La Nina and Pacific Decadal Oscillation Cool the Pacific
Click here to view full image (228 kb)
“The shift in the PDO can have significant implications for global climate, affecting Pacific and Atlantic hurricane activity, droughts and flooding around the Pacific basin, the productivity of marine ecosystems, and global land temperature patterns. ” – NASA JPL
A cool-water anomaly known as La Niña occupied the tropical Pacific Ocean throughout 2007 and early 2008. In April 2008, scientists at NASA’s Jet Propulsion Laboratory announced that while the La Niña was weakening, the Pacific Decadal Oscillation—a larger-scale, slower-cycling ocean pattern—had shifted to its cool phase.
This image shows the sea surface temperature anomaly in the Pacific Ocean from April 14–21, 2008. The anomaly compares the recent temperatures measured by the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) on NASA’s Aqua satellite with an average of data collected by the NOAA Pathfinder satellites from 1985–1997. Places where the Pacific was cooler than normal are blue, places where temperatures were average are white, and places where the ocean was warmer than normal are red.
The cool water anomaly in the center of the image shows the lingering effect of the year-old La Niña. However, the much broader area of cooler-than-average water off the coast of North America from Alaska (top center) to the equator is a classic feature of the cool phase of the Pacific Decadal Oscillation (PDO). The cool waters wrap in a horseshoe shape around a core of warmer-than-average water. (In the warm phase, the pattern is reversed).
See the entire story here:
http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=18012
See the PRESS RELEASE from JPL here:
http://www.jpl.nasa.gov/news/news.cfm?release=2008-066
Look out California agriculture. The wine industry, fruits and nut growers will be hit with a shorter growing season and more threats of frost, among other things.
Recently in Nevada County, much of their grape crop was wiped out. From The Union in Nevada County (h/t Russ Steele)
Nevada County’s agricultural commissioner will seek disaster relief from the state after tens of thousands of dollars worth of crops were ruined from last week’s freezing temperatures.
Orchard trees, wine grapes and pastures were hardest hit, Pylman said. The commissioner is compiling a report of damages that he will send to the state Office of Emergency Services in coming weeks.
“Growers don’t have anything to harvest. That’s a disaster in my mind,” Pylman said.
In Paradise, CA, Noble Orchards reports damage to their Apple crop from recent colder weather, as well as reports of issue with vineyards in the Paradise ridge area suffering from frost damage recently.
Here is a short history of PDO phase shifts:
In 1905, PDO switched to a warm phase.
In 1946, PDO switched to a cool phase.
In 1977, PDO switched to a warm phase.
California agriculture has ridden a wave of success on that PDO warm phase since 1977, experiencing unprecedented growth. Now that PDO is shifting to a cooler phase, areas that supported crops during the warm phase may no longer be able to do so.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Guys, the PDO is a *regional* phenomenon. Look at the temp map; you’ll find that there are lots of areas in the Pacific with a positive temperature anomaly. In other words, PDO is about the *distribution* of heat, not the total amount present in the atmosphere/ocean system.
In the big picture, there is one thing that warms the earth: the sun.
Likewise, there is one thing that cools it: radiative loss to space.
Variations in the first are natural, ongoing, and pretty well understood-including by the scientists who wrote the IPCC reports. (See the site RealClimate.org, if you are truly interested in understanding these issues.)
Man’s modification of the atmosphere–directly measured and beyond any dispute–affects the second. More long-wave radiation is absorbed and re-radiated as infra-red; the upper stratosphere cools (and this too has been directly measured) and the lower atmosphere–the troposphere–warms.
Natural variability will still exist; you will still have colder and warmer years. But the lowered rate of radiative heat loss superimposes an upward temperature trend on that natural variability. And that is what we see: global temps have *not* ceased to rise, contrary to much of the recent hoopla. Temps in the US Northwest may be another story over the short to medium term if the PDO observations are correct; but that just means somewhere else will be warm instead.
I have been in a brief discussion with a science journalist in England who tells me that all temperatures on all continents have increased over the last decade or so (shown by temperature anomolies since 1900). He sent me a graphic from IPCC to illustrate this. This seems to go against what I read on here. Can someone tell me which is correct?
He had originally said he trusted satellite data more than surface stations, because I had argued about the lack of control over the decades with heat islands etc. These IPCC figures must be based on surface readings I assume.
I wouldn’t be too quick to dismiss the PDO as having little more then a regional influence on temperatures. While it may not be a direct forcing it could have indirect consequences such as increased cloud formations which would reflect radiation and cause, in this case, a negative feedback influence on forcings.
I’m wondering does anyone have a link to the effects of a shift to a cool phase on the climate on the western side of the Pacific. I live in Japan and am struggling to find much info on how it’s going to effect us.