Submitted by Anonymous on Sun, 04/08/2007 - 18:28

Around about how big is the pack of ice, and do you know how fast it is drifting?

                           -John Seager

Class-Beckendorf

Hi Robert and Kathy, We sure enjoyed you web conference. My phone died at the end, before Wesley (one of my students) could ask about the temparture of the sea ice. With the influx of warmer waters, has the sea ice temperature also changed. Also what is the temperature of the ice?
Kirk 

Brandon Gillette

It was great to hear you and Cathy today during the webinar.  It sounds like you're getting a lot done and that your're having a great time doing it.  It's making those of us that aren't leaving for a while very jealous.  Or at least just me anyway.  Enjoy the rest of your trip and safe travels home!

Class-Beckendorf

 Robert,
One of my students would like to know if you can feel the ice pack moving?
Thanks
Kirk

Robert Harris

Hi John,
In the winter almost the entire Arctic Ocean freezes, except for a few special places called Polynas. I flew 90 miles north the other day and everywhere I looked there was ice. In some places there were cracks with open leads. In the spring the ice along the shore breaks up and melts. The rest of ice is a patch work of old multiyear ice, that has been melted and frozen and looks like a mosaic, and seasonal or first year ice that is flatter and thinner. The wind and currents slowly move this big ice pack creating stresses and strains the cause the ice to crack and slowly grind together, like the massive plates involved in plate tectonics. We are averaging about 10 km/day.

Robert Harris

Hi Kirk,We really can't tell that the ice pack is moving, just by standing there.  It is a little like feeling the Earth moving through space.  We know it is moving, but we aren't aware of it.  It is a frame of reference problem.  Since we and everything around us is moving, we don't notice the movement, because we don't have anything to judge the movement against.  We have evidence of the movement when we check the latitude and longitude on the Global Positioning  System, and when the ice separates forming leads and crashing together forming pressure ridges.
Robert