The ocean's color affects heat, storm formation

In the middle of hurricane season, a new study adds a surprising new chapter to the study of tropical cyclones.

It suggests that the color of the water has an impact on storm formation. Greener, more storms. Darker blue, less storm activity.

Entirely bizarre, it seems, until you read further. And then it makes a lot of sense.

Here is the American Geophysical Union's press release on the paper, “How ocean color can steer Pacific tropical cyclones,” by Anand Gnanadesikan, Gabriel A. Vecchi, Whit G. Anderson, and Robert Hallberg, all of the NOAA Geophysical Fluid Dynamics Laboratory , and Kerry Emanuelof the Dept. of Earth, Atmosphere and Planetary Sciences, MIT, Cambridge, MA.

Here's the upshot of this: The ocean's color is affected by how much plant life is in it, and the amount of green chlorophyll impacts how far the sunlight penetrates.

Less chlorophyll, and the sunlight goes deep, heating a lot of the ocean at various depth. More chlorophyll, and the sun penetrates not far, heating up only the surface areas, and making the surface water hotter than it otherwise would be.

What it means is that suddenly the already problematic business of storm forecasting gets even trickier, or, as the paper says, “our results suggest that climate modelers wishing to make statements about tropical cyclones need to be extremely careful in describing the physics of the upper ocean.”

In the past, there have been suggestions that a warmer global climate could increase water temperatures, making storms more frequent and stronger. But very recent research suggests that the amount of plant life in the oceans may be crashing, arguing under Gnanadesikan paper for fewer storms.

For more on this research, see our immediately previous post at Raising Islands.

© Jan TenBruggencate 2010