Sea Ice News #27

This week we continue to see strong gains in Arctic Sea Ice. JAXA’s extent paused briefly, but has resumed a strong upwards climb, now exceeding 2005 for this date.

JAXA AMSR-E Sea Ice Extent -15% or greater – click to enlarge

In other news, NSIDC released an interesting video using Google Earth.

Here’s the NSIDC animation showing the entire satellite Arctic sea ice record.

According to the Google Earth Blog:

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They’ve recently updated their files to show data from 2010, and the results are quite stunning:

According to their site, the 2010 low (reached on September 19) was the third lowest on satellite record:

Average ice extent for September 2010 was 4.90 million square kilometers (1.89 million square miles), 2.14 million square kilometers (830,000 square miles) below the 1979 to 2000 average, but 600,000 square kilometers (230,00 square miles) above the average for September 2007, the lowest monthly extent in the satellite record. Ice extent was below the 1979 to 2000 average everywhere except in the East Greenland Sea near Svalbard.

The U.S. National Ice Center declared both the Northwest Passage and the Northern Sea Route open for a period during September. Stephen Howell of Environment Canada reported a record early melt-out and low extent in the western Parry Channel region of the Northwest Passage, based on analyses of the Canadian Ice Service. Two sailing expeditions, one Norwegian and one Russian, successfully navigated both passages and are nearing their goal of circumnavigating the Arctic.

You can check it out for yourself using this KMZ file. Or, if you’d prefer, you can simply watch the video below that shows all of the data in the KMZ.

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In following the link from The Google Earth blog to the NSIDC page link they cite, I noted the September Average extent graph, which is different than the usual annual minimum extent graphs we see.

And of course, it looks like a “death spiral” to paraphrase Dr. Mark Serreze, but it is only 30 years of data, so who’s to say it isn’t part of a longer cycle? One thing that has always bugged me about NSIDC is that they don’t provide data to go with their plots, and of course none was listed with this one, so I decided to use the large size of that plot to hand digitize the values.

Here’s the manually digitized data I got from that NSIDC September average extent graph. Values are year, and average September extent in million square kilometers:

1979 7.20

1980 7.80

1981 7.25

1982 7.45

1983 7.55

1984 7.20

1985 6.90

1986 7.60

1987 7.50

1988 7.50

1989 7.10

1990 6.25

1991 6.60

1992 7.55

1993 6.50

1994 7.20

1995 6.20

1996 7.90

1997 6.75

1998 6.60

1999 6.25

2000 6.35

2001 6.80

2002 5.95

2003 6.20

2004 6.10

2005 5.60

2006 5.90

2007 4.30

2008 4.70

2009 5.40

2010 4.90

I wondered what JAXA would show for September averages. Fortunately since JAXA provides the daily data here, it was easy to bring it into a spreadsheet and calculate the average. Here’s the values I got from my spreadsheet. Values are year, and average September extent in million square kilometers, rounded to nearest hundredths:

2002 6.11

2003 6.28

2004 6.16

2005 5.70

2006 5.98

2007 4.60

2008 5.08

2009 5.53

2010 5.45

Note that 2002 didn’t have a full month of valid daily data, but it appeared to have enough since JAXA plots September extent on their own graph. I plotted them both, using Dplot, and here’s the output:

Feel free to check my work, the output of the spreadsheet I used to calculate the JAXA averages is here: JAXA_2002-2010_SeptAvg

…as a PDF file of values (WordPress.com won’t let me upload XLS files)

It seems that the differences between NSIDC and JAXA average September extent are getting larger since 2007, and that JAXA is always showing more extent than NSIDC. In September 2010 there’s a whole half million square kilometer difference between the two averages. It’s curious.

Speaking of NSIDC, Dr. Walt Meier has asked to do a guest post here, and I’ve approved a slot for him, so I’m going to hold much of my weekly discussion in deference to him. In the meantime, the WUWT Sea Ice Page has a wide collection of images and graphs from both hemispheres to brief you.

Also, if you have not seen it yet, this book review from WUWT contributor Verity Jones on what the Russian Arctic and Antarctic Research Institute thinks about the Arctic Ice loss (they predict a rebound) is well worth a read.

Update: the JAXA average calcs might be in error, an artifact of how the spreadsheet cells return, unfortunately I won’t be able to check again and replot until late tonight, see upcoming announcement. – Anthony