Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Pacific Dictates Droughts and Drenchings

29.01.2004


The cooler and drier conditions in Southern California over the last few years appear to be a direct result of a long-term ocean pattern known as the Pacific Decadal Oscillation (PDO), according to research presented at the 2004 meeting of the American Meteorological Society.


Positive and Negative Phases of Pacific Decadal Oscillation

This image shows the Pacific Ocean sea surface temperature changes associated with positive and negative phases of the Pacific Decadal Oscillation. The colors in these maps represent temperature anomalies--differences from the average sea surface temperature during the cool and warm phases of the PDO. Units are degrees Celsius. Credit: Image courtesy of Steven Hare and Nathan Mantua, University of Washington.


Jason-1 Image of Pacific Ocean, January 23, 2004

The latest remote sensing data from NASA’s Jason satellite show that the equatorial Pacific sea surface levels are higher, indicating warmer sea surface temperatures in the central and west Pacific Ocean. This pattern has the appearance of La Niña rather than El Niño. This contrasts with the Bering Sea, Gulf of Alaska and U.S. West Coast where lower-than-normal sea surface levels and cool ocean temperatures continue (indicated by blue and purple areas). Although subtle, the negative PDO anomaly pattern can be seen in this early 2004 image.

The image above is a global map of sea surface height, accurate to within 30 millimeters. The image represents data collected and composited over a 10-day period, ending on Jan 23, 2004. The height of the water relates to the temperature of the water. As the ocean warms, its level rises; and as it cools, its level falls. Yellow and red areas indicate where the waters are relatively warmer and have expanded above sea level, green indicates near normal sea level, and blue and purple areas show where the waters are relatively colder and the surface is lower than sea level. The blue areas are between 5 and 13 centimeters (2 and 5 inches) below normal, whereas the purple areas range from 14 to 18 centimeters (6 to 7 inches) below normal. Credit: NASA



The study, by Steve LaDochy, associate professor of geography at California State University-Los Angeles; Bill Patzert, research oceanographer at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.; and others, suggests Pacific oceanic and atmospheric measurements can be used to forecast seasonal West Coast temperatures and precipitation up to a year in advance, from Seattle to San Diego.

An important climate controller, the PDO is a basin-wide oceanic pattern similar to El Niño and La Niña but much larger. The PDO lasts many decades rather than just a few months like El Niño and La Niña. The climatic fingerprints of the PDO are most visible in the North Pacific and North America, with secondary influences coming from the tropics. The long-term nature of the PDO makes it useful for forecasting, as its effects persist for so long.


Since mid-1992, NASA has been able to provide space-based, synoptic views of the entire Pacific Ocean’s shifts in heat content with the Topex/Poseidon mission and its follow-up mission, Jason (which began in 2001). Before these satellites were available, monitoring oceanic climate signals in near-real time was virtually impossible.

The remarkable data and images can tag and monitor the shifts in short-term climate events, like El Niño and La Niña, and long-term events such as the PDO. These data provide a 13-year continuous, complete time-series of two major El Niños and two La Niñas, and have made it possible to detect a major phase shift of the PDO. Patzert and LaDochy show these data, combined with longer-term studies of land-based data, provide a powerful set of forecasting tools.

The PDO shifted to a negative, cool phase, leading to wetter conditions in the U.S. Pacific Northwest, and drier than normal conditions in Central and Southern California this decade. Since the last 1997-1998 El Nino, the Los Angeles area had only 79 percent of its normal rainfall, Patzert said. Lake Mead, the great fresh-water reservoir in southeast Nevada, is at less than 50 percent of normal capacity. Also, huge West Coast fires over the past few years have been greatly exacerbated by PDO-induced drought, Patzert added.

"These shifts in the PDO are long-term tendencies, which actually have a bigger economic impact than El Niño," said Patzert. "People talk about floods from El Niño, but what really has a harsh and costly impact is a five-year drought."

"A full cycle of the PDO (cool to warm and back to cool) runs about 50 years," said LaDochy. "Over the next several years there is going to be a tendency toward dry and colder temperatures in the southern U.S. West Coast. It is very difficult to forecast day-to-day here on the West Coast, but we can say with some confidence that over the next five years, we’d better start saving water."

The researchers used over 50 years of U.S. climatic information, and Pacific atmospheric and oceanic data from the National Oceanic and Atmospheric Administration National Centers for Environmental Prediction. By comparing data sets, they saw strong correlations between Pacific climate patterns, temperatures and precipitation trends on the West Coast. They then were able to develop "hindcasts" to explain temperature and precipitation variability for West Coast regions. These decadal cycles also will be useful for explaining future regional climate variability.

NASA’s Earth Science Enterprise is dedicated to understanding the Earth as an integrated system and applying Earth System Science to improve prediction of climate, weather and natural hazards using the unique vantage point of space.

Krishna Ramanujan | GSFC
Further information:
http://www.gsfc.nasa.gov/topstory/2004/0116westcoast.html

More articles from Earth Sciences:

nachricht Research sheds new light on forces that threaten sensitive coastlines
24.04.2017 | Indiana University

nachricht NASA sees the end of ex-Tropical Cyclone 02W
21.04.2017 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>