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Messages - guygee

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1
Thank you for the reference, ajouis, that is a very interesting study. The authors use an extensive data set "standardizing the sea ice melts over the 140 MJJA months from 1979 to 2013", ..."with composites of 23 high (HMR) and 17 low (LMR) melt months."

Most of the discussion on the weak correlation with surface temperature is connected with the author's Figure 10. Below that figure they state:
Quote
The temperature signal over the Arctic Ocean in HMR months is nevertheless small compared to the warming along its coastal boundaries (average of 0.3°C compared to up to 2.0°C over the Taymyr Peninsula at 100°E). This is due to the fact that sea surface temperature will always be close to the freezing point in a partly ice covered ocean.

With the record melt-out of the Siberian Arctic seas and attendant record high SSTs I wonder how the above might be modified this year? Areas that were previously "partly ice covered ocean" are now ice-free.

I also found these two paragraphs in their conclusion very interesting, as a possible prediction of how the rest of this melt season will unfold:

Quote
In the Arctic, HMR months coincide with an anticyclonic tendency (up to 7 hPa; Figure 3a), which enhances the incoming SW radiation at the start of the summer (average of 9 W/m2 over the Arctic Ocean; Figure 8a) and warms the region in general (0.3°C over the Arctic Ocean, up to 2.7°C over Greenland; Figure 10). This atmospheric circulation is associated with a tendency of storms to veer away from the Arctic on a more zonal path (Figure 6a), leaving the Arctic drier  (average reduction of 0.1 mm/d over the Arctic Ocean; Figure 7a) with lowered albedo (represented by the equally sized reduction in snowfall in Figure 7b). A positive snow-albedo feedback emerges.

In August, the enhanced ocean surface evaporation from the retreating sea ice promotes cloud development (represented by the 7 W/m2 reduced incoming SW radiation in Figure 8b and 9 W/m2 increased incoming LW radiation in Figure 9b). Coming into late summer, re-emission of LW radiation surpasses incoming SW radiation at the surface [Curry et al. , 1996]. Hence, the clouds trap heat, providing a mechanism for a positive cloud feedback.

2
Any analysis of global temperatures without including an analysis of the current ENSO state is incomplete, for example see:

https://www.osti.gov/pages/servlets/purl/1511151

https://journals.ametsoc.org/jcli/article/7/11/1719/36167/The-Signature-of-ENSO-in-Global-Temperature-and

3
From guygee in the melting thread:

<snip>

yes, the contrails, if they act like clouds, might have a net warming effect on air temperatures, so if they're gone, then it should cool air temperatures. However, the strength of the melt season is driven primarily by insolation, not air temps, so the great reduction of the clouds should increase the melting, because it allows more sunlight to hit the ice.

As to the effect of some difference due the number of contrails this year as opposed to previous years, I  lack sufficient information to have any informed opinion. Considering all other factors, I doubt the lack of contrails has a large effect.

I don't mean to belittle your statement on insolation, but rather point out that it is not only insolation that drives summertime sea ice melting, but rather a large number of factors including increased warm air intrusion from continental warming, breaking the near-surface inversion over the ice by strong subsidence under the persistent high pressure this year, increased water temperatures both from continental sources and early melting, increased exchange of waters between the Arctic, Atlantic and Pacific, breaking of the halocline due to increased upwelling and strong atmospheric pressure gradients, and probably other positive ongoing feedbacks not mentioned.

In particular, this year, strong subsidence under the center of the high pressure, and strong pressure gradients around the periphery of the high have served to reduce the predominance of the usual near-surface temperature inversion over the ice. Also, over the open water, the inversion lifts. This increases the importance of air temperature in ice melt as opposed to 'more usual' conditions that have prevailed during the satellite era. Granted the persistent high this year also greatly increased direct insolation. As to the relative importance of all of these factors in this melting season, I would welcome any further information you can provide.

4
Arctic sea ice / Re: The 2020 melting season
« on: July 20, 2020, 04:24:53 PM »
Apologies for the OT on clouds, but I've seen the same error here repeatedly regarding the effect of high altitude clouds. These clouds raise temperatures both day and night, since  they are relatively transparent to incoming short wave radiation but tend to reflect outgoing long wave radiation. So their effect on warming is positive both in the day, and, like all clouds, at night. See, for example,
https://earthobservatory.nasa.gov/features/Clouds/clouds3.php

5
Arctic sea ice / Re: The 2020 melting season
« on: April 20, 2020, 08:23:52 AM »
Ozone.
I prefer that this regular update be posted in a new thread, as it does not affect the current melting season as far as I can tell.
Oren - I see you are listed as Moderator and thus you decide "what goes where". However, consider that the ozone level animations are a kind of proxy for the polar stratospheric circulation, also that the stratospheric ozone in the polar vortex will increase rather dramatically at the onset of a Sudden Stratospheric Warming (SSW). Such events do have relevance in the melting season. For a simple example please see:

]https://ozonewatch.gsfc.nasa.gov/facts/warming_NH.html

Actually it is a bit more complicated than the simple view expressed above, see:

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/jgrd.50651
https://arxiv.org/abs/1807.11750

Thus, I think that the ozone measurement animations are relevant to melting, at least in the early part of the melting season.

6
Arctic sea ice / Re: Arctic Image of the Day
« on: August 26, 2018, 12:58:50 AM »
Paper describing extent of the Ward Hunt Ice shelf and major calving, 1961-1962:
https://www.igsoc.org/journal/4/34/igs_journal_vol04_issue034_pg415-424.pdf

Major crack in Ward Hunt Ice shelf reported by NASA:
https://www.nasa.gov/missions/earth/f_iceshelf.html

Discussion of state of Ward Hunt Ice shelf on this forum, 2013, unfortunate that many image links are broken:
https://forum.arctic-sea-ice.net/index.php?topic=219.0

7
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: August 16, 2018, 03:35:20 AM »
I created an account here:
https://search.earthdata.nasa.gov/search
Searched on cryosphere->sea ice->extent and AMSR2,
there is a data set:
AMSR2 DAILY L3 12.5 KM TB AND SEA ICE CONCENTRATION POLAR GRIDS V0
The latest file can be displayed, it is this one, from today:
AMSR_2_L3_SeaIce12km_P00_20180815.he5

I don't have the software to display it myself. I'm not sure why other sites are not updating.
Hope that helps.


8
Arctic sea ice / Re: The 2018 melting season
« on: July 24, 2018, 11:26:12 PM »
Pretty sure this was not relevant to the immediate prior discussion but it got me thinking about Kelvin waves propagating along the shore in the Arctic Ocean, where subsequent upwelling (downwelling) could certainly affect melting. I found this reference interesting,

E.C. Carmack and E. A. Kulikov, (cited by 72)
"Wind-forced upwelling and internal Kelvin wave generation in Mackenzie Canyon, Beaufort Sea", J. of Geophsyical Research, V.103, No.9, pp. 18447-18458, Aug. 1998.

"We here first describe two major upwelling events observed in Mackenazie Canyon in Autumn 1987 (S.3). We then use spectral methods to establish a correlation between upwelling events and a wind field (S.4). Finally, we argue that upwelling within the the canyon generates an internal Kelvin (coastal trapped free) wave that subsequently propagates northeastward along the continental margin."

Reading on to section 5: "The negative correlation for alongshore winds means that the alongshore wind in the northeast (southwest) direction causes isopycnal elevation (depression)."
..."The maximum response of ED to wind forcing is about 4.5 m/(km h^-1) at site SS4 in Mackenzie Canyon."

9
Arctic sea ice / Re: The 2018 melting season
« on: June 23, 2018, 06:06:59 PM »

My guess ist, that in the future we'll talk about this year for what happened on the Atlantic side. Everything else is average or below, but the Atlantic side holds the cards for a stunning event.
What constitutes 'the Atlantic Side" geographically is not the same as the increasing push of salty subsurface Atlantic waters further east along the the Siberian coast into the Laptev Sea and beyond. I think this latter effect, ongoing and increasing, will also prove to be most interesting this year, especially if weather events promote strong mixing later in the melt season.

10
Arctic sea ice / Re: The 2018 melting season
« on: April 03, 2018, 03:40:05 PM »
Again looking like there'd be some pumping action at lunar tempo here but it can't be, can it. ~29 days between local minimums. Noo, it wouldn't, would it?
Worth checking out but tides vary only about 1 foot Norton Sound Nome AK,
https://tidesandcurrents.noaa.gov/noaatidepredictions.html?id=9468756

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Arctic sea ice / Re: The 2017 melting season
« on: July 16, 2017, 04:44:40 PM »
"Make stuff up" sounds rather harsh, but if I understand correctly NOAA SST methodology does add climatology to older data where current data is missing, overview here: http://polar.ncep.noaa.gov/sst/ophi/description.shtml

12
Science / Re: Early Anthropocene
« on: May 29, 2017, 12:26:21 AM »
Brien Foerster has long studied those people with giant skulls, somewhere on his site are photos of a foetus with the same skull type. https://hiddenincatours.com/ here it is. https://hiddenincatours.com/two-american-doctors-examine-elongated-skull-mother-baby-fetus-bolivia/
Further reading on Brien Foerster: https://badarchaeology.wordpress.com/tag/brien-foerster/

13
Science / Re: Early Anthropocene
« on: May 28, 2017, 11:34:30 PM »
I wouldn't be so sure that humans were not in the Americas in the last interglacial. Though perhaps not homo sap. These ones have up to 2 or 3 times as big a brain as us. Though its not just in the Americas that the conehead type is found. There is also the matter of raised garden type geoglyphs of very large scale in the Altiplano with glacial period sediment fans over them. Not to mention extensive submerged Megalithic structures in the Caribbean etc.

The Mitochondrial  DNA maps show a Ice age civilisation spanning the tropical Pacific. Not so the Y chromosome ones. The men tend to invade new territories while the women stay put.
Nobody is "sure", but as G. Laden points out in the link I posted, there is a lack of evidence.

As for contact between Austronesian peoples with the Americas, I think there is strong evidence, not just from human DNA studies but also from plant DNA, e.g. pre-European existence of coconuts on the west coast of Central America, sweet potatoes in the Cook Islands. But again, we do not know when that contact took place, whether it was a founding event or much later. "Invading men" may travel without women (although I think that is a culturally-biased assumption) but that strategy would surely fail for colonists.

 There is quite a lively debate ongoing between linguists, geneticists, archeologists and anthropologists on these issues, and nothing has been settled.  I am none of these, count me in as an interested observer of these sciences, with an emphasis on Science.

There is no 'scientific consensus' as there is with AGW on the origin and details of the first peopling of the Americas.

14
Science / Re: Early Anthropocene
« on: May 27, 2017, 03:01:27 PM »
I am calling this here as "beaver force" after the Clovis period North Americans who believed that there were beavers underneath the Foxe-Laurentide Ice Dome that lifted it up to cause sudden, unpredictable (Jokullhaup) floods.

VeilAlbertKallio,

I have not heard of any oral tradition history from the Clovis people, do you mean another tribe or group of peoples in the early americas?  do you have a source for this information?
Indeed, VeilAlbertKallio is undoubtedly mistaken about any historical knowledge of Clovis-period oral tradition; they are only known from their stone artifacts and evidence of habitation from archaeological sites. One could fill pages of references to peer-reviewed journal articles on this point, but the bare outline is given in this blog post by  anthropologist Greg Laden in light of the highly debated and dubious claims for evidence of hominid activity in the Americas in the previous inter-glacial period, which I found to be interesting, http://scienceblogs.com/gregladen/2017/05/02/about-that-130000-human-occupation-in-california/?utm_source=widgets
P.S. For those interested in more detail, see this review paper:
RM Ellsworth, "The Paleoindian Occupation of the Americas"
https://anthromuseum.missouri.edu/minigalleries/clovistools/EllsworthPaleoindianPaper.pdf
quote: "In contrast to the European Paleolithic archaeological record from the same time period, the Clovis record is largely barren in terms of non-lithic, organic artifactual remains." Further, "Other than a few scratch marks generally accepted to be human-made modifications, there is no portable artwork, carved figurines, cave paintings or petroglyphs that are clearly and definitively dated to the Clovis era..."

15
Arctic sea ice / Re: The 2017 melting season
« on: May 17, 2017, 04:02:49 AM »
   .... IIRC Nares only handles 1/10 of the flow out of Fram, but it drags from the thickest of Lincoln Sea ice.

Any idea how Nares compares with Fram on volume basis?
Looks like Nares export (on any measure) will be unusually large this year, owing to lack of arch formation.
From R. Kwok, GEOPHYSICAL RESEARCH LETTERS, VOL. 37, L03502, doi:10.1029/2009GL041872, 2010, full paper link,
rkwok.jpl.nasa.gov/publications/Kwok.2010.GRL.pdf
"... In 2007, ice arches failed to form. This resulted in the highest outflow of Arctic sea ice in the 13‐year record between 1997 and 2009. The 2007 area and volume outflows of 87 × 10 3 km 2 and 254 km 3 are more than twice their 13‐year means. This contributes to the recent loss of the thick, multiyear Arctic sea ice and represents ∼10% of our estimates of the mean ice export at Fram Strait"
Presumably the 10% figure often quoted applies to volumetric flow, although there is large annual variance.

16
Arctic sea ice / Re: The 2016 melting season
« on: September 07, 2016, 01:05:20 AM »
Am I alone in noticing a change in the denier rhetoric regarding the Arctic? Over the last 18 months I am hearing more and more " wasn't the climate great the last time we were ice free? it'll be the saving of mankind......" ? Are they beginning to realise that this thing is happening and happening soon?
In my experience that one is old, but persistent. I was stupid enough to pose that one to Donella Meadows in the 1980's after a lecture. I happened to be slogging through one of Budyko's early works at the time that seemed to suggest to me the inevitability of iceball earth. She dispatched me easily, with deserved contempt.

17
Arctic sea ice / Re: The 2016 melting season
« on: September 02, 2016, 11:40:55 PM »

Time for another reminder about scale.

Brash ice is pieces not more than two metres across.  The AMSR2 pixels are 12 <i>kilometres</i>, and even the Aqua/Modis visible band pictures are 250 metres per pixel. A single pixel of ice visible on MODIS qualifies as a large floe.

Granularity of ice can be inferred by movement due to ocean currents and wind to sub-pixel accuracy. Search the image processing literature for the term "super resolution", it was a hot topic of research in the 1990's.

19
Arctic sea ice / Re: Arctic Image of the Day
« on: July 31, 2015, 09:41:54 PM »
Thank you Andreas. My eye was initially drawn to the grease ice swirling in the ocean currents, such as the small outflow on the coast above the "heart" in your image, but I now also see the smoke, a diffuse brown haze blowing in the wind, as would be expected.

20
Arctic sea ice / Re: Arctic Image of the Day
« on: July 31, 2015, 03:00:23 AM »
Franz Josef Lands in the Arctic, July 28-30, from LANCE-MODIS System.

The beautiful swirls that look like "smoke" I surmise is grease ice, produced by fresh water melting off the the glaciers and perhaps the pack edge as well. Looks to be a good indicator of the local ocean currents as well as melting and/or refreezing conditions, depending on its persistence.

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Arctic sea ice / Re: The 2015 melting season
« on: July 24, 2015, 08:54:45 PM »
Chris:  This might be useful, not sure what the resolution is:

http://www.esrl.noaa.gov/psd/cgi-bin/db_search/DBSearch.pl?Dataset=NCEP+Reanalysis+Daily+Averages+Surface+Flux&Variable=Downward+solar+radiation+flux

from

http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.surfaceflux.html

The problem with such data is that Excel VBA cannot natively open netcdf. I have an Excel add on that can convert netcdf files to an Excel spreadsheet, however NCEP/NCAR have recently updated their format and that no longer works. Writing my own code to access netcdf 4 is a major project in itself.

To access netcdf I would have to move onto something like R (or Python?) and I just don't have the time to learn a new language. Work pressures often make me think I need to stop blogging as it is, I have only managed to read about 15 new papers so far this year.
Hi Chris - Former lurker here, just signed up to post. A possible solution is Matlab or better yet the free version Octave, adding the netcdf toolbox: http://modb.oce.ulg.ac.be/mediawiki/index.php/NetCDF_toolbox_for_Octave

After installing the toolbox type at the Octave prompt the command "ver" to show the toolbox is installed, i.e. octave:1> ver
Should be easy to write out to a csv file from there. I found this on ResearchGate and will be trying it out soon myself, but on a linux box with libreoffice instead.
Cheers!

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