By Lewis Grasso and Jorel Torres
VIIRS captures interesting imagery in the Arctic. From 0314 UTC to 1233 UTC, 13 February 2019, VIIRS, on-board NOAA-20 and S-NPP, imaged fascinating features in the Arctic. In particular, imagery from Band I4 (3.74um) with a sub-satellite footprint size of 375-meters captured several features: 1) oscillation of an ice field due to lunar tides, 2) the boundary where the ice sheet is melting due to the interaction of relatively warm waters associated with the Gulf Stream, and 3) the melt water and associated currents in the ice-free ocean. Animation below, shows a loop beginning at 0314 UTC and extending to 1233 UTC. Within the loop the dark-greenish color represents the very cold ice sheet, northeast of Greenland, which is located in the lower right corner of the loop. Incidentally, portions of Svalbard, Norway are located in the upper-left corner. The lightest grey color represents the relatively warm ice-free ocean. The rapidly moving cloud-field is evident over the ice free ocean by a black color. Interpretation is the following: periodic oscillations are associated with the lunar tide, note the back and forth motion of the ice sheet. As the boundary of the ice sheet melts, the cold melt water flows into the relatively warm ocean and appears relatively dark. The left most dark plume of melt water is reminiscent of a drop of black ink falling downward in a tank of clear water. We invite the reader to think, when was the last time you have seen this type of view in the Arctic? Kudos to the JPSS Program.