Reading the Future in a Bed of Algae

"For the first time we are seeing the transition from El Niño to La Niña well before other measurements become available," Murtugudde said. The researchers had to look at sea surface temperature, sea surface heights and wind speed to verify the results shown on the SeaWiFS satellite maps in January and February. Though the northerly winds and lower temperatures existed during these earlier months, they had not changed enough for the scientists to get a bead on them using standard monitoring equipment, he explained. "The biology reacts much more to sub-surface conditions of the ocean than these other parameters do," Murtugudde said.

Now that he and other NASA Goddard scientists have a way to read the patterns the phytoplankton make, they should be able to detect the end of the next El Niño a month before other, more conventional detection devices do. In the future the team plans to look at what happens to the algae leading up to an El Niño. "It’s quite likely that some of the biological signatures will appear before the next El Niño. This time we will keep an eye out for them. With ocean color data we should be able to see certain things you cannot see with other measurements," Murtugudde said.

His long-term goal is to gather enough data on events like El Niño and La Niña to improve weather forecasting systems. Today, scientists can predict El Niños up to a year in advance, using complex computer simulations and data from other satellites and buoys. However, estimates of the exact months when El Niños and La Niñas begin and end are often very rough. By observing phytoplankton, scientists can track both the motion of the water on the surface and just beneath the surface. This should allow for more comprehensive models and more accurate predictions.

References

1. Njoku, E. G. and O. B. Brown, Sea Surface Temperature. In Atlas of Satellite Observations Related to Global Change, R. J. Gurney, J.L. Foster and C. L. Parkinson, (Eds.) Cambridge University Press, London, 237-249.
2. Murtugudde, R. G., S. R. Signorini, J. R. Christian, A. J. Busalacchi, C. R. McClain and J. Picaut, 1999. Ocean Color Variability of the Tropical Indo-Pacific Basin Observed by SeaWiFS During 1997-1998. In press, J Geophys. Res., 2-27.

Picking Out a Pattern for El Niño’s End

SeaWiFS is carried aboard the satellite OrbView-2, shown here in an animation orbiting over the great lakes. It provides us important information about the oceans and the life within them. (Animation courtesy Jesse Allen, Goddard Visualization Analysis Lab)