<![CDATA[GREENLAND MELTING - Main forum]]>Thu, 09 Aug 2012 05:26:45 -0500Weebly<![CDATA[Ground data from the Institute for Marine and Atmospheric Research Utrecht, Utrecht University, the Netherlands ]]>Thu, 09 Aug 2012 08:19:41 -0500http://www.greenlandmelting.com/1/post/2012/08/ground-data-from-theinstitute-for-marine-and-atmospheric-research-utrecht-utrecht-university-the-netherlands.htmlPicture
A link to the ground data collected along the K-transect by the Institute for Marine and Atmospheric Research Utrecht, Utrecht University, the Netherlands can now be accessed through a new link under the Data section. An example of the available plots is reported on the left. The institute has been operating several automatic weather stations on the western Greenland ice margin (K-transect) for many years and the data of the current calendar year can be viewed from the link under Data or here. Thanks to Carleen Tijm-Reijmer (IMAU) for sending the link. 

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<![CDATA[Albedo update for 2012]]>Mon, 06 Aug 2012 16:26:36 -0500http://www.greenlandmelting.com/1/post/2012/08/albedo-update-for-2012.htmlPicture
Here's a link to Jason Box 2012 analysis of albedo over the Greenland ice sheet. The reduction of the albedo is a critical factor for enhancing melting over the Greenland ice sheet. The image on the left shows the ice sheet albedo time series updated through July 2012 by Jason Box. 

To better understand the importance of this mechanism you can check a recently published paper on the Cryosphere Discussion by Box et al. (2012) in which we focus on this problem or another paper (Tedesco et al., 2011) that we published on Environmental Research Letters focusing on the role of albedo and accumulation on the 2010 melting recording in Greenland. Both papers are also available in the Scientific Literature section of this site. 

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<![CDATA[NOAA post about melting at Summit]]>Thu, 02 Aug 2012 17:41:13 -0500http://www.greenlandmelting.com/1/post/2012/08/noaa-post-about-melting-at-summit.htmlNOAA today posted the following focusing on melting at Summit during the month of July 2012. 
Here's the full link:

http://www.climatewatch.noaa.gov/article/2012/summer-weighing-heavily-on-greenland-ice-sheet
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<![CDATA[New post on Climatescience.tv]]>Wed, 01 Aug 2012 13:42:09 -0500http://www.greenlandmelting.com/1/post/2012/08/new-post-on-climatesciencetv.htmlPost on the birth and death of the a supra glacial lake in Greenland. ]]><![CDATA[The unique melting at Summit: a microwave perspective¬†]]>Wed, 01 Aug 2012 13:35:02 -0500http://www.greenlandmelting.com/1/post/2012/08/the-unique-melting-at-summit-a-microwave-perspective.htmlThe plot below shows the passive microwave brightness temperature time series over Summit recorded between 1979 and 2011 (the ensemble of gray lines) and the time series recorded during 2012 (black thick line). The ensemble clearly shows that things are relatively stable at Summit, with relatively small interannual variability. 
The plot also shows that the event of July 2012 s unique for the satellite era (1979 - to date) and it lasted for a few days. For those who are not expert in passive microwave remote sensing: as the liquid water appears, the recorded signal jumps to high values, suddenly. This kind of change (sudden and strong) can be related only to the appearance of  liquid water within the snowpack as other changes in the physical properties of the snowpack would produce either a weaker signal or would have a different timescale. Note: this sensitivity of microwaves to water is the same physical principle through which we are able to cook our food using microwave ovens !
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<![CDATA[.. more on Summit temperatures from DMI]]>Tue, 31 Jul 2012 11:22:31 -0500http://www.greenlandmelting.com/1/post/2012/07/-more-on-summit-temperatures-from-dmi.html
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<![CDATA[Update on Summit Greenland temperatures (original by C. Shuman)]]>Tue, 31 Jul 2012 11:09:41 -0500http://www.greenlandmelting.com/1/post/2012/07/summit-greenland-temperatures-original-by-c-shuman.htmlHere's a message that Chris Shuman from UMBC/NASA Goddard posted on cryolist concerning the Summit Greenland temperatures. I am also attaching an updated figure from Chris showing that temperatures at Summit reached high values again over the past few days. I quickly looked at satellite data and though I could not see any melting for those days, the area undergoing melting was going up again. I will post an update later. 
ORIGINAL MESSAGE FROM CHRIS TO CRYOLIST 

For those of you interested in the reported air temperatures at Summit, the NOAA data for 2012 is illustrated here relative to several previous years of their JJA data (up to July 25th so far).
http://jcet.umbc.edu/2012/07/nasa-72412-press-release-green.html

The data shown will be updated periodically through the end of August. And it bears repeating that the snow surface temperature (as tracked by MODIS or the passive microwave sensors, see the NASA press release) can differ by several degrees from the nominal 2 meter air temperature.

Cheers, Christopher

-- 
Christopher A. Shuman - Assoc. Research Scientist
UMBC Joint Center for Earth Systems Technology
Cryospheric Sciences Laboratory, Code 615
Greenbelt, MD 20771 - USA
(301) 614-5706 voice (301) 614-5666 fax
Christopher.A.Shuman@nasa.gov
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<![CDATA[June - July 2012 sets a new melting record for Greenland ... will it be a new seasonal record ?]]>Sun, 29 Jul 2012 10:24:09 -0500http://www.greenlandmelting.com/1/post/2012/07/june-july-2012-sets-a-new-melting-record-for-greenland-will-it-be-a-new-seasonal-record.htmlThe recently observed melt extent record over Greenland has shown the capabilities of remote sensing data to monitor large areas on a daily basis. The melting observed at high elevations over Greenland did not generate meltwater that contributed (or could have contributed) directly to sea level rise, mainly because liquid water refroze after the event, creating the ice layer that has been used to confirm the event. The same remote sensing tools are used to observe melting at lower elevations, where it happens every summer. Here, meltwater can either directly contribute to SLR or it can impact ice sheet dynamics, modulating the ice velocity and shaping the evolution of the englacial summer system of channels through which meltwater flows (see this video, for example). Over the past years, surface melting over Greenland has been increasing, setting new a new record in 2010 and a close-to-record melting season in 2011

So, what happened in 2012 over the rest of Greenland while the warm air was climbing up Summit ? 

The graph below shows the Standardized Melting Index (SMI, obtained from the melting index by subtracting the mean for the period 1979 - 2012 and dividing by the standard deviation for the same period) for the period June 1st - July 20th. Values above 0 indicate those cases when melting was above the 1979 - 2012 mean. For the period when data is available, therefore, the SMI set a new record for the satellite era. 
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Standardized melting index for the period 1979 - 2012 when considering only the period June 1st - July 20th
The image below shows the cumulative number of melting days over Greenland for the period June 1st - July 25th. Beside the large melt extent occurring in July 2012, note the high number of melting days along the southeast coast as well as the width of the area subject to considerable melting along west Greenland. Over the southeast coast, during the period June 1st - July 25th, melting lasted up to 30 days above the mean.
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Number of melting days estimated for the period June 1st - July 25th of every year from space borne microwave data
Since the past  week or so, melting has decreased with respect to the breaking-record values of June and mid July, mostly as a consequence as the shift to a neutral phase of the NAO. Depending on how melting will evolve in August, the 2012 melting season might set a new melting record. Nevertheless, 2012 is already positioning among the top melting years, with the cumulative melting index until July 25th being close to the cumulative melting index for the whole 2010 and higher than the one for the 2011 season. 
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<![CDATA[July 2012 update on Surface temperature at Summit from C. Shuman]]>Sun, 29 Jul 2012 09:29:36 -0500http://www.greenlandmelting.com/1/post/2012/07/july-2012-update-on-surface-temperature-at-summit-from-c-shuman.htmlChris Shuman, from UMBC/NASA GSFC has posted this update concerning surface temperature at Summit. The original message to cryolist follows ....

For those of you interested in the reported air temperatures at Summit, the NOAA data for 2012 is illustrated here relative to several previous years of their JJA data (up to July 25th so far).
http://jcet.umbc.edu/2012/07/nasa-72412-press-release-green.html

The data shown will be updated periodically through the end of August. And it bears repeating that the snow surface temperature (as tracked by MODIS or the passive microwave sensors, see the NASA press release) can differ by several degrees from the nominal 2 meter air temperature.

Cheers, Christopher

-- 
Christopher A. Shuman - Assoc. Research Scientist
UMBC Joint Center for Earth Systems Technology
Cryospheric Sciences Laboratory, Code 615
Greenbelt, MD 20771 - USA
(301) 614-5706 voice (301) 614-5666 fax
Christopher.A.Shuman@nasa.gov
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<![CDATA[Video of Watson bridge at Kangerlussuaq on July 21, 2012]]>Fri, 27 Jul 2012 07:21:51 -0500http://www.greenlandmelting.com/1/post/2012/07/video-of-watson-bridge-at-kangerlussuaq-on-july-21-2012.htmlHere's a video of the Watson bridge taken on July 21 from the helicopter flying us back from the ice. The bridge collapsed on July 12, 2012 because of the river flood. Great images here from the Earth Observatory website. More videos filmed during the collapse are also below. 
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