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}}

Geo-Tagging Photos

I have ~2700 photos from my recent trip to Antarctica. All but a few dozen were taken while on the ship, and the GPS track of the ship is known. The few that were taken off ship were within a three mile radius while deploying the ITP. If you don’t have a ship recording your GPS for you, you can get simple GPS systems for less than $100, or even a few $10s of dollars on eBay. The TrackStick is good for this type of project as it does not have a screen or realtime outputs.

I wanted to geotag all my photos by adding the latitude and longitude to the JPEG EXIF data. I was going to code it as the algorithm is quite simple (for each image, get the creation time, find the GPS location nearest that time in the GPS list, and add the (lat,lon) coordinates to the image), but not surprisingly this problem has already been solved. Repeatedly.

Three steps are required.

1. Convert your GPS data into GPX format. If you are comfortable on the command line then use gpsbabel. If not, then go here for a web interface to gpsbabel. If you need help post in the comments. If you were on NBP09-01 a GPX file of our cruise is here.
2. Add the GPS coordinates to the image EXIF tags. There are many tools that will take a GPX or NMEA file and add latitude and longitude coordinates to your photos. I use gpicsync and photoGPSEditor looks nice too.
3. Output KML files. gpicsync does this for you, and has a list of other software that might help here. You can also upload your photos to Picasa and get a KML file that way (instructions).

The end result might look like this.

NBP09-01 Press Release

I tried to give some details about the cruise while it was happening, but if you want a PR overview the first big NBP09-01 press release has been issued by the NSF.

Photos from Antarctica

If you’ve been following this blog you’ve seen a dozen or so low-quality photos posted during my trip. Now you can see full resolution pictures. In total, I took 2718 photos during the 54 days between when the Nathaniel B. Palmer (NBP) left Punta Arenas, Chile and returned. I’ve selected 350 of the best ones and uploaded them. There are 31 from the sea ice science projects, 54 of the NBP itself, 66 of animals (added to the animal photos from last year), 101 of the Pine Island Glacier, and 98 miscellaneous photos of the Amundsen and Bellingshausen seas, sea ice, sunsets, and sunrises.

You can view all of the photos listed above in the various Antarctica photo albums, or you can view them all geospatially (KMZ) in Google Earth. The ship recorded GPS a few times a second, and I have a one-minute (temporal) resolution data file that I used to geotag the photos.

Notes: If you are viewing the photos on the website, you ought to have the Cooliris plugin installed. Load times might be a bit slow, this computer is hosted at home. If you don’t see any photos in Google Earth you’ll need to drag the time slider to the right. They’ll pop up as you pass the time they were taken.

NBP Photos Geotagged in Google Earth

Land Ho!

Woke up this morning (lat: -53.591, lon: -72.3015) in the Straits of Magellan. The deck of the ship is green, and has been for the last 50 days, but just like last year, seeing mountains covered with green trees is a shock to the system.
 
Another 10 or so hours and I’ll walk again on solid ground.
 
Signing off for the foreseeable future, -k.

Stormy

The last 48 hours have been interesting. We were in a fairly severe storm. Wind speeds were around 60 knots, which is just under a hurricane, or 11 on the Beaufort scale. Max pitch was 12 degrees and roll was 22, or about 40 degrees side to side. Which is quite a bit of horizontal travel when you are on the bridge 68 feet in the air. Waves were about 30 feet.
 
You can’t really sail in weather like that, so we just pointed into the waves to keep the ship as stable as possible. Unfortunately that meant spending a day pointing to the northwest, away from home.
 
Today: Calm. About 15 hours from land. Tomorrow: Sailing through the Straits of Magellan. Then Terra Firma.

Sun{rise,set} over Sea Ice

We have been sailing home at 9-10 knots for the past few days and will continue to do so for the next 130ish hours.
 
The waypoint computer shows we have about 114 hours and 1050 nautical miles to our next waypoint, which is the entrance to the Straits of Magellan, still about 24 hours from port.
 
Current location is lat: -63.427, lon: -99.812

More Penguins

Holy Iceberg and Reflections

ITP

It turns out with 9 days left I have some unused email quota, so those of you reading this get to see some pictures from the last six weeks. This one is from the end of the ITP deployment.
 
Don’t expect much variety. There are only a few things I can photograph down here: Boat, Ice, Light, Penguins, People, and Water. Or if you prefer by quantity instead of alphabetic: Light, Water, Ice, Penguins, People, Boat.