Arctic Ice Compared to AMO

I am not a graphics wizard, but I took the Arctic Ice image from NSIDC, and graphed the AMO.

And then I flipped the AMO.  Looks like AMO has an effect on Arctic Sea Ice.



  1. I always like to remind people that coincidence is not necessarily causation. We can reverse it and pose the possibility that Sea Ice coverage has an effect on the AMO, or that the linkage is evident but a third (fourth, fifth, etc.) factor is in the mix.

    Nonetheless, good observation!


  2. Barring something else unusual in this arctic melt season, it appears that the National Ice Center (NIC) ice charts have also reached the ice extent minimum for the year. As discussed last month, NIC produces operational ice charts with a different method than the microwave-based Indices that are exclusively reported in the media.

    As of Sept. 21, 2012, NIC reports the minimum (so far):

    8/10ths 3,275,795 sq. Km.
    Marginal zone 923,871 sq. Km.
    Ice Extent 4,199,666 sq. Km.

    For comparison, NIC reports the 2007 minimum on Sept. 11, 2007:

    8/10ths 3,547,333 sq. Km.
    Marginal zone 1,018,054 sq. Km.
    Ice Extent 4,565,387 sq. Km.

    Whether comparing the pack ice (>80%) or the total extent including the marginal zone (10% to 80% concentration), 2012 is reported as ~8% less than 2007, or a reduction in arctic ice extent of 365,721 sq. Kms.

    Considering that 2012 started with a higher maximum in March than 2007 did (15.97 M. sq. Km. Vs. 15.81 M. sq. Km.), it truly is a remarkable single melt season this year. There was warm water from the Atlantic, a rare late summer cyclone and persistent air temperature near freezing, only now dropping towards normal for the time of year. Release of heat from more open water probably contributed to the latter effect. Still, the numbers say that a lot of ice remains in the Arctic, and it is not wise to extrapolate from one season to an ice-free arctic.

    What remains is to see what effect this event may have on weather patterns, and what kind of recovery will be seen in the months ahead.

    For those who want to know more about NIC ice charts:

    “Arctic charts include information on sea ice concentration and edge position as well as (since about 1995)information on ice type. The charts are constructed by analysts using available in situ, remotely sensed, and model data sources. Data sources and methods of chart construction have evolved since 1972 resulting in inconsistencies in the data record; a
    characteristic shared with most operational products. However the arctic-wide charts are the product of manual interpretation and data fusion, informed by the analyst’s expertise and by ancillary products such as climatologies and ice information shared by foreign operational ice services. They are therefore often more accurate, especially since the addition of synthetic aperture radar to data sources in the mid 1990s, than are the passive microwave derived sea ice data sets commonly used by researchers. This is especially true for ice edge location because of its operational importance. NIC provides charts free of charge on their Web site.”

    “Often a wide marginal ice zone of 40% to 60% is not detected in passive microwave (this was noted anecdotally in earlier studies by the authors comparing passive microwave with ice chart and other analyses), and this appears to be the case here. Also, the NIC partial ice concentration for multiyear shows that thinner types are present in higher concentration near the edge, and passive microwave can fail to detect thinner, younger ice.”

    NIC charts are available here:


  3. […] un artificio grafico piuttosto grossolano ma efficace, l’autore del post dove l’immagine è stata pubblicata mette a confronto l’estensione del ghiaccio marino artico con l’Oscillazione […]


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