This sounds like a new one?
It’s 5,600 miles of racing; north from Melbourne to Hong Kong starting on 2 January 2018. A quick glance at a map will tell you that there’s plenty of land between those two spots. At this point, we don’t know if the race officials will limit the course options, so we’ll deal with it in general terms – and this is another north to south leg passing through multiple...
Climate zones, right? We’re back to racing through?Climate Zones?
We are indeed, remember, the earth’s oceanic climate features distinct bands, lying horizontally and looping the globe, running out from the Equator to the Poles in a mirror image.
So which ones are we going to hit this time?
Melbourne has a temperate climate, lying as it does on a latitude that puts it on the border between the?Westerly Storm Track?(low pressure systems circulating west-to east around Antarctica and the Arctic) and the?Subtropical High Pressure Zone?(a stable, semi-static area of High Pressure lying between 30 and 38 degrees) for the Pacific. Let’s assume that the boats will head east from the start line, in which case the first section will be hugging the coast around Victoria, New South Wales and Queensland until they set out across the Coral Sea.
The key feature of this section will be variability, and early on it’s quite possible that low pressure systems nudging north from the Southern Ocean will boost the fleet for a wild ride round the corner of Australia. Or it could be dominated by high pressure, in which case the daily cycle of heating and cooling of the land will create local thermal winds that the teams will need to focus on.
Once they get a bit further north, they will steadily come into the influence of the?Trade Winds?(moderate to strong winds that blow consistently towards the equator from the south-east in the southern hemisphere), and these will likely dominate the racing across the Coral Sea.
Umm... aren’t there some islands in the way?
Lots, going north from the Coral Sea the fleet will have to thread their way past Papua New Guinea and the Solomon Islands.
And I’m guessing we aren’t done with climate zones either?
Nope, somewhere towards the top of the Coral Sea they are likely to hit the?Doldrums?(a region of low pressure that envelopes the earth’s oceans roughly at the equator, famous for thunderstorms, light winds, rain and sudden unexpected gusts). This could be a more difficult transition than the one in the Atlantic on Leg 2, because in this part of the world the Doldrums occur in a double belt, separated by a band of easterly Trade Winds. The nearby islands will likely further mix up the weather, so the exit from the Coral Sea could prove to be a critical section of this leg. Not least because, once they are through it, they will be into the north-east Trade Winds (they blow consistently towards the equator from the north-east in the northern hemisphere) and a straight-line drag race to the finish.
Any other hazards?
Tropical Cyclones:?The January start date for this leg puts them well into the cyclone (hurricane-sized storms) season for this part of the Pacific, and there is a good chance that the leg will be influenced one way or another by a cyclone somewhere in the Pacific.
North-east Monsoon:?Once the fleet break clear of the Doldrums, Papua New Guinea and the Solomon Islands they will be headed north-west in the north-easterly Trade Winds. So this should be a pretty fast section, more or less a straight-line drag race all the way to the finish line in Hong Kong.
However... the Trade Winds develop into the North-East Monsoon, a wind created by the clockwise flow around the huge high pressure that builds up over central Asia at this time of year. It can blow really strongly down the South China Sea. In past races when the fleet have been forced to sail east, upwind into the North-East Monsoon, it has broken boats and people. This year they are going north-west and it should just mean a spectacularly quick finish to the leg.
Not much history on this one?
None – this is the first time that the race has gone this way, so it’s a good time to make some!