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George Phillies

Based on a casual reading, an obvious question becomes: What is the North Atlantic Oscillation doing this year?

John Christensen

Shanks for sharing Neven - great analysis by NSIDC!

@George,

Agreed, it will be very interesting to follow NAO, as I had never considered the correlation between negative NAO and Greenland (and Arctic?) ice melt to be this strong.

Current outlook is undecided - as it often is..:

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/new.nao_index_ensm.html

Boa05att

Future increases in Arctic precipitation linked to local evaporation and sea-ice retreat

Precipitation changes projected for the end of the twenty-first century show an increase of more than 50 per cent in the Arctic regions. This marked increase, which is among the highest globally, has previously been attributed primarily to enhanced poleward moisture transport from lower latitudes. Here we use state-of-the-art global climate models to show that the projected increases in Arctic precipitation over the twenty-first century, which peak in late autumn and winter, are instead due mainly to strongly intensified local surface evaporation (maximum in winter), and only to a lesser degree due to enhanced moisture inflow from lower latitudes (maximum in late summer and autumn). Moreover, we show that the enhanced surface evaporation results mainly from retreating winter sea ice, signalling an amplified Arctic hydrological cycle. This demonstrates that increases in Arctic precipitation are firmly linked to Arctic warming and sea-ice decline. As a result, the Arctic mean precipitation sensitivity (4.5 per cent increase per degree of temperature warming) is much larger than the global value (1.6 to 1.9 per cent per kelvin). The associated seasonally varying increase in Arctic precipitation is likely to increase river discharge and snowfall over ice sheets (thereby affecting global sea level), and could even affect global climate through freshening of the Arctic Ocean and subsequent modulations of the Atlantic meridional overturning circulation

http://www.nature.com/nature/journal/v509/n7501/full/nature13259.html

D

If the source of the rainfall and snowfall is local to the Arctic the net salinity change of the Arctic will be zero. Is there something I missed in that Nature article from just reading the abstract? (I'm in a rurual area w/o a subscription).

It appears that there's a fundamental mistake in that article.

sofouuk

... come on.

“The origins of, and mechanisms behind, projected Arctic moistening are still unclear, however. Is it caused by an intensified local Arctic hydrological cycle19, or does it result from a global hydrological response to altered evaporation rates and moisture fluxes in lower latitudes8? This is an important issue, for several reasons: (1) if the local response dominates, Arctic precipitation may be strongly linked to Arctic warming and sea-ice retreat; (2) in that case the effect on Arctic Ocean freshening will probably be limited because evaporation and precipitation effects on surface salinity will then largely cancel out (only a remote origin will lead to overall net freshening);

it's usually worth giving professional scientists (especially those who manage to get published in Nature) the benefit of the doubt

Bill Fothergill

@ D

Yeah, I had thought that much of the additional Arctic precipitation would have originated as enhanced evaporation from the area around where the Ferrel and Polar cells meet.

However, I would be reticent about suggesting that Nature has published a fundamentally flawed article based simply on my reading and interpretation of the abstract.

I think the verb tense used in the abstract needs to be read very carefully. It talks about "projected increases over the 21st Century". We've still got about 86% of the 21stC to go, therefore that should be basically interpreted as future tense.

Precipitation originating from the lower latitudes obviously must affect Arctic surface salinity (and the thermohaline circulation?)

I could easily be wrong, but I'm interpreting the abstract as suggesting that the primary source of enhanced evaporation will shift poleward during the time period in question.

LRC

Of course without reading everything we have no way of seeing what their reasoning is. One possible scenario is: In the past, most Arctic systems would come south bring what moisture it had, combine it with a humid warm system from the south and dump everything in the mid latitudes. Two things are starting to occur now. 1) with higher Arctic temps more evaporation is occurring and air can retain more water. 2) weather systems can retain more of their energy as the SSTs get higher and therefore move farther north. This dual effect means that where in the past a lot of activity occurred in the mid latitudes that is getting moved farther north and therefore precipitation that never used to occur in the north now does. The tricky thing would be to figure out where most of that water is coming from. From local or could the systems now become big enough that most of the water actually comes from the south.
They appear to concentrating mainly are precipitation and not melt. Although with more precipitation more melt will occur. My thinking is that most 'melt' will be from catastrophic events ending up with exportation to warmer areas. You saw that in 2007 and in 2012 in the Arctic with the massive exportation of ice. You also see that constantly with glaciers.

Blaine

@D: You are indeed correct that if the moisture source is local, the change in Arctic Ocean salinity will be small. It's still nonzero, because it redistributes moisture within the Arctic, but the sign isn't even that obvious.

The results for precipitation change and salinity change were previously known, and only the evaporation data is new. This leads to the abstract language overemphasizing the evaporation in a way which can seem strange if you didn't know this already. Further their "mostly" local amounts to around 60%, and "lesser degree" of advected inflow amounts to around 40%.

Nature puts their figures online, so this isn't hard to check out from anywhere.

Blaine

That salinity change graph is interesting in that, while overall salinity does go down in the simulations, this is far from uniform. It goes down the most in the nearshore Kara and Laptev, where they big Russian rivers come in, but it goes up substantially over most of the Eurasian Basin. The amount is likely underestimated, since the models tend to underestimate the branch of the Northern Spitsbergen current that continues north past Svalbard, and there is some positive feedback, as higher salinity draws in warmer, more saline currents and this increases local evaporation.

Pete Williamson

Thanks for the link, lots of pretty images.

I'm confused though. The website has this mass balance graph on it

http://polarportal.dk/fileadmin/polarportal/mass/Grace_curve_La_EN_20140100.png

I always assumed this was the total mass change of the icecap, that is how this GRACE data has been presented. It shows little mass change over the full melt/accumulation cycle for 2013. This is in contrast to the previous large 2012 season. Yet the report says there has been a lerge mass loss (equal to 1.2mm) So what am I not understanding?

TenneyNaumer

Just because an article has gone through the peer-review process and gets published in Nature doesn't mean that anyone should assume the results to be received wisdom.

Lately (in the last year or so), some real doozies have been published in Nature, the sort of article that makes you go, "WT#!?!"

D

I have been very careful with my words. Scientific papers are frequently misrepresented by journalists who don't understand the subtleties of the science. I am hoping this group can examine the details so that we understand the strengths and weaknesses of the paper.

Evaporation over the Arctic could change the distribution of salinity in the Arctic ocean. Indeed we are already seeing shifts in Arctic ocean salinity, probably related to increased sea ice movement that has taken place as sea ice has become younger, thinned and weakened.

The Siberian side of the Arctic has become more saline and the Beaufort sea's salinity has dropped. Open water over the Siberian Arctic would tend to increase evaporation and salinity, enhancing this trend ,if the water vapor were advected from the Siberian side to the Canadian side.

Moreover, if mixing increases in the Arctic ocean, the transport of salt in and out of the Arctic is likely to change. It's not a simple problem accounting for the Arctic's inputs and outputs from the deep ocean through the troposphere.

I'm not commenting here to praise the researchers or bury them. I'm here to examine their work.

Sam

Well, I can't say what the NAO is doing. But, the Pacific Decadal oscillation is going nuts.

http://www1.ncdc.noaa.gov/pub/data/oisst/navy-anom-bb.gif

D

Sam - Almost all the tropical oceans are warming as trade winds weaken and tropical convection in Indonesia and the western Pacific weakens. It's a classic strong El Nino pattern.

Those warm waters off of Alaska are starting to heat up the Canadian side of the Arctic and shift the long wave pattern in the atmosphere. The cool flow from the Canadian arctic to the Great Lakes is shut off now. Warmth is on both sides of Hudson's bay. The sea ice melt is speeding up in Hudson's bay and the Labrador sea.

It's possible the ice arch in the Nares strait is under attack by shifting winds. There's been a big crack up in the ice northwest of the strait.

We'll see whether the PDO shifted after the El Nino is over.

Hans Gunnstaddar

"Well, I can't say what the NAO is doing. But, the Pacific Decadal oscillation is going nuts."

Sam, I see the PDO, but what about the huge hot zone just below the southern tip of Greenland. Is that the norm at this time of year?

michael sweet

Pete,

I think the mass balance data you linked does not include melting of the ice sheet from contact with the ocean. Mass balance data is only the surface accumulation of snow and melting of snow and ice. Icebergs and bottom melt are also a big loss of ice from Greenland.

Blaine

Pete, Michael-

He's referring to this. That was written before the GRACE data became available, and their estimate clearly missed badly. Yes, they're only closely modeling surface mass balance, and assuming glacier loss model they're using is rather simple.

2013 is unique as being the NAO+ year with a low albedo, so they didn't have much data to train their model on. Presumably dark snow doesn't matter as much if there isn't much sunlight that year.

There are some low probability explanations that can't be ruled out yet which would explain why a reasonable surface mass balance estimate wouldn't give the right mass loss. 2012 could have left a relatively thick ice layer, so there was extra surface refreezing, there could just have not been enough surface water to drill moulins on much of the area leading to surface refreezing, low flow could have led to deep refreeze from relic cold, and low flow could have led to flow channels not developing, so the water would still be sitting there under the ice.

Probably they need a big tweak of the weather dependence in their model.

Sam, D-
El Nino/La Nina is mostly a short-period zonal flow phenomenon, and the greater number of events aren't much linked to the PDO. Sometimes they're quite closely linked, though.

If you stop arbitrarily restricting the domain to either the Equatorial or North Pacific and look at global oscillation modes, in addition to normal ENSO, the mode which emerges (Mode 3 here) is a combination of warm PDO, northward flow Pacific Meridional Oscillation, and La Nina.

That graphic is what SST looked like in 2013 and 1996. With the La Nina flipped to El Nino, it looks like this. If the El Nino flips the full EOF3 state, you get this.

Bill Fothergill

Ah, the good old PDO

Dr Roy Spencer PhD characterises this as possibly being "Key to the Global Warming Debate" and therefore that must be the case.
http://www.drroyspencer.com/global-warming-background-articles/the-pacific-decadal-oscillation/

Of course, one could ask the following questions about the graphic at the bottom of his article...

1) Is there some reason why temperature measurements somehow stop after 2004?

2) Is there some reason for restricting the geographical region to 70N and above?

3) Is there some reason for restricting measurements to land stations only? (I could be wrong, but I'm pretty sure that since the graphic is credited as being from the "Jones et al" dataset, this relates to the CRUtemp data.)

4) How does the ratio of land:sea surface area above 70N compare with the global (3:7) or NH (2:3) ratios?

It happens more frequently with every passing year, but I've just had a weird feeling of deja vu whilst writing this. Either I've said something very similar here or at SKS recently, or it was in a conversation I had a couple of weeks back with an employee in the Koch brothers empire. (He basically thought that the sun shone out their fundamentals.)

Plea for help: Can anyone show me how to select the zone covering 70N and above from CRUtemp? I'd like to see that graphic extended up to 2013.

wayne

If ECMWF gets their circulation right this time expect a super drop in extent soon..... The high pressure is projected to maintain where I thought it would be. So far cloud coverage is strong, as normal, lets see if the High clears some.

Sam

The part Spencer gets wrong is thinking of this as an either/or situation. The PDO, like the other oscillations is just that an oscillation. That oscillation happens on top of the global rising temperature from anthropogenic CO2 forcing. We are in deep doo doo.

If the PDO were in charge that might well contribute to a pseudo plateauing of temperatures. That is worse, not better. It lulls people into the wrong first order conclusions and delays action, making human contributions to heating vastly worse. At the same time it reduces the time available for action from some ridiculously small period to negative space, where no response is possible at all.

And that indeed seems to be where we are. We have awakened the dragon. It rolled over as it gathers itself, just before it roasts us all.

The part of the PDO change that caught my eye is the immense area of warming extending all the way to the Pacific Coasts, and the extent of the heating, 3C.

The location is different from classic PDO warm phases (shifted eastward), hence my comment that it is going nuts.

I suspect that we have changed conditions sufficiently that the global circulations and oscillations are shifting.

And that highlights another problem. We are just now beginning to build marginally adequate models. And we, scientists and more so decision makers, are beginning to take these models (albeit cherry picking the low ball end of their results) as if they were the reality they model.

The reality is quite different. The models are greatly under predicting the rate of change. That happens for all sorts of reasons that everyone here knows so well, mostly because of the missing large positive feedback loops, and missing factors (clathrate breaks, tundra collapse, tundra fires, insect driven ecosystem devastation, ...). Still, I fear that even with all this, the changes in the underlying systems different from how they are modeled is likely even bigger.

Probably the largest of those will be the collapse of the great oceanic circulation (northern part at least), and the collapse of the northern three cell atmospheric circulation to a single cell system.

If those happen, all of our concerns (whether the local impacts to Greenland ice melt, or others) will be dramatically impacted.

Sam

econnexus

The videos from the Transformational Climate Change conference are now available. More over on the forum:

http://forum.arctic-sea-ice.net/index.php/topic,865.msg27043.html#msg27043

Very few people understand what it is to live in a 3 degree, 4 degree, 5 degree world and that needs to change!

Dan Ellis-Jones

This is a bit OT, sorry.

I've been looking at the NH Jet Stream for a while now, and it's looking quite ill.

Could one of you clever chaps with more experience than me give your impression of what's going on? Is this normal for this time of year (new normal), or is it very wavey and highly sporadic, and slow?

And what might be the consequences of this - blocking highs, warm/cold air masses where they shouldn't be?

I really wish I did a meteorology degree!

Susan Anderson

Dan Ellis-Jones, if you are not familiar with Jennifer Francis' work, that might be one place to look. I'm more amateur than most, so apologize if this is coals to Newcastle. I'd agree the jet stream is going haywire, but defer to more expert opinion.

Meanwhile, I've been reflecting on El Nino (now getting obvious), hurricane Amanda, and circulation, and visited a favorite site for global water vapor, and think this is pretty interesting. Hurricanes being very large engines that could, there seems to me a lot of driving going on there. This seems a little OT for Greenland melt, but not sure so very much so, since it's all interconnected.

Wild times icumen in.

http://synoptic.envsci.rutgers.edu/site/sat/sat.php?sat=nhem&url=../imgs/wv_nhem_anim.gif

Susan Anderson

On Jennifer Francis, this is a little old, but not too long:

https://www.youtube.com/watch?v=37wcfLeZ9u8

She has done a lot of work, so no doubt a simple search will find more recent and more complete material.

Jim Hunt

@Susan - See also:

Does the Arctic Sea Ice Influence Weather in the South West?

for a discussion between Jennifer Francis and one of her (scientific!) critics about the jet stream and other stuff.

Shared Humanity

I have been enjoying your links to Transformational Climate Change....

...but I fear it is a lot worse than this...

"Very few people understand what it is to live in a 3 degree, 4 degree, 5 degree world and that needs to change!

My biggest fear is that none of us actually know what it is to live in such a world. While some have a better idea than others, as temps rise, we are all going to be shocked!

I think Sam, above, has the idea. There are very big things, poorly understood. Sam has listed two. There are bound to be others.

Shared Humanity

One of these big things which I believe is related to this topic is.....

What happens as a cold pole forms over Greenland 6 to 9 months out of the year? I think this is already emerging and impacting us as NH snow and Arctic sea ice melts more rapidly. How will this impact the polar jet stream if at all? What about Greenland melt? Is this a positive or negative feedback?

Jim Hunt

@SH - Whoops! A Freudian slip? I should have written "Transformational Climate Science". Thanks for your kind words though.

There's now another video from the conference over on the forum about the IPCC WG I "physical science basis". Prof. Peter Cox says:

Is it still possible to avoid 2 degrees using conventional mitigation? In fact it's likely to be blown out of the water!

Jai Mitchell

Dan,

do you mean like this cut off low that formed spontaneously in the middle of the Atlantic 10 days ago?

I have been documenting some of the very strange patterns I have witnessed in the forum here: https://forum.arctic-sea-ice.net/index.php/topic,784.0.html

I think it is a combination of warming polar regions coupled with increased relative humidity in the mid latitudes caused by the significantly (step change since 1998 to now) increased rates of energy deposition into the oceans through some kind of cloud seeding program in the tropical Indian and Pacific oceans.

This is the only way I can figure that there can be a record of extremely abnormal low Relative Humidity http://goo.gl/O91aws coupled with cool air temperatures http://goo.gl/UfBk4Z in a region where we have one of the highest sea surface temperatures on record http://alturl.com/7qquv

I believe that cloud seeding forces latent heat back into the oceans. . .right?

Pete Williamson

Thanks for the explanation.

So if I understand you could describe the 2013 season as relatively quiet season for Greenland.

A typical (recent) year is that there is there is normally a rather large nett accumulation of mass at the surface. This is offset by an even larger mass carving and melting in the ocean terminating glaciers.

The 2012-2013 season there was a smaller net accumulation at the surface (but still positive). The winter looked normal but summer showed a greater nett loss than normal. But there was very little iceberg carving that year so overall the total mass of Greenland changed very little.

Although surface mass balance is obviously a big factor it looks like variability in carving events can really swing things one way or another when it comes to overall mass change of Greenland ice.

TenneyNaumer

A nicely done retraction:

Retraction: High predictability of the winter Euro–Atlantic climate from cryospheric variability

http://www.nature.com/ngeo/journal/v7/n6/full/ngeo2164.html

Blaine

Pete -
They graph the output of their surface mass balance model from Sept-Sept. For 2013 (Sept 2012-Sept 2013), the mass balance was slightly above the recent norm, but well below the longer-term average, about 2/3 melt of the winter accumulation. The GRACE total mass balance was near zero, and even slightly positive, where a significant drop would have been expected including discharge, at least if their model is right and discharge is about the same as other recent years.

They have a similar, if opposite problem with 2012. Their surface mass balance is near zero, but the GRACE mass loss is huge. To match the GRACE mass loss requires either a huge jump in discharge or a significant negative surface mass balance.

The likeliest explanation is a still problem with their model. It's done a reasonable job of predicting a lot of previous years, but it's still a model output based on weather analysis and albedo, not the received surface mass balance from God. I was just pointing out that it's still an unresolved problem and there are a lot of other things that it could conceivably be.

Dan Ellis-Jones

Susan - Yes, I'm aware of Jennifer Francis' work. But thanks for the links! And I remember talking about the effect of ice melt on weather/jet stream almost a decade ago when I worked in the Western Australian Office of Climate Change, back when most people thought Arctic ice melt was highly unlikely in the 21st C.

What I was referring to was the REALLY weird pattern of the jet stream over the last month or so. It really seems to have forgotten what it's meant to be doing! I understand the 'long term' (decade or so) change in the jet stream, but about a month or so ago, it was relatively strong and, although wavey, still within normal bounds. Now it seems to be slow, broken, wavey and curling back on itself.

Thanks Jai - I'll take a look at your links.

It'll be interesting to see how the next month pans out with regards to the jet stream and thus the weather.

Noticed that Climate Reanalyzer is predicting vast swathes of the Arctic Ocean will rise above freezing air temps for much of next week. In fact a huge area over the North Pole is predicted to be in positive territory. Also, quite a bit of western Russian looks like it'll have 30c+ temps for a few days at least next week - which might be interesting for wildfires. Alaska and northern Canada also get some pretty warm pulses too.

Is this being forecast by other sources?

Remko Kampen

Dan said I've been looking at the NH Jet Stream for a while now, and it's looking quite ill.

So it is. Smeared out subtrop high first seen in July 2006. Then, the Sandy block. Now, this sickening pattern - I mean that, I feel queasier by the week looking at forecast charts or any synoptic of the day - seems to become normal.

Some remarks on this I made here:
http://neven1.typepad.com/blog/2014/05/piomas-may-2014.html#comments
at Remko Kampen | May 16, 2014 at 11:51 and Remko Kampen | May 18, 2014 at 18:31 .

Stuck circulation patterns. Results are dire and include e.g. the Balkan floods of last week.

Remko Kampen

Jai 's been "... documenting some of the very strange patterns I have witnessed in the forum here" - great job, that thread into daily check by me now.

Jim Hunt

Professor Catherine Mitchell has now published her own article about the proceedings at the Transformational Climate Science conference the week before last:

http://bit.ly/ecotcs2

Her conclusion?

We as individuals and communities in civil society have to do all we can to get our politicians, neighbours, businesses, energy suppliers and so on to take climate change seriously. Climate and energy policy must take note of the IPCC warning and act now.

Pete Williamson

Blaine I'm surprised to hear God isn't involved in the calculation ;)

I hope you'll bare with me a little longer because I'm trying to get my head around all the different 'data' source.

GRACE - this is gravity measurements from satellites and gives the overall change is mass. This requires a model to convert the raw satellite data into changes in mass? We (I mean you) are happy with this data?

SMB - This is model output of snow accumulation, evaporation, melting sublimation(?) at the surface? Based on weather inputs to a model(temp, wind, snowfall etc). You are saying you think this may have gone a bit wonky for the 2013 season?

Discharge/carving/melt at glacier front. - Annual estimates are based on ....what method? Or this just derived from the difference between GRACE and SMB? Or calculated independently for each season?

There seems to be a mismatch. I'm not seeing how that is arising. Or are you saying it's not clear which bit is off?

thanks

Blaine

Pete -
Don't for get their innovation which is including realtime satellite ice color measurements in the model, which makes a large difference with the ice getting as dark as it does lately.

I believe that for discharge they're just taking the difference and assuming that it's smooth, without large changes from year to year.

I tend to trust the GRACE data more than trusting the discharge to be smooth more than I trust their model, but it isn't obvious which bit is off.

Blaine

Here Comes the Sun

After a very warm Arctic winter with very low ice formation, it's been a very cold spring with a huge near-perpetual low over the central Arctic basin, repeatedly fed by moisture injections both through the Laptev Sea and across the Bering Strait (thanks, Jai).

This looks set to change immediately, as GFS is forecasting the sun to break out simultaneously on May 31 across the Arctic Ocean, Canada, Greenland and eastern Russia, and to stay that way for at least a week.

They are also forecasting the development of an actual Arctic Dipole in the second week of June, with both a Greenlandic high and a low over the Russian coast and not well out in the Arctic Ocean.

Given the recent persistence of the NAO index in summer (it's been the same sign in both July and August as in June for each of the last 7 years in a row), the prediction of a solidly negative NAO in early June would seem to indicate a significantly stronger melting season than I would have guessed a week ago.

Blaine

Geh. The Arctic Ocean, Canada, Greenland and western Russia, although eastern Russia gradually gets a bit less cloudy too.

Neven

Blaine, please don't pre-publish my ASI update (title and all). :-)

Colorado Bob

OT =

Reported winds hit 90 mph, knocking out power and temporarily suspending metro service, stranding people in train stations and diverting flights, according to Gulf News.

"The high temperature in New Delhi Friday was 113 degrees," explains weather.com senior meteorologist Jon Erdman. "However, with dry air below cloud base, thundershowers produced little rain, but instead a lot of wind, churning up dust."

http://www.wunderground.com/news/india-dust-storm-deadly-20140530

P-maker

Bob

If you really wish to go OT, why not try something like this:

http://www.aqua.dtu.dk/english/News/2014/05/140514_Bluefin_Tuna_caught_hunting_for_mackerel

which tells a story of unprecedented bycatches off the East Coast of Greenland in August 2012.

On one hand, the story of global tuna fishing is as depressing as the story of whale hunting and sea ice disappearance. On the other hand, this story also gives us a glimpse of hope, that one day in the not so distant future, the last Atlantic bluefin tuna on this planet will be able to swim across the Arctic Ocean and meet up with the last surviving Pacific bluefin tuna, and - who knows - get together for a fresh start...

Steve Bloom

"I remember talking about the effect of ice melt on weather/jet stream almost a decade ago when I worked in the Western Australian Office of Climate Change"

Out of curiosity, was this talk cued by Lisa Sloan's paper?

Chris Biscan

It's crazy how much the -PDO period in the mid 1940s to late 1970s coincides with major nuclear testing.


I am not saying there is any correlation but damn.

http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.B.gif


Looking at GISS temps drops right at the start of outdoor nuclear testing. Obviously we would presume that they are took weak to cause cooling but the tests did get stronger. Then right after the biggest outdoor test ever with the TSAR bomb temps drop of substantially.

There was also a long term rise in sun spot activity peaking in the 1950s while temps dropped and GHGs kept rising.


Global nuclear testing tapered off big time during tne 1960s. The coincidence is quite note worthy but could just be completely coincidental.

sofouuk

"The coincidence is quite note worthy but could just be completely coincidental"

by definition, as it were - clearly there is no causal connection :-/

I Ballantinegray1

For a 'butterflies wing' a nuclear test is a biggie! I remember My grandparents blaming rotten weather on the Nuke testing.......maybe they had a point? To every action there is an equal and opposite reaction......

seattlerocks

Chris, it may not be so coincidental. I have heard that before and this effect might have been not negligible at all. And The initial 40's cooling, when nuclear test aggregated energy was very small, could have been caused by all the soot that the destruction of european and japanise cities brought about, this time by conventional bombs.

seattlerocks

Nuclear winter theory explains cooling by direct soot from nuclear explosions but even more by the debris and burning that they cause. If we could estimate sun blocking by debris fron german flattened cities and napalm burnt japan cities. Not to mention hiroshima and nagasaki, 'low' power nukes but that caused more destruction than any nuclear test. Sorry for the OT spamming but I get lit when talking about nukes

DavidR

The 'decline' in temperatures after 1940 also coincides with a change from most sea surface temperatures being taken by British ships to most being taken by American ships.
Analysis of the techniques used by the two countries has shown that the US method reduced the estimated SST's by about half a degree. This accounts for a significant part of the observed decline.

Liam Baker

Sorry to drag this thread further off-topic.

Nuclear winter is afaik caused by the formation of large pyro-cumulus clouds, which due to solar heating of the dark smoke plume can break through the tropopause and carry substantial soot and debris into the stratosphere (where it tends to 'stick around'). Large forest fires and volcanic eruptions can cause the same problem.

Shared Humanity

Hmmmm....quick string of comments regarding ship movements and nuclear testing as a cause of global cooling mid-20th century. While interesting as a Forum topic, this is way off topic for this thread. You should take this discussion to the forum so I don't have to skip these comments in order to get at the relevant ones that help me understand Greenland melt.

Shared Humanity

Also....if you do take this rather obscure discussion to the Arctic Sea Ice Forum, please find an appropriate thread to hold the discussion. I visit there daily as well and this discussion would not belong on a thread that is discussing the 2014 melt season or some of the excellent threads set up discussing the Antarctic. The good news is there are literally hundreds of discussions on the Forum. I am sure there is one that would be appropriate. If not, you can create one.

iceman

@ Jai Mitchell "I believe that cloud seeding forces latent heat back into the oceans. . .right?"

meaning the latent heat of condensation when cloud seeding causes precipitation? Most of that is released into the atmosphere. Some fraction goes into the water droplets that form. But the amount the rain adds to ocean water would be secondary compared to the loss of latent heat from surface evaporation in the first place.

My lay reading of NOAA reports etc. is that " increased rates of energy deposition" has been mainly in subsurface layers: increased evaporation from anomalously warm surface waters raises salinity; denser water sinks, moving sensible heat downward... until the next Kelvin wave.

Some cool stuff in your new thread on the forum btw.

Jai Mitchell

iceman,

hmmm yes, you are right, of course the latent heat of condensation/freezing is released to the atmosphere:

I had been looking at the abnormally dry air over the Western Pacific Warm Pool and knew that seeding would create this, however, the process of dynamic seeding of tropical cumulus increases cloud heights, but we are observing an 8% decrease in cloud heights

combining this with the anomalously colder than expected air temperatures over the warm pool, thre is just something strange going on here.

The problem I am having in understanding this is that the rate of surface warming in this region is 66% greater than the global average Link to Chun-Yi Lin's paper "The thermal trend in the western pacific warm pool"

Hygroscopic warm cloud seeding produces warm rain. . .Indonesia has been doing this now for some years to combat air pollution. There is more heat being driven into the deep ocean here than is supposed to happen and the models have practically failed this last decade with cooler air temperatures above the warm pool than are expected. Combine this with the sudden shift to a negative PNA index in April of 2012 and things look much too sudden and dramatic to be from natural causes.

re: the forum, thankyou! you too!

Kevin McKinney

OT, but I don't really 'do' the Forum much. Regarding the "WW II dip", Hank Roberts recently posted an interesting paper on RC which linked GMST during (and immediately following) the War years to the near-collapse of fishing activity in the North Atlantic, to the subsequent recovery of the fish stocks, and then to (relatively) rapid oceanic drawdown of CO2. Don't have the link, but I thought it was a fascinating idea.

james cobban

Apologies for being OT, but this is just a quick observation for fun, and there's no open thread.

Daily Kos has an article on the Sixth Great Extinction

http://www.dailykos.com/story/2014/05/30/1301299/-Is-it-time-we-start-saying-the-E-word?detail=email

which states: "The Cretaceous Tertiary Impact Event: an asteroid 10-15 km or 6-9 miles in diameter impacted Earth at Chicxulub, in Mexico's Yucatan Peninsula. The explosion would have been a billion times larger than the nuclear bomb dropped on Hiroshima."

It's interesting to note that according to the bomb counter at the top of Neven's blog we've already accumulated more than twice the energy of the asteroid that caused the last great extinction. It's not a very good comparison because the asteroid event was instantaneous, with plenty of ejecta and particulate matter, whereas this accumulation has been slowly building since 1998. But still. Doesn't look good.


Steve Bloom

"things look much too sudden and dramatic to be from natural causes"

You need to re-scale your physical intuition, Jai. 'ware the ornery beast.

Steve Bloom

Agreed, SH. Maybe Neven should add a general category for conspiracy theorizing? The WWII/nuclear testing stuff are long-refuted denialist memes, and it's most unfortunate to see them tolerated here.

james cobban

The Daily Kos article I mentioned above also has an interesting video about methane anomalies, using data from Methane Tracker. Commenter Apocalypse4Real is mentioned around the 8:20 mark.

http://www.dailykos.com/story/2014/05/30/1301299/-Is-it-time-we-start-saying-the-E-word?detail=email


"A must see video below, have your medication of choice handy as you will need it

Video 1 of 2. This is a short intro to the Unified Methane Layers functionality on methanetracker.org.

Basically you're looking at two layers per day (0-12z and 12-24z) that contains only the methane over 1950ppb of all 100 layers from IASI for each (am and pm). Those two layers are shown at 6am (0-12z) and 6pm (12-24z) each day. The visualization using the Google Earth plugin allows you to pick a from and to data range that makes it easier to visualize the actual geographical scope of the venting episode, as well as identify specific geographic locations and dates to run a more detailed analysis using the "Individual Methane Layers" functionality."

Neven
The WWII/nuclear testing stuff are long-refuted denialist memes, and it's most unfortunate to see them tolerated here.

I 'tolerate' it, because I have never heard about it. But I agree that it fits better on the ASIF.

Pete Williamson

Blaine sorry for the delay but I tried a bit of scientist bothering and emailed PolarPortal about the apparent discrepancy between the GRACE data and reported mass balance. Here is their reply, it seems like the GRACE data for the 2013 summer is unavailable (they just infilled the grapg for that period)

"Your question is really good, and the answer is actually quite simple: The GRACE mission is already way past the originally intended duration, but the satellites are still flying. But systems do fall out once in a while and, as an example, the 2013 summer data are unavailable due to power system problems. The 2013 summer data are thus missing from the Polar Portal GRACE figure. The linear interpolation across the summer negative peak suggests an extremely low (even no) loss summer and therefore is very misleading. We will work on a different way of representing this."

Nick Naylor

Does anyone know why GRACE is being kept alive beyond its intended lifetime? I'm hoping we're not going blind due to lack of funding.

Chris Reynolds

Nick,

If it's still working why trash it?

There are plenty of firms working with kit that still works despite being decades old. I've even come across operational kit with nixie tube displays.

Nick Naylor

I'm certainly not saying we should trash it. I just hope we plan to have something reliable up there if GRACE doesn't pass away gracefully.

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