Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

El Nino’s surprising steady pacific rains can affect world weather

21.08.2003


EL NiñoS STEADY PACIFIC RAINS

These composite images show that the largest amounts (red) of stratiform rain, up to 60%, occur in the central Pacific during El Niño, such as occurred in the 1998 event. 1999 and 2000 were not El Niño years. CREDIT: University of Washington/NASA


GRAPHING EL Niño RAINS

These graphs were created from the TRMM satellite’s Precipitation Radar. The top graph shows that almost 60% of the rains that fell around 135 degrees latitude around the equator (central Pacific Ocean) were stratiform, so 40% were convective (thunderstorms). The bottom graph shows that almost 150 mm (5.9 inches) of rain fell in that area during an El Niño. CREDIT: UWA/NASA


Scientists using data from a NASA satellite have found another piece in the global climate puzzle created by El Niño. El Niño events produce more of a steady rain in the middle of the Pacific Ocean. This is important because whenever there is a change in the amount and duration of rainfall over an area, such as the central Pacific, it affects weather regionally and even worldwide.

The findings appeared in a paper authored by Courtney Schumacher and Robert Houze, atmospheric scientists at the University of Washington, Seattle, who used data from NASA’s Tropical Rainfall Measuring Mission (TRMM) satellite to look at rainfall over the Pacific during the 1997-1998 El Niño. The study was published in a recent issue of the American Meteorological Society’s Journal of Climate.

El Niño occurs when warm water shifts from the western to the eastern Pacific Ocean and trade winds that usually blow from east to west across the equator diminish. As a result, rainfall patterns around the globe change during the life of these periodic climate events, and in some areas create floods or droughts. By identifying the changes in rainfall in one area of the globe, such as the central Pacific Ocean, scientists continue to piece together the El Niño puzzle that will help them improve rainfall forecasts around the world during the life of El Niño.



Schumacher and Houze noticed an unusually steady rainfall over the central Pacific, much like a gray day with light rain and drizzle. That is surprising over the central Pacific, an area normally known for thunderstorms that build up during the heat of the day from rapidly rising air or convection, and then rain themselves out within an hour.

"Instead, the rainfall we saw is called ’stratiform rain,’ which are weaker rains that cover larger areas," Schumacher said. It’s the type of rain that makes people want to stay inside all day.

Seeing the difference between the convective and stratiform rain is very important to climatologists. Rain type matters because when water condenses and raindrops form, heat is released. That heat is a main driver in the circulation or movement of the atmosphere. "Convective rain, like from thunderstorms, releases heat lower in the atmosphere, while the steady, light, stratiform rain releases heat higher in the atmosphere," Houze said.

Heat released at different levels of the atmosphere affects the vertical and horizontal movement of air. As a result, the heat from different types of rain can alter weather patterns, such as the familiar jet stream which impacts the United States. Weather prediction models benefit from better knowledge of the changing jet stream patterns, because storms like summer thunderstorms and winter snowstorms follow the path of the jet stream.

The researchers noted that because increased stratiform rains warm the upper levels of the atmosphere, that additional heat strengthens the way air moves higher up and over a larger area than thunderstorm-generated rainfall. The larger area of air affected can impact weather patterns around the world.

Although scientists are still uncertain why such large amounts of stratiform rain happen in the middle of the Pacific, especially during El Niño, observations from the TRMM satellite have allowed them to recognize this pattern. By identifying the type of rainfall, climatologists and meteorologists can make better rainfall forecasts in other areas of the world during the event.

"That’s the beauty of NASA’s TRMM satellite," said Jeff Halverson, TRMM outreach scientist from NASA’s Goddard Space Flight Center, Greenbelt, Md. "TRMM can see what’s happening in remote areas of the tropics that can have affects on the rest of the world."


TRMM is a joint NASA/Japanese Space Agency mission to study tropical rainfall and its implications for climate. Each day, the TRMM spacecraft observes the Earth’s equatorial and tropical regions.

This research was funded by NASA’s Earth Science Enterprise (ESE), the National Science Foundation and the National Oceanic and Atmospheric Administration. NASA’s ESE 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.

Rob Gutro | Goddard Space Flight Center
Further information:
http://www.trmm.gsfc.nasa.gov
http://www.gsfc.nasa.gov/topstory/2003/0818elNino.html
http://www.ametsoc.org/AMS/

More articles from Earth Sciences:

nachricht New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz

nachricht Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>