Global mapping of Arctic sea ice drift : a unique database

For several years, the CERSAT has been providing sea ice data and maps from various scatterometers (microwave radar) and radiometers onboard earth observation satellites (ERS-1, ERS-2, ADEOS-1, QuikSCAT, SSM/I, AMSR-E).

The scatterometer is initially designed to measure winds over ocean surface, but it can also be used to detect sea ice edge and sea ice type (first year, multi-year). Radiometer is commonly used for sea ice concentration. Using correlation technique between successive maps, sea ice drifts can be estimated from both of these sensors.

IFREMER/CERSAT provides continuous Arctic sea ice drift maps from 1992, a unique database in the world.

From 1992 until 1999, 3 and 6 day-lags drifts are estimated from SSM/I radiometer. Since 1999, drifts are estimated from the combination of QuikSCAT scatterometer and SSM/I radiometer (merged drift), this product has been validated over 5 winters. Since 2002, AMSR-E radiometer provides higher resolution data, adapted to regional studies; due to its resolution, drifts can be estimated at 2 day-lag. Monthly merged drift maps are also available.

 

Figure 1 shows an example of 3 day-lag drift. Beaufort gyre and sea ice flux exit through Fram strait between Greenland and Spitzberg are sharply marked.

The comparison between merged (figure 2) and AMSR-E (figure 3) 3 day-lag drift maps shows that the higher resolution sensor AMSR-E provides drifts in coastal areas (canadian archipelago and North of Alaska). Angular resolution is also improved and drift vectors are more reliable but data gaps are visible, AMSR-E is thus well adapted to regional studies.

More information : ftp://ftp.ifremer.fr/ifremer/cersat/products/gridded/psi-drift/