Mike Bryant (05:37:56) : Your comment is awaiting moderation

I have sent these questions to Dr Chapman at CT.

Dr William Chapman,
Can you please explain a couple of things on the Cryosphere Today “Compare side-by-side images of Northern Hemisphere sea ice extent” product, please? Why does the snow in the more recent dates cover areas that were previously sea inlets, fjords, coastal sea areas, islands and rivers? (Water areas, most easily discernible in the River Ob inlet) Why does the sea ice in the older images cover land areas? (Land areas, most easily discernible in River Ob inlet) See this overlay: http://i44.tinypic.com/330u63t.jpg
Looking forward to your answer,
Mike Bryant

I wonder if you have seen the overlay Lucia.
Thanks for looking at this,
Mike Bryant

(Correlation is -0.75)

However, my gut instinct says it could be also well less than 3 Mio km^2

So long!

Lars

As discussed in our April analysis, the ice cover this spring shows an unusually large proportion of young, thin first-year ice; about 30% of first-year ice typically survives the summer melt season, while 75% of the older ice survives. For a simple estimate of the likelihood of breaking last year’s September record, we can apply survival rates from past years to this year’s April ice cover. This gives us 25 different estimates, one for each year that we have reliable ice-age data (see Figure 2). To avoid beating the September 2007 record low, more than 50% of this year’s first-year ice would have to survive; this has only happened once in the last 25 years, in 1996. If we apply the survival rates averaged over all years to current conditions, the end-of-summer extent would be 3.59 million square kilometers (1.39 million square miles). With survival rates similar to those in 2007, the minimum for the 2008 season would be only 2.22 million square kilometers (0.86 million square miles). By comparison the record low extent, set last September, was 4.28 million square kilometers (1.65 million square miles).

In the light of this, I do find the graph from Alan S. Blue (#2523) interesting. Despite the less amount/extent of perennial ice, the reduction rate in March and April seems less than previous years.
A possible explanation could be a period of “beneficial” wind patterns (both wind speed i.e. wave action, and/or direction governing outbound transportation).

Cassanders
In Cod we trust

-2.1, 0.0, 0.0001, 0.99, 3, 4 and a bit, precisely 5, six, 6.2, 6.4, 6.6, 6.8, …., more than 9

Cassanders
In Cod we trust

It is funny about my name. When I first married, I got my university ID. I showed it at the library, the librarian looked at me and said: “Oh, I would have guessed you were Swedish just by looking!”

I laughed and said, “Funny, no one ever said that before. Last month, my last name was Tiernan and people thought I looked Irish!”

But here goes:
“Bensin” = Gas, “Bensinstasjon”= Gas station,
“Lokalisering” = Localization,
“Prinsippet” = Principle

Hence: The Gas Station Localization Principle. (GSLP, hereafter)

I think we in the Scandinavian languages shun huphenations to a large extent (in contrast to anglophones). I susspect the (indeed long and cumbersome) word is coined with two objects : 1) to be descriptive, 2) to be eye-catching due to its length and cumbersome pronounciation. (It is therefore easily remembered)

The principle does indeed aspire to explain why gas stations tend to cluster themselves around town/cities rather then spreading more uniform between them (or in the middle). It also offers a strategy on where to put a new gas station (catching the largest number of potential customers) when knowing where the other gas stations are placed allready.

The principle is probably easiest demonstrated with a betting situation.
Assume that you compete with ONE opponent in guessing how many peas there are in a jar. The competitor with the most accurate number win. You opponent says 200. You judge the jar, and consider the opponents bet to be an considerable undersetimate. You suggest 350. Alas, it actually turns out to be 270 peas in the jar, and you looses, despite being correct WRT your opponent’s estimate/guess being too low..
The betting strategy according to GSLP would be to claim 201 (if you opponent says 200, and you think that is an underestimate).

I guess you see why I referred to Martin Ringo?

Cassanders
In Cod we trust

“Bensinstasjonslokaliseringsprinsippet”?

Hmmm… well, despite having name that sounds like I must be 100% Swedish, I’m afraid “Liljegren” was acquired by marriage, and “Lucia” comes from my Cuban grandmoterh. So… I have no idea what that word might mean in English.

Many of use are using the classic American Army method called “SWAG” (Scientific Wild Ass Guess). Could that be related to “Bensinstasjonslokaliseringsprinsippet”?

I’ll go on record and suggest 6.81 mill sq. Km.

I have employed what in Scandinavian is called “Bensinstasjonslokaliseringsprinsippet”. I have not been able to fins an anglophone version. (Are you up to it, Lucia?). Basically it explains why gas stations are not uniformly distributed between towns, but tends to agglomerate close to them.

Nevermind: when employng said principle, my bet is on the side I’ll find most probable, but just enough to beat Martin Ringo

I do in fact have a number of other cues.
1) To my knowledge, both the NAO and AMO are now departing from the former simultaneous positive phase towards a negative phase
2) While SST anomalies in the NW Atlantic and the Barents sea has lead to substantial ice extent anomalies around Spitzbergen, Franz Josef’s land and Novaja Semlja, the turning of NAO and AMO might reverse this trend.
3) While SST in the Baltic-, North-, Norwegian Seas as well as the Denmark Strait is above the 1978-1998 mean, the SST conditions E of the USA apperas to be cooling. This water will reach The Barents Sae and the Polar areas before anticipated ice minimum in September (and may slow the melting).

Cassanders
In Cod we trust

http://www.athropolis.com/arct.....t-roch.htm
http://freestudents.blogspot.c.....ssage.html
http://en.wikipedia.org/wiki/St._Roch

Their first try took 2 years as they were frozen in the ice!! The second try was a real example of open water and only took 86 days.

I don’t really know what perennial ice is, and so I am not sure how let alone where to get the data. If perennial is simple a constant, it doesn’t effect any of the results from regressions simple or complex. If perennial ice varies, it could be useful in that it, the perennial, could have a different error structure which if removed from the annual ice extent would leave a (presumably) more visible — and with some luck — a more traditional error structure. All that would allow for a more accurate (smaller coefficient variance) estimate and tighter forecast bounds. It might also allow for a multi-equation estimation where the error terms are correlated between equations (as well as over time). (For those of you who pay attention to the issues of estimation, the multiple equation system with cross-equation, correlated errors is where one can usefully use Feasible Generalized Least Squares or, when the dependent variables of one equation are the independents of another, Three Stage Least Squares.)

So if you can write sea ice extent as X(t) = Y(t) + Z(t), where Y and Z can be correlated but have some part of independent variation, then one can usually improve on the estimate and consequently the forecast of sea ice extent. Is there such a breakdown?