuff.

On lots of different levels.

As I've said, your only interest in the bottom thirty meters of the atmosphere.

That's where we're sailing, that's where we live in, right?

Meteorologists are interested in the atmosphere to 11 kilometers.

Plains, or all kinds of stuff, right?

So, we're only interested in the boat.

And for that, we choose simple variables.

Wind at ten meters, rain, pressure, that's all we need.

We only take very small part of what's available in this group format to

determine our strategy and where we want to go.

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