Zeev's Turnips Talk Politics (ZTTP)

[MLD38]

La Nina's brewing, forecasters warn
http://news.yahoo.com/s/ap/20070228/ap_on_re_us/la_nina_2
LA NIÑA MAY SOON ARRIVE
http://www.noaanews.noaa.gov/stories2007/s2805.htm


Info on La Niña and El Niño/Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO):

El Niño & La Niña & PDO
http://topex-www.jpl.nasa.gov/science/pdo.html
Pacific Decadal Oscillation (PDO) in the news: (background)
Jan 2000, "Pacific Ocean Showing Signs of Major Shifts in the Climate"
http://www.nytimes.com/library/national/science/012000sci-environ-climate.html?oref=slogin
...researchers said the pattern, prevalent this winter and last, might predominate for 20 or 30 years...data reflect a naturally occurring oscillation in ocean conditions, not a sign of global climate change...If the satellite images do indeed signal the beginning of a new climatic regime in the Pacific, there will be fewer and weaker El Niños and more La Niñas,"...
April 2004: Moody Pacific Unleashes Another Climate Mystery
http://www.nasa.gov/vision/earth/environment/PDO.html
includes
..."there are many other things going on in Earth's oceans that affect our weather. One is the Pacific Decadal Oscillation (PDO), first coined by researchers at the University of Washington in 1996 and now described as a long-lived El Nino-like pattern of Pacific climate variability, because both have similar climate fingerprints.
But, the PDO can last a great deal longer, 20 to 70 years, unlike El Nino or La Nina that typically persist less than 18 months. Also, while sea temperatures change most dramatically near the equator during El Nino or La Nina, the most drastic changes are typically seen in the North Pacific with the PDO.
These shifts in location of cold and warm water in the Pacific alter the path of the jet stream, the conveyor belt for storms across the continent. Changes in the jet stream result in considerable, long-term changes in weather patterns.
Recently, unusual atmospheric conditions, not consistent with the PDO or other phenomenon, have been observed in the North Pacific, leading some scientists to believe the ocean's full fury is still being underestimated, as it might possess another "climate-controller" in its arsenal."...
In the section, "Another 'Mood' for the Pacific?":
( PDO's warm (positive) phase and PDO's cool (negative) phase )
..."Previous research has suggested that temperature and pressure changes in the North Pacific and the resultant impact on the western U.S. climate could be explained simply by a "shift" in PDO phase.
Like El Nino or La Nina, the PDO comes in two distinct flavors.
During the warm (positive) PDO phase, the waters in the central North Pacific are cool, and those along West Coast of North America are warm. The opposite is true with the cool (negative) phase."...

Blog entries on PDO:
http://blogsearch.google.com/blogsearch?hl=en&client=news&q=%22Pacific+Decadal+Oscillation%2...

El Niño webpage:
http://www.elnino.noaa.gov/
is a disruption of the ocean-atmosphere system in the Tropical Pacific having important consequences for weather and climate around the globe.
Also see:
What is an El Niño?
http://www.pmel.noaa.gov/tao/elnino/el-nino-story.html
El Niño/Southern Oscillation (ENSO) Diagnostic Discussion
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.shtml
Pacific Decadal Oscillation (PDO) ( similar to El Niño/Southern Oscillation or ENSO) -
http://www.cpc.ncep.noaa.gov/products/outreach/glossary.shtml#P
A recently described pattern of climate variation similar to ENSO though on a timescale of decades and not seasons.
It is characterized by SST anomalies of one sign in the north-central Pacific and SST anomalies of another sign to the north and east near the Aleutians and the Gulf of Alaska. It primarily affects weather patterns and sea surface temperatures in the Pacific Northwest, Alaska, and northern Pacific Islands.
Two main characteristics distinguish PDO from El Niño/Southern Oscillation (ENSO):
(1) first, 20th century PDO "events" persisted for 20-to-30 years, while typical ENSO events persisted for 6 to 18 months;
(2) second, the climatic fingerprints of the PDO are most visible in the North Pacific/North American sector, while secondary signatures exist in the tropics- the opposite is true for ENSO.
Several independent studies found evidence of just two full PDO cycles in the past century:
(1) cool" PDO regimes prevailed from 1890-1924 and again from 1947-1976,
(2) while "warm" PDO regimes dominated from 1925-1946 and from 1977 through (at least) the mid-1990's.
Causes for the PDO are not currently known. Likewise, the potential predictability for this climate oscillation are not known.



La Niña webpage:
http://www.elnino.noaa.gov/lanina.html
is characterized by unusually cold ocean temperatures in the equatorial Pacific, as compared to El Niño, which is characterized by unusually warm ocean temperatures in the equatorial Pacific
Also see: What is La Niña?
http://www.pmel.noaa.gov/tao/elnino/la-nina-story.html

NOAA's El Nino/La Nina page:
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/enso.shtml

FAQ: El Niño and La Niña influence
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/prelude_to_ensofaq.shtml
Menu Items:
General Questions
Present Conditions
Forecasts
Typical U.S. Impacts
Typical Global Impacts
Hurricanes and Tornadoes
Predicting and Monitoring
Additional Links

Example:
Typical U.S. Impacts (El Niño and La Niña)
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensofaq.shtml#USimpacts

Example: (under sub-heading Hurricanes and Tornadoes)
How do El Niño and La Nina influence the Atlantic and Pacific hurricane seasons?
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensofaq.shtml#HURRICANES