Since spring 2015, El Nino conditions have developed in the tropical Pacific Ocean.
El Nino is recognized by unusually warm waters adding below the surface in the
eastern tropical Pacific, but it's actually a much broader atmosphere ocean
fluctuation that involves slacking trade winds, eastward shift of tropical clouds, and
precipitation patterns across the tropical Pacific, along with warmer
waters and higher sea levels that spread poleward along the west coast of North
and South America. El Nino brings an enormous change in the amount of heat
and moisture that is transferred from the tropical Pacific to the atmosphere
and this affects weather patterns on a global scale. Here on the california
coast, we may see heightened sea levels, high ocean waves, and sometimes heavy
precipitation. Throughout history, strong El Ninos have caused destruction to
coastlines, floods, droughts, ecosystem shifts, and other disturbances that have
afflicted regional economies, fisheries, and agriculture. A handful of pioneering
scientists, including Tim Barnett here at Scripps Institution of Oceanography at UC
San Diego, began to study and model El Nino in the 1970s.
More broadly, the quest to fully understand El Nino was highlighted to the public when
a very large El Nino developed in 1982. Although this was one of
the most destructive El Ninos in modern history, it arrived almost unnoticed.
A couple of us, one here and one at Lamont, developed mathematical, more sophisticated
mathematical models for El Nino prediction. And they worked out really well.
The first one, however it was done, was done in '82-'83 and at that time there was
a gathering of the US El Nino prediction experts, all seven or eight of us. We had
a meeting because things were strange in the tropics. In 1982, observations and our
ability to forecast El Nino was still in an early phase of development. In summer
that year, the initial data stream indicated exceptionally warm tropical
Pacific waters, but it was so much warmer than average conditions that the data
were rejected. Weeks later, after persistently warm ocean temperatures
kept appearing, the data were correctly taken seriously and it was recognized
that a mighty event was underway. In fact there were _ who said, "There will be no El Nino this
year" and he slammed his fist down at the end of the meeting.
Well of course, a month later we realized we were in the middle of the biggest
event of the century. A lot of new funding came in and the two groups, one in Lamont and one here,
developed numerical prediction models for El Nino and tried them out on the big one
of 1987-88, I think, and nailed it, it was beautiful. By the 1990s, our
capability to detect El Ninos had improved substantially. In summer '97,
when signs of another major El Nino were appearing, Scripps Oceanography began to
sound the alarm and notify the public that an active winter was likely in store.
The next few months where nerve wracking. We had gone out on a limb with the prediction, but
North Pacific and California weather patterns in the early winter were relatively calm,
so the public and the media began to murmur that we had sounded a false alarm.
Finally in late January 1998, North Pacific storms arrived in full force and we
saw our most active winter since the 1982-83 El Nino winter. The '97-98 El Nino was the biggest one in
the past 50 or 60 years, but the '82-83 El Nino was the biggest one before that and we had a lot more
coastal damage in California during the '82-83 El Nino, even though it was samller. And the reason is
because the storms during that El Nino happened to come during high tide,
so there was a lot of coastal damages; these storms came, they raised local sea levels
and the waves crashing on the shore so it was a lot of damage. So, to some extent the
degree of damage you from an El Nino is somewhat of chance, whether or not the storms come when the
tide is high. When we make our forecast we use a number of different data sources
there's a string of buoys across the tropical Pacific that measure both at the
surface and below the surface, which is really useful for initializing our
models and then there's satellites which give us temperatures across the whole
tropical Pacific Ocean and those are the main data sources we use when we
initialize our model. This year, 2015, we are seeing signs of an event that is nearly
as strong as any we've seen in the last 60 years. Scientists at Scripps
Institution of Oceanography had developed and produced an array of tools
that we didn't have during the last great El Ninos. These developments
allow us to track the present El Nino and its impacts with much better
coverage and greater detail. This network, which was instituted shortly after the
'97-98 El Nino, now contains about 4,000 floats that cover every ocean basin and
transmits data in nearly real-time to scientists throughout the world. We have
newer ways to observe the ocean, one of them being profiling floats as in the Argo array,
and something we've done over the past two years, especially Dean Roemmich, has put out
another 40 some odd floats at the equator and then almost ten years ago we
started a project to use underwater gliders to observe the local responses
to large-scale climate variability like El Nino. We started this because we know
that a lot of the climate variability we see locally is caused by forces far away,
like at the equator, so we have gliders that go back and forth along three lines,
repeating those lines roughly every three weeks and they've been doing that since
2006. As this year's event develops, Scripps Oceanography has been a central
player in deploying and demonstrating the power of continuous oceanic observations.
The autonomous devices that are making it possible to observe the El Nino are a
cost-effective technology that has led to new understanding and increased
global predictive capacity. To sustain this network, however, new federal
investments are crucially needed. This network is vital to helping communities
plan for and cope with environmental events and longer period changes.
Understanding how to adapt to El Nino and other future weather extremes will
require a collective effort that goes beyond our community of scientists.
This year, we are looking for the public's help as well.
The existing El Nino has raised concerns about the effects of energetic waves along
the shoreline. Through SCCOOS, we hope to engage the public to actually help us
document some of the damage that will be done or potentially that could be
done during this system. We have developed several products and one of
them is actually this flooding index which gives a three-day indication to the general public
of what the conditions are along the shoreline.
We publish a thing, locally, called the El Nino index, which is a measure of temperature from our
underwater gliders. A lot of people use it to see what the local temperature is
in response to climate variability. We're always trying to find a way that we can
really talk to the people who make the decisions about emergency management,
water management, fire management, for that matter, and you know try to
communicate to them the forecast in the way that's most useful for them.
And earlier this year, Scripps Oceanography launched a new, coordinated effort called the Center for
Climate Change Impacts and Adaptation. This center will draw together expertise
of ocean and climate sciences with that of social scientists, engineers, educators and others.
The center's mission is to help society make informed decisions about adaptation to climate change.
When when when one thinks about the future, where we're going as a field,
there's a tremendous need for climate information, long-term planning,
and so on. And to to do it right, you need not only to be able to predict what the
ocean or the atmosphere are doing but what associated things are doing how is the
soil or at the beach littoral cell going to react to a major change in climate or
wave conditions. So, with this new center that we have, I think it's an excellent
opportunity to construct a model something like that almost a business
model, if you want, that gets us from the El Nino prediction down to what the sea
level rise is going to be at the La Jolla shores this winter.
This year's El Nino presents us with great challenges, but it's an enormous
opportunity. The scientific understanding that we're developing at Scripps is
allowing us to put information to work that should improve public safety and
help plan for future changes.