Sea Ice Motion and VIIRS Spatial Resolutions
It’s nearing wintertime, and over the North and South Poles, sea ice accretion is occurring. Using RAMMB Slider, users can observe sea ice motion and sea ice breakup, via Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on-board the Suomi-National Polar-orbiting Partnership (S-NPP), and NOAA-20 satellites. For unaware users, VIIRS has 22 spectral channels, where 16 channels are at 750-m resolution (i.e. known as ‘Moderate (M) bands’), 5 are at 375-m resolution (i.e. known as ‘Imagery (I) bands’) and the other is the Day/Night Band (DNB) channel at 750-m.
Below is a VIIRS M15 – 10.76um animation, between 5-16 UTC, 20 November 2018, of sea ice motion between Fort Russ, Nunavut, Canada (bottom-left of the animation) and Baffin Island, Canada (upper-middle of the animation). Note, sea ice breakup and erratic sea ice motion are due to varying surface winds. In the imagery, colder brightness temperatures are represented in green and yellow colors, while relatively warmer brightness temperatures are seen in navy blue, aqua and grey colors. Additionally, notice the extremely cold brightness temperatures over Baffin Island (i.e. large areal extent of yellow colors).
Now if users want to use a higher spatial resolution to observe sea ice motion, below is a comparison between the coarser spatial resolution of VIIRS M15 – 10.76um at 750-m to VIIRS I5 – 11.45um at 375-m resolution. The comparison is taken at 1045 UTC, 20 November 2018. Note the sea ice fissures (i.e. crevices and cracks within the sea ice) that are more conspicuous in the I5 that the M15 band.