Posts Tagged ‘Sea Ice’

Refined Ross Sea Outreach Group

Tuesday, November 9th, 2010

User Friendly climatology and sea ice cover information on the Ross Sea - Jessica Castoro, Christel Walker, Abe Gelb

Last week the Climatology group for the Ross Sea posted a really cool website. This website is run by scientists at Scott Bass on Ross Island in Antarctica. It has a lot of information important to scientific data collection. This week we thought we would break this website down a little more for you guys. Some of the information on this website is in units that many people are unfamiliar with, such as Celsius. To convert Celsius to Fahrenheit you have to multiply by 9, divide by 5 and add 32. So let’s say that the temperature on Ross Island was -10.7 ᴼCelsius. What’s that in Fahrenheit, you say? It converts to 12.74 ᴼFahrenheit. That’s a bit of a difference.  Now what about kts? Kts stands for knots. One knot is 1.1508 miles per hour. So let’s say we hear that wind speeds have reached 16.2 kts. How many miles per hour is that? Well its 16.2kts multiplied by 1.1508 which equals…18.64 miles per hour. That’s a pretty fast wind.  What about if we see wind force measured in Bft? What’s a Bft? Bft is the abbreviation for the Beaufort scale. It tells us how intensity of the weather based mainly on wind power. Each Beaufort number includes a certain wind speed so our 18.64 mile per hour wind registers a Beaufort number of 5. It is described as being a “Fresh breeze” and will cause moderate longer waves in the ocean. This can mess up some planned research ideas. Now a wind chill is just the temperature of the air with the strength of the wind. If the wind isn’t blowing it’s pretty cold, but with a strong wind it can get frigid. And what about a dew point? Well, a dew point is the temperature at which the moisture in the air turns into liquid water.  I think my work here is done. These are all the basic conversions and other information you guys need to know in order to interpret all the data on that awesome website. Enjoy 🙂

Jessica Castoro

The Ross Ice Shelf is the largest ice shelf in Antarctica. Most of the ice is underwater because ice is less dense then seawater. It's around the size of France. The shelf itself pushes out into the ocean about one and half to three meters a day, that is the size of a car each day moving out into the ocean. The ice is slowly melting away at an incredible speed, which can cause major problems for both the animals living in the Antarctic and also the coastal landscapes, beaches, cities, and other urban homelands on other continents.

"This is a picture of the movement of glaciers feeding the Ross Ice Shelf. Speedy central ice streams which move up to 800 meters per year, are shown in red; their slower tributaries appear in blue. Like rivers, glaciers have drainage basins. The areas, which collect snowfall that feeds the ice streams and ultimately the ice shelf, are outlined in black." NASA

http://www.antarcticanz.govt.nz/weather/SBweather/sbweather.html

This is a website that shows current weather conditions in Antarctica. It shows temperature, rain & snowfall,and wind measurements. It also has some really cool graphs to show changes in all of these areas. These graphs are updated every ten minutes. Measurements are from the Ross Sea from a weather station operated by New Zealand.

History
Sir James Clark Ross was born on April 15th, 1800. He is most known for discovering the Ross Sea; however, there are some other things he has also accomplished. Some being that he joined the navy at the age of 12 and later became a Captain. His status as Captain is what allowed him control of the British fleet for discovery purposes. In 1841 James Ross discovered Mount Erebus, a 12000? tall mountain in the middle of Antarctica, he named it after one of his ships. He also founded the Ross Sea ice shelf but he originally named it the Victoria Barrier. The Ross sea was found by accident, Ross was originally looking for the southern magnetic force.

Christel Walker

Real-time Sea Ice Variations in the Antarctic

Monday, September 27th, 2010

This week we grabbed data involving current sea-ice concentration. The link elow is an animation showing the variation in sea ice surrounding the Antarctic up to date. Notice the circulatory pattern in the sea ice variation. We made a hypothesis that this pattern was due to the ACC because the concentration in sea ice starts dense in one part of the animation and noticeably circles around the Antarctic. However, notice the sea ice concentration in the Weddell Sea. The amount of sea ice remains relatively constant up until the last day of the animation. We figured this may be due to the actual peninsula blocking most of the ACC and so it never really picks up that concentration in that cut-out.

http://arctic.atmos.uiuc.edu/cryosphere/

We also pulled this image (below) to compare what we saw in the animation to what the NSIDC has. Between the two images, they look pretty similar.  The animation not only matches NSIDC's image, but it also gives you the amount of concentration and this is pretty useful when the gliders are deployed in October.

We also were able to find another source to compare the real-time data we got from other sites.  Below is the latest image from NOAA.  As you can see, it looks very similar to what we found from NSIDC and also from the animation.

http://satepsanone.nesdis.noaa.gov/southern_hemisphere_multisensor.html

Our group will continue to examine satellite images, providing real-time data for everyone to see in the WAP and to keep the Palmer team aware of the conditions when they make the trip in October.

-Colin, Rachel, Eric

the Dragon Slayer’s First Post

Wednesday, September 15th, 2010
THE DRAGON SLAYER

The Polar Marine Ecosystems respond to Rapid Climate Change by selective increased population growth, altering species location and mating grounds, and selective population decreasing. The warming climate change melts sea ice – vital to southern aquatic life – which causes a decline in Antarctic life to focus on one point. To give an example, the Adelie penguins that depend on sea ice for mating, food, and survival lost previous sea ice grounds and are losing new sea ice to live. In addition, since the ocean capacity is increasing due to ice meltation, species are now have more room to reproduce, live, and eat, which leads to selective increased productivity rates. However, the significantly smaller life forms that are the key to ocean life – Antarctic krill – are now small enough for phytoplankton to consume; this is disrupting the prior aquatic food chain. To sum up a very large problem in a small sentence, the major increase of sea ice temperature is creating an incredibly massive chain reaction of aquatic, climatic, and global problems.

Seth Martin     (mar3seth@eden.rutgers.edu)

Sea Ice

Thursday, December 10th, 2009

1-2/10thsSomething I have learned during my time here in Antarctica is that sea ice takes glider piloting to a whole new level. It can be an unpredictable moving obstacle that can mean danger for a glider. So in order to have a better understanding of this obstacle I spent some time learning about the different categories of sea ice and learning how to read sea ice coverage maps. Tom Holden is the Special Support Coordinator at NIC the National Ice Center and each morning his team sends the LTER scientists a sea ice image for the Anvers Island area. We then use these images to monitor the area and decide whether or not it is safe to fly the gliders.

Dec 3rdTypically, my image categorizes the Anvers Island area sea ice into four categories (see image Dec. 3rd). On the December 3rd image you can see an example of the sea ice being broken down into A, B, C and D. Level A ice is classified as 1-2/1oths, Level B is 3-4/10ths, Level C is 5-6/10ths and D is 7-9/10ths. The classification of sea ice is actually based on a percentage, so Level A ice in an area actually means the area is about 10-20% sea ice compared to that of Level D which means an area is about 70-90% sea ice. To go even more in depth Tom sent me the following description which explains how the age of the ice also plays a role in how they analyze the images and than categorize.

The A, B, C and D that you see on the charts, are used to designate attributes to each individual area.  Each area you see is analyzed, based upon the ice type (classification) AND the concentration.  Ice types are based upon thickness and age of the ice.  The purpose for this, is generally, older ice, is harder and thicker. The reason it is harder, is that gravity pulls on the brine content and it drains its way through, leaving nearly pure frozen water behind. New, Young ice is easily broken and Multi-year and glacial is the hardest to break.

Leopard SealUnfortunately, even with all this information the bottom line is still the more sea ice in an area, the more tightly it will be packed together, making it more difficult for a glider to surface. Comparing the various types and actually seeing them in real time and seeing the consistency of the ice allowed me to determine that a glider should be able to surface in Level A ice without problems. However, level B, C and D are a different story and therefore we avoid those areas.

5/10th'sHowever, aside from the fact that sea ice can be a nuisance and prohibit us from taking zodiacs out or potentially cause a glider to not surface it serves many useful purposes. Various species in both the Antarctic and Arctic use sea ice as a means of hunting, breeding, feeding and even resting. Down here in Antarctica we have seen numerous leopard seals hauled out on large chunks of sea ice napping. The same also goes for the various avian species such as the Adelie penguin.