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Post by sigurdur on Nov 24, 2016 7:22:17 GMT
Sig what is Gag Wag or is GAWG. the answer is yes that is fast per 100 year change would be significant. The question in my mind is if the world had had no surge in human kind over the last 1000 years but had simple rebounded from the LIA what would the world be like now? would it even be different? (outside of us) This is not a question about the sound not being there if there is nobody to hear it. That type of ego centrism is the domain of the ruling class in their bubbles of self importance and bewilderment of the Trumpocene. I don't know what the world would be like. I am one of those uneducated deplorables that some think can't possess knowledge. What I do know is that the earth is well within the Holocene temperature parameters. Has the current warming been swift and fleet of Hoof? Not really, if one examines paleontology data. But then, being one of the unwashed masses who doesn't have a formal PhD, how could I make an intelligent Analysis? According to some smart fellers and ladies, what we are observing has never happened before. The paleontology record, as established, must be like some of the current record. Massaged perhaps? Or a fertile field to be Massaged in the Future? The alarm by some indicates a fear of the future because it will change. I just don't get the fear part. I personally embrace change. I really embrace change that based on data looks like a very promising future!
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Post by nautonnier on Nov 24, 2016 9:23:13 GMT
www.livescience.com/4180-sahara-desert-lush-populated.htmlThe climate change at [10,500 years ago] which turned most of the [3.8 million square mile] large Sahara into a savannah-type environment happened within a few hundred years only, certainly within less than 500 years," said study team member Stefan Kroepelin of the University of Cologne in Germany. I know, I know, GAWG or such. It happened within a few hundred years only. Is that rapid climate change? When you consider that the proxies that were used in the study probably have a resolution of around 500 years it could well have been faster than that. However, what is more interesting is that the change was due to a change in weather patterns. The only way that could happen is if the shape or extent of the Hadley and Ferrel cells was to alter. We are already seeing the jet stream marking the Hadley/Ferrel boundary dropping South to the Iberian peninsula. Is it possible that there is an atmospheric pattern in which instead of three cells: Hadley, Ferrel (aka mid-latitude), Polar - there is a four cell pattern or perhaps a two cell pattern with no Ferrel cells? These could be considered 'Strange Attractors' that is different stable climate states that occur when the energy from the Sun is insufficient or too great for the Hadley cell downdraft to be over the Sahara (and the other deserts at that latitude). If so the Kalahari should show the same change at around the same time 10Kyr BP.
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Post by missouriboy on Nov 24, 2016 17:44:51 GMT
Excellent conversation. Pressure patterns and sources of moisture. To the East we have the Indian subcontinent and its well known monsoons at the same latitude. The geographic setup and seasonal pressure patterns are well known ... as are the moisture sources. Changes in the seasonal pressure patterns centered on the high Tibetan Plateau direct traffic here. Strong summer lows 'suck' moisture from the Indian Ocean. The western transition to dry at this latitude is very sharp ... and this boundary pulses east and west based on what? What kind of setup is required to move massive amounts of moisture north of its current placement in the Sahel? Is there a currently absent low-pressure setup in or north of Europe? In a zone dominated by Easterlies, summer moisture would have to come from the Indian Ocean, or, by extreme diversion, from the Atlantic. Winter moisture would have to come from southward diversion of Westerly Atlantic air masses.
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Post by nonentropic on Nov 24, 2016 18:49:35 GMT
The cells are driven by the atmospheric height gradient from convergent to pole.
Naut do you know how this all sits together?
We all know what its like to be on the leading or trailing side of an anticyclone most especially if they choose to stall. It defines the difference between say a barbecue summer or a wet and cool one (Northern Europe) but the cell latitude and number is much more defining from a planetary climate perspective.
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Post by nautonnier on Nov 24, 2016 21:33:22 GMT
The cells are driven by the atmospheric height gradient from convergent to pole. Naut do you know how this all sits together? We all know what its like to be on the leading or trailing side of an anticyclone most especially if they choose to stall. It defines the difference between say a barbecue summer or a wet and cool one (Northern Europe) but the cell latitude and number is much more defining from a planetary climate perspective. The major heat from the sun is at the equator - or more correctly between the tropic of Cancer and Capricorn. This heat causes the convective upcurrents at the intertropical convergence zone (ITCZ). This is like putting heat at a point on a pan of liquid and as it comes to boil watching it start bubbling up where the heat is. This is what drives the entire atmospheric circulation. If the Hadley cells are strong then the jet streams are meridonal and stable but if the convection is weak then the jetstreams and the Ferrel cells follow a more latitudinal path. This is due to the effect of Rossby waves that occur when fast moving fluid runs past slow moving fluid. The Rossby waves are the track of the low pressure areas around the Ferrel cells - these depressions are cloudy - the more Rossby wave loops there are in the jet stream the longer the path of the depressions and the more clouds there are. Clouds increase the albedo of the Earth so there is more cooling. But the reduction in the Hadley cells was due to cooling. So the increase in Rossby waves is a feedback to cooling that increases the cooling.
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Post by icefisher on Nov 25, 2016 17:19:35 GMT
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Post by graywolf on Nov 27, 2016 12:46:57 GMT
www.nature.com/nclimate/journal/v6/n10/full/nclimate3058.htmlI must admit I have been waiting for this research to arrive! We are now at the tail end of Chinese forced Dimming as they push to clean up emmisions to curtail their rising death rates that the pollution is causing in major urban centres? Unlike ourselves the Chinese can buy 'off the shelf' cleaning technologies ( developed in the West when we cleaned up our polluting ways!) and so their move toward a cleaner industrial society will be far faster than we saw in the U.S./Europe due to the technology already being available to scrub out pollution but also their push into using renewables ( not an option in 1970's Europe/U.S.?). As such we will see impact of Asian dimming fall away over the coming decades. The flip of the IPO/PDO may well be linked to higher levels of solar now bathing the areas downwind of Asia as the 'brown cloud' dissipates.
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Post by missouriboy on Nov 27, 2016 16:01:52 GMT
www.livescience.com/4180-sahara-desert-lush-populated.htmlThe climate change at [10,500 years ago] which turned most of the [3.8 million square mile] large Sahara into a savannah-type environment happened within a few hundred years only, certainly within less than 500 years," said study team member Stefan Kroepelin of the University of Cologne in Germany. I know, I know, GAWG or such. It happened within a few hundred years only. Is that rapid climate change? Here is a more recent one using dust content of marine deposits to date the most recent drying of the Sahara. So ... what really did happen between 10,000 and 5,000 yeara BP to moisten a whole east-west slice of a continent? Where did that water come from?www.livescience.com/28493-when-sahara-desert-formed.html
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Post by nautonnier on Nov 27, 2016 16:32:50 GMT
www.livescience.com/4180-sahara-desert-lush-populated.htmlThe climate change at [10,500 years ago] which turned most of the [3.8 million square mile] large Sahara into a savannah-type environment happened within a few hundred years only, certainly within less than 500 years," said study team member Stefan Kroepelin of the University of Cologne in Germany. I know, I know, GAWG or such. It happened within a few hundred years only. Is that rapid climate change? Here is a more recent one using dust content of marine deposits to date the most recent drying of the Sahara. So ... what really did happen between 10,000 and 5,000 yeara BP to moisten a whole east-west slice of a continent? Where did that water come from?www.livescience.com/28493-when-sahara-desert-formed.htmlHypothesis .... I would suspect that the Laurentide ice sheet had to go somewhere. So let's assume that around 10,000 years BP temperatures rose quite fast at the beginning of the Holocene. The ice would start melting and/or sublimating into the air and as shown perhaps an omega blocking high was formed resulting in a persistent jet stream over North coast of Africa rather than its normal position just North of the British isles... That ice sheet was miles thick over all of North America - there's enough water there for a few thousand years of rain. As that happened not only was the Sahara green, Doggerland was a fertile valley linking UK to the Netherlands and just a river valley separating UK from France. The Mediterranean was a fresh water lake. Doggerland and the Mediterranean became the North Sea and the Mediterranean as we know them when Lake Agassiz broke through an ice dam as it melted around 8500yrs BP. This seems to have been a very traumatic time and probably led to the formation of the Black Sea when the Mediterranean sea level rose sufficiently. As the ice sheet slowly melted away the weather patterns would alter to what they are today, the jetstream would then move North and the Sahara become dry as it is now. The alternate hypothesis ....
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Post by missouriboy on Nov 27, 2016 19:30:08 GMT
I like it! Higher pressure in the northern latitudes ... a higher equator-pole pressure gradient compressed into a shorter latitudinal distance. Those moisture-laden westerlies must have been ripping along that southwardly displaced jet. Wonder what that might have done to the Asian Monsoon? This was the same time period that Indo-European peoples were supposedly migrating out of areas in and around the Black-Caspian Seas westward into Europe. By 5000 BP the early waves of settlement may have been in place... haplogroup R1b in the south and west of continental Europe north of the Med, and haplogroup R1a to the north. And to the south, the Sahara was populated ... Like its northern counterpart (R1b-M269), R1b-V88 is associated with the domestication of cattle in northern Mesopotamia. Both branches of R1b probably split soon after cattle were domesticated, approximately 10,500 years ago (8,500 BCE). R1b-V88 migrated south towards the Levant and Egypt. The migration of R1b people can be followed archeologically through the presence of domesticated cattle, which appear in central Syria around 8,000-7,500 BCE (late Mureybet period), then in the Southern Levant and Egypt around 7,000-6,500 BCE (e.g. at Nabta Playa and Bir Kiseiba). Cattle herders subsequently spread across most of northern and eastern Africa. The Sahara desert would have been more humid during the Neolithic Subpluvial period (c. 7250-3250 BCE), and would have been a vast savannah full of grass, an ideal environment for cattle herding. www.eupedia.com/europe/Haplogroup_R1b_Y-DNA.shtml
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Post by Ratty on Nov 27, 2016 23:49:12 GMT
[ Snipped the serious stuff ] The alternate hypothesis .... Aliens?
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Post by nautonnier on Nov 28, 2016 1:44:04 GMT
[ Snipped the serious stuff ] The alternate hypothesis .... Aliens? Search on "Michael Bentine" Source of the Thames
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Post by Ratty on Nov 28, 2016 6:58:03 GMT
Search on "Michael Bentine" Source of the Thames Goon humour! Love it ......
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Post by acidohm on Apr 14, 2018 11:56:26 GMT
Wow...long link π
PDO has gone negative for the first time in 50 months.
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Post by missouriboy on Apr 14, 2018 15:16:01 GMT
Wow...long link π PDO has gone negative for the first time in 50 months. Welcome back to cold water in the NE-E Pacific. Will it last as long as 1950 to 1980?
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