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jbyrd
slidell
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So; just so that I understand this 'extent' idea. Given that 100 percent of the sea surface has a ratio of 15 percent 'frozen' and 85 percent 'liquid'. (I believe the phrase is 'at least'.) But if 85 percent is 'frozen' and 15 percent is 'liquid' then the 'extent' is the same. (The 'more' side of 'at least'.) Is this the classic 'can't see the forest for the trees'? The forest is right there in front of us though. Take a look at the lance-modis arctic mosaic. Pretend you're Dr.Dolittle and just click on it. Blow it up to 250m resolution. See all those sort of circular 1/2 inch or so sized white circles? (at least on my 19" screen) Those are ice islands 10 to 15 miles across. They didn't get round by bobbing up and down in the sea! If one clicks on either the northeast or north west Ellesmere Island sector today (8/25), they can see an amazingly clear view of the complete fracturing of the ice pack, which appears to be the source of all those 10 mile across (75 sq mi) ice islands. Of course, I guess we should keep in mind that the amsr2 shows southern lake Michigan at 30 percent ice cover and the NOAA RTGSST site shows that the SST of southern lake Michigan is in the low 70's F.
Toggle Commented Aug 26, 2013 on Hole at Arctic Sea Ice
NuinZeeland, Given that the 2 buoys listed are about 1200 miles from the center of the storm (no quotations), and the pressure gradient from the 1028 mb high just north of Alaska to the center of the low at 976 mb, there are probably some pretty ferocious winds in a roughly circular area about 300-500 miles across. Can't tell for sure without being there, and my experience is with tropical storms, but the physics should be similar. Even more interesting from the buoy site you listed, it is possible to calculate the ice drift speed, since the buoys are not moored. My google earth lists lat/lon in degrees minutes and seconds, and I'm too lazy to figure out the conversion to decimal place, which is given on Washington's website, but I came up with a drift speed of about 1.5 mph. as a result of an average wind speed of about 15 mph. I'll leave it to your imagination what triple or quadruple that will do to the ice pack.
Toggle Commented Aug 11, 2013 on Third storm at Arctic Sea Ice
Oops, the previous post was supposed to be under "So how slow was the start". Sorry about that,
Toggle Commented Jul 6, 2013 on PIOMAS July 2013 at Arctic Sea Ice
In agreement with the more pessimistic (optimistic?) opinions shown here, I predict the 2013 extent value will cross the 2012 line between the 15th and the 21st, but the curve will level off shortly thereafter and come in just below 2012. Two other observations/questions though. The interface between cold surface air and relatively warm sea water is the starting point to analyze the situation. Taking into account that by far most of the increased global temperature is being stored in the ocean, and given the immense heat sink capacity of the ocean, while SST's are relevant as a benchmark, the important thing is the actual increase in stored heat over the historical norm. After all, the Canadian arctic continues to have somewhat below normal temps, but for those of us who were watching, Great Bear Lake just went from completely frozen over to essentially ice free in a week. Ice looks about the same at -5 as is does at 30 below, but is has a lot of warming to do to become water from the lower value. In other words it appears that most of the melting is coming from underneath, due to increased heat content of the sea. The other thing might be a little more controversial. While a longer melting or freezing season can be measured and analyzed statistically, the beginning and ending are natural occurrences. The year as we know it is an human construction, set up for our convenience. If the melting is significantly from beneath then certainly currents are involved, if currents are involved then the lunar cycle is involved. If the lunar cycle is involved, there is an 11day difference in the length of the lunar year and the solar year (we'll leave out those variations), so there is at least that much variability in the system. It certainly is interesting however it works though.
Toggle Commented Jul 6, 2013 on PIOMAS July 2013 at Arctic Sea Ice
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Jul 6, 2013