Arctic Ice

[Devonian]

How did that ice we see not get seen by NSIDC?

Perhaps Mr Bolt should re-read WUWT where Steven Goddard makes this apology:

"NOTE OF CORRECTION FROM STEVEN GODDARD:

The senior editor at the Register has added a footnote to the article with

excerpts from Dr. Meier’s letter, and a short explanation of why my analysis

was incorrect.

To expound further - after a lot of examination of UIUC maps, I discovered

that while their 2008 maps appear golden, their 2007 maps do not agree well

with either NSIDC maps or NASA satellite imagery. NSIDC does not archive

their maps, but I found one map from August 19, 2007. I overlaid the NSIDC

map on top of the UIUC map from the same date. As you can see below, the

NSIDC ice map (white) shows considerably greater extent than the UIUC maps

(colors.) The UIUC ice sits back much further from the Canadian coast than

does the NSIDC ice. The land lines up perfectly between the maps, so it

appears possible that the UIUC ice is mapped using a different projection

than their land projection.

Click for larger image

Because the 2007 UIUC maps show less area, the increase in 2008 appears

greater. This is the crux of the problem. I am convinced that the NSIDC

data is correct and that my analysis is flawed. The technique is

theoretically correct, but the output is never better than the raw data.

Prior to writing the article, I had done quite a bit of comparison of UIUC

vs. NSIDC vs. NASA for this year. The hole in my methodology was not

performing the same analysis for last year. (The fact that NSIDC doesn’t

archive their maps of course contributed to the difficulty of that

exercise.)

My apologies to Dr. Meiers and Dr. Serreze, and NSIDC. Their analysis,

graphs and conclusions were all absolutely correct. Arctic ice is indeed

melting nearly as fast as last year, and this is indeed troubling.

- Steven Goddard"

So Steven Goddard is now 'troubled' by the Arctic Ice melt. Perhaps instead of trumpeting him you'll soon be condemning him

Edited August 22, 2008 by Devonian

[cyclonic happiness]

I know this may be a silly question, although I do not intent it to be.

But does anyone know what the ocean currants do under the arctic ice sheet? Where they go, and how they will be affected by the melt?

We all know about the gulf stream and the labrador currant and that, but I don't know what the water does under the ice sheet?

I hope you can help me?

[J10]

Latest Ice Figures as Promised

The Latest Ice Extent is 5,556,875sqkm2 and now below 2003, 2004 and 2006. The figures remain above 2005 but it looks like the ice extent will fall below the 2005 value by the end of August.

However, the rate of ice melt is now slower than the 2007 level over the last couple of days both in terms of absolute levels and in percentage terms. It is very possible that the final ice extent for 2008, will be below 5,000,000sqkm2 but it should be closer to the 2005 figure than the 2007 figure. However this may change and I will give the latest update and whether this is still the case on my next update on Tuesday.

[Mondy]

Delta, please please talk to Will at CT(the person who creates these graphs and pictures).

He's fully admitted that the old graphs and pictures are not as accurate as the new ones, they essentially use old 70's/80's technology which although shows a rough guide just isn't accurate enough for todays measurements/standards.

That'll be William Chapman then? LINK

[Iceberg]

And....?

I mentioned to Will last year about the AMRS-E data that he could obtain from Bremen. (he uses the same data.)

TBH I am not sure what your point is.

[Roger J Smith]

CH, there is a phenomenon in the arctic ice pack known as the clockwise gyre, in other words, the large bulk of pack ice tends to rotate slowly around a point in the western Beaufort Sea in a clockwise direction. This implies that the remnants of the North Atlantic Drift fall under the ice pack around Novaya Zemlya, head for the north pole then veer south to the west of the Canadian arctic pushing the ice slowly around in a great gyre that would take 5-8 years according to research done such as placing drifting camps on the ice. Currents closer to Alaska and Siberia are probably controlled more by seasonal inflow and outflow through the Bering.

[BLAST FROM THE PAST]

Latest Ice Figures as Promised

However, the rate of ice melt is now slower than the 2007 level over the last couple of days both in terms of absolute levels and in percentage terms. It is very possible that the final ice extent for 2008, will be below 5,000,000sqkm2 but it should be closer to the 2005 figure than the 2007 figure.

Oh that will upset GW and Dev won't it

BFTP

[J10]

Oh that will upset GW and Dev won't it

BFTP

This is my full post

The Latest Ice Extent is 5,556,875sqkm2 and now below 2003, 2004 and 2006. The figures remain above 2005 but it looks like the ice extent will fall below the 2005 value by the end of August.

However, the rate of ice melt is now slower than the 2007 level over the last couple of days both in terms of absolute levels and in percentage terms. It is very possible that the final ice extent for 2008, will be below 5,000,000sqkm2 but it should be closer to the 2005 figure than the 2007 figure. However this may change and I will give the latest update and whether this is still the case on my next update on Tuesday.

[Iceberg]

I'd agree with that Jackone.

The melt for the last few days has slowed sharply.

[cyclonic happiness]

CH, there is a phenomenon in the arctic ice pack known as the clockwise gyre, in other words, the large bulk of pack ice tends to rotate slowly around a point in the western Beaufort Sea in a clockwise direction. This implies that the remnants of the North Atlantic Drift fall under the ice pack around Novaya Zemlya, head for the north pole then veer south to the west of the Canadian arctic pushing the ice slowly around in a great gyre that would take 5-8 years according to research done such as placing drifting camps on the ice. Currents closer to Alaska and Siberia are probably controlled more by seasonal inflow and outflow through the Bering.

Thanks for the reply RJ, wow that's really fascinating to think of an ice mass as big as a small continent actually rotating!!!

[Gray-Wolf]

NSIDC's latest 'plot' appears to show the opposite of a slowdown with, over the past couple of days, an acceleration in melt???

I believe we are now at the end of the melt period where we have very little data or records to guide us in our predictions. Last year 'plateaued' for a number of weeks at the end of the melt season, if melt continues through this period then we will exceed last years min. , if we also find levels plateauing then we can look forward to a very 'bitty' stop/start type of 're-freeze' well into December (as of last years pattern). The 'busier' Autumn is in it's storms then the slower ice reformation will be.

[J10]

Does anyone have the figures on which the NSIDC charts are based on?

As the NSIDC charts do not seem to fully agree with the ones I do.

[Devonian]

Does anyone have the figures on which the NSIDC charts are based on?

As the NSIDC charts do not seem to fully agree with the ones I do.

Not specifically no.

Actually, having looked at your excellent spreadsheet, i was going to ask you the same question (since I must have missed the answer) viz what data are you using?

[J10]

Not specifically no.

Actually, having looked at your excellent spreadsheet, i was going to ask you the same question (since I must have missed the answer) viz what data are you using?

The figures come from this website, and one advantage of this is that it goes back a number of years, marking direct comparisons with previous years easy .

http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm

If similar data was available from NSIDC, I would do the same for that.

[doctormog]

NSIDC's latest 'plot' appears to show the opposite of a slowdown with, over the past couple of days, an acceleration in melt???

I believe we are now at the end of the melt period where we have very little data or records to guide us in our predictions. Last year 'plateaued' for a number of weeks at the end of the melt season, if melt continues through this period then we will exceed last years min. , if we also find levels plateauing then we can look forward to a very 'bitty' stop/start type of 're-freeze' well into December (as of last years pattern). The 'busier' Autumn is in it's storms then the slower ice reformation will be.

And as this morning's update highlights, that once again, the NSIDC graphs appear to work from a running average or unvalidated data for the most recent timepoints. Either that or they are based on a rolling average which smooths out after little blips either up or downwards.

The update today removes the apparent acceleration.

[Gray-Wolf]

It does now seem to be showing the melt 'slowdown' that was given out by J1, Doctormog. Makes it hard to keep up with the day to day movements which are of such interest to us at the moment.

No matter what is driving these big melts it is a quite amazing thing to witness.

[Devonian]

The figures come from this website, and one advantage of this is that it goes back a number of years, marking direct comparisons with previous years easy .

http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm

If similar data was available from NSIDC, I would do the same for that.

Is it the data described on this page?

And as this morning's update highlights, that once again, the NSIDC graphs appear to work from a running average or unvalidated data for the most recent timepoints. Either that or they are based on a rolling average which smooths out after little blips either up or downwards.

The update today removes the apparent acceleration.

I think we might be seeing the beginning of a melt rate slow down - but of course we both know it wont just stop, the minima isn't reached yet.

I also begin to think we can rule out 2008 as being anything other than the first or second lowest extent/area/volume since records began.

Edited August 25, 2008 by Devonian

[Iceberg]

Completely agree Dev, the 2005 record will certainly be passed this week. With a large downward jump showing up again yesterday. Most of the predictions seem to be settling on a 300,000 to 600,000 increase from the all time minimum last year, but when you consider we had a 250,000 melt over a 2 day period at the start of August this is a very small amount.

[Devonian]

Completely agree Dev, the 2005 record will certainly be passed this week. With a large downward jump showing up again yesterday. Most of the predictions seem to be settling on a 300,000 to 600,000 increase from the all time minimum last year, but when you consider we had a 250,000 melt over a 2 day period at the start of August this is a very small amount.

Also, as everyone keeps saying, this year isn't as warm as recent years so, it follows (at least to me) that we've seen a seriously large melt in a not very warm year, if this year had ben a 2007 I'm pretty sure we'd have seen another record minima. Thus I think the future for summer Arctic sea ice minimum extent/area, if warming resumes, is a continuing downward trend and that, probably, only a downward trend in global temps can arrest that trend.

IMO.

[Chris Knight]

Is it the data described on this page?

I think we might be seeing the beginning of a melt rate slow down - but of course we both know it wont just stop, the minima isn't reached yet.

I also begin to think we can rule out 2008 as being anything other than the first or second lowest extent/area/volume since records began.

NSIDC archive monthly average area and extent data here, and in several subdirectories as text files going back to 1979.

The format is:

year mo data_type region extent area

1979 9 Goddard N 7.20 4.53

1980 9 Goddard N 7.85 4.83

1981 9 Goddard N 7.25 4.38

1982 9 Goddard N 7.45 4.38

1983 9 Goddard N 7.52 4.64

1984 9 Goddard N 7.17 4.05

1985 9 Goddard N 6.93 4.17

1986 9 Goddard N 7.54 4.66

1987 9 Goddard N 7.48 5.60

1988 9 Goddard N 7.49 5.31

1989 9 Goddard N 7.04 4.81

1990 9 Goddard N 6.24 4.50

1991 9 Goddard N 6.55 4.46

1992 9 Goddard N 7.55 5.37

1993 9 Goddard N 6.50 4.52

1994 9 Goddard N 7.18 5.08

1995 9 Goddard N 6.13 4.38

1996 9 Goddard N 7.88 5.58

1997 9 Goddard N 6.74 4.84

1998 9 Goddard N 6.56 4.24

1999 9 Goddard N 6.24 4.22

2000 9 Goddard N 6.32 4.31

2001 9 Goddard N 6.75 4.55

2002 9 Goddard N 5.96 3.98

2003 9 Goddard N 6.15 4.01

2004 9 Goddard N 6.05 4.35

2005 9 Goddard N 5.57 4.03

2006 9 PRELIM N 5.89 3.96

2007 9 NRTSI-G N 4.28 2.77

For each month - September in this case

The "area" data exclude the polar region not imaged by the sensor, whereas the "extent" data assumes that the area not imaged is fully covered by greater than 15% ice concentration. Better sensors were introduced in 1987, thus there is a discrepancy in the area data.

On their Cryospheric Climate Indicators page they state:

"Monthly averages are considered more accurate indicators of overall trends."

Thus they apparently do not archive daily figures.

[laserguy]

..........only a downward trend in global temps can arrest that trend.

Looks like we're gonna be alright,then. Chill! (sic).

[J10]

Is it the data described on this page?

I think we might be seeing the beginning of a melt rate slow down - but of course we both know it wont just stop, the minima isn't reached yet.

I also begin to think we can rule out 2008 as being anything other than the first or second lowest extent/area/volume since records began.

Unfortunately this does not provide the numerical data needed, however considering the NSIDC use graphs there must be some numerical data around in order to do this.

NSIDC archive monthly average area and extent data here, and in several subdirectories as text files going back to 1979. :

"Monthly averages are considered more accurate indicators of overall trends."

Thus they apparently do not archive daily figures.

The Monthly figures although useful cannot provide the same level of comparison.

[Devonian]

Looks like we're gonna be alright,then. Chill! (sic).

LG, I stated my view, and gave reasons for it, please give reason for yours.

Oh, btw and wrt 'chill!', we're talking about sea ice not trying to draw attention to the (wrongly) perceived characters of other :lol:

Edited August 25, 2008 by Devonian

[laserguy]

LG, I stated my view, and gave reasons for it, please give reason for yours.

You've answered that already,Dev,by saying only a downturn in global temps can save the day. Voila! Why so touchy anyway - I thought my comment had more than a touch of humour about it. Is there really no room left for a little light relief?

[Iceberg]

I'd agree with that Jackone.

The melt for the last few days has slowed sharply.

Typical I say the above and it goes and does the opposite.

180,000 lost in the last two days.

So only 470,938 between this year and last year now.