Santa Cruz
OFF the west coast of North America, a vast triangle of warm water has lured
tropical fish hundreds of kilometres northwards. El Ni帽o, the disruption
of ocean currents now gripping the Pacific, has been held to blame. But this is
one climate anomaly that can鈥檛 be laid at El Ni帽o鈥檚 door.
The triangle of warm water stretches from British Columbia in Canada to Baja
California in Mexico and out to Hawaii. In some places, the sea surface is 6
掳C above normal for the time of year.
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In an El Ni帽o, trade winds that normally blow east to west slacken,
allowing warm surface waters to pool in the eastern Pacific. But Tom Murphree, a
climate physicist at the US Naval Postgraduate School in Monterey, California,
says that the triangle of water has been unusually warm for over a year, and
really started warming in earnest in April, before El Ni帽o could have had
an effect.
Murphree says sea surface temperatures in the region are normally controlled
by a high-pressure system that settles off the coast of northern California,
pulling in wind and cool water from the north. This year, that high was much
weaker and smaller than usual, he says, and this led to warmer water flowing
into the area.
Huug van den Dool of the Climate Prediction Center in Washington DC, agrees.
鈥淚t鈥檚 sort of a coincidence that we have had all this warm water,鈥� he says.