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    Glacier Changes In NE Greenland
    By Patrick Lockerby | June 11th 2013 11:32 PM | 24 comments | Print | E-mail | Track Comments
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    Glacier Changes in NE Greenland


    Substantial cracks in the Nioghalvfjerdsfjorden glacier ice tongue appear to be growing in extent and number.  While not as spectacular as the 2010 calving of the Peterman Ice Island, it is more closely linked to global warming than

    Otherwise known as 79 North, Nioghalvfjerdsfjorden glacier is a floating outlet glacier, about 60 km long and 20 km wide located at 79°30'N, 22° W, draining a large area of the northeast Greenland ice sheet.



    Recently observed cracks in the Nioghalvfjerdsfjorden floating glacier tongue.

    Global warming was predicted to be most prominent in the polar regions, and most especially the Arctic.  Among the impacts of a warming Arctic it was predicted that the effects on Greenland's ice sheet and glaciers would be very pronounced in the North East.

    The land fast ice in the area of Zachariae and Nioghalvfjerdsfjorden glaciers is normally cyclic.  Despite its growth and decay it tends to buttress the glaciers and slow down the rate of calving.  Since the year 2000 the landfast ice which has melted in the summer has not formed a thick and robust replacement in the winter.  Consequently, the sea ice's tendency to slow glacier calving has been greatly reduced over the years.

    As an ice tongue rises and falls with the tide, obviously, there is more water under it at high tide.  That extra water ebbs and flows with the tide, tending to bring in warm sea water and to carry away heat.  Any meltwater coming from under the ice will tend to oppose the incoming tidal water, but it too will tend to carry away heat.  The loss of the Odden, which has not formed since 1997 ; the failure of sea ice to regenerate a shelf of strong landfast ice; the decline in Arctic sea ice volume; the inexorable poleward march of the marginal ice zone and loss of the great ice barrier: all of these are clear signs of warming.  Warmer waters penetrating under an ice tongue will predictably promote basal melt.  Thinner ice will be more prone to crack as it flexes due to the tidal current underneath it.  The animation below highlights some of these cracks.


    Animation of cracks in the Nioghalvfjerdsfjorden floating glacier tongue.

    Of recent years the Zachariae Ice Stream, or ZIS, has been studied in some detail.  The terminus is retreating.
    The reduced sea ice in the region has exposed the ZIS terminus to increased open water in what was typically a region that was dominated by persistent sea ice. The enhanced surface melting is also a concern. In 2012 ZIS has experienced an additional retreat that has separated the main glacier from a melange of glacier ice and fast sea ice on the northeast side of the terminus, that had survived the last major tongue disintegration of the southern floating arm of ZIS in 2000-2001. The changes have been an going watch by several of the participants at the Arctic Sea Ice blog, which has developed into a wonderful community for daily detailed sea ice observations.
    Mauri Pelto

    The shelf ice in this region has deteriorated in each year from year 2000 to present. Large shelf ice break-offs such of this magnitude are becoming increasingly common in the Northeast region. Over the past 8 melt seasons there have been cases of significant shelf ice loss greater than 1700 km^2 on a year by year basis. Comparing the images on 4 July and 6 July we have an area deformation of 2970km^2. In relation to Columbus, Oh, this glacier change would fit into the metropolitan area of Columbus twice.

    Jason Box, 2008

    ... In the north of Greenland, the dominant form of mass loss is basal melting at the underside of floating ice shelves.

    2) Basal melt rates inferred from steady state conditions average 5-8 m/yr, but reach 20 m/yr in the first 10 km of floating ice. These rates are one order of magnitude or two larger than those inferred for the large ice shelves in Antarctica, and in the higher end of the spectrum of model calculations.

    3) Overall, the northern part of the Greenland Ice Sheet is not grossly out of balance, but probably thinning. Thinning is indicated from its slightly negative
    mass budget at the grounding line, and by the systematic retreat of its grounding lines, except in the case of surge-type glaciers in
    a quiescent phase. The advantage of measuring grounding line retreat over other methods is that it is not dependent on accumulation and ablation.

    4) The mass budget of the large glaciers (Petermann, Niohalvfjerdbrae and Zachariae Isstrom) is more strongly into the negative. Ice thinning is not likely to
    be due to an increase in summer melt alone. Glacier thinning must include a dynamic component as well. This is consistent with the concept of enhanced
    thinning in areas of concentrated flow. This trend is emphasized at lower latitudes, e.g. along the east coast of Greenland.

    PARCA report

    It seems highly unlikely that the NE Greenland warming trend will reverse.  With continued warming the 79 North glacier tongue is likely to break up over the next few years, into ever smaller pieces, until those pieces can flow unobstructed into Fram Strait.  Meanwhile the Zachariae terminus will continue its retreat.

    Edit - added map below to show - ringed - area of interest.  Source athropolis.com.

    .

    Comments

    MikeCrow
    1956 Danish Ice Map
    Never is a long time.
    Hank
    Who knew the Danes had so many airplanes that could fly all over the world taking the pictures they needed to compile this?? With that sort of airpower at their command, I am surprised they surrendered to Germany two hours after being invaded 16 years earlier.
    MikeCrow
    Since the maps go back prior to the invention of the Airplane(and at least some of them indicate unexplored areas), I presumed they did their mapping by ship.
    Never is a long time.
    Hank
    That's even less accurate. Why would you want to post it?
    MikeCrow
    To provide a level of comparison to the past. We have lots and lots of images currently showing modern melting, and very few examples of historical melting to provide perspective.

    If you or Patrick feel it is inappropriate, or a distraction to his post. Please feel free to remove it.
    Never is a long time.
    logicman
    Mike: no way am I going to delete your comments.  Unless, of course, you 'go emeritus' on me.  ;-)

    Hank and Mike: most of the mapping in those days was done by sledging parties.  The Danmark expedition of 1906-1908 corrected Peary's map, but three members died mapping the area around Nioghalvfjerdsfjorden glacier.  Aircraft expeditions supplemented ship-borne surveys.  Drifting ice stations were also used.  Apart from the war years, in any one year from about 1930 on, there could be many scientific expeditions and many hundreds of ships North of the Arctic Circle.
    Hank
    It's his column, I have no complaint with it, I just didn't see where it would add anything. If someone tells me temperatures are 1.%X higher than 100 years ago, even if I think they are right I am compelled to note that temperature readings were not all that accurate. So it goes with pictures. We end up Frankenstein-ing together datasets - like tree rings and temperature data - or images of different accuracy to try and make a complete picture.

    Anyway, it is as accurate as anything else from the 1950s.
    logicman
    ... even if I think they are right I am compelled to note that temperature readings were not all that accurate. So it goes with pictures.

    Agreed.  That's why I try to use old maps only as an adjunct to reliable data.  Unlike Patrick Michaels, who was happy to use a graphic artist's inaccurate sketch map as "proof" of natural cycles.
    logicman
    Mike: thanks for the map, and thanks again for the link to them in my article on warming islands.  In 1956 I was 10 years old and just starting to get interested in reading about polar exploration.  Can you guess when I was born yet, boys and girls?  ;-)

    Just when I was about to write this article my main computer went berserk, taking 30 mins or more to boot up.  It took me many hours to discover that windoze had installed a second copy of the video driver and had also fouled up the swap file.  The upshot was that I was half asleep by the time I wrote the article, else I would have added more images.

    Here is a zoom of the area of interest August 1956.
    Source: http://www.pmel.noaa.gov/arctic/rediscover/dmi_sea_ice_maps/


    And here is a map for 1946.  Caution: white represents areas where no data was collected by Denmark for that year.  That said, the margins fit in with known data.   Specifically: the sea ice margin used to be South of Franz Josef Land all year round.  It is now commonly North of those islands in early summer, as shown in the 2nd image below.




    Part of Arctic mosaic image. Source: NASA Rapid response.
    MikeCrow
    First, I've had a hard time finding the area you've zoomed in on before on other sources. But I think I found the subject island.

    I found it open to the north in 54.
    Never is a long time.
    Not according to the summer DMI maps for 54 they show the ice well south of F Jozef land.

    MikeCrow
    I think Patrick showed 2 different areas.
    1933 has a lot of open water further North East.
    Never is a long time.
    logicman
    I've had a hard time finding the area you've zoomed in on

    Fixed.  Thanks for pointing this out.  I just edited the article, adding an Arctic map.
    MikeCrow
    That's a great addition, Thanks Patrick!
    Never is a long time.
    logicman
    You are most welcome.  Hitting the 'edit' button long after the 'publish' button is an all too familiar experience with me.  ;-)
    MikeCrow
    I noticed your comment on this, and thought you were looking over my shoulder.
    Never is a long time.
    Have you looked at any imagery besides MODIS?

    Hank
    I'm curious, would another instrument really be different? Both MODIS satellites get data from the entire earth every 2 days.
    logicman
    Hank: there is a problem with cloud and snow, which can give rise to false appearances.  Although I like to think that I am reasonably good at interpreting visual spectrum images, radar images or boots on the ground are needed to confirm my observations.
    logicman
    Mauri: thank you for dropping by. 

    No, I haven't had time, but I did some research of your and Jason Box's blogs, as well as some science papers  including Zwally et  al 2011 and The Nioghalvfjerdsfjorden Glacier  Project, North-East Greenland: a study of ice sheet response to climate change, Henrik Højmark Thomsen et al, 1996.
    There is a general consensus that sea ice retards calving and that Zachariae and 79N calving will be accelerating due to warming.  I hope that Neven's excellent team will pick up on this.
    logicman
    Now that more snow cover has melted, the cracks in 79N are more prominent.

    Zachariae shows a fresh calving of icebergs which will be released as soon as the sea ice melts out.



    Zachariae and Nioghalvfjerdsfjorden June 17 2013


    The two arrows in the lower part of the image point to what look like recent fissures.

    .
    I have finished the initial look at 79 Glacier including imagery from this week. There are some rifts but they are longitudinal not transverse.

    logicman
    Thank you for the link, Mauri.

    Regarding the rift you note at the Spaltegletscher: this has been apparent for some years.  The segment which is 'turning the corner' looks like a loose tooth in animations.  Ice islands in that fjord from previous years do not seem to be very mobile.  Perhaps they are grounding somewhat?

    For my readers who did not follow your link:
    ... a prominent feature that at least at this point is not a rift. Pat Lockerby has noted these features in MODIS, but given the lack of water drainage and distinct break, these are not currently cracks.
    Ah, well - I can't be right all the time, but I'll be watching those satellite images very closely.

    :-)

    .
    The longitudinal rifts formed after 2004, the items you point out are two be watched they are a definite surface low and transverse feature that would be a natural location for rifting to develop.