Fog detection: MODIS vs. GOES
Areas of radiation fog were forming during the overnight hours in the river valleys of southwestern Wisconsin, southeastern Minnesota, and northeastern Iowa. These narrow finger-like fog features were apparent on the MODIS 11-3.9 micrometer “fog/stratus product” (upper left panel) due the higher spatial resolution (1 km IR) and better spectral response of the MODIS IR channel data; on the 4 km resolution GOES-12 fog/stratus product (upper right panel), only a few isolated noise pixels showed up in that general region where river valley fog was forming. A closer view with surface observations plotted shows that a few sites were indeed reporting fog at that particular time (especially in the Wisconsin River valley).