Development of Fog Detection Algorithm Using AWiFS Data: A Case Study Over Indo-Gangetic Plains

Fog, a form of cloud in contact with the Earth’s surface, is one of the high-impact weather phenomena in northern India during the winter months. A new day-time fog detection scheme using the normalized difference snow index (NDSI) has been developed. The present analysis focuses on the detection of fog at high spatial resolution using data from the Resourcesat-2 AWiFS. The fog area detected is cross-validated with that detected using INSAT-3DR data at 1 km resolution using the same technique. The NDSI-based technique discussed here has shown a strong potential for fog detection during day-time. This study is also significant as a pre-launch sensitivity study for future GISAT with MX-VNIR, HyS-VNIR, HyS-SWIR, or similar other kinds of present-or-future sensors. Even though GISAT does not have a MX-SWIR channel, a combination of both MX-VNIR and HyS-SWIR with resampled spatial resolution may be useful for day-time fog detection using this technique.