214
H. von Storch, J. S ¨
undermann, and L. Magaard
out that we really didn’t know how the big trade wind field varies from year to year.
When I asked the meteorologists, they could not tell me. That is when we started
to get the ship observations, the wind observations, and crunched 25 years of ship
observations—there were 3 million observations at that time for the equatorial Pacific
Ocean. We learned that the trade wind fields undergo massive changes from year to
year. Analyzing these changes I found out that the biggest changes are not off Peru
or somewhere near the Galapagos, but they are in the Central Pacific, real massive
changes of the Southeast trade winds.
At the same time we were looking at the ideas of Bjerknes, who was working
on the tropical ocean and tropical ocean– atmosphere interaction. There was Namias
at Scripps who was working on the North Pacific—U.S. mainland interactions. In my
personal case, came the insight that the fluctuations of the wind stress on the equator
are producing El Ni˜ no. Of course we had to prove it, which brought the sea level
data in, because the claim was that the thermocline in the western Pacific goes up and
the thermocline in the eastern Pacific goes down. We could prove by means of sea
level data that these two things really happen, because there is a direct relationship
between sea level changes and thermocline changes. Putting these things together
gave the El Ni˜ no theory and also the knowledge that was developed at that time
about equatorial Kelvin waves. But it was basically an observational fact-finding, an
analysis of observations and putting the pieces together.
The fact that sea level is a very convenient variable to monitor the ocean gave
the impetus for establishing the sea level network in the Pacific. With this you could
study dynamics—that was before TOPEX.
Has your work become more systematic over the years? You have told us that you
have dealt with various interesting pieces in the first part and after you have started in
Hawaii that you really zoomed in on one thing and became more and more systematic.
Is that a fair description?
Yes and no, there is certainly a truth in that, but I don’t think that it is intentional,
it is simply based on the fact that your experience grows. You are exposed to more
information; you learn about more processes and therefore you start to integrate your
knowledge. Integrating knowledge is a very important thing.
So it is more or less normal, just a fact of getting older and more experienced.
It is a natural process.
Have you always been in a beginning of a new period, at a new investigation, of new
phenomena in your different stations—first in Indonesia, later in Australia, then in
Scripps, and finally in Hawaii?
Again, yes and no. You know you jump at opportunities. Recognizing the opportunities is important and may be part of learning. These were all natural developments—it
had to come to that, once you study the variability you necessarily get into climate and
into climate change. If you think on the large scale then that is a natural way to go. Most
H. von Storch, J. S ¨
undermann, and L. Magaard
out that we really didn’t know how the big trade wind field varies from year to year.
When I asked the meteorologists, they could not tell me. That is when we started
to get the ship observations, the wind observations, and crunched 25 years of ship
observations—there were 3 million observations at that time for the equatorial Pacific
Ocean. We learned that the trade wind fields undergo massive changes from year to
year. Analyzing these changes I found out that the biggest changes are not off Peru
or somewhere near the Galapagos, but they are in the Central Pacific, real massive
changes of the Southeast trade winds.
At the same time we were looking at the ideas of Bjerknes, who was working
on the tropical ocean and tropical ocean– atmosphere interaction. There was Namias
at Scripps who was working on the North Pacific—U.S. mainland interactions. In my
personal case, came the insight that the fluctuations of the wind stress on the equator
are producing El Ni˜ no. Of course we had to prove it, which brought the sea level
data in, because the claim was that the thermocline in the western Pacific goes up and
the thermocline in the eastern Pacific goes down. We could prove by means of sea
level data that these two things really happen, because there is a direct relationship
between sea level changes and thermocline changes. Putting these things together
gave the El Ni˜ no theory and also the knowledge that was developed at that time
about equatorial Kelvin waves. But it was basically an observational fact-finding, an
analysis of observations and putting the pieces together.
The fact that sea level is a very convenient variable to monitor the ocean gave
the impetus for establishing the sea level network in the Pacific. With this you could
study dynamics—that was before TOPEX.
Has your work become more systematic over the years? You have told us that you
have dealt with various interesting pieces in the first part and after you have started in
Hawaii that you really zoomed in on one thing and became more and more systematic.
Is that a fair description?
Yes and no, there is certainly a truth in that, but I don’t think that it is intentional,
it is simply based on the fact that your experience grows. You are exposed to more
information; you learn about more processes and therefore you start to integrate your
knowledge. Integrating knowledge is a very important thing.
So it is more or less normal, just a fact of getting older and more experienced.
It is a natural process.
Have you always been in a beginning of a new period, at a new investigation, of new
phenomena in your different stations—first in Indonesia, later in Australia, then in
Scripps, and finally in Hawaii?
Again, yes and no. You know you jump at opportunities. Recognizing the opportunities is important and may be part of learning. These were all natural developments—it
had to come to that, once you study the variability you necessarily get into climate and
into climate change. If you think on the large scale then that is a natural way to go. Most