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Is this the South East Trades?

Posted: Mon 10th March 2008 in Blog
Position: 5° 44' S, 100° 58' W

Many of you may have heard the term "Trade Winds", other words like "Azores High" sometimes appear. I'm hoping we've found the south east trades that will drive to the Marquesas.

High Pressure = Good weather so open a bottle of Wine!
Low Pressure = Bad weather open a bottle of scotch
You need a corkscrew  (screws in clockwise) for wine,
you unscrew a bottle counter clockwise.
Helps you remember that in the Northern
Hemisphere
wind Spirals clockwise out of a high
and counter clockwise into an low.

I'll try and explain, I'll start with the Atlantic, because I know it best. Around the Equator (in all oceans) lies the Inter-tropical Convergence Zone aka the doldrums, abbreviated to I.T.C on the diagram. This is as mentioned an area of hot fickle weather, with thundery showers and erratic winds. Above and bellow it should be the trade winds. North east trades blow in the Northern Hemisphere north of the doldrums. Over simplifying they're driven by the Azores High, an area of high pressure that usually sits over the Azores, of the coast of Portugal. Wind spirals out of a high pressure in the Northern hemisphere in a clockwise direction due to the Coriolis effect The southern hemisphere it spirals out anti clockwise. Its this high that generates a steady flow of wind from the north east at the Canaries that Yachts use to cross to the Caribbean. This is the North East Trades. The Northern Atlantic North Easters are some of best examples of trade winds in the world.

South of the Equator (and the I.T.C) the rules are reversed, Coriolis spins the wind the other way generating South East Trades.

Trade Winds
Simplified Diagram of the Trade Winds We're trying to use.

This occurs in the pacific too. Where mountain ranges and Land impose they get overridden by local effects, but out in the open ocean you should get them. We've been in the Doldrums since Panama City, the Pacific Doldrums are slightly north of the Atlantic ones. We've been sailing south west out of the Galapagos in the hope of getting out of the light, hot sticky and variable weather and into the Trades. Wind is light, but steady from the South East. Woot!. I'm (and I suspect I'm not the only one) praying that this is the trades and we'll get some steady wind.

This phenomenon also explains why England is so wet, and cape horn in so miserable. The UK is north of the Azores high. So its tending to get warm Caribbean air that's come North of the Azores High, generating the Warm Wet weather we all know and love. The weather at cape horn is worse, the UK weather is generated by the Atlantic, cape horn has the same ocean on both sides, so the lows roll around the bottom of the world.

EDIT: God this was badly spelt, and when I was trying to sound intelligent too.

[Printable]
Share

Is this the South East Trades?

Posted: Mon 10th March 2008 in Blog
Position: 5° 44' S, 100° 58' W

Many of you may have heard the term "Trade Winds", other words like "Azores High" sometimes appear. I'm hoping we've found the south east trades that will drive to the Marquesas.

High Pressure = Good weather so open a bottle of Wine!
Low Pressure = Bad weather open a bottle of scotch
You need a corkscrew  (screws in clockwise) for wine,
you unscrew a bottle counter clockwise.
Helps you remember that in the Northern
Hemisphere
wind Spirals clockwise out of a high
and counter clockwise into an low.

I'll try and explain, I'll start with the Atlantic, because I know it best. Around the Equator (in all oceans) lies the Inter-tropical Convergence Zone aka the doldrums, abbreviated to I.T.C on the diagram. This is as mentioned an area of hot fickle weather, with thundery showers and erratic winds. Above and bellow it should be the trade winds. North east trades blow in the Northern Hemisphere north of the doldrums. Over simplifying they're driven by the Azores High, an area of high pressure that usually sits over the Azores, of the coast of Portugal. Wind spirals out of a high pressure in the Northern hemisphere in a clockwise direction due to the Coriolis effect The southern hemisphere it spirals out anti clockwise. Its this high that generates a steady flow of wind from the north east at the Canaries that Yachts use to cross to the Caribbean. This is the North East Trades. The Northern Atlantic North Easters are some of best examples of trade winds in the world.

South of the Equator (and the I.T.C) the rules are reversed, Coriolis spins the wind the other way generating South East Trades.

Trade Winds
Simplified Diagram of the Trade Winds We're trying to use.

This occurs in the pacific too. Where mountain ranges and Land impose they get overridden by local effects, but out in the open ocean you should get them. We've been in the Doldrums since Panama City, the Pacific Doldrums are slightly north of the Atlantic ones. We've been sailing south west out of the Galapagos in the hope of getting out of the light, hot sticky and variable weather and into the Trades. Wind is light, but steady from the South East. Woot!. I'm (and I suspect I'm not the only one) praying that this is the trades and we'll get some steady wind.

This phenomenon also explains why England is so wet, and cape horn in so miserable. The UK is north of the Azores high. So its tending to get warm Caribbean air that's come North of the Azores High, generating the Warm Wet weather we all know and love. The weather at cape horn is worse, the UK weather is generated by the Atlantic, cape horn has the same ocean on both sides, so the lows roll around the bottom of the world.

EDIT: God this was badly spelt, and when I was trying to sound intelligent too.