Use of Remote Sensing in Weather and Climate Forecasts

Abstract

Satellites basically measure the radiance coming from the earth’s surface and cloud tops. By making such measurements at appropriate wavelengths and applying physical and statistical techniques, it is possible to compute a wide range of products for weather monitoring and forecasting. Further, the satellite meteorological data on a global scale are vital inputs in Numerical Weather Prediction (NWP) models as initial conditions. For a tropical country like India where high-impact convective events are very common, it is necessary to have good quality high density observations both in spatial and temporal scale to ingest into an assimilation cycle of NWP models. In view of the importance of satellite data, accurate estimation of satellite observations could be the only viable alternative solution for data sparse regions. Availability of multi-spectral imager channels in INSAT3D/3DR satellites with the staggering mode of temporal frequency at every 15 min provides us a new way to look at the weather events over the Indian region. The most effective ways to utilize these products are by combining the channels using red–green–blue (RGB) composites of INSAT3D/3DR satellite with its microphysical properties and RAPID SCAN mode. The RAPID scan mode has a higher temporal resolution, i.e., approximately 4 min unlike 30-min of conventional mode, for analyzing weather phenomena particularly intensification, propagation, and decay of various types of weather systems including nowcasting applications. Further, INSAT3D/3DR sounder provides continuous upper level temperature and moisture profiles with a spatial resolution of 10 × 10 km with temporal resolution of half an hour. With its sounder payload, the amount of the water vapor present in the atmospheric column in the form of total precipitable water (TPW) is being retrieved operationally and can be considered as a precursor for mesoscale activities.