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 Scientists shed light on carbon's descent into the deep Earth
19.07.2017 | European Synchrotron Radiation Facility

nachricht Thawing permafrost releases old greenhouse gas
19.07.2017 | GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

Leipzig HTP-Forum discusses "hydrothermal processes" as a key technology for a biobased economy

12.07.2017 | Event News

 
Latest News

Researchers create new technique for manipulating polarization of terahertz radiation

20.07.2017 | Information Technology

High-tech sensing illuminates concrete stress testing

20.07.2017 | Materials Sciences

First direct observation and measurement of ultra-fast moving vortices in superconductors

20.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>