http://oceanservice.noaa.gov/education/kits/currents/media/conveyor_slideshow/26-conveyer-belt-6.jpg
This animation shows the path of the global conveyer belt. The blue arrows indicate the path of deep, cold, dense water currents. The red arrows indicate the path of warmer, less dense surface waters.
http://oceanservice.noaa.gov/education/kits/currents/06conveyor2.html
U.S. DEPARTMENT of COMMERCE
NATIONAL OCEANIC and ATMOSPHERIC ADMINISTRATION
The Global Conveyor Belt
Thermohaline circulation drives a global-scale system of currents called the “global conveyor belt.” The conveyor belt begins on the surface of the ocean near the pole in the North Atlantic. Here, the water is chilled by arctic temperatures. It also gets saltier because when sea ice forms, the salt does not freeze and is left behind in the surrounding water. The cold water is now more dense, due to the added salts, and sinks toward the ocean bottom. Surface water moves in to replace the sinking water, thus creating a current.
This deep water moves south, between the continents, past the equator, and down to the ends of Africa and South America. The current travels around the edge of Antarctica, where the water cools and sinks again, as it does in the North Atlantic. Thus, the conveyor belt gets "recharged." As it moves around Antarctica, two sections split off the conveyor and turn northward. One section moves into the Indian Ocean, the other into the Pacific Ocean.
These two sections that split off warm up and become less dense as they travel northward toward the equator, so that they rise to the surface (upwelling). They then loop back southward and westward to the South Atlantic, eventually returning to the North Atlantic, where the cycle begins again.
The conveyor belt moves at much slower speeds (a few centimeters per second) than wind-driven or tidal currents (tens to hundreds of centimeters per second). It is estimated that any given cubic meter of water takes about 1,000 years to complete the journey along the global conveyor belt. In addition, the conveyor moves an immense volume of water—more than 100 times the flow of the Amazon River (Ross, 1995).
The conveyor belt is also a vital component of the global ocean nutrient and carbon dioxide cycles. Warm surface waters are depleted of nutrients and carbon dioxide, but they are enriched again as they travel through the conveyor belt as deep or bottom layers. The base of the world’s food chain depends on the cool, nutrient-rich waters that support the growth of algae and seaweed.
http://oceanservice.noaa.gov/education/kits/currents/06conveyor3.html
U.S. DEPARTMENT of COMMERCE
NATIONAL OCEANIC and ATMOSPHERIC ADMINISTRATION
The Global Conveyor Belt
The global conveyor belt is a strong, but easily disrupted process. Research suggests that the conveyor belt may be affected by climate change. If global warming results in increased rainfall in the North Atlantic, and the melting of glaciers and sea ice, the influx of warm freshwater onto the sea surface could block the formation of sea ice, disrupting the sinking of cold, salty water. This sequence of events could slow or even stop the conveyor belt, which could result in potentially drastic temperature changes
http://www.komonews.com/weather/blogs/scott
KOMOnews.com
Add it to the pile: March sets record for all-time warmest in Seattle
By Scott Sistek Published: Apr 1, 2015 at 5:00 AM PDT
The end-of-the-month blogs these days seem to write themselves, just change the month...
For the fourth time in the past six months, Seattle has set the record for all-time warmest month. March 2015 now joins brethren October, December and February as the warmest on record at Sea-Tac Airport (70 years of data) by average monthly temperature -- found by taking the high and low and divided by two.
This month, the average temperature was 50.5 degrees, just beating 1992's 50.3 degrees. By average high temperature, we came in second place at 57.8 degrees, lagging only behind 1992's 59.1 degrees.
(The readings are behind three others from before Sea-Tac was "born" and records were kept in Downtown Seattle, including a 53.1 average temperature reading in 1941.)
March has featured a bit of extremes, with a mix of sunshine and very warm temperatures for several days, and drenching rains the next. The 2.20 inches of rain that fell on March 15th was the second wettest March day at Sea-Tac. On the other hand, 11 of the 31 days were 60 degrees or warmer, and only three days of the month were considered below normal and none since March 4.
The month also appears to be cementing that Feb. 1 may go down as our last day of the season with a high under 50 degrees which usually that date isn't until well into March, sometimes April.
And March will now make it 13 consecutive months that we've had above normal temperatures.
I've made a short graph to show our amazing warm stretch by average monthly temperature and where the months rank overall in parenthesis -- again this is through 70 years of data):
And as the blog I wrote two weeks ago says (and will probably write again in two weeks), the long range forecasts show no stopping to the overall warm weather pattern -- perhaps lasting through the summer.
KOMOnews.com
- posted by H.V.O.M - Kerry Wayne Burgess 11:10 PM Pacific Time Spokane Valley Washington USA Wednesday 01 April 2015
