KenMankoff

The role of Pine Island Glacier ice shelf basal channels in deep-water upwelling, polynyas and ocean circulation in Pine Island Bay, Antarctica

The role of Pine Island Glacier ice shelf basal channels in deep-water upwelling, polynyas and ocean circulation in Pine Island Bay, Antarctica

Several hundred visible and thermal infrared satellite images of Antarctica’s southeast Amundsen Sea from 1986 to 2011, combined with aerial observations in 2009, show a strong inverse relation between prominent curvilinear surface depressions and the underlying basal morphology of the outer Pine Island Glacier ice shelf. Shipboard measurements near the calving front reveal positive temperature, salinity and current anomalies indicative of melt-laden, deep-water outflows near and above the larger channel termini. These buoyant plumes rise to the surface and are expressed as small polynyas in the sea ice and thermal signatures in the open water. The warm upwellings also trace the cyclonic surface circulation in Pine Island Bay. The satellite coverage suggests changing modes of ocean/ ice interactions, dominated by leads along the ice shelf through 1999, fast ice and polynyas from 2000 to 2007, and larger areas of open water since 2008.

@article{Mankoff:2012The-role,
	Title = {{The role of Pine Island Glacier ice shelf basal
                  channels in deep water upwelling, polynyas, and
                  ocean circulation in Pine Island Bay, Antarctica}},
	Author = {Kenneth D. Mankoff and Stanley S. Jacobs and
                  Slawek M. Tulaczyk and Sharon E. Stammerjohn},
	Journal = {Annals of Glaciology},
	Number = {60},
	Volume = {53},
	Year = {2012},
        DOI = {10.3189/2012AoG60A062}}

Pine Island Glacier and Pine Island Bay

Pine Island Glacier and Pine Island Bay

Pine Island Bay in the southeast Amundsen Sea, Antarctica, on 16 Nov 2008. Upwelling, melt-laden outflow plumes emerge from beneath the adjacent Pine Island Glacier ice shelf (top center) and mix in the bay waters. Warm red colors show sea surface temperatures more than a degree warmer than the near-freezing dark blue color. Cyclonic circulation in the bay is framed by the ice shelf, land ice and sea ice, in gray-scale with the darker shades colder. Landsat Enhanced Thematic Mapper Plus image, thermal infrared (channel 6H), subset of scene #LE72331132008321EDC00.

@article{Mankoff:2012The-role,
	Title = {{The role of Pine Island Glacier ice shelf basal
                  channels in deep water upwelling, polynyas, and
                  ocean circulation in Pine Island Bay, Antarctica}},
	Author = {Kenneth D. Mankoff and Stanley S. Jacobs and
                  Slawek M. Tulaczyk and Sharon E. Stammerjohn},
	Journal = {Annals of Glaciology},
	Number = {60},
	Volume = {53},
	Year = {2012},
        DOI = {10.3189/2012AoG60A062}}

WISSARD Introduction

A video (and written) news segment on part of my PhD project:

GLIMMER Ice Shelf Modeling (OS X HowTo)

A new beta version of the Community Ice Sheet Model, Glimmer-CISM, has been released. Below are instructions to compile and run it on OS X.

# build NetCDF
export CFLAGS=-m32
export FFLAGS=-m32
./configure --prefix=/Users/mankoff/local/netcdf-4.1.1 \
          --disable-cxx --disable-curl  --disable-dap
make && make install
say netCDF done

# build GLIMMER
cd ~/local/src/
wget http://download.berlios.de/glimmer-cism/glimmer-1.7.0.tar.gz
tar zxvf glimmer-1.7.0.tar.gz 
cd glimmer-1.7.0/

# OS X has issues with 32 and 64 bit libraries. 
# The -m32 flag forces 32 bit compilation.
# The following should be one long line:
./configure --prefix=/Users/mankoff/local/glimmer-1.7.0 \
     --with-netcdf=/Users/mankoff/local/netcdf-4.0.1 \
     FC=gfortran F77=gfortran CFLAGS=-m32

make
make install
say GLIMMER done

There are a few ways to test the installation. The source folder provides a test folder:

export PATH=/Users/mankoff/local/glimmer-1.7.0/bin:$PATH
cd ~/local/src/glimmer-1.7.0/tests/shelf
python circular-shelf.py circular-shelf.PP.config
python confined-shelf.py confined-shelf.PP.config
say GLIMMER Test Done # Takes a while. Turn up your volume

Running the above command will result in NetCDF files being created in the output/ subdirectory. You can view the contents of example.nc with most any generic NetCDF viewer. While theses tests run over a given period of time, the output only has one time stored. If you want to see an evolution of the ice shelf, older test suites available from the previous code repository site should be used:

cd ~/tmp/
wget http://forge.nesc.ac.uk/download.php/200/glimmer-example-0.6.tar.gz
tar zxvf glimmer-example-0.6.tar.gz
cd glimmer-example-0.6/
~/local/glimmer-1.7.0/bin/glide_launch.py ./example.config 
say done

Examine the output file example.nc to see ice sheet evolution over time. Basal melt is shown below:

@article{Rutt:2009,
  Author = {Ian C. Rutt and Nicholas R. J. Hulton and Antony J. Payne},
  Title = {{The Glimmer community ice sheet model}},
  Year = {2009}}
  Journal = {J. Geophys. Res.},
  Volume = {114},
  Number = {F2},

Pine Island Glacier Publication TimeMap

In which I present a rough geo-spatial-temporal map of Pine Island Glacier (PIG) publications.

Geo-spatial-temporal time-map of Pine Island Glacier (PIG) publications

More »

Storms in Santa Cruz

Starting yesterday, and continuing through the week, and possibly through much of next week, Santa Cruz is experiencing some extreme weather. NOAA warns of the following:

High Surf Warning
Wind Advisory
High Wind Watch
Coastal Flood Watch
Hazardous Weather Outlook

Where, for example, High Wind Watch means winds 25-40 mph with gusts up to 60. Almost all week long.

I could not sleep in the storm last night. Perhaps because the thunder was so loud and so close that car alarms went off. And the windows rattled a lot.

It might also have to do with Antarctic boats. I’ve spent more than 3 months of the past year on a boat, and the last few storms I’ve been through like this made me nauseous, but also rocked me to sleep. I missed the rocking last night, which is good, since I’m in a house and not a boat.

Webcam and webcam.

More Photos from Antarctica (LMG09-09)

I’ve finally gotten around to uploading some photos from the latest trip to Antarctica. We sailed on the Laurence M. Gould through the Drake Passage and the Bellingshausen Sea, then along the Antarctic Peninsula to Palmer Station. We saw a lot of ice and some wildlife.

If you want to read about the trip you can do so here or by clicking on the LMG09-09 tag to the right.

If you were on the ship here is a GPX file so you can geotag your own photos.

Phosphorescing Sea Ice

This footage was shot by Harriet Mankoff on September 22nd 2009 in the Drake Passage near 60 degrees South. It shows what I have labeled “phosphorescing sea ice” due to the white flashes at the wave crests. The sea is covered by pancake ice and slush. At the wave crest the slush builds up enough that the water drains out of the slush and it looks brighter. The reverse happens in some of the troughs.

An Interview

I was in an interview last month highlighting some of the work done by The Climate Project. Watch below.

Land Ho (Again)

As I write this we are once again in the Straits of Magellan. Land (green, not white) is visible on both sides of the ship. Some dolphins are porpoising in our wake.

Internet and solid ground and fresh vegetables await us in just a few hours. Then, ~36 hours of travel home.

Trip summary:

Science & operations: 23 days at sea. 23 CTDs. Max wave height was about 30 feet. Strongest winds were about 100 mph! Minimum air temperature (on boat) was -7.51 C, although it got quite a bit colder on the glacier. Minimum latitude: -64.99.

Pleasure: 1 Glacier hike. 1 Antarctic hot tub. 1 Zodiac ride.

Fauna: 1 Minke whale, 2 dolphins, a dozen or so seals, and one penguin colony (several hundred large, but far enough away they were just gray dots).