|
Post by missouriboy on Oct 11, 2015 2:47:03 GMT
Busily reading it now. Have you ever run across a 'decent' estimate of what mean English temperatures might have been at the height of the Little Ice Age? Degrees C below current would be lovely! Ball parks, crap shoots, and scientific wild-ass guesses (SWAG) will do if properly cited!
|
|
|
Post by missouriboy on Oct 11, 2015 4:48:31 GMT
OK ... so the three images show what has happened in the N. Atlantic over the last three Julys. You can see that the colder waters in the upper 700 m are moving progressively eastward and the rate of progression increased in 2015. You'll note how the 10-C contour line is being bent progressively southward. I have looked at cross section after cross section of the current velocities and can find no dramatic differences in placement or velocity over the 12 year time period in the branching, northeastward flowing currents of the NAD. The North Atlantic Drift looks very much alive and well. It's still moving water largely in the upper 800 m in very distinct channels according to Argo. What has occurred is a change in the temperature of the water these currents are moving through and I can't tell exactly why. In 2015 there appears to be a large increase in the cross-sectional size of the highest velocity surface water coming down the Denmark Strait. This colder water appears to be partially pooling in the upper basin at about 32-35 degrees W Longitude and getting caught up in the eastward-flowing currents which are moving it back toward Northern Europe. In addition, the cold water in the channels west of Greenland is also expanding. I have been looking at the southward flowing cold water return channels and they are still there. If anything, they appear to have gotten bigger. This is all based on visual assessments of the embedded Argo chart functions, which don't really let you output or quantify overall velocities for irregular polygons. The area surrounding the Gulf Stream is getting warmer, but that water does not appear to be making the northward journey, although the currents are. The eastward arm of the sub-tropical gyre is still chugging along. Very perplexing. However Acidohm, those cold northern waters appear intent on paying you a visit ... and there's a big, deepening pool of cold water building off your western flank.
|
|
|
Post by acidohm on Oct 11, 2015 5:49:40 GMT
OK ... so the three images show what has happened in the N. Atlantic over the last three Julys. You can see that the colder waters in the upper 700 m are moving progressively eastward and the rate of progression increased in 2015. You'll note how the 10-C contour line is being bent progressively southward. I have looked at cross section after cross section of the current velocities and can find no dramatic differences in placement or velocity over the 12 year time period in the branching, northeastward flowing currents of the NAD. The North Atlantic Drift looks very much alive and well. It's still moving water largely in the upper 800 m in very distinct channels according to Argo. What has occurred is a change in the temperature of the water these currents are moving through and I can't tell exactly why. In 2015 there appears to be a large increase in the cross-sectional size of the highest velocity surface water coming down the Denmark Strait. This colder water appears to be partially pooling in the upper basin at about 32-35 degrees W Longitude and getting caught up in the eastward-flowing currents which are moving it back toward Northern Europe. In addition, the cold water in the channels west of Greenland is also expanding. I have been looking at the southward flowing cold water return channels and they are still there. If anything, they appear to have gotten bigger. This is all based on visual assessments of the embedded Argo chart functions, which don't really let you output or quantify overall velocities for irregular polygons. The area surrounding the Gulf Stream is getting warmer, but that water does not appear to be making the northward journey, although the currents are. The eastward arm of the sub-tropical gyre is still chugging along. Very perplexing. However Acidohm, those cold northern waters appear intent on paying you a visit ... and there's a big, deepening pool of cold water building off your western flank. Wow...that for me is the money shot of all the work you've done so far!! I agree and have observed the heat building in the gulf stream and attributed this to the current failing and not moving the water up initially but what you report concurs with scientific research. I think part of the problem with the gulf stream area may be with the amount of eddies? There are some serious vortex down there, the primary current seems extremely narrow and any water outside of this current may even track south for over a year as can be seen by the tracks of individual Argo bouys on the Google Earth Layer that can be downloaded from the argo website. I agree ocean currents are very perplexing, they certainly do not follow linear dynamics!! I have been looking into research into any relationship between Solar activity and ocean currents, last week however had to go to Croatia to take care of our apartments so have lost a week to 'work' and socialising with family there (hic! ) I'll look back into it and post anything relevant here and see if any possible answer get dragged up. Thanks for all your time and effort Missouriboy......That is a great insight into the N Atlantic ocean...interesting times!! Incidently, people complaining how cold it feels here in the UK...just something that randomly comes out in conversation, but its not great for this time of year
|
|
|
Post by acidohm on Oct 11, 2015 5:53:01 GMT
What a great find Acidholm!!!!!!! Kinda makes Manns recent attempts using a stick he found and an icecube look like kiddy drawings. I mean really that man only produced one kind of graph and then flips it around in photoshop!! If we take the Gulf Stream Transport strength as credible based on the bivalve proxy, can we see a relationship between this and global temps...or even solar activity? Activity, as i look at it, may be tricky as it is a relatively short record....
|
|
|
Post by missouriboy on Oct 11, 2015 10:52:27 GMT
Incidently, people complaining how cold it feels here in the UK...just something that randomly comes out in conversation, but its not great for this time of year Amazing what a couple of degrees will do, ehh??? And there ain't no cold like a water cold ... it cuts to the bone! How many lost C did it take to freeze the Thames solid? I understand it was wider and shallower in those days.
|
|
|
Post by sigurdur on Oct 11, 2015 11:58:04 GMT
I don't think we understand all the ins and outs of solar activity yet.
|
|
|
Post by acidohm on Oct 12, 2015 9:00:14 GMT
Incidently, people complaining how cold it feels here in the UK...just something that randomly comes out in conversation, but its not great for this time of year Amazing what a couple of degrees will do, ehh??? And there ain't no cold like a water cold ... it cuts to the bone! How many lost C did it take to freeze the Thames solid? I understand it was wider and shallower in those days. Very good point mboy....The Thames has changed a lot, it would be interesting to compare pictures of the time with its existing state.
|
|
|
Post by missouriboy on Oct 12, 2015 16:34:43 GMT
For those of you interested in comparing 2009-10 (and other years) to current N. Atlantic temperatures. I extracted temperature data from Argo for the upper 700 m and discreet latitudinal strips (30-40 N, 40-50 N & 55-65 N) and constructed my own deviations from the 12-year means for each strip. Each of these include the three primary current zones: the eastward leg of the N. Atlantic sub-tropical gyre (32-37 N); the main portion of the NAD from 40-50 N; and the northernmost NAD current from 55-65 N. I also constructed a section from 30-40 N covering the northeastward flow of the Gulf Stream. I have included a plan-view map for comparison showing deviations from the 12-year mean for the entire basin for the periods 7/09-6/10 and 1/14-7/15. As always, this takes more than one post.
|
|
|
Post by missouriboy on Oct 12, 2015 16:38:19 GMT
In as much as the colder portions of the N, Atlantic contributed to the 2009-10 European winter, you can see that the cool down occurred further south and further west from Europe. The 2014-15 cool down is further north and much closer to Europe. It also appears more extensive than the 2009-10 event. Unfortunately, I do not have access to pressure patterns and dominate wind directions that could be compared to the ocean temperatures. Nautonnier is correct. in as much as your weather comes from the west, your temperatures, particularly at the coast, are more likely to reflect sea-surface temperatures. If, however, pressure patterns set in that change that western to southwestern flow ... might I suggest a warmer coat. You will also note that there appears to be heat building up in the northern area of the Gulf Stream, but, so far, it is not appearing in the NAD. And yet, I cannot visually observe any dramatic change in the velocities of the northward flowing currents??? It does appear that there has been an increase in the southward flow of cold water from the north (I have to try and verify this). But. colder water also appears to building up in the north ... something's afoot, but it's signature is not obvious ... or my brain is too dull to grasp it.
|
|
|
Post by missouriboy on Oct 12, 2015 19:09:18 GMT
Salinity in the North Atlantic Salinity appears to be associated with water temperature. Cold northern waters are about 2 parts lower than warmer southern waters. The deviation from the 12-year mean is very small ... in 2014-15, about 0.2 parts per 1000 (?). They do not specify their units. I don't remember ever seeing a threshold value for salinity changes that would supposedly impede sinking associated with the overturning circulation. NEW NOTE: The Abrupt Climate Change Paper posted by Code includes a table that shows salinity values for: 1970 2000 NE Atlantic 34,96 34.90 Denmark Strait 34.92 34.87 Labrador Sea 34.90 34.86 These values are just slightly below surface salinity values shown today? ??
|
|
|
Post by acidohm on Oct 12, 2015 19:24:51 GMT
So...I read that as north atlantic usually less saline then tropics, and up till recently north atlantic was more saline then average however recently less so..
Just thinking along lines of rationality of 'Greenland melting desalinating n atlantic'
Don't think this very interesting data supports this?
|
|
|
Post by flearider on Oct 12, 2015 22:13:45 GMT
So...I read that as north atlantic usually less saline then tropics, and up till recently north atlantic was more saline then average however recently less so.. Just thinking along lines of rationality of 'Greenland melting desalinating n atlantic' Don't think this very interesting data supports this? i'd say the cooler it gets the less salts it can hold being frozen water drops most of the salts .. so with there being a very lrg cold spot things are right until greenland starts turning green again i'd not worry so much
|
|
|
Post by missouriboy on Oct 12, 2015 23:13:52 GMT
Large Increase in the Flow of Water Exiting Southward From West of Greenland between 2004 and 2015. Plots in this and the next post show three variables plotted on an east-west cross-section at 59 N latitude extending vertically from 0 to 2000 meters. Temperature and salinity measurements are shown from 0 W to 80 W longitude. Velocity is shown for the channel west of Greenland from 45 to 60 W longitude. The plots in this post are for Jan.-Dec., 2004. The next post compares the same plots for jan., 2014 - July, 2015.
|
|
|
Post by missouriboy on Oct 12, 2015 23:32:41 GMT
What is immediately apparent is the large increase in cross-sectional area and mean velocity of the southward flowing current between 2004 and 2014-15. This current extends to 1600 m in 2014-15. The southward flow is bordered by two counter-currents moving northward. There do not appear to be any significant differences in salinity between the two periods. Warmer waters are typically more saline, but the overall difference appears to be less than 2 parts per 1000 (?). If the increase in flow represents glacial melt water, then it appears to be sinking perfectly fine on its own, with no apparent help from salinity changes. Water temperatures in the East at depth got colder in the 11-year interval.
|
|
|
Post by missouriboy on Oct 12, 2015 23:48:38 GMT
So...I read that as north atlantic usually less saline then tropics, and up till recently north atlantic was more saline then average however recently less so.. Just thinking along lines of rationality of 'Greenland melting desalinating n atlantic' Don't think this very interesting data supports this? i'd say the cooler it gets the less salts it can hold being frozen water drops most of the salts .. so with there being a very lrg cold spot things are right until greenland starts turning green again i'd not worry so much Sig's relatives would probably be happy to get the green back in Greenland.
|
|