UCI, NASA reveal new details of Greenland ice loss
Data are dramatically increasing knowledge of how the ocean is melting the ice sheet
Credit: UCI
Irvine, Calif., February 9, 2017 – Less than a year after the first research flight kicked off NASA’s Oceans Melting Greenland campaign, data from the new program are providing a dramatic increase in knowledge of how Greenland’s ice sheet is melting from below. Two new research papers in the journal Oceanography, including one by UCI Earth system scientist Mathieu Morlighem, use OMG observations to document how meltwater and ocean currents are interacting along Greenland’s west coast and to improve seafloor maps used to predict future melting and sea level rise.
OMG is a five-year campaign to study the glaciers and ocean along Greenland’s 27,000-mile coastline. Its goal is to find out where and how fast seawater is melting the glacial ice. Most of the coastline and seafloor around the ice sheet had never been surveyed, so the 2016 flights expanded scientists’ knowledge of Greenland significantly. Future years of data collection will reveal the rate of change around the island.
The water circulating close around the Greenland Ice Sheet is like a cold river floating atop a warm, salty ocean. The top 600 feet (200 meters) of colder water is relatively fresh and comes from the Arctic. Below that is saltwater that comes from the south, 6 to 8 degrees Fahrenheit (3 to 4 degrees Celsius) warmer than the fresher water above. The layers don’t mix much because freshwater weighs less than saltwater, so it stays afloat.
If a glacier reaches the ocean where the seafloor is shallow, the ice interacts with frigid freshwater and melts slowly. Conversely, if the seafloor in front of a glacier is deep, the ice spills into the warm subsurface layer of saltwater and may melt relatively rapidly. Satellite remote sensing can’t see below the surface to discern the depth of the seafloor or study the layers of water. OMG makes these measurements with shipboard and airborne instruments.
Improving maps used to project sea level rise
In the first paper, UCI’s Morlighem used the OMG surveys to improve maps of the bedrock under some of the West Coast glaciers. Glaciologists worldwide use these and other maps in modeling the rate of ice loss in Greenland and projecting future losses.
A coastal glacier’s response to a warming climate depends heavily not only on the depth of the seafloor in front of it, as explained above, but on the shape of the bedrock below it. Before OMG, virtually the only measurements Morlighem had of these critical landscapes were long, narrow strips of data collected along flight lines of research aircraft, sometimes tens of miles inland (upstream) from a glacier’s ocean front. He has been estimating the shape of the bedrock outside of the flight lines with the help of other data such as ice flow speeds, but formerly had no good way to check how accurate his estimates are at the coastline.
Morlighem noted, “OMG [data are] not only improving our knowledge of the ocean floor, they’re improving our knowledge of the topography of the land, too.” This is because the campaign’s seafloor survey revealed features under the ocean, such as troughs cut by glaciers during the last ice age, which must continue upstream under the glacial ice. Therefore, Morlighem said, “By having OMG’s measurements close to the ice front, I can tell whether what I thought about the bed topography is correct or not.” Morlighem was pleasantly surprised to discover that 90 percent of the glacier depths he had estimated were within 160 feet (50 meters) of the actual depths recorded by the OMG survey.
Tracking meltwater far into the North
In the second paper, Ian Fenty of NASA’s Jet Propulsion Laboratory, Pasadena, California, and coauthors, including Morlighem, tracked water up the West Coast to see how it changed as it interacted with hundreds of melting coastal glaciers. They found that in northwest Greenland, cold and fresh water flowing into glacial fjords from the melting surface of the ice sheet is cooling the warmer subsurface water, which circulates clockwise around the island. In one instance, evidence for meltwater-cooled waters was found in fjords 100 miles (160 kilometers) downstream from its source. Fenty noted, “This is the first time we’ve documented glacier meltwater significantly impacting ocean temperatures so far downstream. That shows meltwater can play an important role in determining how much ocean heat ultimately reaches Greenland’s glaciers.”
The OMG data have enough detail that researchers are beginning to pinpoint the ice-loss risk for individual glaciers along the coast, according to principal investigator Josh Willis of JPL. “Without OMG, we wouldn’t be able to conclude that Upernavik Glacier is vulnerable to ocean warming, whereas Cornell Glacier is less vulnerable,” he said.
###
The two papers are available online:
Improving bed topography mapping of Greenland glaciers using NASA’s Oceans Melting Greenland (OMG) data, https://doi.org/10.5670/oceanog.2016.99
Oceans Melting Greenland: Early Results from NASA’s Ocean-Ice Mission in Greenland, https://doi.org/10.5670/oceanog.2016.100
How important is wind strength and direction ? A change in wind patterns could have an influence ?
https://earth.nullschool.net/#current/wind/surface/level/orthographic=-67.90,68.06,1183/loc=-42.404,72.950
According to the Danish M I dept.foehn type winds are very common on greenland ,&caused last summers locally recorded high temperatures
I thought this could bee of interest : http://www.ifremer.fr/co-argoFloats/cycle?detail=false&ptfCode=6901023&cycleNum=168&active=true&ocean=A&lang=en&techChart=false
one of the Argo vessels close to Greenland.
Or this-evidence of melting glaciers and paste during the last 100 Years.
http://notrickszone.com/#sthash.TytkidZR.dpbs
DMI.dk data. Dramatic ice gain on Grenland. Or dramatic negative ice loss. As you wish. About 100 Gt more than normal.
Yes, the last two years and the beginning of this year give even the hope that a trend reversal was achieved. Namely, the increase in ice due to increased precipitation could approximately compensate ice loss by melting at the foot of the glaciers. It can also be due to the decadally fluctuating precipitation, whether the Greenland ice mass loss and how large it is. At the present time, the mass of the melted ice is not a cause for hysteria in relation to the mass of the ice stock, nor is it the case with Antarctic ice.
It gained a tad more to around 125 Gt above average. This is its highest point above the average line to date. I am very curious to see what is going to happen this summer. Will the smb stay above the trend line into and through the summer melt season?
The GIS grew a lot during the LIA. No surprise that it might be shrinking a bit now that some 320 years have passed since the Maunder Minimum depths of the LIA.
Same old , same old Greenland glaciers melting.
1952, Greenland
“Cmdr. Simpson said:
“Glaciers have recently been
melting steadily at an in-
creasing rate. We will make
tests gauging the exact speed”
http://trove.nla.gov.au/newspaper/article/49247357?searchTerm=greenland%20melting&searchLimits=
1950-
First, its climate is getting warmer. This is not a century change but something
that is going on almost before your eyes. The temperature of the sea water is up several degrees, Freuchen said, the seals are retreating, and codfish and mosquitoes are advancing. This ls helping to cause a revolution in the lives of the native
Eskimo.
http://trove.nla.gov.au/newspaper/article/57081978?searchTerm=greenland%20melting&searchLimits=
http://trove.nla.gov.au/newspaper/article/49247357?searchTerm=greenland%20melting&searchLimits=
1940- GREENLAND GLACIERS MELTING
Examiner (Launceston, Tas. : 1900 – 1954) Thursday 1 February 1940 p 9 Article
Greenland’s Climate Becoming Milder
The Courier-Mail (Brisbane, Qld. : 1933 – 1954) Monday 6 May 1940 p 5 Article
1930 – LOCAL AND GENERAL Greenland’s Ice Cap Melting
North-Eastern Advertiser (Scottsdale, Tas. : 1909 – 1954) Tuesday 18 November 1930 p 2 Article
1923- NORTH POLE MELTING. MANY GLACIERS VANISHED.
Daily Mercury (Mackay, Qld. : 1906 – 1954) Saturday 7 April 1923 p 9 Article
1910 – RECEDING GLACIERS.
The Braidwood Dispatch and Mining Journal (NSW : 1888 – 1954) Wednesday 28 September 1910 p 4 Article
… timber. The Jacobshaven glac-ier in Greenland has retreated four miles since 1850,
The return from the LIA. A completely natural process. But people have always tended to overstate. 1920, 1950 and even today. Dramas sell better than documentaries.
Image from Griff’s link above.
I measured that this morning. It is right around 125+ Gt above average. This being the 3rd winter in a row where the winter trend has been above average, I would hazard a guess that something in the climate system has changed. Perhaps this is related to the concept of the polar see saw effect.. Antarctica went on a tear for above average sea ice for 4 years before crashing back to average around mid 2015. Maybe it is Greenland’s turn to experience a similar growth for a period of some years.
Ice is melting. Melting, melting. Oh what a wicked world. Who would have thought driving SUVs could destroy my beautiful icy-ness. Melting, melting……
So the claim is, the Greenland ice cap is melting at the rate of 0.01% per year. This implies that the ice mass is measured to an accuracy of 1 part in 10,000 or better. Is this plausible? I think not.
Radio altimetry studies across the whole icecap show loss of volume…
So is the accuracy of that measurement better than 1 in 10,000 or not? Is the whole icecap measured? What is the baseline the measurement is made against? What are the errors in the measurement? If a trend was measurable how do know it is not a cyclical variation governed by an unknown variable or variables.
If you think this minute change in the volume of the Greenland icecap is related to composition of the atmosphere where is your proof?
Your extraordinary claim requires extraordinary evidence, if you have none you are speculating.
It’s not loss of volume. It is subsidence of the land under Greenland from the accumulation of ice on top. Radio altimetry… My ass.
Seaice1: if you make the y-axis of your solar cycle graph to start from zero you get the same curve as plotting the mean absolute global temperature y-axis starting from zero. Because the global mean temperature is strictly dependent on solar activity, the graphs shoul be equal. No need for greenhouse.
Interesting the discussion on absolute versus relative ice mass changes in Greenland or for solar cycle,but psychologically the presentation or framing has a big impact on how people think of things,advertisers and propagandists have known this a long time. E.g . Kahneman and Tversky, Choices, Values, and Frames (1983) and same in prior papers which i will not look up correct cite …
“Imagine that you are about to purchase a jacket
for $125 and a calculator for $15. The calculator salesman
informs you that the calculator you wish to buy is on sale
for $ 10 at the other branch of the store, located 20 minutes
drive away. Would you make a trip to the other store?”
– 68% of the respondents were willing to drive to save $5 on the $15 calculator (66.67% by price of item),
Now change to calculator with price of $125 and can do same drive to purchase it at $120 with jacket set price at $15 (00.04% by price of item),but still same absolute $5 saved by trip.
– now only 29% of respondents were willing to make the same trip to save $5 (on a $125 item).
Try the same on CO2 at 300 to 400 ppm, a 33.3% rise, or just a 00.01% rise as percent of atmosphere being minor trace gas as it is relative to Nitrogen, Oxygen, and Argon adding up to 100% w/o the rounding.
Now what gets me is that while there has been all this focus on CO2, Oxygen in atmosphere it largely ignored. More CO2 means less O2 and O3 as the O which is formerly in atmosphere is combined with C and released as CO2 when burning fossil fuels (or cows farting). IF you look at Oxygen, the percent of atmosphere does not change much – in percentage terms – alike CO2, but in absolute terms the decrease in atmospheric O2 is comparable to increase in C02. Both impact outgoing absorption in the infrared range according to greenhouse theory.
The relative change in O seems insignificant relative to self or atmosphere,but the absolute quantity of Oxygen trending down is completely comparable to rise in CO2.
No one talks about reduced oxygen reducing greenhouse effect (or theoretically canceling out effect of CO2). Ignorance is bliss when getting funding to study one while ignoring other, but I have not done any serious search for papers on this (theoretical greenhouse effects or reduced oxygen molecules [turned into CO2]) and only know the cognitive bias or psychology – a candle seems to emit much more light in a dark room than in a well lit one. Relative change in atmospheric Oxygen is not much being at 21% , but absolute terms its decline is similar to CO2 rise. Enlighten me if know more.
http://www.ces.fau.edu/nasa/images/Energy/GHGAbsoprtionSpectrum-690×776.jpg
http://www.earthonlinemedia.com/ebooks/tpe_3e/energy/selective%20absorbers.jpg
Check my reasoning on this:
Robert,
It is not the Ozone or O3 you list as 0.000004 ppm in graph, but O2 which is 20.95%. Again, O2 in relative terms has not changed, still 20.95%, but in absolute terms, the quantity of O2 in the atmosphere has been declining at a greater rate than the quantity of CO2 has been rising.
(We know or have studied O3 enough, concentrated in the upper atmosphere where incoming UV converts O2 to O3 and also blocks the UV, lets just look at O2 which is mainly in lower atmosphere)
See, O2 Dropping Faster than CO2 Rising
http://www.i-sis.org.uk/O2DroppingFasterThanCO2Rising.php
Now, if we theoretically accept O2 as a greenhouse gas, it’s reduction in the atmosphere would theoretically counteract rising CO2 since it also absorbs in the outgoing IR band (O2 a few microns less wavelength than CO2, yet overlaps H2O less than CO2).
I see almost nothing on this discussed, the reduction in O2 is almost completely ignored.
http://2.bp.blogspot.com/-z0099m2A1dI/Un9NrLLKIZI/AAAAAAAAAtU/oYmZOjynqPk/s1600/spectra.png
http://wordpress.mrreid.org/wp-content/uploads/2014/06/common-gases-604×362.png
I would assume O2 is rising ground level since CO2 has increased green plant life producing it by satellite observations, and its existence in atmosphere is traceable to plant life starting 600 mil. years ago, but now is falling in molecules terms for atmosphere at a similar rate that CO2 rises.
Why is not the absolute decrease in atmospheric O2 which is more than quantity rise in CO2 ever discussed? You add a few molecules of CO2 and take out the same or more of O2. Seems alarmists are ignoring latter (and as in alarmist ice age scare years back, remember looking at impacts of soot or aerosols in atmosphere blocking incoming radiation and ignoring CO2?, this is flip version with CO2 and O2 for claimed outgoing radiation).
This is not my area. Is O2 absorption nonlinear and saturated similar to CO2 at higher levels for outgoing IR so it does not matter? Anyone care to answer/comment?
Magic tricks or illusions are often based on visual concentration or focus on one area to hide something else going on.
https://www.youtube.com/watch?v=ZKry81bf2qw (need to watch twice to see what was missed)
You see bad statistics all the time, even in peer reviewed journals, abet more in mass stream media or think tanks churning out propaganda masked as science where the have to produce evidence to support a preconceived bias. Correlation is not causality. I would assume a high correlation between those who think the MMR vaccine causes autism and AGW believers despite very good scientific evidence opposite. There are many left out variables. The atmosphere and temperature is a very complex system with hundreds of intercorrelated variables, not just CO2.
This concept of absolute vs. relative gets lost most dramatically around attribution to SST. The argument (see Karl, 2016) is that AWG is warming the oceans and this is where the man-made warming signature can be found.
Similar to your reference around absolute changes in oxygen, the uncertainty in evaporation is greater than the entire CO2 “forcing” increase from a 100ppm increase. Thus, a puff of wind can cool the ocean more than all industrial CO2 can warm it.
“The Air-Ocean Interface
Water is almost transparent to visible radiation and sunlight can penetrate down through
clear ocean waters to depths of ~100 meters [Hale & Querry, 1973]. The light is absorbed
mainly by the rather weak overtones of the water infrared vibrations and converted into heat. The oceans cool through a combination of evaporation and long wave infrared (LWIR) emission from the surface [Yu et al, 2008]. The First Law of Thermodynamics (conservation Any flux difference is converted into a change in ocean temperature. Over most of the LWIR spectral region, the ocean surface exchanges radiation with the atmosphere. On average, there is a slight exchange heating of the atmosphere by the ocean. This net heat transfer depends on the thermal gradient or air -ocean temperature difference as required by the Second Law of Thermodynamics. LWIR emissive cooling occurs within a relatively small spectral emission window in the 8 to 12 micron region (~1200 to 800 wavenumbers). The penetration depth of LWIR radiation into the ocean is less than 100 micron, about the width of a human hair.
Small increases in LWIR emission from the atmosphere are converted into increases in
ocean surface evaporation that are too small to detect in the wind driven fluctuations
observed in surface evaporation. Between 1977 and 2003, average ocean evaporation
increased by 11 cm per year from 103 to 114 cm per year. This was caused by an increase in average wind speed of 0.1 meters per second [Yu, 2007]. The uncertainty in the estimate was 2.7 cm per year which is larger than the upper ‘clear sky’ limit to the evaporation produced by a 100 ppm increase in CO2 concentration over 200 years. It is simply impossible for a 100 ppm increase in atmospheric CO2 concentration to have any effect on ocean temperatures. Figure 4 illustrates the basic energy transfer processes at the air-ocean interface. Figure 5 shows the spectral properties of water in the visible and the IR. Figure 6 shows ocean evaporation and the effect of changes in wind speed. An increase of 1.7 Watts per square meter in downward LWIR ‘clear sky’ radiation translates into an upper limit increase in evaporation rate of 2.4 cm per year. ”
http://venturaphotonics.com/GlobalWarming.html
The trouble about this whole the-ocean-is-melting-greenland concept is that on the whole the Greenland ice and the ocean don’t come into contact. The Greenland icecap is almost completely on ground higher than sea-level and reaches the ocean on a broad front only in a few areas in the northeast and northwest. That NASA image at the top is from Melville Bay, which has the longest stretch of icefront calving into the ocean. As a matter of fact I think they are probably quite disappointed by their results since they show that even a short retreat of the ice even in this area would expose an ice-free coast and more or less stop calving.
There is apparently remarkably little fjord morphology in the mapped area which suggests that the ice-front has been very stable in this sector. This fits in well with recent results from the Camp Century ice-core that show that the ice-front has never retreated more than 100 kilometers in the Melville bay area during at least the last million years.
Robertv February 10, 2017 at 5:05 am…
Than I presume that very cold fresh water is more dense than warmer fresh water. How cold has fresh water to become to sink through the warm salt water? Or is that impossible ?
———————————————————————————————————————
Fresh water at 4 degrees C has an density so close to 1000kg/cubic metre it doesn’t matter.
Fresh water that is warmer or cooler has a lower density.
Seawater has a salinity of around 3.5% [it varies a bit]. That is 3.5% of the mass of seawater is made up of dissolved salts. Seawater at 4 degrees C has a density of about 1028kg/cubic metre.
Seawater at a temperature of 80 degrees C has a density of 998kg/cubic metre.
So for cold fresh water to sink through warm seawater you would require a situation where fresh water at 4 degrees C was overlying seawater at 80 degrees C……….not an impossible situation but rather unlikely.
Willis E. has noted that seawater rarely or never exceeds 30°C, due to evaporation etc.
In practice meltwater always stays at the top until mixing with the salt water. On the other hand cold very salt water will sink, even through colder but less salt water. Google “brine rejection”.