KenMankoff

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).

Dolphin

Dolphin, surfing the wake of the Laurence M. Gould in the Straits of Magellan.

Hurry up and Wait

There are a few key mantras I’ve learned to repeat while I’m down here:

Be Flexible. It’s a Harsh Continent. Hurry Up and Wait.

We’re dealing with all three of those right now.

We have left Palmer Station but have sailed South rather than North or homeward. About 40 nautical miles SSW of Palmer Station is Hugo Island. Next to Hugo is a small rock called Santa Claus Rock (I think). On this rock sits a malfunctioning weather and GPS station and we are tasked with fixing it.

Fixing it involves sending a shore party out in a Zodiac. They will attempt a landing amid breaking waves on a snow-covered rocky beach. If successful, they will then attempt to fix the weather/GPS station, and motor back to the ship. Then we sail north to port in Punta Arenas, Chile, where we catch a plane home.

Unfortunately there are strong winds, thick fog, dense sea ice, and large swells under the ice. So we are sitting and waiting. If the weather clears, the ice thins, and the waves are calm enough to land the Zodiac then perhaps we’ll be able to repair the station. Otherwise we’ll wait, perhaps up to 3 days, at which point we must head home due to port call deadlines. Another cruise, in a few months, will make another attempt.

The weather component measures the… weather. And the GPS component is measuring continental rebound. During the last ice age there was a lot more ice here. This ice weighed a lot and pushed the crust of the earth down. The ice left relatively quickly, but the crustal rebound continues today. This process will continue in the future as more ice melts, and seas rise, due to both natural and human-induced climate change. A side-effect of this is that over long periods of time, certain places might experience relative sea-level drop rather than rise, although they are likely to get wet over the short term.

In a Boat

Harriet Mankoff in The Laurence M. Gould docked at Palmer Station, Antarctica.