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Nasa and El Nino

Sky ViewIn January, 1998, I dug out my old cutoff shorts, dusted off my bicycle and went for a relaxing ride around a neighborhood that at that time of year is normally buried under two feet of snow and where a winter day above 30 degrees is considered balmy. It was 85 degrees that day in Canada. Later this year, on the Pacific Coast Highway in Southern California, I watched the driver of a Miata frantically attempt to keep the water level in his car from reaching the dashboard, using only a takeout coffee cup. Through the torrential downpour, the driver tried to follow a 4X4 through a very large puddle and lost. The Paita sailors, who frequently navigate along the coast in small craft... name this countercurrent the current of "El Nino" (the child Jesus) because it has been observed to appear immediately after Christmas. As this countercurrent has been noticed on different occasions, and its appearance along the Peruvian coast has been concurrent with rains in latitudes where it seldom if ever rains to any great extent, I wish, on the present occasion, to call the attention of the distinguished geographers here assembled to this phenomenon, which exercises, undoubtedly, a very great influence on the climatic conditions of that part of the world.

Senor Dr. Luis Carranza
President of the Lima Geographical Society, 1895
If these occurrences seem strange, they are by no means unusual. They are simply part and parcel of a global weather phenomenon that we have come to know as "El Nino".
Due to the severe weather conditions that have recently affected many parts of the planet, El Nino has become a household name. Forest fires in Florida, tornadoes in California and floods in Manitoba, are just a few El Nino events that made the headlines this past year.
For most people El Nino, the harbinger of unusual weather, was a temporaray inconvenience expected to depart with the arrival of summer. And to a large extent, the weather has returned to normal. What very few people don't realize is that El Nino has not actually gone away. Or perhaps more accurately, it has gone away but it will soon return. Despite what most of us may think, this is not the first El Nino and it is not likely to be the last. The reality is that El Nino is not a one time freak phenomenon; it is just another part of the earth's natural weather pattern.
What we must keep in mind is that the severity of the floods, tornadoes, and droughts of the past year may not be entirely attributable to El Nino. There is a possibility that the global climate pattern is actually shifting. If this is the case the weather events of the past year need to be taken very seriously, as the future of global food production may potentially be in jeopardy. For now, continued study of the earth's weather systems will allow countries to better prepare and mitigate the effects of floods and droughts.
With El Nino wreaking havoc on the world's seasonal weather predictions, scientists have recognized the need for more advanced forecasting models. Currently, operational responsibility for weather forecasting is the jurisdiction of the National Oceanographic and Atmospheric Administration (NOAA). However, since El Nino has global impact, weather observations networks have come to include satellite monitoring. In the US, this has occurred with the help of NASA.

ABILITY Magazine recently spoke to NASA scientist, Dr. Tony Bassalachi about NASA's role in the study of El Nino and how satellite monitoring may help improve the future predictability of El Nino events.

Chet Cooper: What is El Nino?

Tony Bassalachi: The first thing to realize about the El Nino phenomenon is that it doesn't exist in the ocean by itself and it doesn't exist in the atmosphere by itself. It is a result of the two being coupled, beginning in the tropical Pacific. This coupling point is an area that spans one third the circumference of the globe. Because of its magnitude, we now know that it affects world weather patterns.

CC: How are El Nino and La Nina related?

TB: El Nino and La Nina are basically one in the same. They are part of the same process. You can basically think of it as the flip-side or opposite of El Nino. That's very simplistic, but whereas the tropical Pacific is warm during El Nino, it's colder than normal during La Nina. Now, why doesn't every El Nino have a La Nina that follows it? We really don't know. But we do understand the fundamental cyclical processes that give rise to El Nino, then to La Nina and back to El Nino again on these three to seven year time scales.

CC: How is NASA involved?

TB: One of the things that the 1997-98 El Nino really brought home was that you can't just focus your attention on the tropical Pacific Ocean. You really need to also take into account the contributions from the water temperatures in the tropical Atlantic and the tropical Indian oceans. To monitor El Nino and increase our overall understanding of the interaction between the ocean and the atmosphere helps improve our forecasting ability and is the real reason that we really need the satellites. The satellites provide us with a sort of global overview. From NASA's perspective, there is a need for global coverage that some of the satellites provide. However, in the future it will be a blend of the sort of satellites NASA is putting up and instruments that NOAA is putting in the ocean that will really offer the hope of improving our forecast field and predictions, for the betterment of societies around the world. I don't just mean for developing countries in the tropics, but also for developed countries such as North America as well.

CC: Before El Nino actually arrived there was considerable warning and evidence that something big was happening. What's the history of tracking this type of phenomenon?

TB: The last El Nino event of the century was in 1982-83. That El Nino event really caught the scientific community off-guard in that we didn't know that an event was underway until several months after the fact, because we just didn't have the observation capability we have today. So, as a result of getting caught unaware, the international scientific community really mobilized and focused effort on improving prediction models, putting more observation into the ocean and more satellites in orbit. It was called the TOGA program, Tropical Ocean Global Atmosphere program, which was part of the World Climate Research Program, within the World Meteorological Organization. That was about a ten year program from 1985 to 1994. The sort of ability we have now to monitor El Nino in real time and the predictive skill that we have today is a direct result of the intense international effort during that decade.

CC: How is NASA involved in forecasting global weather patterns?

TB: The operational responsibility for weather forecasting in this country is NOAA's responsibility. So, they have the operational forecast model. They also have the operational observational network for weather forecasting.
At NASA, we don't do operational forecasts. What we are doing is developing new satellites, using them in a monitoring mode and assessing the extent to which new satellite observations advance forecast skill, so that in the future, provided we can make them affordable, these observations satellite systems can be transferred to NOAA. If a satellite platform is shown to advance forecast skill, then NASA's responsibility is to make it affordable, demonstrate how one can develop the models to utilize and exploit this observational information, and then hand the systems to NOAA for them to use in an observational sense. So, in that regard, NASA is looking to develop new satellite based measurement platforms and models for the ocean and atmosphere that can assimilate those observations.

CC: Where are we in terms of the technology used for tracking? Have there been many advances in technology in the US since the TOGA program in 1994?

TB: No, and that's a potential problem in the US right now. Our colleagues, overseas, have access to computer platforms that we don't have access to here in the US. Basically, since the end of the Cold War the market just isn't there anymore for super computers in this country. So, the Japanese are building computer platforms, which countries outside the US have access to, but for whatever reasons, we really don't. So, it's going to be interesting to see how this super computing problem plays out in the years ahead.

CC: Is global warming in some way linked to El Nino and are humans contributing to the increased severity of El Nino events?

TB: Obviously researchers are looking at the extent to which global warming is anthrogenic [human caused]. There is already natural variability going on and there is a suspicion, but we don't know for certain, that if you put more energy into the system, you have a warmer climate that these natural modes of oscillation like El Nino would intensify.

CC: Do we know why the 1997 El Nino event was so much more severe than the 1982-83 event?

TB: No, we don't understand why this event was as large as it was. Was it a result of global warming? We don't know. But there are signs that the warming in the Indian Ocean and the warming in the Atlantic Ocean was related to El Nino.

CC: With the information gathered to date, is there an emerging explanation for the changing and unseasonable temperatures of the oceans?

TB: There are some ideas. Again, nothing is one hundred percent certain, but there's some suggestions that this El Nino event changed the major heat sources to the atmosphere. What I mean by heat sources are these areas where we have a lot of rising moist air, called convection zones. So, for example, normally we have a lot of warm, moist air rising over Indonesia, which sinks over Ecuador and Peru. That explains why there is a lot of rainfall in Indonesia and dry conditions over Ecuador and Peru. During El Nino that heat source shifts eastward, which means that the rising air is further to the east, which also means the descending air is further east, not in its normal location. There's some thinking that as a result of this heat source being moved away from Indonesia, it has changed the circulation patterns for both the atmosphere and the ocean currents of the Indian Ocean.

CC: But what causes the rising air to shift?

TB: El Nino. Normally the warmest water of the world's oceans is in the far west tropical Pacific. It's about eighty six degrees Fahrenheit and it's kept in place by the trade winds. During El Nino that system breaks down, the trade winds weaken, and the winds that brought the cold water to the surface in the eastern equatorial Pacific are no longer there. So, the warm water essentially begins to migrate eastward.

CC: From what you can tell, is El Nino an indicator of a large shift in the global climate, or is it just another part of the earth's natural variability?

TB: I would say that it is premature to speak of shifts. Clearly, we have seen a tendency towards more severe events...floods, droughts, tornadoes. That's been documented. However, the ultimate cause of that is still under debate.

 


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