Sea Ice is not flat - Let's discuss Thickness

The season 2011 again revealed sea ice extent is the less informative the lower sea ice concentration is in the Arctic. Actually you may call it a red herring hiding the true nature of sea ice decline. It is time to put on 3D glasses and talk about volume and thickness.

To the end of this season the discussion focused on whether the ocean surface covered by sea ice was less or more this September or in 2007’s. That’s like comparing the buying power of different currencies by measuring the size of the banknotes.

These rose-colored spectacles called extent and area do not tell us winter sea ice currently looses thickness at an averaged rate of 10 centimeters and more per year. They filter out bottom melting during summer easily sums up to a meter during a month with a maximum rate of 10cm per day.

Finally both parameter prevent us from realizing that if melting trends continue or accelerate we’ll witness in a few years how millions of square miles of first year ice a few centimetres thick surprisingly turn into sea water just within a few days leaving only scattered floes of older ice.

-> continue reading

Microwave versus Envisat Radar Satellite Images

Envisat's radar images reveal a high fragmentation of the sea ice. It seems the algorithms using microwave echo to generate concentration maps are not optimized for the current state of the 'ice pack'.

While ESA's satellite operates with a resolution of 30mx30m, the pixel size of the AMSR-E instrument is factor 200 lower. Compare out for example the North of the Laptev Sea.

Also interesting is how the different microwave echo approaches depend on the resolution to calculate sea ice extent.

The NSDIC prefers a low resolution instrument for historical reasons and sees the extent of 2011 currently ...

-> continue reading

Microwave versus Radar Satellite Images

Envisat's radar images reveal a high fragmentation of the sea ice. It seems the algorithms using microwave echo to generate concentration maps are not optimized for the current state of the 'ice pack'.

While ESA's satellite operates with a resolution of 30mx30m, the pixel size of the AMSR-E instrument is factor 200 lower. Compare out for example the North of the Laptev Sea.

Also interesting is how the different microwave echo approaches depend on the resolution to calculate sea ice extent.

The NSDIC prefers a low resolution instrument for historical reasons and sees the extent of 2011 currently ...

-> continue reading